NIST Special Publication 1620

Summary of NIST/GSA 

Cooperative Research on the Use of 

Elevators During Fire Emergencies

NIST Special Publication 1620

Summary of NIST/GSA 

Cooperative Research on the Use of 

Elevators During Fire Emergencies

Richard D. Peacock, Editor

Building and Fire Research Laboratory 

January 2009

U.S. Department of Commerce 

Carlos M. Gutierrez, Secretary 

National Institute of Standards and Technology 

Patrick D. Gallagher, Deputy Director 
Certain commercial entities, equipment, or materials may be identified in this

 document in order to describe an experimental procedure or concept adequately. Such

identification is not intended to imply recommendation or endorsement by the

National Institute of Standards and Technology, nor is it intended to imply that the

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Special Publication 1620

Natl. Inst. Stand. Technol. Spec. Publ. 1620, 349 pages (January 2009) 

CODEN: NSPUE2
v

Table of Contents

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Introduction

Historically, building egress systems have evolved in response to specific large loss 

incidents. Currently, systems are designed around an antiquated concept of providing 

stair capacity for the largest occupant load floor in the building with little or no 

consideration of occupant behavior, needs of emergency responders, or evolving 

technologies. Aggressive building designs, changing occupant demographics, and 

consumer demand for more efficient systems have forced egress designs beyond the 

traditional stairwell-based approaches, with little technical foundation for performance 

and economic trade-offs.

Underlying any building system designed to provide occupant protection in the event of a 

fire emergency is the need to provide a sufficiently safe environment for a period of time 

long enough to allow the occupants to take appropriate protective action. Passive and 

active fire protection systems in buildings such as compartmentation, structural integrity 

design, sprinklers, or construction and furnishing materials controls limit the extent of 

fire growth and spread to provide greater times for occupant actions (typically referred to 

as the available safe egress time or ASET). Conversely, egress system capacity, the use 

of protected areas of refuge, occupant training, emergency planning efforts, and 

understand occupant behavior in the event of an emergency can all aid to a reduction in 

the time necessary for occupants to reach a point of safety (typically referred to as the 

required safe egress time or RSET). The NIST/GSA program focuses on optimizing 

RSET.

This report addresses one aspect that has the potential to significantly impact the RSET, 

the use of elevators during fire emergencies. Summaries are included of NIST research 

conducted as part of a cooperative effort funded in part by the U.S. General Services 

Administration (GSA). This research has formed the technical basis for significant 

revisions to building code provisions that consider the impact of all aspects building 

design including the use of elevators by occupants and first responders, appropriate 

design of stairwells, the use of refuge areas, and other active and passive fire protection 

measures that may be included in a building design. 

The papers included in this report describe the history and scientific underpinnings of 

current egress requirements in model codes1,2. Provisions for egress stairways are traced 

from the early 20th century where a minimum stair width of 510 mm was first 

recommended to the now more typically used 1.12 m width. While based largely on 

common practice in the 1930s, this width was also seen as appropriate to allow the entire 

population of a building to fit on a single flight of stairs and remain in the relative safety 

 1 Bukowski, R.W., Emergency Egress from Buildings, Part 1: History and Current Regulations 

for Egress Systems Design, 7th International Conference on Performance-based Codes and Fire 

Safety Design Methods, Auckland, NZ, SFPE, 2008.

2 Bukowski, R.W. and Kuligowski, E.D., The Basis for Egress Provisions in U.S. Building Codes, 

InterFlam 2004, Edinburgh, UK, July 2004.
of the stairwell during a fire event1

. Details of current prescriptive requirements are also 

described and related to estimates of building egress times for a range of specific building 

occupancies2. 

Like stairwell provisions, the use of elevators during fire emergencies was considered as 

well. As early as 1914, properly protected elevators were seen as essential in taller 

buildings, but automatic elevators were deemed unsuitable in a 1935 report1.

More recently, there has been considerable attention to the use of elevators to speed up 

building evacuation. This included studies of the feasibility of elevator evacuation, 

human behavior, and the use of elevator lobbies as areas of refuge3. Protection from heat, 

flame, smoke, water, overheating of machinery, and loss of electrical power were seen as 

important to elevator design3. Using model calculations for example buildings, elevator 

evacuation was estimated to speed evacuation by 16 % to 25 % compared to evacuation 

by stairs alone; the taller the building the greater the impact.

Detailed studies of smoke protection for elevator hoistways4,5, the need for enclosed 

elevator lobbies6, use of elevators for evacuation of disabled occupants7, structural, 

sprinkler, and elevator control designs5, and egress procedures8 have provided the 

technical basis for new requirements for elevator use. Working with the American 

Society of Mechanical Engineers (see, for example, reference 5), the International Code 

Council (ICC), and the National Fire Protection Association (NFPA), and others, NIST 

and GSA, through this research, led a revolution in code provisions for the use of 

elevators by occupants and first responders during fire emergencies. The 2009 edition of 

the Life Safety Code9 and Building Construction and Safety Code10 includes adoptable 

(though not required) provisions for elevators for occupant evacuation prior to Phase I 

recall and for fire fighter emergency operations. The 2009 edition of the International 

 3 Klote, J.H., An Overview of Elevator Use for Emergency Evacuation. CIB-CTBUH 

Conference on Tall Buildings. Proceedings. Task Group on Tall Buildings: CIB TG50. CIB 

Publication No. 290. October 20-23, 2003, Kuala Lumpur, Malaysia, Shafii, F.; Bukowski, R.; 

Klemencic, R., Editors, 187-192 pp., 2003.

4 Klote, J. H., Hazards Due To Smoke Migration Through Elevator Shafts -Volume I: Analysis 

And Discussion. Final Report. National Institute of Standards and Technology, NIST GCR 04-

864-1, June 2004

5 Bukowski, R. W.; Fleming, R. P.; Tubbs, J.; Marrion, C.; Dirksen, J.; Duke, C.; Prince, D.; 

Richardson, L. F.; Beste, D.; Stanlaske, D., Elevator Controls, NFPA Journal, Vol 100, No 2, 42-

57, March/April 2006.

6 Bukowski, R.W., Is There a Need to Enclose Elevator Lobbies in Tall Buildings?, Building 

Safety Journal, Vol 3, No 4, 26-31, August 2005.

7 Bukowski, R.W., Protected Elevators and the Disabled, J Fire Protection Engineering, 42, 44-

46, 48-49, Fall 2005.

8 Bukowski, R.W., Emergency Egress Strategies for Buildings, Interflam 2007. (Interflam '07). 

International Interflam Conference, 11th Proceedings. September 3-5, 2007, London, England, 

159-168 pp, 2007.

9

 NFPA 101, Life Safety Code, 2009 Edition, National Fire Protection Association, Quincy, MA 

September 2008.

10 NFPA 5000, Building Construction and Safety Code, 2009 Edition, National Fire Protection 

Association, Quincy, MA October 2008.
Building Code will also include similar requirements on elevator use for fire fighter 

access and occupant egress.

The following papers were published as part of this research.

• Bukowski, R.W., Protected Elevators for Egress and Access During Fires in Tall 

Buildings, Strategies for Performance in the Aftermath of the World Trade 

Center. CIB-CTBUH Conference on Tall Buildings. Proceedings. Task Group 

on Tall Buildings: CIB TG50. CIB Publication No. 290. October 20-23, 2003, 

Kuala Lumpur, Malaysia, Shafii, F.; Bukowski, R.; Klemencic, R., Editors, 187-

192 pp., 2003.

• Klote, J.H., An Overview of Elevator Use for Emergency Evacuation. CIBCTBUH Conference on Tall Buildings. Proceedings. Task Group on Tall 

Buildings: CIB TG50. CIB Publication No. 290. October 20-23, 2003, Kuala 

Lumpur, Malaysia, Shafii, F.; Bukowski, R.; Klemencic, R., Editors, 187-192 pp., 

2003.

• Kuligowski, E. D., Elevators for Occupant Evacuation and Fire Department 

Access. CIB-CTBUH Conference on Tall Buildings. Proceedings. Task Group 

on Tall Buildings: CIB TG50. CIB Publication No. 290. October 20-23, 2003, 

Kuala Lumpur, Malaysia, Shafii, F.; Bukowski, R.; Klemencic, R., Editors, 193-

200 pp, 2003.

• Kuligowski, E.D., and Bukowski, R.W., Design of Occupant Egress Systems for 

Tall Buildings, Use of Elevators in Fires and Other Emergencies Workshop. 

Proceedings. Co-Sponsored by American Society of Mechanical Engineers 

(ASME International); National Institute of Standards and Technology (NIST); 

International Code Council (ICC); National Fire Protection Association (NFPA); 

U.S. Access Board and International Association of Fire Fighters (IAFF). March 

2-4, 2004, Atlanta, GA, 1-12 pp, 2004.

• Klote, J. H., Hazards Due To Smoke Migration Through Elevator Shafts -Volume 

I: Analysis And Discussion. Final Report. National Institute of Standards and 

Technology, NIST GCR 04-864-1, June 2004

• Klote, J. H. Hazards Due to Smoke Migration Through Elevator Shafts. Volume 

2. Results of Tenability Calculations. Final Report. National Institute of Standards 

and Technology, NIST GCR 04-864-2, June 2004

• Bukowski, R.W. and Kuligowski, E.D., The Basis for Egress Provisions in U.S. 

Building Codes, InterFlam 2004, Edinburgh, UK, July 2004.

• Bukowski, R.W., Is There a Need to Enclose Elevator Lobbies in Tall Buildings?, 

Building Safety Journal, Vol 3, No 4, 26-31, August 2005.
• Bukowski, R.W., Protected Elevators and the Disabled, J Fire Protection 

Engineering, 42, 44-46, 48-49, Fall 2005.

• Bukowski, R. W.; Fleming, R. P.; Tubbs, J.; Marrion, C.; Dirksen, J.; Duke, C.; 

Prince, D.; Richardson, L. F.; Beste, D.; Stanlaske, D., Elevator Controls, NFPA 

Journal, Vol 100, No 2, 42-57, March/April 2006.

• Bukowski, R.W., Emergency Egress Strategies for Buildings, Interflam 2007. 

(Interflam '07). International Interflam Conference, 11th Proceedings. September 

3-5, 2007, London, England, 159-168 pp, 2007.

• Bukowski, R.W., Emergency Egress from Buildings, Part 1: History and Current 

Regulations for Egress Systems Design, 7th International Conference on 

Performance-based Codes and Fire Safety Design Methods, Auckland, NZ, SFPE, 

2008.

A summary of each of the NIST papers that support these outcomes is included below. 

The complete text of each of the papers is included as appendices to this report.
R. W. Bukowski, Protected Elevators for Egress and 

Access During Fires in Tall Buildings

Included as Appendix A

Bukowski, R.W., Protected Elevators for Egress and Access During Fires 

in Tall Buildings, Strategies for Performance in the Aftermath of the 

World Trade Center. CIB-CTBUH Conference on Tall Buildings. 

Proceedings. Task Group on Tall Buildings: CIB TG50. CIB Publication 

No. 290. October 20-23, 2003, Kuala Lumpur, Malaysia, Shafii, F.; 

Bukowski, R.; Klemencic, R., Editors, 187-192 pp., 2003.

Bukowski, R.W., Protected Elevators for Egress and Access During Fires 

in Tall Buildings, Workshop on Building Occupant Movement During 

Fire Emergencies. Proceedings. Session 2.4. June 10-11, 2004, 

Gaithersburg, MD, Peacock, R. D.; Kuligowski, E. D., Editors, 14-21 pp, 

NIST SP1032, January 2005.

The events of September 11 have generated renewed interest in the use of protected 

elevators for egress and access. U.S. building codes contain requirements for accessible 

elevators for assisted evacuation of people with disabilities. Firefighter lifts, required in 

tall buildings in some countries, are being discussed to improve both the safety and 

efficiency of firefighting operations. The desire for increased egress capacity of tall 

buildings to facilitate simultaneous evacuation has rekindled interest in elevators as a 

secondary means of egress for all occupants. Elevators used for each of these purposes 

share many of the same design characteristics and the need for an extraordinary level of 

safety and reliability. This paper will review the technology, safety, and reliability issues 

associated with the use of elevators during fire emergencies for all three of these purposes 

and the solutions being considered to address them. Operational procedures and 

arrangements that influence system design considerations will be suggested. An 

innovative system for operating the elevators under the remote, manual control of the fire 

service will be described. Important human factors issues including communication, 

signage, and training will be identified. Initial plans for a demonstration project in a U.S. 

government building, as a proof-of-concept will be presented.
J. H. Klote, An Overview of Elevator Use for Emergency 

Evacuation

Included as Appendix B

Klote, J.H., An Overview of Elevator Use for Emergency Evacuation. 

CIB-CTBUH Conference on Tall Buildings. Proceedings. Task Group on 

Tall Buildings: CIB TG50. CIB Publication No. 290. October 20-23, 

2003, Kuala Lumpur, Malaysia, Shafii, F.; Bukowski, R.; Klemencic, R., 

Editors, 187-192 pp., 2003.

Throughout most of the world, warning signs next to elevators indicate that they should 

not be used in fire situations. However, the idea of using elevators for fire evacuation has 

gained considerable attention. This paper is an overview of what has been learned from a 

number of research projects conducted at the U.S. National Institute of Standards and 

Technology (NIST) in the 1980s and 1990s concerning the use of elevators during 

building fires. An elevator system intended for evacuation needs to have protection from 

heat, flame, smoke, water, overheating of elevator machine room equipment, and loss of 

electrical power. In addition, such an elevator system needs to have a control approach to 

assure protection of people traveling in the elevator. In areas of high seismic activity, 

attention needs to be paid to earthquake design. Smoke protection technology for elevator 

evacuation systems has been developed. Water exposure due to sprinklers and fire hoses 

is a concern because of the effect that water can have on electrical and electronic elevator 

components, and tests have been conducted to determine water leakage rates and observe 

water leakage patterns. Further, the development of an elevator evacuation system needs 

to take into account human behavior so that building occupants will be willing and 

capable to use the system in an emergency. The computer program for elevator 

evacuation (ELVAC) was developed to estimate time for elevator evacuation, and 

ELVAC has been used to demonstrate the extent to which elevators can speed up 

emergency evacuation. 
E. D. Kuligowski, Elevators for Occupant Evacuation 

and Fire Department Access

Included as Appendix C

Kuligowski, E. D., Elevators for Occupant Evacuation and Fire 

Department Access. CIB-CTBUH Conference on Tall Buildings. 

Proceedings. Task Group on Tall Buildings: CIB TG50. CIB Publication 

No. 290. October 20-23, 2003, Kuala Lumpur, Malaysia, Shafii, F.; 

Bukowski, R.; Klemencic, R., Editors, 193-200 pp, 2003.

This paper will present a study of the potential for elevators to reduce occupant egress 

time and fire department access time for fires in tall buildings. Potential reductions in 

egress and access times will be compared for some specific cases where times for current 

procedures are available. The paper will review past research in elevator usage and the 

structure of existing models for elevator evacuation. From this review, the assumptions 

and limitations of the current elevator and egress models will be discussed, and future 

plans for improvement of the existing egress prediction techniques will be presented.
E. D. Kuligowski and R. W. Bukowski, Design of 

Occupant Egress Systems for Tall Buildings

Included as Appendix D

Kuligowski, E.D., and Bukowski, R.W., Design of Occupant Egress 

Systems for Tall Buildings, Use of Elevators in Fires and Other 

Emergencies Workshop. Proceedings. Co-Sponsored by American Society 

of Mechanical Engineers (ASME International); National Institute of 

Standards and Technology (NIST); International Code Council (ICC); 

National Fire Protection Association (NFPA); U.S. Access Board and 

International Association of Fire Fighters (IAFF). March 2-4, 2004, 

Atlanta, GA, 1-12 pp, 2004.

This paper presents a discussion of the features of protected elevator systems that can 

provide safe and reliable operation both for fire service access and for occupant egress 

during fires. These features include water tolerant components, fail-safe power, lobbies 

on each floor designed as areas of refuge, smoke protection, occupant communications, 

and real time monitoring of the elevator position and operating conditions from the fire 

command center. Egress simulations are used to quantify the improvements in efficiency 

that can be realized by incorporating elevators into the access and egress procedures for 

tall buildings. Finally, operational procedures will be discussed for the most appropriate 

use of vertically zoned elevator systems that are found in most tall buildings. These 

procedures would form the basis for the elevator control software that needs to be 

developed for such systems.
J. H. Klote, Hazards Due To Smoke Migration Through 

Elevator Shafts -Volume I: Analysis And Discussion

Included as Appendix E

Klote, J. H., Hazards Due To Smoke Migration Through Elevator Shafts -

Volume I: Analysis And Discussion. Final Report. National Institute of 

Standards and Technology, NIST GCR 04-864-1, June 2004

During building fires, smoke often migrates through elevator hoistways to locations 

remote from the fire. One of the reasons for concern is that a closed elevator door has a 

leakage area of approximately 0.056 square meters (0.6 square feet). This is a report of a 

project to study the hazards due to smoke flow through elevator hoistways. Smoke flow 

and the resulting hazard to life are analyzed for 27 scenarios in 5 buildings ranging from 

6 to 58 stories. A fire scenario is the outline of events and conditions that are critical to 

determining the outcome of alternate situations and designs. In addition to the fire 

location and heat release rate, the fire scenario includes the status of the doors and other 

building systems. Other factors addressed are outside temperature, wind, height of 

elevator hoistway, height of building, leakage paths in the building, leakage of elevator 

doors, and other shafts. Stairwells are also included. Both sprinklered and nonsprinklered fires are included. Smoke transport throughout the buildings was simulated 

by a combination of zone fire modeling and network modeling. Options considered for 

mitigating hazards due to smoke flow through hoistways include (1) the use of enclosed 

elevator lobbies with automatic closing doors, (2) temporary barriers and (3) judicious 

positioning of cars within the hoistway. The results of the calculations showed that the 

use of enclosed elevator lobbies increased the time to reach hazard criteria significantly 

as compared the results without such lobbies. The use of automatic roll down barriers 

tended to increase the time to reach hazard criteria to some extent. The use of judicious 

positioning of elevator cars had no effect on the time to reach hazard criteria.
J. W. Klote, Hazards Due to Smoke Migration Through 

Elevator Shafts. Volume 2. Results of Tenability 

Calculations

Included as Appendix F

Klote, J. H. Hazards Due to Smoke Migration Through Elevator Shafts. 

Volume 2. Results of Tenability Calculations. Final Report. National 

Institute of Standards and Technology, NIST GCR 04-864-2, June 2004

This project looks at the hazard to life due to smoke migration through elevator hoistways 

and the effectiveness of methods to reduce that hazard. This report of this project is in 

two volumes. The first volume presents the analysis and discusses the results of that 

analysis. The second volume consists of the complete results of the tenability 

calculations.
R. W. Bukowski and E. D. Kuligowski, The Basis for 

Egress Provisions in U.S. Building Codes

Included as Appendix G

Bukowski, R.W. and Kuligowski, E.D., The Basis for Egress Provisions in 

U.S. Building Codes, InterFlam 2004, Edinburgh, UK, July 2004

Some of the earliest public safety-from-fire regulations in the US are requirements for 

egress stairs -adopted by New York City in 1860. One of the first model regulations 

promulgated by the National Fire Protection Association (NFPA) was the 1927 Building 

Exits Code, predecessor of the Life Safety Code. Thus the need to move occupants out of 

harms' way in building fires has long been central to fire safety regulations. The need to 

move occupants to a safe place was underscored in numerous historical fire disasters. 

Locked exits contributed to the high number of fatalities (150) in the 1911 Triangle 

Shirtwaist Factory fire and exit doors that opened inwards blocked by crowds was cited 

in the 492 fatalities of the Cocoanut Grove fire (1942). Incidents like these resulted in 

public outcry for stronger code provisions but even today egress problems leading to high 

numbers of deaths persist. The 100 fatalities at the Station Club in Rhode Island in 2003 

provide the most recent example. Since the Rhode Island fire, NFPA and other code 

authorities are reviewing current requirements for level of safety, especially for assembly 

spaces. These current prescriptive codes used for building design contain a list of egress 

specifications depending upon certain aspects of the building, such as the type of 

occupancy, the configuration of the space, the presence of sprinklers, and the type of 

construction of the building. These code specifications aid the designer in providing a 

certain level of life safety for their building, but little effort has been put into quantifying 

this level of life safety in terms of egress times. This paper attempts to describe the 

prescriptive design process for specific types of buildings. Secondly, by applying some 

assumptions to the egress specifications listed in the codes, an estimate of resulting egress 

times for maximum occupant loads were performed for specific occupancies. The egress 

times were obtained using multiple calculation methods and include estimates of premovement time, time to exit the occupied room, and time spent to travel one flight of 

stairs. Lastly, additional egress issues, such as merging flows and the use of elevators for 

occupant egress, are discussed.
R. W. Bukowski, Is There a Need to Enclose Elevator 

Lobbies in Tall Buildings?

Included as Appendix H

Bukowski, R.W., Is There a Need to Enclose Elevator Lobbies in Tall 

Buildings?, Building Safety Journal, Vol 3, No 4, 26-31, August 2005.

Several proposals have been submitted in recent years to model building code 

organizations to require enclosure of elevator lobbies in order to restrict the movement of 

smoke to other parts of buildings via hoistways. A significant development in this area 

occurred recently when the National Institute of Standards and Technology (NIST) -

which was already involved with a consortium of industry representatives, codes and 

standards developers, and other interested parties in a study of the protection of elevators 

for occupant evacuation and fire service access - was asked by the U.S. General Services 

Administration (GSA) to research the conditions under which enclosed elevator lobbies 

were called for. This article will provide an overview of the progress made to date on this 

line of research.
R. W. Bukowski, Protected Elevators and the Disabled

Included as Appendix I

Bukowski, R.W., Protected Elevators and the Disabled, J Fire Protection 

Engineering, 42, 44-46, 48-49, Fall 2005.

The Americans With Disabilities Act (ADA) was passed in 1990 to provide equal access 

to public buildings for all Americans. An objective of the ADA regulations was to permit 

people with disabilities access to the places where they live, work, and play with little 

thought of how they would get out in case of emergency. Fifteen years later, the fire 

protection engineering community is still addressing this important issue. The purpose of 

this article is to present the issues that need to be addressed in the development of 

elevators that can be used in fires to safely evacuate occupants, particularly those with 

limited mobility that affects their ability to use stairs. The ADA accessibility 

requirements are intended to result in public buildings that can be accessed and used by 

people with a range of limitations including vision, hearing, and mobility. The guidelines 

provide for signs that include Braille markings, strobe lights and other visible warnings, 

and doors with powered openers that are wide enough for wheelchairs. Smaller changes 

in elevation require ramps or platform lifts that eliminate barriers to wheelchair users.
R. W. Bukowski, et. al., Elevator Controls

Included as Appendix J

Bukowski, R. W.; Fleming, R. P.; Tubbs, J.; Marrion, C.; Dirksen, J.; 

Duke, C.; Prince, D.; Richardson, L. F.; Beste, D.; Stanlaske, D., Elevator 

Controls, NFPA Journal, Vol 100, No 2, 42-57, March/April 2006.

It is important that all parties, from rescue personnel to building designers understand the 

intent of the fire service operation provisions of ASME A17.1, Safety Code for Elevators 

and Escalators. The development of the passenger elevator is tied directly to the 

emergence of tall buildings. While various types of freight lifts were found in warehouses 

and factories before the advent of the high-rise, these were considered too dangerous to 

move people. In 1854, however, Elisha Graves Otis demonstrated an automatic safety 

brake that changed the landscape. Within a few years, his steam elevators had eliminated 

one of the major limits to building height. But, while elevators proved to be one of the 

safest forms of transportation, there were instances where people were killed while using 

elevators during building fires. Heat sometimes activated call buttons bringing cars to the 

fire floor where smoke prevented the doors from closing (light beams are in modern day 

elevators to detect people in the doorway) and water in the shaft sometimes shorted out 

electrical safety devices or may have caused failure of braking systems. Thus, the use of 

elevators for occupant egress or fire department access was discouraged. In 1973, the 

elevator industry developed a system that recalls elevators and takes them out of service 

if smoke is detected in the lobbies, machine room, or hoistway. Mandated in the 

American Society of Mechanical Engineers (ASME) A17.1, Safety Code for Elevators 

and Escalators,1 for all automatic passenger elevators, this system involves two distinct 

phases of emergency operation.
R. W. Bukowski, Emergency Egress Strategies for 

Buildings

Included in Appendix K

Bukowski, R.W., Emergency Egress Strategies for Buildings, Interflam 

2007. (Interflam '07). International Interflam Conference, 11th 

Proceedings. September 3-5, 2007, London, England, 159-168 pp, 2007.

The primary strategy for the safety of building occupants in emergencies (especially 

fires) is by facilitating their relocation to a safe place. In other than a few institutional 

occupancies (health care and detention facilities), this generally involves the use of stairs 

as part of a protected means of egress (MOE) for vertical evacuation. For tall buildings 

with large populations, providing sufficient stair capacity for simultaneous egress has 

been considered practical by code making organizations, so the strategy of phased 

evacuation has been employed. To this point in time, little attention has been paid to the 

special needs of people with disabilities and other (permanent or temporary) physical 

limitations in moving on stairs. The aftermath of September 11,2001 new attention is 

being paid to many issues, especially emergency egress from tall buildings. A number of 

experts have called for a fundamental linking of egress strategies including all of the 

possible components that might be employed. In September 2006 a workshop was 

organized in Atlanta by CIB Wl4:Fire and T50:Tall Buildings, with one of the discussion 

topics devoted to this issue. This paper is ended to continue that discussion.
R. W. Bukowski, Emergency Egress from Buildings, Part 

1: History and Current Regulations for Egress Systems 

Design

Included as Appendix L

Bukowski, R.W., Emergency Egress from Buildings, Part 1: History and 

Current Regulations for Egress Systems Design, 7th International 

Conference on Performance-based Codes and Fire Safety Design 

Methods, Auckland, NZ, SFPE, 2008.

Bukowski, R.W., Emergency Egress from Ultra-Tall Buildings, Tall & 

Green, Typology for a Sustainable Urban Future, CTBUH, Dubai UAE, 

March 2008.

The increasing height of buildings coupled with changing demographics and public 

concerns about the safety of tall buildings have led to a call for a fundamental rethinking 

of egress systems. This paper provides a review of the approaches currently found in 

building regulations internationally, and attempts to identify the origins of these 

specifications including the extent to which they may be based on scientific data or 

consensus opinion. The case for moving to a performance metric of time is presented and 

a set of criteria for evaluating egress systems against safe egress time is suggested. 

Performance criteria based on practical objectives are suggested but these and suggested 

regulatory thresholds need to be vetted through the existing consensus process of model 

code development and regulatory adoption followed in the adopting jurisdiction. The 

result should be a design approach that addresses the needs of occupants and buildings of 

all heights with criteria based on sound engineering principles.
Appendix A

Protected Elevators for Egress and Access During Fires 

in Tall Buildings
 Proceedings of the CIB-CTBUH Int. Conf. on Tall Buildings, 20-23 October 2003, Malaysia 

PROTECTED ELEVATORS FOR EGRESS AND ACCESS 

DURING FIRES IN TALL BUILDINGS 

Richard W. Bukowski, P.E., FSFPE 

NIST Building and Fire Research Laboratory 

100 Bureau Drive MS8664

Gaithersburg, Maryland 20899 USA 

+1 301 975 6853 

Richard.Bukowski@nist.gov

The events of September 11, 2001 have generated renewed interest in the use of protected 

elevators for egress and access. U.S. building codes contain requirements for accessible 

elevators for assisted evacuation of people with disabilities. Firefighter lifts, required in tall 

buildings in some countries, are being discussed to improve both the safety and efficiency of 

firefighting operations. The desire for increased egress capacity of tall buildings to facilitate 

simultaneous evacuation has rekindled interest in elevators as a secondary means of egress 

for all occupants. Elevators used for each of these purposes share many of the same design

characteristics and the need for an extraordinary level of safety and reliability. 

HISTORY 

The development of the passenger elevator is tied directly to the 

emergence of tall buildings. While various types of freight lifts were found 

in warehouses and factories these were considered too dangerous to

move people. In 1854 Elisha Graves Otis demonstrated an automatic 

safety brake that changed the landscape. Within a few years his steam 

elevators had eliminated one of the major limits to building height. But 

while elevators proved to provide one of the safest forms of transportation 

there were instances where people were killed while using elevators during

building fires. Heat sometimes activated call buttons bringing cars to the 

fire floor where smoke prevented the doors from closing (light beams are 

used to detect people in the doorway) and water in the shaft sometimes 

shorted out safety devices. Thus the use of elevators for occupant egress 

or fire department access was discouraged. 

In the 1973 the elevator industry developed a system that recalls the 

elevators and takes them out of service if smoke is detected in the lobbies, 

machine room, or hoistway. Mandated in the Safety Code for Elevators

and Escalators1 (ASME A17.1) for all (automatic) passenger elevators this

system involves two, distinct phases of emergency operation. In Phase 1, 

the detection of smoke or heat in specific locations results in the elevators 

being immediately recalled to the ground floor (unless this is where smoke 

was detected), the doors open, and the elevators are locked out of service. 

The responding fire department can then choose to use the elevators 

under manual control of a firefighter in the car by use of a special firefighter

key, in what is called Phase 2 operation. While Phase 2 is sometimes 

used to evacuate people with disabilities, some fire department “standard 

operating procedures” for high-rise firefighting depend on the stairs for 

access, staging, and operations. ASME publishes a Guide for Emergency 

Personnel2

 (A17.4) that includes detailed instructions for firefighters’ service operation. 

Figure 1 - Typical 

electric elevator

CURRENT REQUIREMENTS FOR EMERGENCY USE ELEVATORS 

All U.S. building codes contain a requirement for accessible elevators as a part of the 

accessible means of egress in any building with an accessible floor above the third floor. 

These requirements are all identical, being extracted from the ADA Accessibility Guidelines

(ADAAG) and mandated under the Americans with Disabilities Act (ADA). 

A recent survey3

 by the International Organization for Standardization (ISO) TC178 

Committee identified at least twelve countries that require firefighter lifts in tall buildings 
Richard W. Bukowski P.E., FSFPE 

(generally those exceeding 30 m in height) to provide for fire department access and to 

support operations as well as to evacuate people with disabilities. England has such a 

requirement supported by a British Standard (BS 5588 Part 5)4 requiring firefighter lifts in 

buildings exceeding 18 m (60 ft) in height. Firefighter lifts are also provided in the Petronas 

Towers, the world’s tallest buildings in Kuala Lumpur, Malaysia. 

The NFPA’s Life Safety Code (NFPA 101)5 includes provisions for egress elevators to be 

provided as a secondary means of egress for air traffic control towers where the small 

footprint prohibits two, “remote” stairs. These are secure facilities not open to the public and 

with limited numbers of occupants. 

While the above requirements exist for elevators for 

emergency use by firefighters and people with 

disabilities, there are currently no codes or standards 

in the world for egress elevators for use by building 

occupants. There is, however, an example of a 

structure that uses elevators as the primary means of 

egress and fire service access. This is the 

Stratosphere Tower in Las Vegas, Nevada (Fig 2). 

Essentially an eleven-story building sited atop an 250

m (800-foot) tower, it has a single emergency stair that

is considered impractical. Thus the four, double deck 

elevators are designed for emergency use. One is 

reserved for use by the fire department with the 

remaining three used under manual control to 

evacuate all occupants from the two lower floors that 

are designed as areas of refuge. Occupancy of the 

tower is limited to the number of people that can be

evacuated by the elevators in one hour

6

. 

COMMON CHARACTERISTICS 

Whether for access by the fire service or for egress, 

elevators provided for use in fire emergencies share several characteristics intended to 

assure safety and reliability. They are required to be installed in a smokeproof hoistway 

constructed to a 2-hr fire resistance and pressurized against smoke infiltration. Enclosed

lobbies are required on every floor, which are also 2-hr (1-hr in fully sprinklered buildings) and 

pressurized. In fact, the lobby is crucial to safe operation since elevator doors are particularly 

susceptible to jamming under even mild pressure differences. Thus, the smoke control 

system should pressurize the shaft and lobby together so that there is a minimal pressure 

difference across the door. 

Figure 2 - Stratosphere Tower in 

Las Vegas

The lobbies are provided with a 2-way communication system to the building fire command 

center so that people in the lobby can be informed of the status of any impending rescue. 

Emergency power to operate the elevator in the case of main power failure is also specified. 

Water intrusion into the hoistway can short out safety components such as switches that 

prevent the doors from opening unless there is a car present, and even the safety brake; so 

water protection or waterproof components are needed. 

Within the United States, any use of the elevator for fire service access or for rescue of 

people with disabilities is done under manual control of a firefighter in each car under Phase 

2 recall. The elevator industry cannot guarantee that its automatic controls will react 

appropriately to all hazards that might occur and cannot assure safe operation. Thus, the 

trained operator must be able to recognize hazardous conditions and cease operations. This 

represents a resource allocation problem for most fire departments that simply cannot assign

a firefighter to every car. Further, the susceptibility of safety controls to failure from water 

results in a requirement for an automatic shutdown of elevator power before activation of fire 

sprinklers in the machine room or hoistway. This would result in any operating elevator cars 

to suddenly come to a halt. 
 Proceedings of the CIB-CTBUH Int. Conf. on Tall Buildings, 20-23 October 2003, Malaysia 

SOLUTIONS FOR RELIABLE EMERGENCY ELEVATORS 

The first solution is to eliminate the susceptibility to water by using waterproof components 

and eliminating the requirement to shut down power. Next is to eliminate the need for 

firefighters to operate each car. 

Here we propose operating the elevators 

under remote manual control. The 

elevator industry would identify every 

parameter critical to the safe operation of

the elevator and these would be monitored 

and displayed in real time on the standard 

fire service interface7 recently

implemented in the National Fire Alarm 

Code8

 (NFPA 72). This interface was

developed as a tool for incident 

management that can collect information

from its own sensors and other building

systems (through a common communication 

protocol such as BACnet) and display the 

information in a format common to all 

manufacturers’ systems. The interface 

further supports specific control functions so that the operator could manually initiate recall if 

any monitored parameters exceed the allowable operating envelope (Fig 3). 

Figure 3 - NIST prototype fire service 

interface 

Because continuous monitoring of the system is crucial to safe and reliable operation, we 

propose incorporating a triple redundant communication pathway. The fire alarm system is 

currently required to incorporate two redundant communication trunks usually run up the two 

stairways. Either trunk is sufficient for the full system operation and two-way communication 

to the entire building. While these trunks are “remote” it is possible that a single event could 

sever both trunks, rendering the portion of the system above the breaks inoperable. We 

propose providing a wireless link between the bottom (generally the fire command center) 

and the top of the system as a third, independent pathway. This would maintain full operation 

of the system should both trunks fail. This would add little cost, ensure high reliability, and 

can be done with current technology. 

One outstanding reliability question involves the provision of emergency power to the 

elevators. Most tall buildings have triple redundant power systems with generators on site. 

The problem is that the power is generated at the base of the building and the hoisting and 

controllers are at the top. How do we provide a reliable transmission path between the two? 

It may be possible to use a battery/inverter system in the machine room with sufficient 

capacity to move the cars safely to the bottom. Similar systems powered from small batteries

are used in seismic areas to move cars a single floor.

DEVELOPMENT OF OPERATING PROCEDURES 

Prior research and recent advances can address all of the technology issues identified as 

critical to the safe and reliable operation of elevators during fires. The remaining piece is the 

development of operating procedures for access, egress, and rescue of the disabled that are 

sensitive to the human factors issues and to the need for these activities to occur 

simultaneously in tall buildings. Thus the systems must be designed and used such that they

do not interfere with all these uses. 

Firefighter Lifts 

Many US fire departments have adopted operating procedures for fires in tall buildings that 

incorporate elevator access that are similar to those described in a draft CEN/ISO standard9

for firefighter lifts. The primary differences relate to the fact that most firefighter lifts are 
Richard W. Bukowski P.E., FSFPE 

dedicated to this use and 

thus are immediately 

available to the fire 

service on their arrival. In 

the US firefighters use the 

passenger elevators that 

are either still operating or 

are waiting at the ground 

floor in Phase 1 recall. 

The procedure is for the 

firefighters to use the lift 

to transport people and 

equipment to the 

protected lobby 2-3 floors 

below the fire floor where 

they stage for their 

suppression operations. 

The firefighters then move 

up the stairway to the fire 

floor with a standard 

length of hose (30 m is 

common in the US and 60 

m in Europe), which is 

connected to the standpipe

located in the stairs. This is

important because once 

charged with water the hose becomes very stiff. The hose is usually looped down the stairs 

and back up so that it can be advanced onto the fire floor more easily. Working from the 

stairway also provides a protected area to which the firefighters can retreat in case the fire 

threatens them. The common hose lengths dictate the distribution of firefighter lifts within a 

building in the same way as the distribution of standpipes. For example, the New York City 

building regulations require standpipes located so that one is within 40 m (125 feet) – 30 m 

(100 feet) of hose plus 10 m (25 feet) of water throw from the nozzle of any point on a floor. 

Figure 4 is an illustration of firefighting procedures utilizing a firefighter lift, taken from the 

CEN/ISO draft. 

Figure 4 - firefighter lifts carry people and equipment to 

the floor below the fire with attack staged from the stairs9

This operating procedure highlights the importance and interrelationship of the firefighter lift, 

protected lobbies, associated stairway and standpipe. These components form a system 

described in BS5588 as a firefighting shaft. The need for an associated stairway impacts on 

the arrangement of the components and on the designation of multiple cars of an elevator 

group as firefighter lifts. It also raises issues of the firefighting lift and stair used for occupant 

egress. 

Egress Assistance for People with Disabilities 

Standards for firefighter lifts all include their use by firefighters to provide evacuation 

assistance for people with disabilities. Even in the US where there are no firefighter lift 

standards the building codes require accessible elevators (part of an accessible means of 

egress) that are used by the fire service to evacuate people with disabilities. The procedures 

generally are that such occupants proceed to the protected lobby (sometimes called an area 

of refuge) and request evacuation assistance through a two-way communication system (to 

the fire command center) provided. 

Not covered is any procedure for coordinating the use of the lift for evacuation assistance 

with that of firefighting. First priority will be given to moving firefighters and equipment to the 

staging floor to allow the start of suppression operations. Then a firefighter would 

presumably be assigned to begin to collect waiting occupants in the lift under manual control. 

Command staff in the fire command center could inform the operator on which floors there 

are occupants waiting and these could be gathered in some logical order and taken to the 
 Proceedings of the CIB-CTBUH Int. Conf. on Tall Buildings, 20-23 October 2003, Malaysia 

ground floor. If there are more occupants than can be 

assisted in a single trip there is a question about the order in 

which they are removed. Presumably, this would be done for 

the floors nearest the fire first, then above the fire and finally 

below the fire. Because these people are required to wait it is 

especially important to provide this two-way communication 

system to the lobby (Fig 5) so that they can be reassured that 

assistance is coming. The real-time monitoring system

described earlier would assure that conditions in the occupied

lobbies remain tenable. 

Occupant Egress Elevators 

As mentioned earlier, with only rare exceptions for special 

cases, elevators are taken out of service in fires and people 

are advised never to use elevators during fires. This policy 

does not represent a severe hardship for most buildings and 

occupants, but poses problems for people with (mobility) 

disabilities and for tall buildings where stairway egress times 

can be measured in hours. 

Figure 5 - Maintaining

communication with 

waiting occupants is crucial

Operational procedures for occupant egress elevators raise some interesting issues. First, 

how can overcrowding be avoided? Elevators have weight switches that disable an elevator 

that is overcrowded. Without a floor warden or firefighter controlling the loading it is likely that 

occupants may attempt to overcrowd an elevator during emergency evacuation. Similarly, 

the elevators are unlikely to be capable of handling a large fraction of the floor load – the 

system specified for air traffic control towers is designed for elevator evacuation of not more 

than half the occupants. How will at least half the occupants be encouraged to take the 

stairs? One possibility is to limit the capacity of the lobbies so the excess is forced into the 

stairways. Another is the phased direction of the elevators to evacuate floors near the fire 

first. If occupants have the choice of waiting in the lobby or beginning to move to safety down 

stairs, what choice will they make? 

Egress elevators are most likely to be utilized in tall buildings and here the elevator systems 

are vertically zoned in 30- to 40-floor sections. How would elevator evacuation be operated 

with vertically zoned elevators? One example where this is being done is for an 88-story 

building currently under construction in Melbourne, Australia. In the Eureka Place Tower, 

elevators in the third of the building containing the fire are taken out of service and occupants 

all use the stairways to the next (lower) transfer floor where they board express elevators to 

grade. People with disabilities are assisted by firefighters in their dedicated lifts within the 

zone of origin. This strategy is similar to the Petronas Towers where occupants above the 

sky bridge level use stairs to that level, move across to the other tower, and use the elevators 

to grade. 

Coordination of emergency elevator uses 

Finally, the complete integration of the elevators 

into the emergency operational plans in tall 

buildings presents some coordination issues

that will need to be addressed. One example is 

whether firefighter lifts and egress elevators can 

share common lobbies (Fig 6). Occupants 

awaiting egress may interfere with staging of 

suppression operations. Another is access to 

stairs and the use of the stairs for mounting the 

fire attack as discussed previously. A third is 

the sequence of egress operations. First priority 

would be given to egress of occupants from a 

few floors around the fire floor. Next a group of Figure 6 - Will shared lobbies lead to

interference between operations and 

egress?
Richard W. Bukowski P.E., FSFPE 

floors above the first group should be evacuated but if a disabled person enters a lobby on 

another floor at what point should that person be extracted? These sequencing delays would 

likely cause people on other floors to use the stairs rather than awaiting the elevators. 

Should people above the fire take the stairs to a point and then transfer to the elevators while 

people below the fire should take the stairs all the way? NIST plans to incorporate elevators 

into evacuation models so that a series of simulations can be conducted to identify the most 

effective operational procedures. NIST is also working with the US elevator industry to 

develop control software that can adapt to changing conditions and maintain safe and reliable 

operation of the elevator system. 

Concluding remarks 

Operational procedures and sequencing will have an effect on the design and arrangement of 

the entire egress system and need careful thought. The operational procedures selected 

must take into account complex human behavioral issues to be successful and also have 

significant impacts on the design and arrangement of the systems. Thus these issues should 

be discussed and resolved as a system so that appropriate requirements can be developed 

for standardization. Finally, there are significant advantages in developing common 

approaches globally. With the degree to which people travel internationally it is highly 

advantageous to have consistent emergency procedures so that people know how to react 

and do not depend on instructions that may not be understood clearly due to language 

difficulties. 

REFERENCES 

 

1

 Safety Code for Elevators and Escalators, ASME A17.1-2000, American Society of Mechanical 

Engineers, NY, 2000 

2

 Guide for Emergency Personnel, ASME A17.4-1999, ibid 3

 Comparison of worldwide lift (elevator) safety standards – Firefighters lifts (elevators), ISO/TR 

16765:2002(E), International Organization for Standardization, Geneva, Switzerland, 2002 

4

 Fire Precautions in the Design, Construction, and Use of Buildings, BS 5588 Part 5 1991, Code of 

Practice for Firefighting Lifts and Stairs, British Standards Institution, London 

5

 Life Safety Code (NFPA 101 2000, National Fire Protection Association, Quincy, MA 02269 

6

 Quiter, J. R. Application of Performance Based Concepts at the Stratosphere Tower, Las Vegas, 

Nevada. Rolf Jensen and Associates, Inc., Deerfield, IL. Fire Risk and Hazard Assessment 

Symposium. Research and Practice: Bridging the Gap. Proceedings. National Fire Protection Research 

Foundation. June 26-28, 1996, San Francisco,CA, 118-126 pp, 1996. 

7

 Bukowski, R. W. Development of a Standardized Fire Service Interface for Fire Alarm Systems. 

National Institute of Standards and Technology, Gaithersburg, MD Fire Protection Engineering, 4,6-8, 

SFPE Bethesda, MD, Spring 2000. 

8

 National Fire Alarm Code NFPA 72 (2002 ed.) Nat Fire Prot. Assn., Quincy, MA 02269, 2002. 

9

 Safety rules for the construction and installation of lifts – Part 72:Firefighter lifts, CEN TC10, 

Committee for European Standardization, Brussels, BE. 
Appendix B

An Overview of Elevator Use for Emergency Evacuation
Proceedings of the CIB-CTBUH International Conference on Tall Buildings, 8-10 May 2003, Malaysia

AN OVERVIEW OF ELEVATOR USE FOR EMERGENCY EVACUATION

John H. Klote 

John H. Klote, Inc. – Fire and Smoke Consulting 

Leesburg, VA, USA 

Abstract 

Throughout most of the world, warning signs next to elevators indicate that they should not be used in fire situations. However, 

the idea of using elevators for fire evacuation has gained considerable attention. This paper is an overview of what has been 

learned from a number of research projects conducted at the U.S. National Institute of Standards and Technology (NIST) in the 

1980s and 1990s concerning the use of elevators during building fires. An elevator system intended for evacuation needs to have

protection from heat, flame, smoke, water, overheating of elevator machine room equipment, and loss of electrical power. In 

addition, such an elevator system needs to have a control approach to assure protection of people traveling in the elevator. In

areas of high seismic activity, attention needs to be paid to earthquake design. Smoke protection technology for elevator 

evacuation systems has been developed. Water exposure due to sprinklers and fire hoses is a concern because of the effect that 

water can have on electrical and electronic elevator components, and tests have been conducted to determine water leakage 

rates and observe water leakage patterns. Further, the development of an elevator evacuation system needs to take into account 

human behavior so that building occupants will be willing and capable to use the system in an emergency. The computer 

program for elevator evacuation (ELVAC) was developed to estimate time for elevator evacuation, and ELVAC has been used to 

demonstrate the extent to which elevators can speed up emergency evacuation. 

Keywords: Elevators, Evacuation, Fire, Human behavior, Piston effect, Smoke Control, Smoke. 

1. Introduction 

Throughout most of the world, warning signs next to elevators indicate they should not be used in fire 

situations. These elevators are not intended as means of fire egress, and they should not be used for fire 

evacuation (Sumka 1987). Frequently, the fire service uses elevators during fires for mobilization and rescue. 

The idea of using elevators to speed up emergency evacuation has gained considerable attention. Elevator 

evacuation has also gained interest as a means of emergency egress for people with mobility limitations. 

Bazjanac (1974, 1977) examined the effect of using elevators to speed up building evacuation. In the 1980s 

and 1990s, the U.S. National Institute of Standards and Technology (NIST) conducted a number of research 

projects that examined the use of elevators during building fires. This paper is an overview of what has 

been learned from this research. For NIST work concerning elevator smoke control, readers are referred to 

Klote (1980, 1983, 1984, 1988, 1995). A joint U.S. and Canadian project also studied elevator smoke 

control (Klote and Tamura 1986a, 1986b, 1987, 1991a, 1991b; Tamura and Klote 1988, 1989a, 1989b, 

1990). 

NIST projects examined the feasibility of using elevators for emergency evacuation (Klote 1993a, Klote et al. 

1992a, 1993, Klote and Braun 1996, Klote, Levin and Groner 1994, 1995). NIST sponsored studies of 

human considerations regarding elevator evacuation (Groner and Levin 1992, 1995; Levin and Groner 1992, 

1994a, 1994b, 1995). Because elevator lobbies can be used for staging areas or areas of refuge, NIST 

research concerning these areas is also of interest (Klote 1993b, Klote et al. 1992b). 
Klote 

2. Concern With Elevator Evacuation 

The 1976 edition of the Life Safety Code (NFPA 101 1976) listed the following "problems" involved with the

use of elevators as fire exits1

: 

!" Persons seeking to escape from a fire by means of an elevator may have to wait at the elevator

door for some time, during which they may be exposed to fire, smoke or developing panic. 

!" Automatic elevators respond to the pressing of buttons in such a way that it would be quite

possible for an elevator descending from floors above a fire to stop automatically at the floor

involved in the fire and open automatically, exposing occupants to fire and smoke. 

!" Modern elevators cannot start until doors are fully closed. A large number of people seeking to 

crowd into an elevator in case of emergency might make it impossible to start. 

!" Any power failure, such as the burning out of electric supply cables during a fire, may render the

elevators inoperative or might result in trapping persons in elevators stopped between floors.

Under fire conditions there might not be time to permit rescue of trapped occupants through 

emergency escape hatches or doors. 

In addition, there are other concerns. Fire or smoke might damage elevator equipment. Water from

sprinklers or fire hoses could short out or cause other problems with electrical power and control wiring for 

the elevator. Overheating of elevator equipment could result in malfunction of elevators. Pressurization for

smoke control could result in elevator doors jamming open, limiting movement of the car. Piston effect due

to elevator car motion could pull smoke into the elevator lobby or the hoistway (elevator shaft). However, it

is possible to design an emergency elevator evacuation systems (EEES) with a high level of protection

relative to these concerns. 

Fig. 1 Elevator system including elevator equipment, 

machine room, hoistway and elevator lobby 

3. EEES Concept 

An EEES includes the elevator equipment, hoistway, machine room, and other equipment and controls needed 

for safe operation of the elevator during the evacuation process. Because people must be protected from fire

and smoke while they wait for an elevator, the system must include protected elevator lobbies (Figure 1). 

Such protected elevator lobbies also help to prevent the fire from activating elevator buttons so that elevator

cars are prevented from being called by the fire to the fire floor2

. 

 

1

This edition of the Life Safety Code was the last edition to list these "problems". 

2

Even buttons that are not heat sensitive can short out when subjected to the elevated temperatures of a fire. 
Klote 

An EEES must have protection from heat, flame, smoke, water, overheating of elevator machine room 

equipment, and loss of electrical power. In addition, an EEES must have a control approach that assures 

protection of the people traveling in the elevator. In areas of high seismic activity, attention must be paid to 

earthquake design. Further, the development of an EEES needs to take into account human behavior so that 

building occupants will be willing and capable to operate the system in an emergency. The following sections 

address these issues. 

The concern about people crowding into an elevator and doors not closing is significant only when there are 

enough people to form a crowd. Some EEESs might only be intended for use by a small number of people. 

Examples of such low use EEESs are (1) a system intended only for use by a few persons with mobility 

limitations, and (2) a system at an air traffic control tower (ATCT). For the purposes of this paper, a small 

number of people is taken to be a number that will not result in crowding that could force elevator doors to 

remain open and prevent motion of the car. For other applications, the conventional methods of people 

movement (Pauls 2002, Nelson and Mowrer 2002, Klote and Milke 2002) can be used to evaluate the potential 

for crowding. 

4. EEES Protection 

4.1 Heat and Flame 

Compartmentation is one of the oldest methods of fire protection and has been extensively used to limit the 

spread of fire. Compartmentation is also one approach to smoke protection, and this is addressed in the next 

section. As a convenience to the reader the concepts of compartmentation are briefly described here, and for 

further information readers are referred to Barnett (1992), Boring, Spence and Wells (1981), Bushev et al. 

(1978) and Campbell (1991). 

Buildings are divided into compartments formed by fire barriers. These barriers are walls, partitions and floorceiling assemblies that have a level of fire resistance. The traditional approach to evaluate fire resistance is to 

subject a section of a barrier to a standard fire in a standard furnace. Each building fire is unique in duration 

and temperature, and it is not surprising that the performance of barriers in building fires differs to some 

extent from the performance in standard tests. Historically, the goal of fire resistant construction was property 

protection, but the goals of current codes include life safety. The building codes require specific levels of fire 

resistance for specific applications with the goal of protecting life. 

4.2 Smoke 

The mechanisms that can be used to provide smoke protection are air flow, buoyancy, compartmentation, 

dilution and pressurization. Detailed information about these mechanisms is presented by Klote and Milke 

(1992, 2002). Because of the concern about supplying oxygen to the fire as discussed by Klote and Milke, air 

flow is not recommended for smoke protection of EEESs. Buoyancy is primarily used to manage smoke in 

large spaces such as atria and shopping malls. Systems that rely on buoyancy are inappropriate for smoke 

protection of EEESs. 

Pressurization Systems: Systems relying on compartmentation with pressurization are designed on the 

basis of no smoke leakage into protected spaces. Accordingly, analysis of such pressurization systems is less 

complex than that of systems using compartmentation alone or compartmentation with dilution. Acceptance 

testing and routine testing of pressurization systems is done by measurement of the pressure difference 

produced when the system is operating. Such testing provides a level of assurance about system performance 

during a fire. For systems that have windows breaking, windows opening, or doors opening to the outside; 

smoke control systems by pressurization as discussed later can maintain pressurization during such pressure 

fluctuations. Considering the potential for windows to break during unsprinklered fires, pressurization systems 

are recommended for smoke protection of EEESs in unsprinklered buildings. 

Piston Effect: Elevator car motion results in increased air pressure in the direction of motion. There is a 

concern that this piston effect could reduce the effectiveness of an elevator smoke control system. An 

analysis of elevator piston effect was developed and experimentally verified (Klote 1988; Klote and Tamura 
Klote 

1986a). Based on this analysis, Klote and Milke (1992, 2002) provide a simple method for design evaluation 

of elevator piston effect. 

Elevator Doors Jamming: Elevator doors jam open when the force of the door mechanism is insufficient to 

overcome the force of friction. The friction force increases with the pressure difference from the hoistway to 

the lobby. In tall buildings, elevator doors frequently jam open during extremely cold weather. This is caused 

by stack effect induced pressure differences. Elevator mechanics commonly adjust the door closing forces to 

prevent door jamming. During elevator smoke control operation, the possibility of door jamming may 

decrease or increase. If the leakage area of the elevator lobby doors is less than that of the elevator doors, 

the pressure difference across the elevator doors can be less than that normally occurring. In field tests 

conducted by Klote (1984), no door jamming was encountered at pressure differences as high as 75 Pa (0.3 in 

H2O). When door jamming was encountered in an elevator without smoke control, it was found that only a 

small additional force applied by the palms of the hands was sufficient to overcome jamming. Fire fighters 

can be taught to overcome door jamming this way, and elevator doors could be fitted with grips or handles to 

aid in this effort. 

4.3 Water 

During a building fire water from sprinklers and fire hoses can damage electronic, electrical, and mechanical 

components of an EEES. The water exposure of some suppression and firefighting devices are listed in Table 

1. For fires in the hoistway, elevator lobbies or machine room, the most appropriate action seems to be to take 

the elevators out of service. Fires in the hoistway or elevator lobbies can easily result in untenable conditions 

within the EEES. Further, an elevator cannot be expected to operate when there is a fire in the machine room, 

because of elevator equipment exposure to elevated temperatures. If there is a fire in the hoistway, elevator 

lobbies or machine room; the EEES should be shut down. Because of the limited fuel load, relatively small 

compartment size and the fire resistive construction, fires in the hoistway, elevator lobbies or machine room 

are not believed to have as high a potential for hazard as fires in many other building spaces. If evacuation is 

needed, other vertical paths (other elevators and stairs) can be used. 

Table 1.Water flows of some suppression and firefighting devices 

Device L/min gpm 

12.7 mm (0.50 in) Sprinkler Head 67-200 17.7-53 

29 mm (1.125 in) Solid-Stream Hose Nozzle 950 250 

Manually Held Hose with Spray Nozzle 40-1150 11-300 

Master Flow Devices 1900-7500 500-2000 

Water Leakage of Elevator Doors: Klote and Braun (1996) conduced experiments of the water flow 

around elevator doors and into the hoistway in a specially built facility at NIST (Figure 2). The elevator doors 

were supplied by an elevator manufacturer. The tests consisted of a water exposure in the elevator lobby, and 

water leakage of the elevator doors was determined by collecting water in the tank shown in Figure 2. The 

water exposure was a ceiling sprinkler, sidewall sprinkler, standing water set up, or a fire hose. The positions of 

the sprinklers is shown in Figure 2. Figure 3 shows the set up for the standing water test. The set up for the 

fire hose test is shown in Figure 4. The results of their study are summarized in Table 2. 
Klote 

Fig. 2 Laboratory facility for testing water leakage of elevator doors 
Klote 

Fig. 3 Set up standing water tests 

Fig. 4 Set up for fire hose tests 
Klote 

Table 2. Results of elevator door1 water leakage tests (Klote and Braun 1996) 

Measured Water Leakage 

Type of Water Exposure Water Exposure L/s gpm 

Ceiling Mounted Sprinkler2 29 L/s 46 gpm 0.22 3.3 

Sidewall Sprinkler2 2.8 L/s 44 gpm 0.13 2.1 

Standing Water 12 mm 0.5 in. 0.84 13 

Fire Hose 28 L/s 440 gpm 13.5 210 

1

The results above are for standard gibs and brackets around elevator doors. 

2

Test conducted with open floor drain in elevator lobby. The depth of water (standing water) at 

the bottom of the elevator doors was not measured, but it appeared to be on the order of 2.5 

mm (0.1 in.). 

Approaches to Minimize Water Damage: For fires outside the EEES, the two major locations of concern 

about water damage are the machine room and the hoistway. Two potential approaches to minimize water 

damage are: 

1. use of elevator components that can function in a wet environment, and 

2. prevention of water from entering the hoistway or machine room. 

Some methods that might be used to minimize or prevent water from entering the hoistway (elevator shaft) 

are use of sloping floors, floor drains and doors with seals. Other methods might include exterior elevators or 

elevators located in their own towers and are separated from the building by a section of exterior walkway or 

an exterior elevator lobby. 

Currently no elevators have been developed with water resistant components for operation during fire 

evacuations. However, many elevators operate outdoors on exterior walls of buildings with many of the 

system components exposed to rain, wind and extremes of temperature. These outdoor conditions are 

believed to be much more severe than those associated with water flow inside a hoistway due to a building 

fire. Without routine testing for water resistance, components that degraded from years of use or were 

accidentally damaged would go undetected and unrepaired. 

Further research and development are needed to find reliable methods of protection the EEES from water 

damage. 

4.4 Overheating Of Elevator Machine Room Equipment 

Loss of cooling can result in loss of elevator service due to overheating of elevator equipment, and precautions 

need to be taken to minimize the likelihood of such overheating. The maximum operating temperatures of 

most elevator equipment are in the range of 30 to 35 C (86 to 95 F). There are several approaches to 

providing the necessary machine room cooling, but dedicated air conditioning equipment has significant 

advantages. Dedicated equipment located in the machine room or outside the building eliminates the 

possibility of damage to this equipment from fire outside the machine room to the extent that the fire resistive 

construction withstands the fire. Further, dedicated equipment uses less electrical power than non-dedicated 

equipment with resulting advantages concerning reliability of electrical power. 

4.5 Electrical Power 

Reliability of electric power consists of assuring a source of power and assuring continued distribution of power 

to where it is used. Some components that can be used to ensure reliability of power are fire protected 

distribution, redundant feeds, power from multiple substations outside the building, and emergency generator 

sets. Because elevator evacuation can tolerate short duration power loss, uninterruptable power supplies are 

not necessary. Any consideration of reliability of electric power should consider potential causes of power 

failure and the consequences of that failure. 
Klote 

4.6 Earthquakes 

The concern with earthquakes is that the counterweight could become dislodged from its rails resulting in a 

collision between the elevator car and the counterweight. Such a collision could result in injury or fatality to 

elevator passengers. In areas of high seismic activity, some elevators have strengthened rails and a seismic 

switch to sense significant acceleration. The strengthened rails allow safe elevator operation up to a specific 

level of earthquake induced acceleration. If the seismic switch senses acceleration greater than this specific 

level, the elevators are put into an emergency mode to prevent collision with the counterweight and then 

taken out of service. Such an approach can be applied to EEESs that are in areas of high seismic activity. 

5. Availability

When an elevator in an EEES is out of service for scheduled or unscheduled maintenance, it cannot be used 

for evacuation. If there are many elevators in a building, the number of elevators used for evacuation can be 

selected to allow for a percentage that may be out of service. 

In buildings with only one elevator, the above redundancy approach to assuring availability is not possible. 

Two other approaches to maximize availability are off hours maintenance and short turn around repairs. 

Scheduled maintenance can be done during off hours when the building is shut down or in a low state of 

activity. Maintenance contracts can put a premium on fast repair for unscheduled maintenance. When an 

elevator is out of service, a sign should clearly indicate this so that valuable evacuation time is not wasted 

waiting for an elevator that can not come. 

6. Elevator Control 

Readers are familiar with automatic elevator controls that are common in passenger elevators in most of the 

world. There are two other modes of operation: elevator recall and firefighters operation. Upon alarm of a 

smoke detector in an elevator lobby, the elevator goes into a recall mode in which the car is moved to the exit 

landing and removed from service. In the event of a fire on the exit floor, the elevator goes to an alternate 

floor and is taken out of service. This recall is referred to as Phase I. The landing to which the car is moved is 

the exit floor or an alternate floor if smoke was detected on the exit floor. After recall, firefighters can operate 

the elevator, and such operation is under the control of the firefighter inside the elevator. This firefighter’s 

operation is referred to as Phase II. 

Some approaches that might be used to control elevators during an elevator emergency evacuation are: 

!" normal use (with less sensitive detectors), 

!" Phase II, and 

!" other mode of elevator operation. 

In an EEES, the elevator (including the elevator lobbies, hoistway and machine room) is protected from the 

fire effects as discussed above. Thus the elevator is operating in an environment without fire. There is no 

physical reason why an elevator so protected cannot continue to operate normally provided that the smoke 

detector in the elevator lobby does not go into alarm. As stated earlier, an alarm from this smoke detector will 

result in Phase I elevator recall. Typical smoke detectors are very sensitive, and they can be put into alarm by 

a quantity of smoke so small that a person might not notice. Such small amounts of smoke may enter the 

lobby when lobby doors are opened for evacuation. Such low levels of smoke are not a tenability concern. To 

avoid unwanted elevator recall, the smoke detectors in the elevator lobbies that initiate Phase I operation can 

be replaced with less sensitive detectors such as heat detectors. 

Using normal operation during evacuation is not appropriate for evacuation of large numbers of people, where 

a full elevator car might stop at every floor on its way to the exit floor. However, normal mode would be 

appropriate for evacuation of small numbers of people, such as a few persons with disabilities in an office 

building or the small number of workers in an ATCT. The computer program for elevator evacuation (ELVAC) 

by Klote, Alvord, Levin, and Groner (1992) can be used to estimate time for elevator evacuation. 
Klote 

The fire service, using Phase II operation, could also use elevators for evacuation of small numbers of people. 

Further, it is possible that building personnel could operate the elevators under Phase II for evacuation before 

the fire service arrives. Use of Phase II by non-fire service people would require that the elevator operators 

be trained and that the general approach not adversely affect fire service operations. Phase II service must 

only be provided by people who are aware of the location and extent of the fire and of its potential for 

endangering people using elevators. 

Approach 3 listed above is a mode of elevator operation that could be developed specifically for emergency 

evacuation. Features that could be considered for this emergency evacuation mode might include the ability 

to prioritize evacuation and the ability to cancel calls from a floor with untenable conditions in the elevator 

lobby. Such capabilities may be needed for evacuation of large numbers of people. 

If EEESs are to be developed for evacuation of large numbers of people from buildings, further research and 

development are needed to find appropriate methods of elevator control. 

7. Human Considerations 

Designing and building elevators that can be safely used during a fire emergency is only half the job. The 

building occupants must be willing to use the EEES and be able to use it. The NIST feasibility study of 

elevator evacuation at ATCTs (Klote, Levin and Groner 1994; Levin and Groner 1994a) included visits to 13 

control towers where interviews were conducted with air traffic controllers and other personnel. 

The interviews consisted of informal discussions that lasted about 15 minutes. Considering the twenty year 

campaign to teach people not to use elevators during fires, it was expected that occupants would have a 

strong preference for using stairs during fires. It was not surprising that nearly all those interviewed 

expressed a strong preference for using stairs as the first choice escape route. There were considerable 

differences among the interviewees on how willingly they would use elevators if there was smoke in the stairs. 

A few would use it without hesitation, and a few indicated they would try other alternatives (wait for 

helicopters, escape to catwalk, or use ladders). The majority indicated that they would use elevators if it were 

necessary with little delay but with considerable concern. 

At some ATCTs there were complaints about elevator service. It is well known in the elevator industry that 

buildings with only one elevator have more complaints about out-of-service elevators than buildings with 

multiple elevators. When there is only one elevator, occupants have to walk when elevators are not operating. 

In addition to complaints about out-of-service elevators, there were complaints about rough rides, and at one 

ATCT a cable for the counterweight had broken. While none of these occurrences were life threatening, the 

occupants at these towers were emphatic in expressing reluctance about elevators for fire evacuation. At 

ATCTs with few complaints about elevator service, occupants were more willing to accept the idea of EEES. 

Good maintenance of the elevator will encourage people to trust the EEES. 

Communication is important to inform people waiting for elevators of the status of elevator evacuation and to 

inform people outside the building about the status of those waiting. The communication devices can be 

intercoms or telephones, but they must be capable of two way conversation. One device is needed in each 

elevator lobby, and another is needed at a location accessible to the emergency personnel. 

In order to develop confidence in EEESs, education is needed to describe the safety features. Such education 

should also address general aspects of fire evacuation. This education can be by a combination of formal 

training classes, viewing videos, performing fire drills, reading an emergency plan and group discussions. 

Levin and Groner (1994) provide more information about such education. 

8. Speeding Up Evacuation 

The extent that elevators could be used to speed up evacuation in General Services Administration (GSA) 

office buildings was calculated by Klote et al. (1992a). For horizontal movement and movement on stairs, 

conventional methods of people movement were used. For movement on elevators, the computer program 

ELVAC (Klote 1993a) was used. ELVAC uses the generally accepted methods to calculate people movement by 

elevators (Strakosch 1983). 
Klote 

Time

Constant

Acceleration

Constant Velocity

Transit ional

Acceleration

Leveling

Transit ional

Decel eration

Constant

Decelerati on

Figure 5. Velocity of elevator that reaches normal operating velocity

For many trips, elevator motion is depicted in Figure 5. Motion starts with constant acceleration, followed by 

transitional acceleration, and constant velocity motion. Constant acceleration ends when the elevator

reaches a predetermined velocity which is typically about 60% of the normal operating velocity. For office 

buildings, normal operating velocity generally is from 1 to 9 m/s (200 to 1800 fpm), and acceleration is

from 0.6 to 2.4 m/s2

 (2 to 8 ft/s

2

). Deceleration has the same magnitude as the acceleration, and total 

acceleration time equals the total deceleration time. Usually elevators do not stop exactly at the desired

floor at the end of deceleration, so the elevator must be moved slowly up or down to get it nearly level with 

the floor. For cars not reaching normal velocity, the elevator car velocity is simpler. 

In addition to elevator motion, ELVAC includes the (1) the start up time before elevator evacuation for the

car to go to the discharge floor, (2) time for passengers to enter and leave the elevator on each trip, (3) 

the time for elevator doors to open and close on each trip. ELVAC also incorporates the following

inefficiencies: (1) trip inefficiency (2) basic transfer inefficiency, (2) door inefficiency and (3) other 

inefficiency. Klote (1993a) discusses these inefficiencies and provides some values. 

Table 3. Summary of Elevator Evacuation Calculations of the GSA Study (Klote, et al. 1992a) 

Building Location

Number 

Of Stories 

Optimum 

By Elevator1

Speed Up 

Evacuation By2

General Services Building Washington, DC 7 NA NA 

Hoffman Building II Alexandria, VA 13 33% 25% 

White Flint North Building Bethesda, MD 18 17% 16% 

Jackson Federal Building Seattle, WA 36 65% 22% 1

The optimum by elevators is the percent of occupants using elevators that results in the fastest building evacuation. In

these calculations, the upper floors were evacuated by elevator, and the other floors were evacuated using stairs. 2

This is the decrease in evacuation time using the optimum combination of elevators and stairs over evacuation by stairs

only. 

Table 3 is a summary of the elevator evacuation calculations of the GSA study. In these calculations, some 

of the elevators were considered out of service and not used for the evacuation calculations. Calculations 

were based on a number of upper floors being evacuated by elevators, and the rest of the occupants used 

stairs. For the General Services Building, there was no combination of elevators and stairs that was as fast 

as evacuation by stairs alone. The General Services Building is a large monumental building that takes up a 

city block in down town Washington, DC. One of the reason that elevators could not speed up evacuation of 

this building is that it has high stair capacity. 

The calculations show that the elevator use has the potential to speed up evacuation significantly for the 

other three buildings studied. The extent to which elevators have the potential to speed up evacuation

depend on many factors including the number of floors in the building, the capacity of the elevators, the

capacity of the stairs, and the number of elevators in service during evacuation. However, it appears that in

general to he potential benefit of using elevators is greater for taller buildings. 
Klote 

Conclusions 

The use of elevators to speed up emergency evacuation is feasible. An EEES must have protection from heat, 

flame, smoke, water, overheating of elevator machine room equipment, and loss of electrical power. In areas 

of high seismic activity, attention must be paid to earthquake design. Further research is needed to (1) 

develop reliable methods of protection the EEES from water damage, (2) develop appropriate methods of 

elevator control, (3) develop appropriate approaches to getting people to accept and use EEES in emergencies.

Acknowledgements 

So many people have made valuable contributions to elevator research during the 1980s and 1990s that it is not possible 

the thank them all, but the following come to mind. Bernard Levin and Norm Groner provided valuable input concerning 

human behavior. Daniel Alvord helped with the development of ELVAC. Emile Braun contributed to the elevator water 

tests. Development of this overview paper is part of a research project sponsored by NIST, and Richard Bukowski is 

NIST’s technical representative for that research project. 

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Appendix C

Elevators for Occupant Evacuation and Fire Department 

Access
Proceedings of the CIB-CTBUH International Conference on Tall Buildings, 8-10 May 2003, Malaysia 

ELEVATORS FOR OCCUPANT EVACUATION AND FIRE DEPARTMENT 

ACCESS 

E. KULIGOWSKI 

National Institute of Standards and Technology, Gaithersburg, MD 20899, USA 

Abstract

This paper will present a study of the potential for elevators to reduce occupant egress time and fire department access time 

for fires in tall buildings. Potential reductions in egress and access times will be compared for some specific cases where 

times for current procedures are available. The paper will review past research in elevator usage and the structure of 

existing models for elevator evacuation. From this review, the assumptions and limitations of the current elevator and 

egress models will be discussed, and future plans for improvement of the existing egress prediction techniques will be 

presented. 

Keywords: Elevators, evacuation, firefighter lifts, elevator evacuation, evacuation models 

1. Introduction

The recent events have caused fire safety experts to question the adequacy of phased evacuation plans 

for high-rise buildings. Also, the issue of lengthy travel times and physical exertion of firefighters 

ascending stairs of a high-rise building to reach the fire floor is a concern. Inquiries of fire departments 

following the incident indicates that most have adopted access by elevator policies for buildings 

exceeding 6 stories, but there are currently no provisions for firefighter lifts in the U.S. elevator codes. 

During total evacuation of a tall building, it is likely that there would be significant congestion in the 

stairways with a larger number of occupants, when compared with occupant numbers during phased 

evacuation, at the same time as firefighters traveling against the flow. Increasing the number or width 

of the stairwells in a building represents an extremely expensive option, especially for existing buildings. 

A viable option is to design elevators capable of providing a safe exit route out of the building for 

occupants and safe access to the fire area for firefighters. Several issues concerning elevator use in 

emergencies, such as human behavior, control, training, equipment reliability, and communication, 

should be addressed before this mode of vertical transportation can be implemented. 

1.1 Current Requirements for Firefighter Lifts 

Firefighter lifts are protected elevators provided in tall buildings for use by the fire department for 

moving people and equipment to the fire area and which also may be used by the fire department to 

provide evacuation assistance to people with disabilities. The provision of lifts dedicated to fire 

department use in an emergency is required in at least 12 countries around the world. As a recent 

survey by the ISO TC178 committee shows1

 operating procedures for fire department use of elevators 

are similar. For example they are generally required in buildings taller than 30 m, are provided with 

enclosed lobbies on each floor, and are housed in a two hour smoke protected shaft. Emergency 

power to the controllers and motor is required and the cars are operated under manual control by a 

firefighter. 

British Standard 5588, Part 5 entitled Code of Practice for Firefighting Stairs and Lifts2

 describes what is 

referred to as a firefighting shaft. This is a dedicated, protected elevator with lobbies on every floor 

and an associated stairway fitted with a standpipe. The procedure is to move people and equipment to 

the lobby three floors below the fire. The hose team then advances up the stairs from the elevator 

drop-off position, connects to the standpipe, and proceeds with the attack. Enough firefighting shafts 

are required so that any point on a floor can be reached with 60 m of hose. The commentary describes 

several advantages to fire department dedicated lifts, such as reduction of travel time to the access 

floor, preservation of the building for a longer period of time, and increased safety to the occupants of 

the building. The standard also recognizes that firefighters who climb several flights of stairs outfitted 

with heavy gear and equipment may lose needed energy to fight the fire by the time they reach the fire 

floor. 
Kuligowski 

In the US, ASME A17.1-2000, the Safety Code for Elevators and Escalators3, does not provide for the 

use of elevators in emergencies either by firefighters or by occupants (except as noted below). Since 

1973, A17.1 has contained emergency procedures that take the elevators out of service if smoke is 

detected in any lobby or in the machine room or hoistway. Under this condition the elevators are 

directed immediately to the ground floor where the doors open and the elevators are locked out (called 

Phase I recall). Subsequently, the responding fire department can reactivate individual cars under 

manual control using a special key (Called Phase II operation). U.S. building regulations require that 

buildings taller than three floors and likely to be used by people with disabilities be provided with an 

accessible elevator protected in a manner similar to that described for firefighter lifts. A means of 

summoning assistance from the fire department is required and they would use that elevator under 

Phase II operation to evacuate the disabled person. 

The use of elevators for fire department access would enable the firefighters to ride to a specific floor, 

depending upon what is specified by the department’s Standard Operating Procedures (SOPs)4

. 

Examples of U.S. City Fire Department’s SOPs5

 state that the elevators would take firefighters from the 

lobby to the floor two floors below the fire floor while others, e.g. the Chicago Fire Department6

, state 

that the elevator would stop three floors below the fire. In either case, the firefighters from an engine 

company, for instance, would exit the elevator on the designated floor, travel via stairs to establish a 

hose line one to two floors below the fire floor, and continue stair travel with the hose line to the fire 

floor. 

1.2 Research on Egress Elevators 

In a fire emergency, elevators are not only the focus for fire department access, but for evacuation 

purposes as well. Work was done in the early 1990s at the National Institute of Standards and 

Technology (NIST)7,8,9,10,11 on the use of elevators for evacuation in which pros and cons were 

established that still exist today. The advantages noted for elevator evacuation are the following: 

! Occupants usually exit buildings the same way that they enter 

! Elevator evacuation takes less physical effort 

! Stair congestion is an unpleasant experience 

! Overall evacuation time is decreased 

! Elderly or disabled occupants may rely on elevators as their only option 

On the other hand, with an elevator evacuation plan, there are many issues to consider and prepare for 

in an emergency. First, the 30 year campaign cautioning the public against using elevators in the event 

of a fire could severely lessen the occupants’ confidence in the elevator system. Also, occupants could 

become impatient and overcrowd the elevator, which causes the car to stop functioning and remain at 

the floor indefinitely10. One way for these issues to be addressed is through a training program and 

extensive evacuation plan for the building. The evacuation plan of a single rise elevator system could 

involve, for example, the use of elevators by the higher floors of the buildings, stairs used by the lower 

floors, and fire wardens on each floor directing his/her occupants to the correct evacuation route8

. 

Since training may not be as helpful for visitors of the high rise building, the use of fire wardens 

becomes even more important in elevator evacuation. 

For an 88-floor residential building in Melbourne, Australia, an evacuation strategy has been used in the 

building design to allow for elevator use during evacuation. The Eureka Place Tower12 is separated, 

according to the elevator arrangement, into vertical evacuation zones. The plan states that occupants 

within the vertical zone that includes the fire floor would evacuate via the stairs until they reach the 

next transfer floor. At the transfer floors, which are located on levels 24 and 52 of the Eureka Place 

Tower, the occupants would then take the express elevators to the ground floor. The express elevators 

will be located in separate shafts in order to avoid water and smoke damage, and will be accompanied 

by other lifts provided for firefighter access. 

Along with an evacuation plan, a reliable voice communication system can provide information on the 

progress of the fire and evacuation system8

. Also, a decision made on the appropriate control of the 

elevator system (manual or automatic) in an emergency lends itself to certain advantages and 

disadvantages presented in the literature13,14,15. 
Kuligowski 

1.3 Elevator Evacuation Models 

In order to capture the differences in evacuation by stairs only, elevators only, or both, evacuation 

modeling and calculations can be done. ELVAC7

 is the only commonly available model dedicated to the 

calculation of evacuation time by elevators. Other elevator models, typically used for elevator design 

within a building, can also be used to calculate the transit time of the last person to reach the lobby, 

which is ultimately the evacuation time of the building. These models have limitations when using 

them to simulate total evacuation of a building, as well as make assumptions, which will be addressed 

later in this report. 

The three topics covered in this report focus on a firefighter lift case study, the U.S. General Services 

Administration (GSA) building evacuation case study, and a review of current elevator evacuation 

models. The case studies will be used to estimate the ultimate reduction in travel time by incorporating 

elevators into the evacuation plan for occupant evacuation and fire department access. For the 

firefighter lift study, firefighter travel via stairs will be compared to travel by elevator to a designated 

floor accompanied by continual travel via stairs to the fire floor. In the GSA evacuation study8

, several 

ELVAC and stair evacuation calculations were made to show the reduction in travel time when both 

elevators and stairs are used simultaneously for evacuation, instead of stairs only. Finally, the 

limitations and assumptions of current elevators models will be discussed as well as future needs in the 

area of elevator evacuation modeling. 

2. Firefighter Lift Case Study 

For this case study, the commercial building used was designed by a Dallas architectural firm and 

stretches 40 stories above ground and 4 parking levels below. A typical floor of the building contains 

approximately 3000 m2

 of floor space, with 500 m2 occupied by the core space. The core contains 

elevators, 2 stairwells, bathrooms, mechanical closets, etc. 

The stairs are located diagonally across the core area from each other, each measuring 1.2 m (3.9 ft) 

wide with 26 7/11 steps per flight. The 7/11 terminology refers the height of the riser followed by the 

depth of the tread in inches, meaning that for each step, the riser height is 17.8 cm (7 in) and the tread 

width is 27.9 cm (11 in). The height of each floor is 4.5 m (15 ft), creating a travel distance of 11 m 

(36 ft) per flight of stairs, including the landing distance. 

The elevators for a commercial building are assumed to have a speed of 5.08 m/s (1000 fpm), per 

Table 10.7 of the Vertical Transportation Handbook16, and average acceleration of 1.5 m/s2

 (5 ft/s2). 

For this case study, it is also assumed that a crew of 5 firefighters and their equipment will be traveling 

in the elevator and stairs together at one time. There are other characteristics that were assumed for 

the elevators that only affect the outcome of this case study in a trivial manner, such as the full car 

load, type of door, the door inefficiency, and door closing time. 

For this case study, the fire is placed on the 35th floor. Two groups of five firefighters are analyzed in 

their attempts to reach floor 35. Group 1 traverses 34 flights of stairs from the lobby to floor 35. 

Group 2 takes the elevators to the 33rd floor and travels the stairs an additional 2 flights. Hand 

calculations were made for firefighter travel up the stairs, while hand calculations and the ELVAC model 

were used to calculate the one-way elevator travel time from the lobby to the 33rd floor. ELVAC is 

primarily a model used to calculate gross elevator evacuation time from buildings, and the hand 

calculated one-way elevator travel time was used to check ELVAC results. 

To obtain firefighter travel speeds on stairs and horizontal building components, adjustments were 

made to data already recorded from people movement studies17,18,19. Frantzich’s data show a range of 

velocities for upstairs movement from (0.5 to 0.75) m/s, Fruin gives values of (0.5 to 0.65) m/s and 

Predtechenskii and Milinskii state a range of (0.33 to 0.92) m/s for low density situations. On one 

hand, these values may be low if studied during nonemergency situations, but alternatively, firefighters 

are typically equipped with heavy gear and equipment, on the order of 25 to 45 kg per firefighter, 

which should be accounted for. The primary walking speed used in this case study for firefighter travel 

up stairs is 0.35 m/s (adjusted from 0.5 m/s for heavy gear). Another velocity used came from the 
Kuligowski 

New York Fire Department’s rule of thumb that states firefighters average 60 seconds per floor 

(unobstructed flow), which is not sustainable throughout the ascent of high-rise buildings. 60 seconds 

per floor will be used as the conservative ascent time and 0.35 m/s will be used as the other extreme. 

For horizontal building component speed, again the standard value of 1.2 m/s20 was adjusted to a 

conservative value of 0.8 m/s for gear and heavy equipment. 

The breakdown of the elevator calculations are as follows (multiple values indicate a range of travel 

speeds for that calculation): 

Group 1: 

o The time to traverse 34 flights of stairs = 17 min at 0.35 m/s; 34 min at 60 seconds per flight 

(more conservative) 

Group 2: 

o The one way travel time of the elevator from the lobby to the 33rd floor = 45 s with 5.08 m/s 

elevator speed 

o The horizontal travel time from the elevator to the stairs on the 33rd floor = 30 s at 1.2 m/s; 

45 s at 0.8 m/s (more conservative) 

o The time to traverse two flights of stairs = 60 s at 0.35 m/s; 120 s at 60 seconds per flight 

(more conservative) 

The travel times calculated for both Groups in this case study neglect firefighter response time to the 

building, travel to the elevator or stairs from the building entrance, and time spent on the floor locating 

the point of attack, since both need to perform these activities in a fire situation. 

After performing an additional calculation of adding the elevator travel, horizontal travel, and stair 

travel times together for Group 2, the results are as follows: 

! Group 1: 17 to 34 min 

! Group 2: 2.5 to 3.5 min 

It may seem obvious that an elevator would give some advantage in speed over stair use. But, when 

other factors, such as heavy gear and equipment and increased elevator technology play a role, 

elevators substantially become a more viable and constructive option. The difference between use of 

stairs (Group 1) and elevators (Group 2) for firefighter ascent is approximately (15 to 30) minutes. This 

is a large difference in time lost due to stair use, especially when a fire can grow significantly in a 

matter of minutes. By using elevators as the primary means of ascent, Group 2 was able to reach the 

fire at least 15 min earlier in this case study. In fifteen minutes, the environment can be less toxic for 

the occupants, the fire smaller, and the property less damaged. Also, Group 2 would have more energy 

to exert on fire fighting activities on the floor, when compared to Group 1. The limitation associated 

with the calculation was the estimation made in the firefighter movement speed, as shown by the range 

of results in both Groups. 

3. Elevator Evacuation Study 

In the early 90s, four GSA buildings were analyzed as potential applications to incorporate elevator 

evacuation8

. The four selected were the Hoffman Building II (Virginia), White Flint North Building 

(Maryland), Jackson Federal Building (Seattle), and General Services Building (Washington, DC), and 

were chosen to gather different building heights, elevator capabilities, and architectural characteristics. 

For each building, evacuation times were calculated for the following conditions: 1) Total evacuation of 

the building by stairs only; 2) Total evacuation of the building by elevators only; and 3) Total 

evacuation of the building by various distributions of occupants to stairs and elevators (the optimal time 

value is shown in Table 1). For the stair calculations, Klote et al.8

 used the people movement 

methodology laid out by Nelson and MacLennan21. For these calculations, people on each floor were 

assumed to be waiting at the door to the stairs as soon as evacuation begins. For the elevator 

calculations, the ELVAC model7

 was used which simulates 2-stop elevator trips until the entire building 

has been evacuated. Again, for these calculations, people were assumed to be waiting at the closest 

elevator lobbies as soon as evacuation began. Table 1 shows the characteristics of each building, 
Kuligowski 

including the number of floors, the number of stairs and elevators used, and the total population of 

each building. Also, the table shows the total evacuation time of the building (minutes) if only stairs 

were used, the total evacuation time if only the elevators were used, and the last column shows the 

optimal (fastest) gross evacuation time when a combination of stairs and elevators are used. 

Additionally, the Hoffman building and the White Flint North Building’s analysis did not use the full 

capacity of elevators available to the building. The Hoffman building used 5 out of the 6 elevators in 

each group and the White Flint building used 4 out of the 6. This was due to the fact that the existing 

elevator lobbies were incapable of holding as many people as would be discharged from all elevators 

simultaneously, and in that case, the evacuation capacity of the elevators was restricted by the size of 

the lobby. 

Building Floors Stairs/ 

Elevators 

Total 

Population 

Evac. 

Time by 

Stairs 

Evac. 

Time by 

Elevators 

Optimal 

Time by 

Both 

Hoffman 13 2/ 2 groups of 5 3506 14.9 min 24.3 min 11.2 min 

White Flint 18 2/ 1 group of 4 1425 14.3 28.6 12.0 

Jackson 36 2/ 3 rises of 6 3021 23.1 16.5 12.8 

GSA 7 6/ 6 groups of 2 3621 7 17 6.3 

Table 1: Summary of GSA buildings and modeling results

In each of the four buildings analyzed, the optimal time was reached by designing for a combination of 

floors or percentage of the floor dedicated to elevator usage while the other portion of the building 

evacuated by stairs. The use of elevators for evacuation made the largest contribution for the tallest 

building, which was the Jackson Federal building equipped with low, mid, and high rise elevators. The 

elevator designation that provided the optimal result for this building was the following: 65 % of 

occupants from the mid and high rise floors, all occupants from floors 11 through 14, and only 3 % on 

floors 1 through 13. All others in the Jackson building used the stairs. For the single rise elevator 

systems in the Hoffman, White Flint, and GSA buildings, the elevator designation that provided the 

optimal result was for total elevator evacuation from the upper floors of the building and stairs from the 

lower floors. Overall, it was shown that by using a combination of evacuation systems, stairs and 

elevators, the total evacuation time of the building can be reduced by a substantial amount, especially 

with taller buildings. This study is limited by the averaged movement calculations used, and the 

assumption that all occupants were waiting at the stair or elevator lobbies as soon as the evacuation 

began. Also, another limitation is that occupants were not studied using both stairs and elevators 

during a single evacuation route, as performed in the evacuation plan for the Eureka Place Tower. 

4. Elevator Evacuation Modeling 

While the GSA calculations were made using the ELVAC model, there are certainly limitations associated 

with this and other current elevator evacuation models. Due to the fact that elevators are rarely used 

for occupant evacuation, other than by the fire department in Phase II, few evacuation models are 

available that incorporate evacuation via elevators. The commercial models presently being used to 

simulate building evacuation in a fire situation typically model movement by stairs only, with or without 

the incorporation of behavior simulation. There has yet to be a commercially-available, complete 

simulation package to describe the entire fire scenario, including premovement and action decision 

making, environmental conditions inside the building, occupant behavior, and movement throughout 

the building via stairs, escalators, and elevators. The limitations of the current models extend beyond 

the obvious lack of elevator simulation. There is also a lack of data on occupant behavior during 

elevator use in evacuation. The uncertainties on whether or not occupants will feel comfort in using 

elevators arise from the lack of data on occupant overcrowding of cars on a floor, impatience due to 

long waits in the elevator lobby, and behavior around their particular social unit (for example, will 

groups remain together and let an elevator pass if there is not enough room in the car for the entire 

group?). Another modeling uncertainty is how the model will simulate the evacuation plan that will 

take place in the building. The model may need to incorporate fire wardens, manual and automatic 

control of the elevators, and multi-use of stairs and elevators by the same group of occupants. 
Kuligowski 

As mentioned earlier, ELVAC8 is a model dedicated to the simulation of building evacuation by elevator 

only. ELVAC, as will be explained, only gives the gross evacuation time of the building, and along with 

its assumptions, may cause the model to lose accuracy in calculation, especially when compared to a 

complete simulation model. The model uses the 2-stop evacuation approach, meaning that the car 

travels from the lobby to a specific floor and then back down to the lobby, independent of the number 

of tenants occupying the car. ELVAC also assumes that all occupants using the elevators for 

evacuation are waiting at the elevator lobbies as soon as evacuation begins. Changes could be made 

to ELVAC to move towards more of a simulation model, such as equipping the elevators with load 

sensors, which most have, that would recognize when a car has additional space and enable the car to 

pick up more occupants on the way down to the lobby. Also, in an actual evacuation, it is certain that 

people would be arriving at the elevator lobby at different times, and the load sensor device would aid 

in evacuation of stragglers to the lobby area after most of the occupants have been evacuated. ELVAC, 

by giving only the gross evacuation time, does not simulate the car movement from floor to floor and 

the times associated with these movements. In an actual fire evacuation, it is most likely that the cars 

will move to the fire floor (and floors above and below) to evacuate these occupants first. By 

incorporating car simulation into ELVAC, evacuation times by elevators may be more accurate, 

especially for worst case scenarios when the fire is on a high floor of the building. Lastly, ELVAC does 

not account for the actual design of the control of the elevators. This difference in control may cause 

delays in start-time if operated by a human, instead of computer. 

ELEVATE and the Building Traffic Simulator (BTS) are both models used to design the elevators for 

buildings, including the number and size of the cars, for normal daily operation. ELEVATE, a 

commercial model, can be used to indirectly calculate total evacuation time by identifying the time that 

the final person has arrived at the ground floor from the elevators22,23. The user must specify a 

destination to the ground floor as 100 % and the arrival rate (persons per 5 minutes) of the building’s 

occupants to the elevator lobbies. As of now, evacuation modeling procedures are not specified in the 

users manual. BTS24,25, on the other hand, is a currently noncommercial model capable of simulating 

evacuation via the building’s transportation devices, which includes elevators (with different control 

methods), escalators, and stairs. The model uses input of the building’s floor shape, position of the 

transportation devices, passenger traffic (e.g. arrival rates to the lobbies), passenger selection of 

transports, and passenger walking speeds (to simulate tenants who may need to walk from one 

transportation device to the other during movement and/or movement on stairs) to model an 

evacuation. According to its developers24,25, evacuation can be modeled defining the occupant’s 

walking speed, space requirement, and decision on which transportation mode(s) to use throughout the 

evacuation. Both ELEVATE and BTS provide a step toward simulation evacuation models, since these 

models are continually aware of occupant loads and positions (in elevator cars or stairs, depending on 

the model) in time throughout the evacuation. On the other hand, like ELVAC, there is no introduction 

of fire conditions and human behavior, as a complete simulation evacuation package could include. 

Also, for each of the three models, occupants are either automatically waiting at the elevator lobbies 

(ELVAC) or given an arrival rate (people/time period – ELEVATE, BTS) for appearing at the designated 

transport device, which neglects specific behavior and movement time delays occurring from their 

original position to the location of the transport device. 

The three elevator models discussed in this report, ELVAC, ELEVATE, and BTS, all have advantages and 

disadvantages for using each for evacuation simulation purposes. ELVAC gives the gross evacuation 

time of the building by elevators only and assumes that all occupants are waiting at the elevator lobbies 

as soon as the evacuation begins. ELEVATE will simulate down-peak (evening rush hour for the 

building, for example) elevator movement with 100 % probability of movement to the ground floor, and 

BTS will also simulate down-peak movement of the occupants using elevators, escalators, and stairs 

during their exit journey. The simulation models, ELEVATE and BTS, have the extra advantage of 

continual data on the current position of the cars and occupants, as well as an attempt to model 

premovement behavior through the use of occupant arrival rates to the elevator lobbies. However, 

none of these models incorporate specific behavior and movement time delays that occur before 

reaching the transport device, human behavior in relation to elevator and stair use during a fire, and 

the condition of the fire in the building during the evacuation. These are main reasons why a complete 

evacuation simulation package would be a valuable asset for evacuation design. It should be noted 

that relevant literature in human behavior is sparse26,27,28,29; because elevators are not commonly used 

for design of the evacuation system of a building, data on humans and elevator use is lacking for this 

simulation package. 
Kuligowski 

5. Conclusions

Elevator use in emergency situations can make a significant time saving contribution to travel towards 

the fire for the fire service and the evacuation of the occupants in the building. The calculations done 

for the firefighter case study showed that firefighters traveled to the fire floor (15 to 30) min faster via 

elevators when compared to stair access. The stair travel calculation, using two different estimates for 

the firefighter walking speeds, resulted in a range of travel time values differing by a factor of two. 

Research is needed in the area of firefighter movement to assess which travel times within the 

calculated range (17 to 34 min) are more accurate. 

Also, the evacuation time of occupants using a combination of stair calculations and ELVAC calculations 

for the elevators shows improvement over stair or elevator movement alone for the GSA examples 

studied. This is especially true for the taller building with multi-rise elevators. With these calculations, 

assumptions were made that the occupants were waiting at the elevator lobbies and staircases as soon 

as evacuation began. Also, the occupants were assumed to use only the stairs or the elevators during 

their descent, unlike the evacuation plan of the Eureka Place Tower, in which a resident could use a 

combination of the two during egress. 

Lastly, there is a need for a complete simulation package that includes movement of the occupants on 

stairs, elevator movement of the cars and occupants, environmental conditions in the building due to 

the fire, the contribution of the building to fire and egress, and human behavior and movement during 

the entire evacuation. Currently, there are evacuation models that focus on all of these aspects except 

elevator usage, and elevator models that neglect these aspects of building evacuation except for 

elevator usage. Unfortunately, much data is lacking about the behavior of occupants using elevators 

during an emergency, which needs to be addressed. 

Overall, elevators lessen the travel time of firefighters and occupants to their prospective destinations, 

if used properly and with an appropriate emergency plan. There are many obstacles which need to be 

met in order for these plans to work properly. Recently, there has been an awakening to the 

importance of research in these areas for eventual use in buildings all over the world. 

Acknowledgements 

The author recognizes the help of Mr. Richard Bukowski, of the National Institute of Standards and Technology, as an 

advisor of this project. The assistance in research on elevators modeling from Roger Howkins and Dr. Richard Peters 

(ELVATE), Dr. John Klote (ELVAC), and Dr. Marja-Liisa Siikonen (BTS) is also appreciated. Mr. Mike Scianna, Commander – 

Bureau of Operations, Chicago Fire Department, and Mr. John O’Donoghue, Fire Officer, Massachusetts Firefighting Academy 

provided information about FD operations in high-rise buildings. Finally, Mr. Jason Averill provided the building used for FD 

access calculations30. 

References

1

Comparison of worldwide lift (elevator) safety standards – Firefighters lifts (elevators), ISO/TR 16765:2002(E), 

International Organization for Standardization, Geneva, Switzerland, 2002. 

2

Fire Precautions in the Design, Construction, and Use of Buildings, BS 5588 Park 5 1991, Code of Practice for Firefighting 

Lifts and Stairs, BSI, London. 

3

Safety Code for Elevators and Escalators, ASME A17.1-2000, Amer Soc Mech Eng, NY, 2000. 

4

Klaene, B. and Sanders, R. (2001), Firefighters’ Use of Elevators, Using elevators during a fire requires establishing specific

SOPs, NFPA Journal, Vol. 95, No. 4, July/August 2001. 

5

Phoenix Fire Department Standard Operating Procedures, http://phoenix.gov/FIRE/20205.html. 

6

Verbal/Email Communication: Michael Scianna, Chicago Fire Department. October 2002. 

7

Klote, J.H. (1993), A Method of Calculation of Elevator Evacuation Time, National Institute of Standards and Technology, 

Gaithersburg, MD, Journal of Fire Protection Engineering, 5(3), 1993, pp. 83-95. 

8

Klote, J.H., Alvord, D.M., Levin, B.M., and Groner, N.E. (1992), Feasibility and Design Considerations of Emergency 

Evacuation by Elevators, National Institute of Standards and Technology, Gaithersburg, MD, NISTIR 4870. 
Kuligowski 

9

Klote, J.H. and Alvord, D.M. (1992), Routine for Analysis of the People Movement Time for Elevator Evacuation, National 

Institute of Standards and Technology, Gaithersburg, MD, NISTIR 4730. 

10Klote, J.H., Deal, S.P., Donoghue, E.A., Levin, B.M., and Groner, N.E. (1993), Fire Evacuation By Elevators, Elevator World, 

June 1993. 

11Klote, J.H., Levin, B.M., and Groner, N.E. (1995), Emergency Elevator Evacuation Systems, Proceedings of the 2nd

Symposium on Elevators, Fire, and Accessibility, Baltimore, MD, April, 1995. 

12Aloi, S. and Rogers, J. (2002), Reach for the Sky, Fire Prevention & Fire Engineers Journal, Vol. 62, No. 219, FPA London, 

April 2002. 

13Levin, B.M, and Groner, N.E. (1995), Some Control and Communication Considerations in Designing an Emergency 

Elevator Evacuation System, Proceedings of the 2nd Symposium on Elevators, Fire, and Accessibility, Baltimore, MD, April, 

1995. 

14Groner, N.E. (1995), Selecting Strategies for Elevator Evacuations, Proceedings of the 2nd Symposium on Elevators, Fire, 

and Accessibility, Baltimore, MD, April, 1995. 

15Groner, N.E. and Levin, B.M. (1992), Human Factors Considerations in the Potential for Using Elevators in Building 

Emergency Evacuation Plans, George Mason University, Washington, DC, July 1992. 

16Strakosch, G.R. (1998), The Vertical Transportation Handbook Third Edition, John Wiley & Sons, Inc., New York, USA. 

17Frantzich, H. (1996), Study of Movement on Stairs During Evacuation Using Video Analysis Techniques, Department of Fire 

Safety Engineering, Lund Institute of Technology, Lund University, March 1996. 

18Fruin, J.J. (1987), Pedestrian Planning and Design, Revised Edition, Elevator World, Inc. Mobile, Alabama. 

19Predtechenskii, V.M. and Milinskii, A.I. (1978), Planning for Foot Traffic Flow in Buildings, Amerind Publishing Co. Pvt. Ltd.,

New Delhi, 1978. 

20Nelson, H.E. and Mowrer, F.W. (2002), Section 3, Chapter 14 Emergency Movement, The SFPE Handbook of Fire 

Protection Engineering, Third Edition, National Fire Protection Association, Quincy, MA. 

21Nelson, H.E. and MacLennan, H.A. (1995), Section 3, Chapter 14 Emergency Movement, The SFPE Handbook of Fire 

Protection Engineering, Second Edition, National Fire Protection Association, Quincy, MA. 

22Caporale, R.S., Elevate Traffic Analysis Software (Eliminating the Guesswork), ELEVATE website: http://www.petersresearch.com/elevators/Elevate/Papers/EW%20review/engin.pdf

23Verbal/Email communication: Roger Howkins, ELEVATE; Richard Peters, Peters Research, UK. August 2002. 

24Siikonen, M.-L., Susi, T., and Hakonen, H. (2001) Passenger Traffic Flow Simulation in Tall Buildings, Elevator World, Inc., 

August 2001. 

25Email communication: Marja-Liisa Siikonen, Kone Elevators, Finland. August, November 2002. 

26Bryan, J.L. (1977), Smoke as a Determinant of Human Behavior in Fire Situations (Project People). Final Report, University 

of Maryland, College Park, MD, National Bureau of Standards, Gaithersburg, MD, NBS GCR 77-94; 304 p. June 30, 1977. 

27Wood, P.G. (1980), Chapter 6 A Survey of Behaviour in Fires, Fires and Human Behaviour, Canter (ed.), John Wiley & 

Sons, Ltd., New York. 

28Quarantelli, E.L. (1975), Panic Behavior in Fire Situations: Findings and a Model From the English Language Research 

Literature, Proceedings from the UJNR Panel on Fire Research and Safety, 4th Joint Panel Meeting, February 5-9, 1979, 

Tokyo, Japan, 405-428 pp.

29Jin, T. (1997), Studies on Human Behavior and Tenability in Fire Smoke, Fire Safety Science – Proceedings of the Fifth 

International Symposium, International Association for Fire Safety Science, 3-21 pp. 

30Averill, J.D. (1998), Performance-Based Codes: Economics, Documentation, and Design, National Institute of Standards 

and Technology, Gaithersburg, MD, NIST-GCR-98-752. 
Appendix D

Design of Occupant Egress Systems for Tall Buildings
CIB 2004 5/14/2004

Design of Occupant Egress Systems for Tall Buildings 

CIB2004 Session Number: HTB T1 Occupant Issues 

Authors: 

Erica D. Kuligowski 

Richard W. Bukowski, P.E., FSFPE 

Abstract: 

This paper presents a discussion of the features of protected elevator 

systems that can provide safe and reliable operation both for fire service access 

and for occupant egress during fires. These features include water tolerant 

components, fail-safe power, lobbies on each floor designed as areas of refuge, 

smoke protection, occupant communications, and real time monitoring of the 

elevator position and operating conditions from the fire command center. Egress 

simulations are used to quantify the improvements in efficiency that can be 

realized by incorporating elevators into the access and egress procedures for tall 

buildings. Finally, operational procedures will be discussed for the most 

appropriate use of vertically zoned elevator systems that are found in most tall 

buildings. These procedures would form the basis for the elevator control 

software that needs to be developed for such systems. 

1
CIB 2004 5/14/2004

Design of Occupant Egress Systems for Tall Buildings 

Erica D. Kuligowski & Richard W. Bukowski, P.E., FSFPE*

National Institute of Standards and Technology 

ABSTRACT 

This paper presents a discussion of the features of protected elevator systems that can 

provide safe and reliable operation both for fire service access and for occupant egress during

fires. These features include water tolerant components, fail-safe power, lobbies on each floor 

designed as areas of refuge, smoke protection, occupant communications, and real time 

monitoring of the elevator position and operating conditions from the fire command center. 

Egress simulations are used to quantify the improvements in efficiency that can be realized by

incorporating elevators into the access and egress procedures for tall buildings. Finally, 

operational procedures will be discussed for the most appropriate use of vertically zoned elevator 

systems that are found in most tall buildings. These procedures would form the basis for the 

elevator control software that needs to be developed for such systems. 

INTRODUCTION

The unexpected collapse of the World Trade Center buildings has prompted a reexamination of the way egress systems are designed for tall buildings. Current designs specify a 

certain number, width, and spacing of stairs that depend upon the assumed occupant load and

building use. The egress system at each floor is sized for the number of occupants on that floor, 

reflecting the assumption that tall buildings will be evacuated by partial or phased evacuation 

procedures. In the discussion of the need to design for simultaneous evacuation of tall buildings, 

concerns have been raised about the adequacy of relying solely on stairs to move large numbers 

of people from significant heights. 

These discussions naturally turn to whether the elevators that normally provide vertical 

transportation can be designed to supplement the stairways and provide a safe exit route during 

fires. It is speculated that if future buildings were required to be designed for simultaneous 

evacuation under current egress design practices, there will be a building height beyond which 

the stairs would occupy such a large portion of the floor area that such buildings would be 

impractical. Despite a 30-year policy in the U.S. codes against the use of elevators in fires, many 

experts now feel that elevators can be made safe for occupant egress. Some of the relevant 

research was done in the 1980s by NIST in support of egress elevators in air traffic control 

towers1,2 where the small footprint prohibits the provision of two, remote stairs. NIST is once 

again working with the U.S. codes and standards organizations and the affected industries to 

address any remaining technical issues and to develop performance requirements for elevator 

egress systems. This paper presents a discussion of the features of protected elevator systems 

that can provide safe and reliable operation both for fire service access and for occupant egress 

during fires. 

CURRENT REQUIREMENTS FOR EMERGENCY USE OF ELEVATORS

All U.S. building codes contain a requirement for accessible elevators as a part of the 

means of egress in any building with an accessible floor above the third floor. These 

 

*

 E.D. Kuligowski is a fire protection engineer and R.W. Bukowski is a senior research engineer, Building 

and Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, MD. 

2
CIB 2004 5/14/2004

requirements are all identical, being extracted from the ADA Accessibility Guidelines (ADAAG) 

and mandated under the Americans with Disabilities Act (ADA). 

A recent survey3 by the International Organization for Standardization (ISO) TC178 

Committee identified at least twelve countries that require firefighter lifts in tall buildings (generally 

those exceeding 30 m (98 ft) in height) to provide for fire department access and to support 

operations as well as to evacuate people with disabilities. England has such a requirement 

supported by a British Standard (BS 5588 Part 5)4

 requiring firefighter lifts in buildings exceeding 

18 m (60 ft) in height. Firefighter lifts are also provided in the Petronas Towers, the world’s tallest 

buildings in Kuala Lumpur, Malaysia. 

The NFPA’s Life Safety Code (NFPA 101)5 includes provisions for egress elevators to be 

provided as a secondary means of egress for air traffic control towers where the small footprint 

prohibits two, “remote” stairs. However, these are secure facilities not open to the public and with 

limited numbers of occupants. 

While the above requirements exist for elevators for emergency use by firefighters and 

people with disabilities, there are currently no codes or standards in the world for egress 

elevators for use by general building occupants. Since 1973, ASME A17.1, the Safety Code for 

Elevators and Escalators6

, has contained emergency procedures that take the elevators out of 

service if smoke is detected in any lobby, in the elevator machine room, or hoistway. Under this 

condition the elevators are directed immediately to the ground floor where the doors open and the 

elevators are locked out (called Phase I recall). Subsequently, the responding fire department

can reactivate individual cars under manual control using a special key (called Phase II 

operation). 

Several issues concerning elevator use in emergencies, such as equipment reliability, 

communication, control, human behavior, and operational procedures, need to be addressed

before this mode of vertical transportation can be implemented. 

FEATURES OF PROTECTED ELEVATORS 

Safe and Reliable Equipment7,8

If used in an emergency, an elevator needs to be able to withstand the problems 

associated with heat, smoke, and water from a fire. It is important to address issues of water 

tolerant elevator parts, fail-safe power, enclosed lobbies on all floors, and smoke protection of the 

equipment, hoistway, and lobby. 

Because water can come from many different sources, such as sprinkler systems and fire 

fighting operations, the elevator must be equipped with water tolerant components. Water can

possibly enter in an elevator shaft and short out safety components such as switches that prevent 

the doors from opening unless there is a car present, and even compromise the safety brake. 

Elevators can be designed to operate on the outside of buildings, so it is clear that water-tolerant 

technology is available and used today. 

Another reliability issue is emergency power for the elevators if the main power fails. 

Current codes require at least one elevator that serves every floor to be provided with emergency 

power. If the power and control wiring is installed within the hoistway the elevator would continue 

to operate as long as the hoistway was intact. 

To protect occupants from the fire while awaiting the elevator and provide an area of 

refuge for people with disabilities, enclosed lobbies should be provided on each floor of the 

building. The lobby also protects the hoistway from direct exposure to the fire and smoke that 

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might threaten the elevator car moving past the floor of the fire. These lobbies would require at

least 1 hour fire rated, smoke tight enclosures (assuming a fully-sprinklered building). 

Elevators would be installed in a smokeproof shaft constructed to a 1 hour fire resistance 

and pressurized against smoke infiltration. This would prevent smoke and heat from moving

through the building via the shafts. The elevator lobby would be pressurized to protect it from 

smoke and to minimize pressure differences across the hoistway door that can jam the door 

mechanism.

Emergency communication7,8

Occupants and firefighters can communicate with the Fire Command Station via two 

systems, the emergency phone in the elevator car and a two-way voice communication system

provided in the lobby. This allows the occupants in the lobby to remain informed of the status of 

any impending rescue. Further it allows the fire command personnel to understand the number 

and situation of the occupants on each floor waiting for the elevators. 

Control 

The firefighter manually operating the elevator (Phase II operation) knows little about the 

fire conditions in other parts of the building, especially the conditions in the elevator machine 

room to which the controller is exposed. Using the newly developed fire service interface9,10 it is 

possible to provide real-time monitoring of elevator system status and any conditions that may

threaten its continued safe operation. This interface was developed as a tool for incident 

management that can collect information from its own sensors and other building systems 

(through a common communication protocol such as BACnet) and display the information in a 

format common to all manufacturers’ systems. The interface further supports specific control

functions so that the operator could manually initiate recall if any monitored parameters exceed

the allowable operating envelope. 

Because continuous monitoring of the system is crucial to safe and reliable operation it 

would employ a triple redundant communication pathway. The fire alarm system is currently 

required to incorporate two, redundant communication trunks usually run up the two stairways. 

Either trunk is sufficient for the full system operation and two-way communication to the entire

building. While these trunks are “remote” it is possible that a single event could sever both 

trunks, rendering the portion of the system above the breaks inoperable. By providing a third 

wireless link between the bottom (generally the fire command center) and the top of the system, 

this should maintain full operation of the system if both trunks fail. This would add little cost, high 

reliability, and can be done with current technology. Emergency power could be supplied by 

conductors run up the hoistway, so that power is available as long as the hoistway is intact. 

EGRESS SIMULATIONS

In order to quantify the increase in efficiency of fire department access and egress via 

elevators, two studies were performed. The first involves fire department access to a fire floor in 

a high-rise building. The fire department access times using elevators were compared with 

access times using stairs. The second case study reviews work done at NIST in the early 90s to 

show the benefit of elevators for egress in four GSA buildings11. 

Firefighter Lift Case Study

For this case study, the commercial building used was designed by a Dallas architectural 

firm and stretches 40 stories above ground with 4 parking levels below. A typical floor of the 

building contains approximately 3000 m2

 (32,292 ft2) of floor space, with 500 m2 (5382 ft2) 

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occupied by the core space. The core contains elevators, 2 stairwells, bathrooms, and 

mechanical closets. 

The stairs are located diagonally across the core area from each other, each measuring 

1.2 m (44 in) wide with 26 7/11 steps per flight. The 7/11 terminology refers the height of the riser 

followed by the depth of the tread in inches, meaning that for each step, the riser height is 0.18 m 

(7 in) and the tread width is 0.28 m (11 in). The height of each floor is 4.5 m (15 ft), creating a 

travel distance of 11 m (36 ft) per flight of stairs, including the landing distance. 

The elevators for a commercial building are assumed to have a speed of 5.08 m/s (1000 

ft/min), per Table 10.7 of the Vertical Transportation Handbook12, and average acceleration of 1.5 

m/s2 (5 ft/s2). For this case study, it is also assumed that a crew of 5 firefighters and their 

equipment will be traveling in the elevator and stairs together at one time. There are other 

characteristics that were assumed for the elevators that only affect the outcome of this case study 

in a trivial manner, such as the full car load, type of door, the door inefficiency, and door closing 

time. 

For this case study, the fire originates on the 35th floor. Two groups of five firefighters 

are analyzed in their attempts to reach floor 35. Group 1 traverses 34 flights of stairs from street 

level to floor 35. Group 2 takes the elevators to the 33rd floor and travels the stairs an additional 

2 flights. Hand calculations were made for firefighter travel up the stairs, while hand calculations

and the ELVAC model were used to calculate the one-way elevator travel time from the lobby to 

the 33rd floor. ELVAC is a model used to calculate gross elevator evacuation time from 

buildings, and the hand calculated one-way elevator travel time was used to compare to ELVAC 

results. 

The travel times calculated for both Groups in this case study neglect firefighter response 

time to the building, travel to the elevator or stairs from the building entrance, and time spent on

the floor locating the point of attack, since both need to perform these activities in a fire situation. 

To obtain firefighter travel speeds on stairs and horizontal building components, 

adjustments were made to data already recorded from people movement studies13,14,15

. 

Frantzich’s data show a range of velocities for upstairs movement from (0.5 to 0.75) m/s, Fruin 

gives values of (0.5 to 0.65) m/s and Predtechenskii and Milinskii state a range of (0.33 to 0.92) 

m/s for low density situations. On one hand, these values may be low if studied during 

nonemergency situations, but alternatively, firefighters are typically equipped with heavy gear and 

equipment, on the order of 25 to 45 kg per firefighter, which should be accounted for. 

The primary walking speed used in this case study for firefighter travel up stairs is 0.35 

m/s (adjusted from 0.5 m/s13,14,15 for heavy gear). Another velocity used came from the New York 

Fire Department’s rule of thumb that states firefighters average 60 seconds per floor 

(unobstructed flow), which is not sustainable throughout the ascent of high-rise buildings. 60 

seconds per floor will be used as the conservative ascent time and 0.35 m/s will be used as the 

other extreme. For horizontal building component speed, again the standard value of 1.2 m/s16

was adjusted to a conservative value of 0.8 m/s for gear and heavy equipment. 

The breakdown of the elevator calculations are as follows (multiple values indicate a 

range of travel speeds for that calculation): 

Group 1: 

o The time to traverse 34 flights of stairs = 17 min at 0.35 m/s; 34 min at 60 seconds per 

flight (more conservative) 

Group 2: 

o The one way travel time of the elevator from the lobby to the 33rd floor = 45 s with 5.08 

m/s elevator speed 

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o The horizontal travel time from the elevator to the stairs on the 33rd floor = 30 s at 1.2 

m/s; 45 s at 0.8 m/s (more conservative) 

o The time to traverse two flights of stairs = 60 s at 0.35 m/s; 120 s at 60 seconds per flight 

(more conservative) 

After performing an additional calculation of adding the elevator travel, horizontal travel, 

and stair travel times together for Group 2, the results are as follows: 

!" Group 1: 17 to 34 min 

!" Group 2: 2.5 to 3.5 min 

It may seem obvious that an elevator would give some advantage in speed over stair 

use. But, when other factors, such as heavy gear and equipment and increased elevator 

technology play a role, elevators substantially become a more viable and constructive option. 

The difference between use of stairs (Group 1) and elevators (Group 2) for firefighter ascent 

ranged between (15 and 30) min. This is a large difference in time lost to travel by stair, 

especially when a fire can grow significantly in a matter of minutes. By using elevators as the 

primary means of ascent, Group 2 was able to reach the fire at least 15 min earlier in this case 

study. In 15 min, the environment can be less toxic for the occupants, the fire smaller, and the 

property less damaged. Also, Group 2 would have more energy to exert on fire fighting activities 

on the floor, when compared to Group 1. The limitation associated with the calculations was the 

estimation made in the firefighter movement speed, as shown by the range of results in both

Groups. 

Elevator Evacuation Study 

In the early 90s, four General Services Administration (GSA) buildings were analyzed as

potential applications to incorporate elevator evacuation11. The four selected were chosen to 

gather different building heights, elevator capabilities, and architectural characteristics. 

For each building, evacuation times were calculated for the following conditions: 1) Total 

evacuation of the building by stairs only; 2) Total evacuation of the building by elevators only; and 

3) Total evacuation of the building by various distributions of occupants to stairs and elevators 

(the optimal time value is shown in Table 1). 

For the stair calculations, Klote et al.11 used the people movement methodology laid out 

by Nelson and MacLennan17. For these calculations, people on each floor were assumed to be 

waiting at the door to the stairs as soon as evacuation begins. For the elevator calculations, the 

ELVAC model18 was used which simulates 2-stop elevator trips (movement occurs only between 

the specific floor and the ground floor) until the entire building has been evacuated. Again, for 

these calculations, people were assumed to be waiting at the closest elevator lobbies as soon as 

evacuation began. 

Table 1 shows the characteristics of each building, including the number of floors, the 

number of stairs and elevators used, and the total population of each building. Also, the table 

shows the total evacuation time of the building (minutes) if only stairs were used, the total 

evacuation time if only the elevators were used, and the last column shows the optimal (fastest) 

gross evacuation time when a combination of stairs and elevators are used. Additionally, the 

Hoffman building and the White Flint North Building’s analysis did not use the full capacity of 

elevators available to the building. The Hoffman building used 5 out of the 6 elevators in each 

group and the White Flint building used 4 out of the 6. This was due to the fact that the existing 

elevator lobbies were incapable of holding as many people as would be discharged from all 

elevators simultaneously, and in that case, the evacuation capacity of the elevators is restricted 

by the size of the lobby. 

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Table 1 Summary of GSA buildings and modeling results

Building Floors Stairs/

Elevators 

Total 

Population 

Evac. 

Time by 

Stairs

Evac. 

Time by 

Elevators 

Optimal 

Time by 

Both 

Hoffman 13 2/ 2 groups of 5 3506 14.9 min 24.3 min 11.2 min 

White Flint 18 2/ 1 group of 4 1425 14.3 28.6 12.0 

Jackson 36 2/ 3 rises of 6 3021 23.1 16.5 12.8 

GSA 7 6/ 6 groups of 2 3621 7 17 6.3 

In each of the four buildings analyzed, the optimal time was reached by designing for a 

combination of floors or percentage of the floor dedicated to elevator usage while the other 

portion of the building evacuated by stairs. The use of elevators for evacuation made the largest 

contribution for the tallest building, which was the Jackson Federal building equipped with low, 

mid, and high rise elevators. The elevator designation that provided the optimal result for this 

building was the following: 65 % of occupants from the mid and high rise floors, all occupants 

from floors 11 through 14, and only 3 % on floors 1 through 13. All others in the Jackson building 

used the stairs. Even though the percentage distributions of occupants to stairs or elevators are 

quite detailed and complicated in this example, they are presented in order to show the generality 

that more occupants from the higher floors would use the elevator and more occupants from the 

lower floors would be distributed to the stairs. In an actual evacuation plan, the distribution of 

occupants to certain building components (stairs or elevators) should be more straightforward 

and easy to follow. 

For the single rise elevator systems in the Hoffman, White Flint, and GSA buildings, the 

elevator designation that provided the optimal result was for total elevator evacuation from the 

upper floors of the building and stairs from the lower floors. Overall, it was shown that by using a 

combination of evacuation systems, stairs and elevators, the total evacuation time of the building 

can be reduced by a substantial amount with taller buildings. This study is limited by the 

averaged movement calculations used, and the assumption that all occupants were waiting at the 

stair or elevator lobbies as soon as the evacuation began. Also, another limitation is that 

occupants were not studied using both stairs and elevators during a single evacuation route. 

OPERATIONAL PROCEDURES

Prior research and recent advances can address all of the technology issues identified as 

critical to the safe and reliable operation of elevators during fires. The remaining piece is the 

development of operating procedures for firefighter access, occupant egress, and rescue of the 

disabled that are sensitive to human factors issues and the need for these activities to occur 

simultaneously in tall buildings. Thus, the systems must be designed and used such that they do 

not interfere with all three uses. 

Firefighter Lifts 

Many US fire departments, Phoenix Fire Department for example19, have adopted

operating procedures for fires in tall buildings that incorporate elevator access that are similar to 

those described in a draft CEN/ISO20 standard for firefighter lifts. The primary differences relate 

to the fact that most firefighter lifts are dedicated to this use and thus are immediately available to 

the fire service on their arrival. In the US, firefighters use passenger elevators that are either still 

operating or are waiting at the ground floor in Phase 1 recall. 

The procedure is for the firefighters to use the lift to transport people and equipment to 

the protected lobby 2-3 floors below the fire floor where they stage for their suppression 

operations, as discussed earlier in the firefighter lift case study. The firefighters then move up the 

stairway to the fire floor with a standard length of hose (30 m (98 ft) is common in the US and 60

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m (197 ft) in Europe), which is connected to the standpipe located in the stairs. This is important 

because once charged with water the hose becomes very stiff. The hose is usually looped down 

the stairs and back up so that it can be advanced onto the fire floor more easily. Working from 

the stairway also provides a protected area to which the firefighters can retreat in case the fire 

threatens them. The common hose lengths dictate the distribution of firefighter lifts within a 

building in the same way as the distribution of standpipes. For example, the New York City 

building regulations require standpipes located so that one is within 38 m (125 ft) (30.5 m (100 ft) 

of hose plus 7.6 m (25 ft) of water throw from the nozzle) of any point on a floor. 

This operating procedure highlights the importance and interrelationship of the firefighter

lift, protected lobbies, associated stairway and standpipe. These components form a system 

described in BS55882 as a firefighting shaft. The need for an associated stairway impacts on the 

arrangement of the components and on the designation of multiple cars of an elevator group as 

firefighter lifts. 

Occupant Egress Elevators 

As mentioned earlier, with only rare exceptions for special cases, elevators are taken out 

of service in fires and people are advised not to use elevators during fires. This policy does not 

represent a severe hardship for most buildings and occupants, but poses problems for people

with (mobility) disabilities and for tall buildings where stairway egress times can be measured in 

hours. Coupled with the recent loss of public confidence in the structural stability of tall buildings 

caused by the collapse of the World Trade Center, there are increasing pressures to find ways in 

which elevator assisted egress can be provided safely. 

Operational procedures for occupant egress elevators raise some interesting issues. 

First, the 30-year campaign cautioning the public against the use of elevators in the event of fire 

could severely lessen the occupants’ confidence in the elevator system. Also, occupants could 

become impatient and overcrowd the elevator, which can cause the car to stop functioning and

remain at the floor indefinitely21. Due to a fundamental lack of understanding of human use of 

elevators in emergencies, the time for which occupants will wait at an elevator is also unknown. 

Without proper preparation and training, occupants may become fearful of the dangerous 

conditions and decide to use the stairs. If the building is designed for a certain distribution of

occupants between stairs and elevators, this could cause congestion in the stairway. It seems 

natural to suggest that fire wardens, who understand the capabilities of elevators in such 

emergencies, will lead the occupants to safety by following the planned evacuation procedure for 

their floor. The evacuation plan of a single rise elevator system could involve, for example, the 

use of elevator by the higher floors of the building, stairs by the lower floors, and the fire wardens 

on each floor directing his/her occupants to the correct evacuation route11. However, this implies

that the fire wardens are present at the time of the emergency, have the appropriate training, and 

that the other occupants will follow their directions. Another concern for the evacuation 

procedures is whether or not the elevators attend to the disabled population first before 

evacuating other building occupants. This is crucial to understand because if a disabled 

occupant resides on a floor designated to take the stairs, the building should be aware of the 

occupant’s needs and plan accordingly. Overall, it will be essential to understand the human 

behavior of the occupants during their interaction with the elevators. Work has been done in the 

human factors engineering and psychology fields about such a concern22,23,24, but much more 

work still needs to be completed to update current elevator use and concerns in light of 

September 11, 2001. For instance, will social groups within the building stay together throughout 

the duration of the evacuation, or will they allow group break-up during elevator descent? This is 

crucial because of the possibility of sending elevators without full capacity to the ground floor. 

Egress elevators are most likely to be utilized in tall buildings, some with systems that are 

vertically zoned in 30- to 40-floor sections. A concern for these tall buildings is how elevator 

evacuation would be operated with vertically zoned elevators. One example where this is being

done is for an 88-story building currently under construction in Melbourne, Australia25. In the 

8
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Eureka Place Tower, elevators in the vertical third of the building containing the fire are taken out 

of service and occupants all use the stairways to the next (lower) transfer floor where they board 

express elevators to grade. People with disabilities are assisted by firefighters in their dedicated 

lifts within the zone of origin in order to evacuate the building. This strategy is similar to the 

Petronas Towers where occupants above the sky bridge level use stairs to that level, move 

across to the other tower, and use the elevators to grade. 

Egress Assistance for People with Disabilities26

Standards for firefighter lifts all include their use by firefighters to provide evacuation 

assistance for people with disabilities. Even in the US where there are no firefighter lift standards 

the building codes require accessible elevators (part of an accessible means of egress) that may 

be used by the fire service to evacuate people with disabilities. These elevators are normally 

used for travel in nonemergency situations, but may be used by the fire service for disabled 

occupant egress if an emergency occurs. The procedures generally are that such occupants 

proceed to the protected lobby (sometimes called an area of refuge) and request evacuation

assistance through a two-way communication system (to the fire command center) provided. 

Exceptions are provided for fully sprinklered buildings. 

Not covered is any procedure for coordinating the use of the lift for evacuation assistance 

with that of firefighting. First priority will be given to moving firefighters and equipment to the 

staging floor to allow the start of suppression operations. Then a firefighter would presumably be 

assigned to begin to collect waiting occupants in the lift under manual control. Command staff in 

the fire command center could inform the operator on which floors there are occupants waiting 

and these could be gathered in some logical order and taken to the ground floor. If there are 

more occupants than can be assisted in a single trip, there is a question about the order in which 

they are removed. Presumably, this would be done for the floors nearest the fire first, then above 

the fire and finally below the fire. Because these people are required to wait, it is especially 

important to provide this two-way communication system to the lobby so that they can be 

reassured that assistance is coming. The real-time monitoring system described earlier would

assure that conditions in the occupied lobbies remain tenable. 

CONCLUSION 

Elevator use in emergency situations can provide safe and reliable operation both for fire 

service access and for occupant egress. A combination of reliable features, appropriate 

equipment, and effective operational procedures allows for successful evacuation of buildings via 

elevators and stairwells. 

During a fire situation, the elevator needs to be able to withstand the effects of smoke, 

heat, and water. The current elevator technology can successfully perform this duty with the 

inclusion of water tolerant elevator parts, fail-safe power, lobbies of all floors, and smoke 

protection of the equipment, shaft, and lobby. Also, to aid in the use of elevators for fire 

department access and occupant egress, the use of emergency communication and remote

manual control accompanied by continuous monitoring of the fire situation add another level of

safety to elevator use. The Fire Command Station is continuously made aware of the increasing 

danger to occupants and the firefighters, and can change their evacuation, rescue, and 

firefighting strategies accordingly. 

Elevators can make a significant time saving contribution to travel towards the fire for the 

fire service and the evacuation of the occupants in the building. The calculations done for the 

firefighter case study showed that firefighters traveled to the fire floor 15 min to 30 min faster via 

elevators when compared to stair access. The stair travel calculation, using two different 

estimates for the firefighter walking speeds, resulted in a range of travel time values differing by a 

factor of two. Research is needed in the area of firefighter movement to assess which travel 

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times within the calculated range 17 min to 34 min are more accurate. Also, the evacuation time 

of occupants using a combination of stair calculations and ELVAC calculations for the elevators 

shows improvement over stair or elevator movement alone for the GSA examples studied. This

is especially true for the taller building with multi-rise elevators. 

Lastly, operational procedures are crucial in ensuring quick movement to safety for all 

occupants and emergency responders in the building. It is key for the occupants to recognize 

their main mode of travel (elevator or stairs) and understand the wait times associated. As part of 

this, other occupants may have priority, such as the disabled. 

With all elements in place, safe and reliable features, operational procedures, and 

comfort in using elevators by occupants and firefighters, the use of elevators can provide a faster 

and safer route for evacuating a high-rise building. 

REFERENCES 

1

Klote, J.H, Levin, B.M., and Groner, N.E., “Feasibility of Fire Evacuation by Elevators at FAA 

Control Towers,” NISTIR 5445; 110 p. May 1994.

2

Levin, B. M.; Groner, N. E., “Human Factors Considerations for the Potential Use of Elevators for 

Fire Evacuation of FAA Air Traffic Control Towers,” NIST GCR 94-656; 23 p. August 1994. 

3

Comparison of worldwide lift (elevator) safety standards – Firefighters lifts (elevators), ISO/TR 

16765:2002(E), International Organization for Standardization, Geneva, Switzerland, 2002 

4

Fire Precautions in the Design, Construction, and Use of Buildings, BS 5588 Part 5 1991, Code 

of Practice for Firefighting Lifts and Stairs, BSI, London 

5

Life Safety Code (NFPA 101) 2000, Nat Fire Prot Assn, Quincy, MA 02269 

6

Safety Code for Elevators and Escalators, ASME A17.1-2000, Amer Soc Mech Eng, NY, 2000 

7

Klote, J.H., Levin, B.M., and Groner, N.E., “Emergency Elevator Evacuation Systems,” Fire and 

Accessibility, 2nd Symposium, Proceedings, April 19,21, 1995, American Society of Mechanical

Engineers, New York, NY, 131-150 pp., 1995. 

8

 Chapman, E.F., “Elevator Design for the 21st Century: Design Criteria for Elevators When Used 

as the Primary Means of Evacuation During Fire Emergencies. American Society of Mechanical 

Engineers (ASME); Elevators, Fire and Accessibility, 2nd Symposium, Proceedings, April 19-21, 

1995, New York, NY, 157-162 pp., 1995.

9

Bukowski, R. W. Development of a Standardized Fire Service Interface for Fire Alarm Systems. 

National Institute of Standards and Technology, Gaithersburg, MD Fire Protection Engineering, 

4,6-8, SFPE Bethesda, MD, Spring 2000. 

10National Fire Alarm Code (NFPA 72) 2002, Nat Fire Prot Assn, Quincy, MA 02269, “Section

7.10 “Standard Fire Service Interface.” 

11Klote, J.H., Alvord, D.M., Levin, B.M., and Groner, N.E. (1992), Feasibility and Design 

Considerations of Emergency Evacuation by Elevators, National Institute of Standards and 

Technology, Gaithersburg, MD, NISTIR 4870. 

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12Strakosch, G.R. (1998), The Vertical Transportation Handbook Third Edition, John Wiley & 

Sons, Inc., New York, USA. 

13Frantzich, H. (1996), Study of Movement on Stairs During Evacuation Using Video Analysis

Techniques, Department of Fire Safety Engineering, Lund Institute of Technology, Lund 

University, March 1996. 

14Fruin, J.J. (1987), Pedestrian Planning and Design, Revised Edition, Elevator World, Inc. 

Mobile, Alabama. 

15Predtechenskii, V.M. and Milinskii, A.I. (1978), Planning for Foot Traffic Flow in Buildings, 

Amerind Publishing Co. Pvt. Ltd., New Delhi, 1978. 

16Nelson, H.E. and Mowrer, F.W. (2002), Section 3, Chapter 14 Emergency Movement, The 

SFPE Handbook of Fire Protection Engineering, Third Edition, National Fire Protection 

Association, Quincy, MA.

17Nelson, H.E. and MacLennan, H.A. (1995), Section 3, Chapter 14 Emergency Movement, The 

SFPE Handbook of Fire Protection Engineering, Second Edition, National Fire Protection

Association, Quincy, MA.

18Klote, J.H. (1993), A Method of Calculation of Elevator Evacuation Time, National Institute of

Standards and Technology, Gaithersburg, MD, Journal of Fire Protection Engineering, 5(3), 1993, 

pp. 83-95. 

19Phoenix Fire Department Standard Operating Procedures, http://phoenix.gov/FIRE/20205.html. 

20Safety rules for the construction and installation of lifts – Part 72:Firefighter lifts, CEN TC10, 

Committee for European Standardization, Brussels, BE. 

21Klote, J.H., Deal, S.P., Donoghue, E.A., Levin, B.M., and Groner, N.E. (1993), Fire Evacuation

By Elevators, Elevator World, June 1993. 

22Levin, B.M, and Groner, N.E. (1995), Some Control and Communication Considerations in 

Designing an Emergency Elevator Evacuation System, Proceedings of the 2nd Symposium on 

Elevators, Fire, and Accessibility, Baltimore, MD, April, 1995. 

23Groner, N.E. (1995), Selecting Strategies for Elevator Evacuations, Proceedings of the 2nd

Symposium on Elevators, Fire, and Accessibility, Baltimore, MD, April, 1995. 

24Groner, N.E. and Levin, B.M. (1992), Human Factors Considerations in the Potential for Using

Elevators in Building Emergency Evacuation Plans, George Mason University, Washington, DC, 

July 1992. 

25Aloi, S. and Rogers, J. (2002), Reach for the Sky, Fire Prevention & Fire Engineers Journal, 

Vol. 62, No. 219, FPA London, April 2002. 

26FEMA & USFA, “Emergency Procedures for Employees with Disabilities in Office Occupancies,” 

United States Fire Administration, Emmitsburg, Maryland, National Institute of Standards and 

Technology, Gaithersburg, MD, National Task Force on

Life Safety and People with Disabilities, YR. 

11
Appendix E

Hazards Due To Smoke Migration Through Elevator 

Shafts -Volume I: Analysis And Discussion
Hazards Due to Smoke Migration 

Through Elevator Shafts – Volume I: 

Analysis and Discussion. Final Report

John H. Klote

John H. Klote, Inc.

43262 Meadowood Court

Leesburg, VA 20176

NIST GCR 04-864-I

NIST GCR 04-864-I

Hazards Due to Smoke Migration 

Through Elevator Shafts – Volume I: 

Analysis and Discussion. Final Report

Prepared for

U.S. Department of Commerce

Building and Fire Research Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899-8664

By

John H. Klote

John H. Klote, Inc.

43262 Meadowood Court

Leesburg, VA 20176

June 2004

U.S. Department of Commerce

Donald L. Evans, Secretary

Technology Administration

Phillip J. Bond, Under Secretary for Technology

National Institute of Standards and Technology

Arden L. Bement, Jr., Director
Notice

This report was prepared for the Building and Fire Research Laboratory 

of the National Institute of Standards and Technology under Contract number 

SB134-03-W-0477. The statement and conclusions contained in this report 

are those of the authors and do not necessarily reflect the views of the 

National Institute of Standards and Technology or the Building and Fire 

Research Laboratory. 

 ii 

ii 

Table of Contents 

Abstract........................................................................................................................................... 1 

1. Introduction................................................................................................................................. 1 

2. Scenarios..................................................................................................................................... 2 

3. Buildings..................................................................................................................................... 2 

3.1 Fire Type............................................................................................................................... 2 

3.2 Fire Floors............................................................................................................................. 3 

3.3 Building Flow Paths.............................................................................................................. 3 

3.4 Weather................................................................................................................................. 3 

3.5 Building Temperature ........................................................................................................... 3 

3.6 Methods for Reduction of Hoistway Smoke Flow ............................................................... 4 

3.6.1 Enclosed Elevator Lobbies ............................................................................................ 4 

3.6.2 Temporary Barriers........................................................................................................ 4 

3.6.3 Positioning Of Elevator Cars ......................................................................................... 4 

3.7 Arrangement of Doors .......................................................................................................... 4 

3.8 Windows ............................................................................................................................... 4 

4. Analysis of Scenarios.................................................................................................................. 4 

4.1 Smoke Transport................................................................................................................... 5 

4.3 People Movement ................................................................................................................. 5 

4.4 Tenability .............................................................................................................................. 5 

4.4.1 Visibility ........................................................................................................................ 5 

4.4.2 Exposure to Toxic Gases ............................................................................................... 6 

4.4.3 Exposure to Heat............................................................................................................ 7 

5. Discussion of Results.................................................................................................................. 7 

5.1 Fire Types ............................................................................................................................. 7 

5.2 Temperature .......................................................................................................................... 7 

5.3 Methods of Reducing Smoke Flow through Hoistways ....................................................... 7 

5.3.1 Enclosed Elevator Lobbies ............................................................................................ 7 

5.3.2 Automatic Roll Down Barriers ...................................................................................... 8 

5.3.3 Positioning Of Elevator Cars ......................................................................................... 8 

5.4 Outside Temperature............................................................................................................. 8 

6. Future Research .......................................................................................................................... 8 

7. Summary & Conclusions ............................................................................................................ 9 

8. References................................................................................................................................... 9 

Appendix A – Fires....................................................................................................................... 22 

Appendix B – Fuel Properties....................................................................................................... 28 

Appendix C – Wind ...................................................................................................................... 30 
iii 

List of Figures 

Figure 1. Typical Floor Plan of Building A.................................................................................. 15 

Figure 2. Typical Floor Plan of Buildings B and C ...................................................................... 15 

Figure 3. Elevator Layout for Building D..................................................................................... 16

Figure 4. Ground Floor Plan of Building D.................................................................................. 17 

Figure 5. Elevator Layout for Building E ..................................................................................... 18

Figure 6. Ground Floor Plan of Building E .................................................................................. 19 

Figure 7. HRR Curves of Fires Used in This Project ................................................................... 20 

Figure 8. Thermal Tolerance of Naked Humans at Rest With Low Air Movement..................... 21 

List of Tables 

Table 1. List of Scenarios ............................................................................................................ 12 

Table 2. List of Buildings ............................................................................................................ 12 

Table 3. Building Flow Areas...................................................................................................... 13 

Table 4. Calculated Time (minutes) to Reach Tenability Specific Limits .................................. 14 
1 

Hazards Due To Smoke Migration Through Elevator 

Shafts – Volume I: Analysis 

Abstract 

During building fires, smoke often migrates through elevator hoistways to locations remote from the fire. 

One of the reasons for concern is that a closed elevator door has a leakage area of approximately 0.056 

square meters (0.6 square feet). This is a report of a project to study the hazards due to smoke flow 

through elevator hoistways. Smoke flow and the resulting hazard to life are analyzed for 27 scenarios in 5 

buildings ranging from 6 to 58 stories. A fire scenario is the outline of events and conditions that are 

critical to determining the outcome of alternate situations and designs. In addition to the fire location and 

heat release rate, the fire scenario includes the status of the doors and other building systems. Other 

factors addressed are outside temperature, wind, height of elevator hoistway, height of building, leakage 

paths in the building, leakage of elevator doors, and other shafts. Stairwells are also included. Both 

sprinklered and non-sprinklered fires are included. Smoke transport throughout the buildings was 

simulated by a combination of zone fire modeling and network modeling. Options considered for 

mitigating hazards due to smoke flow through hoistways include (1) the use of enclosed elevator lobbies 

with automatic closing doors, (2) temporary barriers and (3) judicious positioning of cars within the 

hoistway. The results of the calculations showed that the use of enclosed elevator lobbies increased the 

time to reach hazard criteria significantly as compared the results without such lobbies. The use of 

automatic roll down barriers tended to increase the time to reach hazard criteria to some extent. The use 

of judicious positioning of elevator cars had no effect on the time to reach hazard criteria. 

1. Introduction 

During a building fire, smoke can travel through building shafts to threaten life at locations remote from 

the fire. The focus of this project is smoke movement through elevator shafts, and methods that might be 

used to reduce the resulting hazard to life. 

After September 11, 2001, many people have indicated a need to reexamine basic concepts and consider 

major failure modes. While less extreme fires are also considered in this project, the focus is on the 

effects of a unsprinklered fire that involves an entire floor of a building. These large unsprinklered fires 

can have durations measured in hours. Because almost all modern buildings are sprinklered, this 

unsprinklered fire is a failure mode that could be due to a variety of causes (inadequate or no water 

supply, failure of a sprinkler system component, fire overpowering the sprinklers, arson, and terrorism). 

In the absence of comprehensive sprinkler performance data for the United States, a sprinkler failure rate 

between 1% and 4% may be considered1

. 

This project looks at the hazard to life due to smoke migration through elevator hoistways and the 

effectiveness of methods to reduce that hazard. These methods are: (1) enclosed elevator lobbies, (2) 

temporary barriers directly in front of elevator doors and (3) judicious positioning of elevator cars. Some 

of the parameters considered for this project are fire size, fire location, outside temperature and wind. 

 

1 Hasemi (1985) indicates sprinkler success rates in Japan of 98% for well maintained systems and 96% for poorly maintained 

systems. For Australia and New Zealand, Marryatt (1988) indicates a sprinkler success rate of 99% or greater for most 

occupancies. 
2 

The time scale for large building fires often consists of a number of hours (Routley, Jennings and Chubb, 

1991; Nelson, 1987, 1989; Best and Demers, 1982). Accordingly, the duration of the simulations for this 

project are two hours. 

This report of this project is in two volumes. The first volume presents the analysis and discusses the 

results of that analysis. The second volume (Klote, 2003) consists of the complete results of the tenability 

calculations. The calculations of this project are for office buildings, but they may have application to 

other occupancies. 

2. Scenarios 

It is not possible to analyze all the scenarios of the relevant parameters, and a rational analysis is used for 

selection of scenarios. This rational approach is based on an understanding of how stack effect, buoyancy 

and wind effect force smoke flow in buildings. 

1. When it is cold outside, stack effect (also called normal stack effect) results in upward airflow in 

building shafts. When a fire is below the neutral plane, normal stack effect can also drive smoke 

upward through shafts to floors above the neutral plane. 

2. When it is hot outside, reverse stack effect results in downward airflow in shafts. For a fire above the 

neutral plane, reverse stack effect might result in downward smoke flow in shafts. 

3. When hot smoke enters a shaft, the elevated temperature of the smoke increases the intensity of 

normal stack effect. 

4. When hot smoke enters a shaft, the elevated temperature of the smoke decreases the intensity of 

reverse stack effect. 

5. When all the building windows are closed, wind forces have a minimum effect on building smoke 

flow. 

6. When the one or more fire room windows are open and the wind direction is toward the open 

windows, wind forces have a significant effect on building smoke flow. 

The points above were kept in mind in development of the scenario list of Table 1. 

3. Buildings 

The buildings have a number of things in common. All of the buildings are office buildings. The floor to 

floor height is 4.0 m (13.1 ft) except for the ground floor which is 6 m (19.7 ft). The buildings have 

basements that house mechanical equipment. See Table 2 for a list of the buildings with information 

about the elevators. Figures 1 to 6 are schematics of the buildings. 

3.1 Fire Type 

This project used the following fires: (1) sprinklered fire, (2) room fire, and (3) floor fire. Details of these 

fires are provided in Appendix A, and the heat release rates (HRR) of these fires are shown in Figure 7. 

The sprinklered fire is representative of what might be expected of an office workstation fire that was 

successfully suppressed by a sprinkler system. The room fire can be thought of as a conference room with 

furniture and some storage materials in cardboard boxes. After ignition, the room fire grows until the 

room is fully involved in fire. 

The floor fire can be thought of as starting in an open floor plan office space. Early in the fire 

development, windows start breaking. After this, the fire is considered to be controlled by the amount of 

ventilation air through the broken windows. On an occupied floor, it might be expected that the occupants 
3 

would take action to prevent the fire from becoming so big. For any number of reasons, a floor might not 

be occupied during a fire, and development of such a fire becomes more likely. 

3.2 Fire Floors 

The fire locations for this project are on the second floor and the top occupied floor of the building. These 

fire locations were chosen to be above the neutral plane and below the neutral plane to allow for the 

effects of normal and reverse stack effect. 

3.3 Building Flow Paths 

Building leakage consists of: (1) construction gaps and cracks in walls, partitions and floors, (2) gaps 

around closed doors, and (3) large openings such as open doors and windows. The values of flow paths 

used for this project are listed in Table 3. 

The leakage values of walls and floors are representative of values that can be expected for tight building 

construction as discussed by Klote and Milke (2002) and NFPA 92A (2000). It is generally recognized 

that the vent at the top of elevator shafts has an impact on airflow and smoke flow in buildings. 

Traditionally, these elevator vents have been required by codes, and the value of the vents used in this 

project are listed in Table 3. 

The effects of door deflection due to exposure to high temperature gases are not included in the leakage 

values. While some data on warping of fire doors during furnace tests is provided by VanGeyn (1994), it 

is believed that there is insufficient information for estimation of the leakage of warped doors in this 

project. 

Failure of compartmentation would require complex and time consuming analysis that is beyond the 

scope of this project. Such failure would be expected at some locations in buildings subjected to a fully 

developed fire that involved a large space such as one or more floors. It is anticipated that such 

compartmentation failure would result in increases in hazard to life. Even without compartmentation 

failure, the analysis of this project provides limited information about the hazard at locations remote from 

the fire and provides information about the relative effectiveness of various methods to reduce hazards 

due to smoke flow through hoistways. 

3.4 Weather 

The temperatures and wind velocities for many locations in the United States and other countries are 

listed in the ASHRAE Handbook of Fundamentals (ASHRAE 2001). The values of design temperature 

and wind speed vary over a wide range for these locations. The values of weather data chosen for this 

project were chosen such that they could occur at many locations in the United States. These values are: 

Winter Outdoor Temperature –16!C (3!F) 

Summer Outdoor Temperature 35!C (95!F) 

Wind Speed 11 m/s (25 mph) 

3.5 Building Temperature 

Generally, an HVAC system maintains the interior of a building in the range of about 21!C to 24!C (70!F 

to 76!F). For airflow and smoke flow in buildings, an important factor is the difference between the 

building temperature and that of the outdoors. For this project, the building temperature is the same as 

that of the shafts, and this building temperature is arbitrarily selected as 23!C (73!F ). 
4 

3.6 Methods for Reduction of Hoistway Smoke Flow 

The following potential methods to reduce the smoke flow through hoistways are considered. 

3.6.1 Enclosed Elevator Lobbies 

Enclosed elevator lobbies consist of walls, doors, floors and ceilings that form a continuous barrier on all 

sides of an elevator lobby. It is the intent that the doors would automatically close in the event of a fire. 

3.6.2 Temporary Barriers 

Two types of temporary barriers can be considered: (1) automatic accordion barriers that form an 

enclosed elevator lobby and (2) automatic roll down barriers located directly in front of the elevator 

doors. For this project, it is considered that the accordion barriers have a fire resistance such that they 

would be expected to remain in place for some time when exposed to a fully developed fire. For this 

reason, the results of the simulations with conventional enclosed lobbies can be thought of as indicative of 

what would happen with enclosed lobbies formed with automatic accordion barriers. 

The automatic roll down barriers would be installed above each elevator door such that they would roll 

down in the event of a fire. It is anticipated that such doors would be activated along with elevator recall. 

For this project, it is considered that the roll down barriers have a fire resistance such that they would be 

expected to remain in place when exposed to a fully developed fire. 

The roll down doors of this project should be thought of as products that could possibly be developed and 

not as commercially available products. The flow area around the roll down doors (Table 3) used for this 

project was based on engineering judgment of what the leakage could be for such a door in an existing 

building. 

3.6.3 Positioning Of Elevator Cars 

The idea of judicious positioning of elevator cars is to locate the elevator cars in the hoistway at a floor 

above the fire floor to provide added resistance to smoke flow to floors above the elevator cars. This 

approach has the drawback that cars fixed in this position cannot be used mobilization or rescue by the 

fire service. However, this project addresses only the smoke restricting potential of the judicious 

positioning approach. When the judicious positioning approach is used, it is considered that all elevator 

cars will be at the floor above the fire floor. The leakage areas for judicious positioning of elevator cars 

(Table 3, Shafts with Cars in Place) are based on hoistway and other dimensions from NEII (1983). 

3.7 Arrangement of Doors 

For this project, it is considered that the stairwell doors and exterior building doors are closed. 

3.8 Windows 

For this project, the windows are considered closed except for fully developed floor fire where the fire 

breaks widows as discussed in Appendix A. 

4. Analysis of Scenarios 

The method of analysis can be considered a hazard analysis that evaluates the hazard to life for each 

scenario. Generally hazard analysis consists of (1) smoke transport calculations, (2) people movement 

(fire evacuation) calculations and (3) tenability calculations. For reasons discussed below, the analyses of 

this project do not include people movement calculations. 
5 

4.1 Smoke Transport 

The method of analysis of this project has been used for a number of applications. Ferreira (1998, 2002) 

describes use of this method for design applications, and Hadjisophocleous, Fu and Lougheed (2002) use 

this method as part of a study of smoke flow in a stair shaft. Klote (2002a) used the method to evaluate 

the hazard due to various combinations of open stairwell doors. Klote (2002b) and Klote and Milke 

(2002) also provide information about use of this method. 

The smoke transport calculations were done by a combination of CONTAMW (Walton 1997; Dols, 

Denton and Walton 2000) and CFAST (Peacock, et al. 1993). The approach is to use CFAST to simulate 

the fire and flow of combustion products to adjacent spaces, and to use CONTAMW for unsteady flow of 

combustion products throughout the building. Numeric realities limit CFAST simulations to a relatively 

small number of rooms. However, CONTAMW can be used to simulate flows in buildings of hundreds 

and possibly thousands of rooms and other spaces. 

CONTAMW is a network airflow program that can simulate contaminant flow. The model was developed 

for indoor air quality, but it has been extensively used for smoke management applications. CONTAMW 

solves the continuity of mass equation for a network that represents a building, and it can solve the 

concentration equations to calculate the concentration of one or more contaminants that flow through the 

network. For fire applications, the major shortcoming of CONTAMW is that it has no energy equation so 

it is unable to calculate the temperature of the spaces in the building. The temperature used in 

CONTAMW simulations are based on the results of CFAST simulations for spaces near the fire. 

CONTAMW Version 2 was used to allow the use of unsteady temperatures. 

CFAST is a two zone fire model. In such a model, the gases in a room are represented two zones: (1) an 

upper layer of hot smoke and (2) a lower layer of relatively uncontaminated air. In the fire room, a smoke 

plume rises above the fire and flows into the upper layer. Also, smoke can flow from one room to another. 

4.3 People Movement 

The hazard of exposure to toxic gases depends on the exposure time. Fire evacuation calculations or 

simulations of people movement can be used to predict exposure times. A more conservative alternative 

is to consider the safety of people with mobility limitations who would need to stay in one place for the 

duration of the fire. For this project, this alternative is used with a 30 minute fire duration. 

4.4 Tenability 

The proprietary computer program, SMOKE4, was used for this project to make the fractional effective 

dose (FED) and visibility calculations described in this section. The FED is a used to predict the toxic 

effect of exposure to combustion gases. Tenability calculations consist of evaluating visibility and the 

effects of exposure to toxic gases and heat. While lack of visibility does not in itself result in fatality, it 

disorients people, and this interferes with evacuation and prolongs exposure time. Exposure to heat can 

either be direct exposure to hot gases or exposure to radiant flux, but exposure to hot gases is the primary 

form of heat exposure for the scenarios of this project. 

4.4.1 Visibility 

For any instant, the visibility can be calculated from 

2.303 i

m i

K S

! C "

where 

Si = visibility at the end of interval i, m (ft); 

K = proportionality constant (8 for illuminated signs, and 2 for non-illuminated signs); 
6 

!m = mass optical density, m2

/g (ft2/lb); 

Ci = concentration of material burned in interval i, g/m3

 (lb/ft3). 

The mass optical density depends on the material burned and combustion conditions (flaming or 

pyrolysis). Mulholland (2002) provides optical densities of a number of materials, and these values range 

from 0.12 m2

/g (590 ft2/lb) to 1.4 m2/g (6800 ft2/lb). It is well known that flaming combustion of 

polyurethane produces a dense black smoke, and this smoke has a mass optical density of 0.33 m2/g (1600 

ft2

/lb). For this project, the mass optical density was chosen as 0.33 m2/g (1600 ft2/lb). 

For this project, the following visibility limits were considered: (1) 8 m (25 ft), (2) 15 m (49 ft), and (3) 

30 m (98 ft). A visibility of 15m (49 ft) or of 30 m (98 ft) would not be expected to interfere with people 

movement in the buildings of this project, but people would probably be aware that there is some smoke. 

However, it is expected that a visibility of 8 m (25 ft) or less would hinder evacuation. For this paper, 

smoke with a visibility of 8 m (25 ft) or less is referred to as obscuring smoke or smoke that obscures

vision. 

4.4.2 Exposure to Toxic Gases 

The methods that can be used to evaluate the effect of exposure to toxic gases are (1) the fractional 

incapacitating dose, (2) the N-gas model, and (3) the fractional effective dose (FED). Klote and Milke 

(2002) provide a detailed discussion of these methods. These methods are typically based on data from 

exposure times of 20 minutes, and they can be used be used to predict the toxic effects of exposures for 

somewhat different times. The exposure times of this project are 2 hours. The mathematical formulation 

of the first two methods is such that the predictions with this exposure time are of questionable value. 

However, the FED has a simple form that leads the author to believe that predictions using the FED for 

this exposure time can be applied for this project. 

The mass concentration of material burned, Ci, was obtained from CONTAMW. The FED can be used to 

obtain an approximation of the effects of exposure to toxic gases. 

1

50

FED = 

LC

n

i

i

C t

t

"

$ #

where 

FED = fractional effective dose at the end of interval i (dimensionless); 

Ci = concentration of material burned at interval i, g/m3

 (lb/ft3); 

#t = time interval, min (min); 

LCt50 = lethal exposure dose from test data, g m-3 min (lb ft-3 min). 

This equation is written here for uniform time intervals as were produced by CONTAMW, and it 

evaluates the FED for the exposure time at the end of interval i (exposure time is n#t). An FED greater 

than or equal to one indicates fatality. The concentration is in mass of the material burned per unit 

volume. A FED of 0.5 can be considered a rough indication of incapacitation. For this project, the 

following terms are used as follows: 

Tenable: FED < 0.5 FED less than 0.5. 

Incapacitating: 0.5 < FED < 1 FED equal to or greater than 0.5 and less than 1. 

Untenable: FED > 1 FED equal to or greater than 1. 

The LC50 is the concentration of airborne combustion products that is lethal to 50% of the subjects 

exposed for a specified time. The lethal exposure dose, LCt50, is the product of the LC50 and the exposure 

time. See Appendix B for the values of lethal exposure dose used in this project. 
7 

4.4.3 Exposure to Heat 

Generally contact with dry air of temperatures greater than 121!C (250!F) can be expected to result in skin 

burns. Also, contact with dry air at a temperature less than approximately 121!C (250!F) leads to 

hyperthermia. Figure 8 shows the data of Blockley (1973) for the thermal tolerance of naked humans at rest 

with low air movement. The thermal tolerance depends on moisture. For humid conditions, it can be seen 

that for a 15 minute exposure the tolerance is about 88!C (190!F), and for a 30 minute exposure the 

tolerance is about 60!C (140!F). 

5. Discussion of Results 

The results of the tenability calculations are listed in Volume II of this report, and these results are 

summarized in Table 4. 

5.1 Fire Types 

As expected, the sprinklered fire (scenario 1) did not result in any significant threat away from region of 

the fire. The fully developed room fires (scenarios 2, 18–21) were not a very significant threat at locations 

remote from the fire room. 

The fully developed floor fires (scenarios 3–17, 22–27) resulted in significant threats at floors remote 

from the fire floor. For these fires, the time to reach smoke obscuration on floors remote from the fire 

ranged from 24 minutes to 100 minutes. While these times are long, they are representative of the times 

involved with some major multiple death fires. 

5.2 Temperature 

The temperatures calculated by CFAST are shown in Appendix A. At some distance from the fire, the 

smoke temperature drops to such an extent that it is not a concern. Because this project focuses on smoke 

flow through the hoistways, temperature exposure is only a minor issue. Further, the temperatures 

resulting from the sprinklered fire are not a concern. For the room fire, the fire room rapidly becomes 

untenable (Figure A1), and the open plan office space on the fire floor remains tenable for some time 

(Figure A2). For the floor fire, the temperature rises rapidly so that the floor quickly becomes untenable 

(Figure A3). However, the temperature in the enclosed elevator lobby remains tenable throughout the fire 

(Figure A5). 

5.3 Methods of Reducing Smoke Flow through Hoistways 

5.3.1 Enclosed Elevator Lobbies 

Many of the scenarios included enclosed elevator lobbies (EEL on Table 1). The use of such lobbies, 

extends the time to obscuring smoke and untenable conditions on floors away from the fire. This can be 

shown in a number of scenarios. For example, scenarios 9 and 10 are the same except that scenario 9 has 

enclosed elevator lobbies, and scenario 10 does not (Table 4). It can be seen that with enclosed elevator 

lobbies, the time to obscuring smoke on the top floor increases from 31 to 66 minutes. Further, without 

enclosed elevator lobbies, the top floor becomes untenable in 56 minutes, and with elevator lobbies it 

does not become untenable during the 120 minute simulation. 

For the scenarios with floor fires, the pairs of scenarios listed below are with and without enclosed 

elevator lobbies. It can be seen that with enclosed elevator lobbies the time to smoke obscuration 

increases significantly. 

Scenarios 

Increase in Time to Smoke Obscuration on Top 

Floor Due to Enclosed Elevator Lobbies 
8 

3, 4 158% 

5, 6 193% 

9, 10 113% 

14, 15 48% 

24, 25 52% 

5.3.2 Automatic Roll Down Barriers 

A number of scenarios included automatic roll down barriers (TB on Table 1). For the scenarios with 

floor fires, the pairs of scenarios listed below are with and without automatic roll down barriers. 

Scenarios 

Increase in Time to Smoke Obscuration on Top 

Floor Due to Automatic Roll Down Barriers 

6, 7 0% 

10, 12 13% 

15, 16 20% 

25, 26 19% 

It can be seen that with automatic roll down barriers, the time to smoke obscuration increases only 

slightly. The predicted performance of these roll down barriers is highly dependant on the leakage of such 

barriers, and roll down barriers with less leakage than used in this project would be expected to perform 

better. 

5.3.3 Positioning Of Elevator Cars 

A number of scenarios included positioning of elevator cars (JPC on Table 1). For the scenarios with floor 

fires, the pairs of scenarios listed below are with and without positioning of elevator cars. 

Scenarios 

Increase in Time to Smoke Obscuration on Top 

Floor Due to Automatic Roll Down Barriers 

6, 8 0% 

10, 13 0% 

15, 17 0% 

25, 27 0% 

It can be seen that with positioning of elevator cars, the time to smoke obscuration remains unchanged 

from that without enclosed elevator lobbies. 

5.4 Outside Temperature 

All the scenarios discussed so far have been with the winter outside temperature. Scenarios 22 and 23 are 

with the summer outside temperature. As expected for these scenarios, the fire was on the top occupied 

floor, and there was little smoke flow to floors below. 

6. Future Research 

As already stated, this study did not include compartmentation failure. Future research is needed to 

evaluate the extent to which compartmentation failure would impact smoke flow through elevator 

hoistways. 

The method of analysis used for this project used two computer models (CFAST and CONTAMW) as 

described earlier. This approach is cumbersome, time consuming, and yields questionable results for 

scenarios involving reverse stack effect. Research is needed to develop a fire model capable of simulating 

smoke flow and temperatures throughout high rise buildings. 
9 

7. Summary & Conclusions 

The intent of this project is to study the hazard to life due to smoke migration through elevator hoistways 

and the effectiveness of various methods to reduce that hazard. 

While compartmentation failure is beyond the scope of this project, such failure would be expected at 

some locations in buildings subjected to a fully developed fire that involved a large space such as one or 

more floors. It is anticipated that such compartmentation failure would result in increases in hazard to life. 

Even without compartmentation failure, the analysis of this project provides limited information about the 

hazard at locations remote from the fire and provides information about of the relative effectiveness of 

various methods to reduce hazards due to smoke flow through hoistways. 

For the buildings and conditions analyzed, the following conclusions are made. 

(1) The fully developed floor fires resulted in significant threats at floors remote from the fire 

floor. For these fires, the time to reach smoke obscuration on floors remote from the fire 

ranged from 24 minutes to 100 minutes. While these times are long, they are representative of 

the times involved with some major multiple death fires. 

(2) Smoke from successfully sprinklered fires did not result in hazard conditions at floors away 

from the fire floor. 

(3) The use of enclosed elevator lobbies increased the time to reach hazard criteria significantly 

(from 52% to 193%) in comparison with analysis without such lobbies. 

(4) The use of automatic roll down barriers tended to increase the time to reach hazard criteria 

(from 0% to 20%) in comparison with analysis without such barriers. If tighter roll down 

barriers had been used for the analysis of this project, it is expected that they would have 

performed better. 

(5) The use of judicious positioning of elevator cars had no effect on the time to reach hazard 

criteria. 

8. References 

ASHRAE 2001. Handbook of Fundamentals, American Society of Heating, Refrigerating and AirConditioning Engineers, Atlanta, GA. 

Aynsley, R. M. 1989. The Estimation of Wind Pressures at Ventilation Inlets and Outlets on Buildings, 

ASHRAE Transactions, Vol. 95, Part 2, pp. 707-721. 

Best, R. and Demers, D. P. 1982. Investigation Report on the MGM Grand Hotel Fire - Las Vegas, 

Nevada, November 21, 1980, National Fire Protection Association, Quincy, MA. 

Blockley, W. V. 1973. Biology Data Book, Federation of American Societies for Experimental Biology, 

Bethesda, MD. 

Dols, W. S., Denton, K. R. and Walton, G. N. 2000. CONTAMW User Manual, National Institute of 

Standards and Technology, Gaithersburg, MD. 

Dyrbye, C. and Hansen, S. O. 1997. Wind Loads on Structures, Wiley, New York, NY. 

Evans, D. D. and Stroup, D. W. 1986. Methods to Calculate the Response Time of Heat and Smoke 

Detectors Installed Below Large Unobstructed Ceilings, Fire Technology, Vol. 22, No. 1, pp. 54-65. 

Evans, D. D., Stroup, D. W. and Martin, P. 1986. Evaluating Thermal Fire Detection Systems (SI Units), 

NBSSP 713, National Bureau of Standards, Gaithersburg, MD. 
10 

Ferreira, M.J. 1998. Analysis of Smoke Control System Design Using a Computer-based Airflow 

Analysis, Pacific Rim Conference, Society of Fire Protection Engineers, Bethesda, MD. 

Ferreira, M.J. 2002. Use of Multi-Zone Modeling for High-Rise Smoke Control Design, ASHRAE 

Transactions, Vol. 108, Part 2. 

Hadjisophocleous, G. V., Fu, Z. and Lougheed, G. D. 2002. Computational and Experimental Study of 

Smoke Flow in the Stair Shaft of a 10-Story Tower, ASHRAE Transactions, Vol. 108, Part 1. 

Hasemi, Y. 1985. Analysis of Failures of Automatic Sprinklers in Actual Fires, UJNR Panel on Fire 

Research and Safety, 8th Joint Meeting May 13-21, 1985. Tsukuba, Japan, pp 794-807. 

Heskestad, G. 1984. Engineering Relations for Fire Plumes, Fire Safety Journal, Vol. 7, No. 1, pp. 25-32. 

Kandola, B. S. 1986a. Comparison of Wind Tunnel Pressure Measurements and Smoke Movement 

Computer Predictions Inside a Five-Story Model building, Fire Safety Journal, Vol. 10, No. 3, pp. 229-

238. 

Kandola, B. S. 1986b. The Effects of Simulated Pressure and Outside Wind on the Internal Pressure 

Distribution in a Five-Story Building, Fire Safety Journal, Vol. 10, No. 3, pp. 211-227. 

Kandola, B. S. 1986c. A Wind Tunnel Building Model for the Investigation of Smoke Movement 

Problems, Fire Safety Journal, Vol. 10, No. 3, pp. 203-209. 

Klote, J. H. 1995. Design of Smoke Control Systems for Elevator Fire Evacuation Including Wind 

Effects, 2nd Symposium on Elevators, Fire, and Accessibility, Baltimore, MD April 19-21, 1995, ASME, 

New York. 

Klote, J. H. 2002a. Tenability and Open Doors in Pressurized Stairwells – Final Report, ASHRAE 1203-

TRP, ASHRAE, Atlanta, GA. 

Klote, J. H. 2002b. Smoke Management Applications of CONTAM. ASHRAE Transactions, Vol. 108, 

Part 2. 

Klote, J. H. 2003. Hazards Due to Smoke Migration through Elevator Shafts – Vol. II: Results of 

Tenability Calculations, John H. Klote, Inc., Leesburg, VA. 

Klote, J. H. and Milke, J. A. 2002. Principles of Smoke Management, ASHRAE, Atlanta, GA. 

Liu, H. 1991. Wind Engineering – A Handbook for Structural Engineers, Prentice Hall, Englewood, NJ. 

MacDonald, A. J. 1975. Wind Loading on Buildings, Wiley, New York, NY. 

Madrzykowski, D. 1996. Office Work Station Heat Release Rate Study: Full Scale vs. Bench Scale, 7th

International Interflam Conference, March 26-28, 1996, Cambridge, England. Proceedings. pp 47-55. 

Madrzykowski, D. and Vittori, R. L. 1992. A Sprinkler Fire Suppression Algorithm, Journal of Fire 

Protection Engineering, Vol. 4, No. 4, pp. 151-164. 

Marryatt, H. W. 1988. Fire – A Century of Automatic Sprinkler Protection in Australia and New Zealand 

1986 – 1986, Australian Fire Protection Association, North Melbourne, Australia. 

Mulholland, G. 2002. Smoke Production and Properties, SFPE Handbook of Fire Protection Engineering, 

National Fire Protection Association, Quincy, MA. 

Nelson, H. E. 1987. An Engineering Analysis of the Early Stages of Fire Development - The Fire at the 

Dupont Plaza Hotel and Casino - December 31, 1986, National Institute of Standards and Technology, 

NISTIR 87-3560. 

Nelson, H. E. 1989. An Engineering View of the Fire May 4, 1988 in the First Interstate Bank Building, 

Los Angeles, California, National Institute of Standards and Technology, NISTIR 89-4061. 
11 

NEII, 1983. Vertical Transportation Standards: Standards for Elevators, Escalators and Dumbwaiters, 

National Elevator Industry, Inc., New York, NY. 

NFPA 2000. Recommended Practice for Smoke Control Systems, NFPA 92A, National Fire Protection 

Association, Quincy, MA. 

Peacock, R. D., et al., 1993. CFAST, the Consolidated Model of Fire Growth and Smoke Transport, 

National Institute of Standards and Technology, NIST Technical Note 1299. 

Purser, D. A. 2002. Toxicity Assessment of Combustion Products, SFPE Handbook of Fire Protection 

Engineering, National Fire Protection Association, Quincy, MA. 

Routley, G., Jennings, C. and Chubb, M. 1991. High-rise Office Building Fire - One Meridian Plaza, 

Technical Report, United States Fire Administration. 

Shaw, C. T. and Tamura, G. T. 1977. The Calculation of Air Infiltration Rates Caused by Wind and Stack 

Action for Tall Buildings, ASHRAE Transactions, Vol. 83, Part 2, pp. 145-158. 

Simiu, E. and Scanlan, R. H. 1996. Wind Effects on Structures: Fundamentals and Application to Design, 

3rd Ed., Wiley, New York, NY. 

Tamanini, F. 1976. The Application of Water Sprays to the Extinguishment of Crib Fires, Combustion 

Science and Technology, Vol. 14, pp. 17-23. 

VanGeyn, M. 1994. National Fire Door Fire Test Project. Positive Pressure Furnace Fire Tests. 

Technical Report. National Fire Protection Research Foundation, Quincy, MA, Report 6285, 201 p. 

Walton, G. N. 1997. CONTAM96 User Manual, NISTIR 6056, National Institute of Standards and 

Technology, Gaithersburg, MD. 
12 

Table 1. List of Scenarios 

 Fire Fire Enclosed Alternative 

Scenario Building1 Type2 Floor3 Elev. Lobby Weather4 Methods5

1 A SP 2 Y W-NW None 

2 A FDR 2 Y W-NW None 

3 A FDF 2 Y W-NW None 

4 A FDF 2 N W-NW None 

5 B FDF 2 Y W-NW None 

6 B FDF 2 N W-NW None 

7 B FDF 2 N W-NW TB 

8 B FDF 2 N W-NW JPC 

9 C FDF 2 Y W-NW None 

10 C FDF 2 N W-NW None 

11 C FDF 2 N W-W None 

12 C FDF 2 N W-NW TB 

13 C FDF 2 N W-NW JPC 

14 D FDF 2 Y W-NW None 

15 D FDF 2 N W-NW None 

16 D FDF 2 N W-NW TB 

17 D FDF 2 N W-NW JPC 

18 D FDR 2 Y W-NW None 

19 D FDR 2 N W-NW None 

20 D FDR 2 N W-NW TB 

21 D FDR 2 N W-NW JPC 

22 D FDF 36 Y S-NW None 

23 D FDF 36 N S-NW None 

24 E FDF 2 Y W-NW None 

25 E FDF 2 N W-NW None 

26 E FDF 2 N W-NW TB 

27 E FDF 2 N W-NW JPC 1

See Table 2. 

2

SP is a sprinklered fire. FDR is a fully developed room fire. FDF for fully developed floor fire. 3

FDR fires are located in a conference room on the floor indicated, and FDF fires are located in the open floor plan 

space on that floor. 

4

W-NW for winter with no wind. S-NW for summer with no wind. W-NW winter with no wind. W-W winter with 

wind. 

5

TB for temporary barriers over elevator car doors. JPC for judicious positioning of cars within hoistways. 

 

Table 2. List of Buildings 

Building 

Number of 

Stories* Passenger Elevators 

Service 

Elevator 

A 6 1 Bank of 3 Elevators None 

B 13 1 Bank of 6 Elevators None 

C 16 1 Bank of 6 Elevators None 

D 35 3 Banks of 6 Elevators: Low, 

Medium & High Rise 

 2 

E 58 3 Banks of 8 Elevators: Low, 

Medium & High Rise 

 2 

*

Does not include mechanical penthouse. 
13 

Table 3. Building Flow Areas 

Component 

Path 

Type1

Path 

Identifier2

Flow 

Coefficient3

Area4

m2/m2 (ft2/ft2) 

Exterior Wall O W-EXT 0.65 0.00017 

Exterior Wall Below Grade5 O W-UG 0.65 0.000085 

Interior Wall O W-INT 0.65 0.00011 

Elevator Wall O W-EL 0.65 0.00084 

Floor O FLOOR 0.65 0.000052 

Roof5

 O ROOF 0.65 0.000026 

Closed Doors: m2 ft2

 Single Door T DR-SI 0.65 0.016 0.17 

 Double Door T DR-DO 0.65 0.027 0.29 

 Elevator Doors6

 T DR-EL42 0.65 0.047 0.50 

 Large Elevator Doors7

 T DR-EL48 0.65 0.049 0.53 

Open Doors: 

 Single Door T DR-SI-O 0.35 1.95 21 

 Double Door T DR-DO-O 0.35 3.90 42 

Shaft Equivalent Area8

: 

 Stairwell O STAIR 0.60 2.3 25 

 3 Car Passenger Elevator O EL-P3 0.60 230 2500 

 4 Car Passenger Elevator O EL-P4 0.06 360 3900 

 2 Car Service Elevator O EL-S2 0.60 160 1700 

Open Elevator Vent9

: 

 3 Car Passenger Elevator O EL-P3V 0.32 0.70 7.5 

 4 Car Passenger Elevator O EL-P4V 0.32 1.05 11.3 

 2 Car Service Elevator O EL-S2V 0.32 0.52 5.6 

Roll Down Barriers T ROLL 0.65 0.011 0.12 

Shafts with Cars in Place: 

 3 Car Passenger Elevator O EL-P3C 0.65 6.5 70 

 4 Car Passenger Elevator O EL-P4C 0.65 9.1 98 

1

 O indicates an orifice path for which flow is in one direction. T indicates a two-directional flow path. The two-directional flow is 

used for doors, and the leakage is uniformly distributed over the height of the door. 2

The path identifiers are used with CONTAMW for data input. 3

The flow coefficient is defined as m A-1/2 (2 ! "p)-1/2 where m is the mass flow through the path, ! is the density of gas flowing 

in the path, and "p is the pressure difference across the path. 4

Areas for walls and floors are listed as area of flow path per unit of area of wall or of floor as appropriate. 5

Due to lack of experimental data, the flow areas of the exterior wall below grade and the roof were estimated at half that of the 

exterior wall and the floor respectively. 

6

This elevator door is 1.07 m (3.5 ft) wide. It is used for all passenger elevators of this study except for Building E. 7

This elevator door is 1.22 m (4.0 ft) wide. It is used for the passenger elevators of Building E and the service elevators. 8

Shaft equivalent areas are used to calculate the pressure losses due to friction in shafts. For more information, see chapter 6 of 

Klote and Milke(2002). 

9

Vent area was calculated at 3.5% of the shaft area but not less than 0.28 m2 (3 ft2). 
14 

Table 4. Calculated Time (minutes) to Reach Tenability Specific Limits

 Top Floor of Top Floor of Top Floor of 

 Fire Floor2 Low Rise2,3 Mid Rise2,4 High Rise2,5

Scenario1 Building Visibility FED Visibility FED Visibility FED Visibility FED 

1 A 5 – – – NA NA NA NA 

2 A – – – – NA NA NA NA 

3 A 1 6 62 – NA NA NA NA 

4 A 1 6 24 49 NA NA NA NA 

5 B 1 6 88 – NA NA NA NA 

6 B 1 6 30 56 NA NA NA NA 

7 B 1 6 30 55 NA NA NA NA 

8 B 1 6 30 56 NA NA NA NA 

9 C 1 6 66 – NA NA NA NA 

10 C 1 6 31 56 NA NA NA NA 

11 C 1 6 40 79 NA NA NA NA 

12 C 1 6 35 63 NA NA NA NA 

13 C 1 6 31 56 NA NA NA NA 

14 D 1 6 – – 52 86 74 – 

15 D 1 6 – – 48 82 50 89 

16 D 1 6 – – 49 80 60 100 

17 D 1 6 – – 48 82 50 89 

18 D – – – – – – – – 

19 D – – – – – – 20 40 

20 D – – – – – – 28 54 

21 D – – – – – – 20 40 

22 D 1 6 89 – – – 1 6 

23 D 1 6 – – – – 1 6 

24 E 1 6 – – 55 92 73 – 

25 E 1 6 – – 48 85 48 85 

26 E 1 6 – – 51 85 57 98 

27 E 1 6 – – 48 85 48 85 1

For descriptions of the scenarios and locations of the fire floor, see Table 1. 2

The tenability limits used for this project are visibility of 8 m (25 ft) and an FED of 1 in the open plan office space of the floor 

indicated. 

3

Buildings A, B and C have only one elevator rise, and data listed for these buildings is for the top occupied floor. For Building D, 

the top occupied floor of the low rise is for floor 13. For Building E, the top occupied floor of the low rise is for floor 23. 4

For Building D, the top occupied floor of the mid rise is for floor 25. For Building E, the top occupied floor of the mid rise is for 

floor 42. 

5

For Building D, the top occupied floor of the high rise is for floor 35. For Building E, the top occupied floor of the high rise is for 

floor 58. 
15 

Figure 1. Typical Floor Plan of Building A 

Figure 2. Typical Floor Plan of Buildings B and C 
16 

Figure 3. Elevator Layout for Building D 
17 

Figure 4. Ground Floor Plan of Building D 
18 

Figure 5. Elevator Layout for Building E 
19 

Figure 6. Ground Floor Plan of Building E 
20 

Figure 7. HRR Curves of Fires Used in This Project 
21 

Figure 8. Thermal Tolerance of Naked Humans at Rest With Low Air Movement 
22 

Appendix A – Fires 

The fires considered for this analysis are: (1) sprinklered fire, (2) fully developed room fire, and (3) fully 

developed floor fire. These fires are discussed below. 

Sprinklered Fire 

Sprinklered fires generally proceed through an incubation period of slow and uneven growth followed by 

a period of established growth. Established growth is often represented by an idealized parabolic equation 

(Heskestad 1984). 

2 Q = t ! ! (A.1) 

where 

Q! = heat release rate of fire, kW (Btu/s); 

 = fire growth coefficient, kW/s2

 (Btu/s3); 

t = time after ignition, s. 

Fires following this equation are called t-squared fires. It is generally recognized that consideration of the 

incubation period is not necessary for design of smoke management systems, and where t is considered the 

time from effective ignition. In the CFAST zone fire model, the following SI version of the above equation 

is used to aid data input2

2

1000

g

t Q

t

" # $ % & % & ' (

! (A.2) 

where 

Q! = heat release rate of fire, kW; 

t = time after effective ignition, s; 

tg = growth time, s. 

When t = tg, the above equation gives a value of Q! = 1000 kW. The growth times used in CFAST are: 

 Growth Type tg (s) 

 Slow 600 

 Medium 300 

 Fast 150 

 Ultra Fast 75 

Madrzykowski (1996) conducted a series of fire tests of office workstations. The growth type that is 

closest to that of these workstation fires is medium growth with a growth time, tg, of 300s. For this study, 

the sprinklered fire will have a growth stage of a medium t-squared fire. 

For this study, the HRR is considered to decrease after sprinkler activation. This HRR decay after sprinkler 

actuation can be expressed as 

( )/ act t t Q Q e act

* * ) $! ! (A.3) 

 

2

 NFPA 92B (2000) and some other sources have a similar equation in English units: 2 1000( / ) Q t t $ g ! which 

gives Q! = 1000 Btu/s when t = tg. 
23 

where 

Q! = post sprinkler actuation HRR, kW (Btu/s); 

Qact

! = HRR at sprinkler actuation, kW (Btu/s); 

t = time from ignition, s (s); 

tact = time of sprinkler actuation, s (s); 

! = time constant of fire suppression, s (s). 

For a number of fuel packages likely to be found in offices, Madrzykowski and Vettori (1992) conducted 

sprinklered fire experiments with a spray density of 0.10 gpm/ft2

 (0.07 mm/s) of water. They determined 

that a fire decay curve with a time constant of 435 s had a higher HRR than most of the sprinklered fires. 

Evans (1993) used this data and data for wood crib fires with sprinkler spray densities of 0.06 gpm/ft2

(0.041 mm/s) and 0.097 gpm/ft2

 (0.066 mm/s) from Tamanini (1976) to develop the following correlation 

1.85

C

w

! ! " (A.4) 

where 

w = spray density, gpm/ft2

 (mm/s); 

C! = 6.15 (3.0). 

While equation (A.4) has not been experimentally verified, it does allow us to adjust the decay time for 

sprinkler densities other than those of Madrzykowski and Vettori. 

Sprinkler actuation depends on gas temperature and velocity near the sprinkler. In a fire a jet of hot gases 

flows radially from where the smoke plume intersects the ceiling. The response time index (RTI) was 

developed as a measure of sprinkler responsiveness that is independent of velocity. The RTI of standard 

sprinklers range from about 77 to 155 m1/2 s1/2 (140 to 280 ft1/2 s1/2), and the RTI of quick-response 

sprinklers (QRS) range from about 28 to 55 m1/2 s1/2 (50 to 100 ft1/2 s1/2). 

Several computer programs have been developed that use correlations for such a ceiling jet and the RTI to 

predict actuation time. The program DETACT-QS (Evans and Stroup 1986) assumes that the thermal 

device is located in a relatively large area, that only the ceiling jet heats the device and there is no heating 

from the accumulated hot gases in the room. The required program inputs are the height of the ceiling 

above the fuel, the distance of the thermal device from the axis of the fire, the actuation temperature of 

the thermal device, the response time index (RTI) for the device, and the rate of heat release of the fire. 

The program outputs are the ceiling gas temperature and the device temperature both as a function of time 

and the time required for device actuation. DETACT-T2 (Evans, Stroup and Martin 1986) is similar to 

DETACT-QS except it is specifically for t-squared fires. Several zone fire models are capable of 

calculating ceiling jet temperatures and predicting actuation, and the CFAST model was used to calculate 

activation time for this project. 

For estimation of activation time in this study, a sprinkler with an RTI of 155 m1/2 s1/2 (280 ft1/2 s1/2) was in 

a 10 m (33 ft) square room with a ceiling height of 2.8 m (9.2 ft). The fire growth was the medium tsquared curve mentioned above. The sprinkler was located under the ceiling and 2.1 m (7 ft) horizontally 

from the center line of the smoke plume. CFAST predicted an activation time of about 252 s at 706 kW 

(670 Btu/s). For calculation of decay after sprinkler activation, a time constant of 435 s was used. 

Conference Room Fire 

This is an unsprinklered fire that is limited to a conference room that was used for storage. The conference 

room includes materials in corrugated cardboard boxes and a number of pieces of upholstered furniture. 

Because some upholstered furniture burns like an ultra fast fire, the ultra fast growth type was used for the 

early stage of this fire until the room flashed over. Flashover is a transition from a locally isolated fire to a 

room totally involved in fire. This transition only takes a few seconds. 
24 

After flashover the airflow through this window controls the HRR, and this HRR can be expressed as a 

function of the door opening to the room 

1/ 2 Q C A H ! vc w w ! (A.5) 

where 

Q! = heat release rate of fire, kW (Btu/s); 

Aw = area of ventilation opening, m2

 (ft2); 

Hw = height of ventilation opening, m (ft); 

Cvc = 1260 (61.2). 

The door opening is 0.914 m (3 ft) wide by 2.13 m (7 ft) high. From equation (A.5), the heat release rate 

of the fully developed fire is 3590 kW (3400 Btu/s). 

To get temperatures to use in CONTAMW, a CFAST simulation was made of the fire in the conference 

room and open office space on the fire floor. The conference room is 3.2 m (10.5 ft) by 4.3 m (14.1 ft). 

This indicated that flashover occurred at 133 s. The temperatures are shown in Figures A1 and A2. 

0

500

1000

1500

0 600 1200 1800 2400 3000 3600 4200

Time (s)

Temperature (C)

Upper Layer

Lower Layer

Average

Figure A1. CFAST simulated temperatures of the conference room 
25 

0

25

50

75

100

125

150

0 600 1200 1800 2400 3000 3600 4200

Time (s)

HRR (kW)

Upper Layer

Lower Layer

Average

Figure A2. CFAST simulated temperatures of the open office area on the fire floor 

The average temperatures shown in Figures A1 and A2 are weighted averages, and they were 

calculated from 

( ) u l

av

T H Z T Z T

H

! " # (A.6) 

where 

Tav = weighted average temperature, 

Tu = upper layer temperature, 

Tl = lower layer temperature, 

H = floor to ceiling height, 

Z = smoke layer interface. 

Open Office Plan Fire 

For the buildings of this study, the gross floor area is in the range of 1900 m2 (20,400 ft2) to 2040 m2

(22,000 ft2

). For these calculations, the net floor area of open office space is taken as 1670 m2 (18,000 

ft2), and the area of the windows is taken as 364 m2 (3920 ft2). One fully developed floor fire was used for 

these buildings. 

The HHR calculations are based on the assumption that as the fire breaks the windows open, the fire is 

ventilation controlled as described by equation (A.5). At 600 s after ignition, the fire starts breaking 

windows, and this continues until all the windows are broken at 1550 s. At 600 s, the area of broken 

window is 2.26 m2

 (24.3 ft2), and at 1550 s all of the windows are broken with a HRR of 680,000 kW 

(645,000 Btu/s). On an area basis, the maximum HRR is 407 kW/m2

 (35.8 Btu/s ft2). Based on 

Madrzykowski’s work (1996), workstation fires can support this level of fire. 

The growth stage of the fire was approximated by a t-square fire that grows to 680,000 kW (645,000 

Btu/s) in 1550 s. From equation A1, the fire growth coefficient is 0.283 kW/s2 (0.268 Btu/s3). 

After the windows are broken, the fire continues to burn at this rate for 1 hour. The workstations burned 

by Madrzykowski do not have sufficient fuel to support this fire for such a time. However, such a fire 
26 

could be supported by other fuel in the office space such as bookcases with books, boxes filled with 

paper, file cabinets filled with records and rolls of drawings. The decay phase of the fire is from 3600 s to 

7200 s, and a time constant of 435 s was used for decay. 

Because of restrictions on data input, CFAST version 3.1.7 could not be used to simulate a fire with such 

a large HRR. For this reason, a scaled down version of the fire had to be simulated by CFAST to obtain 

the temperatures for use in the CONTAMW simulations. CFAST simulations were made of the floor fire 

with (1) an elevator shaft and no enclosed elevator lobby and (2) an enclosed elevator lobby. The 

temperatures from these CFAST simulations are listed in Figures A.3 to A.5. The average temperatures 

were calculated as before. 

0

500

1000

1500

2000

0 600 1200 1800 2400 3000 3600 4200

Time (s)

Temperature (C)

Upper Layer

Lower Layer

Average

Figure A3. CFAST simulated temperatures of open office area 
27 

0

50

100

150

200

0 600 1200 1800 2400 3000 3600 4200

Time (s)

Temperature (C)

Figure A4. CFAST simulated temperature of the elevator shaft without an enclosed lobby 

0

20

40

60

80

100

120

140

0 600 1200 1800 2400 3000 3600 4200

Time (s)

Temperature (C)

Upper Layer

Lower Layer

Average

Figure A5. CFAST simulated temperatures of the enclosed elevator lobby 
28 

Appendix B – Fuel Properties 

The chemical heat of combustion of the mixture of two fuels can be calculated as 

! " ! # ! H f H f H ch ch ch 1 1 2 2 , (B.1) 

and the mass optical density the mixture of two fuels can be calculated as 

 m m m 1 1 2 2 $ $ $ " # f f (B.2) 

where 

!Hch = chemical heat of combustion of the mixture (kJ/kg), 

!Hch1 = chemical heat of combustion of component 1 (kJ/kg), 

!Hch2 = chemical heat of combustion of component 2 (kJ/kg), 

$m, = mass optical density of the mixture (m2

/g), 

$m1 = mass optical density of component 1 (m2

/g), 

$m2 = mass optical density of component 2 (m2

/g), 

f1 = mass fraction of component 1 (dimensionless), 

f2 = mass fraction of component 2 (dimensionless). 

The lethal exposure dose, LCt50, of the mixture can be expressed as 

LC LC LC 50 1 50,1 2 50,2 t f t f t " # (B.3) 

where LCt 50is the lethal exposure dose from test data (Table A1). 

Table A1. Approximate Lethal Exposure Dose, LCt50, for Common Materials (adapted from 

Purser 2002) 

 Nonflaming Fire Fuel Controlled Fire Fully Developed Fire 

Material lb ft-3 min g m-3 min lb ft-3 min g m-3 min lb ft-3 min g m-3 min 

Cellulosics 0.046 730 0.19 3120 0.047 750 

C, H, O plastics 0.031 500 0.075 1200 0.033 530 

PVC 0.031 500 0.019 300 0.012 200 

Wool/Nylon (low N2) 0.031 500 0.057 920 0.0044 70 

Flexible Polyurethane 0.042 680 0.087 1390 0.012 200 

Rigid Polyurethane 0.0039 63 0.0062 100 0.0034 54 

Modacrylic/PAN1

 0.010 160 0.0087 140 0.0028 45 

1

PAN is polyacrylonitrile. 

Cellulosic materials (wood, paper, cardboard, etc.) are very common fuels in building fires. They often 

burn in combination with some amount of polymers. For these calculations the mixture used is 75% 

cellulosic material and 25% polyurethane foam. The properties are listed below. 
29 

 Chemical Heat of Mass Optical 

Component Mass Fraction Combustion (kJ/kg) Density (m2/g) 

Cellulosic Material 0.75 13,000 0.28 

Polyurethane Foam 0.25 17,600 0.33 

Properties of the mixture are 

1 1 2 2 ! " ! # ! " # " H f H f H ch ch ch (.75)(13,000) (.25)(17,600) 14,150 kJ/kg

1 1 2 2 $ $ $ m m m " # " # " f f (.75)(0.28) (.25)(0.33) 0.29 m2

/g 

For a fuel controlled fire, the lethal exposure dose of the fuel mixture is 

-3 LC LC LC (.75)(3120) (.25)(1390) 2690 g m min 50 1 50,1 2 50,2 t f t f t " # " # " . 

For a fully developed fire, the lethal exposure dose of the fuel mixture is 

-3 LC LC LC (.75)(750) (.25)(200) 612 g m min 50 1 50,1 2 50,2 t f t f t " # " # " . 

Mass Consumption 

The mass of fuel consumed in a fire is 

ch

Q m

H " !

! ! (B.4) 

where 

m! = mass of fuel consumed (kg/s), 

Q! = heat release rate (kW). 

The peak values of HRR and mass consumption are listed below for the fires of this project. 

 Peak HRR (kW) Peak Mass Consumption (kg/s) 

Sprinklered Fire 706 0.050 

Conference Room Fire 3,590 0.254 

Open Office Plan Fire 680,000 48.1 
30 

Appendix C – Wind 

For information about wind and smoke management, readers are referred to Kandola (1986a, 1986b) and 

Klote (1995). For additional information about wind pressures on buildings see Aynsley (1989), Shaw 

and Tamura (1977) and Kandola (1986c). Several civil engineering texts provide useful information about 

wind engineering, for example Dyrbye and Hansen (1997); Liu (1991), MacDonald (1975) and Simiu and 

Scanlan (1996). 

The wind velocity at the top of a building wall is 

met a a

met

H met

met

H U U

H

!

!

" # " # $ % & % & ' ( ' ( (C.1) 

where 

UH = wind velocity at the top of the wall, m/s (fpm); 

Umet = measured wind velocity, m/s (fpm); 

Hmet = height of wind measurement, m (ft); 

H = upwind height of the wall, m (ft); 

! met = boundary layer height in the vicinity of the wind anemometer, m (ft); 

! = boundary layer height in the vicinity of the building, m (ft); 

amet = wind exponent in the vicinity of the wind anemometer, dimensionless; 

a = wind exponent in the vicinity of the building, dimensionless. 

General values of boundary layer height, ! , are listed the ASHRAE Handbook of Fundamentals. The 

weather service measures wind data at airports and other locations typically at 10 m (33 ft) above the 

ground. For this project, the wind values are calculated as if the building was located in urban or suburban 

terrain with wooded areas or other similar obstructions. 

The pressure that the wind exerts on a wall can be expressed as 

1 2

2 p K C C U w w h w o met $ ) (C.2) 

where 

2 met 2 a a

met

h

met

H C

H

!

!

" # " # $ % & % & ' ( ' ( (dimensionless); (C.3) 

Cw = wind coefficient (dimensionless); 

)o = density of outside air, kg/m3

 (lb/ft3); 

Kw = 1.00 (0.0129). 

For this project, the values of the above parameters are: 

! met 270 m (900 ft) 

! 370 m (1200 ft) 

amet 0.14 

a 0.22 

Hmet 10 m (33 ft) 

H 67 m (220 ft) Building C 

Umet 11 m/s (25 mph) 

)o 1.37 kg/m3

 (0.0855 lb/ft3) at –16 *C (3 *F) 
31 

From equations (C.1) and (C.3), values of UH and Ch are listed below. 

Umet Umet UH UH

Building m/s mph m/s mph Ch

C 11 25 12 27 1.19 

 

Average values of Cw can be obtained from Klote and Milke (2002) depending on values of h/w and l/w, 

where h = height to parapit, l = length, and w = width. h/w is 1.9 and l/w is 1.5 for Building C. 

Average Values of Cw for Building C: 

Wind Angle, ! A B C D 

0 0.8 -0.25 -0.8 -0.8 

90 -.0.8 -0.8 0.8 -0.25 

The wind angle is used in Klote and Milke and is illustrated in Figure C.1. 

Figure C.1 Wind Angle.

 For a wind angle of zero, the wind pressure is: 

A B C D 

Pa in. H2O Pa in. H2O Pa in. H2O Pa in. H2O 

79 0.31 -25 -0.10 -79 -0.31 -79 -0.31 
Appendix F

Hazards Due to Smoke Migration Through Elevator 

Shafts. Volume 2. Results of Tenability Calculations
Hazards Due to Smoke Migration 

Through Elevator Shafts – Volume II: 

Results of Tenability Calculations. 

Final Report

John H. Klote

John H. Klote, Inc.

43262 Meadowood Court

Leesburg, VA 20176

NIST GCR 04-864-II

NIST GCR 04-864-II

Hazards Due to Smoke Migration 

Through Elevator Shafts – Volume II: 

 Results of Tenability Calculations. 

Final Report

Prepared for

U.S. Department of Commerce

Building and Fire Research Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899-8664

By

John H. Klote

John H. Klote, Inc.

43262 Meadowood Court

Leesburg, VA 20176

June 2004

U.S. Department of Commerce

Donald L. Evans, Secretary

Technology Administration

Phillip J. Bond, Under Secretary for Technology

National Institute of Standards and Technology

Arden L. Bement, Jr., Director
Notice

This report was prepared for the Building and Fire Research Laboratory 

of the National Institute of Standards and Technology under Contract number 

SB134-03-W-0477. The statements and conclusions contained in this report 

are those of the authors and do not necessarily reflect the views of the 

National Institute of Standards and Technology or the Building and Fire 

Research Laboratory. 

 ii 
i 
ii 

Table of Contents 

1. Introduction................................................................................................................................. 1 

2. Key to Tables .............................................................................................................................. 1 

3. References................................................................................................................................... 1 

List of Tables 

Table 01. Results of Tenability Analysis for Scenario 01. ............................................................ 2 

Table 02. Results of Tenability Analysis for Scenario 02. ............................................................ 3 

Table 03. Results of Tenability Analysis for Scenario 03. ............................................................ 4 

Table 04. Results of Tenability Analysis for Scenario 04. ............................................................ 5 

Table 05. Results of Tenability Analysis for Scenario 05. ............................................................ 6 

Table 06. Results of Tenability Analysis for Scenario 06. ............................................................ 8 

Table 07. Results of Tenability Analysis for Scenario 07. .......................................................... 10 

Table 08. Results of Tenability Analysis for Scenario 08. .......................................................... 12 

Table 09. Results of Tenability Analysis for Scenario 09. .......................................................... 14 

Table 10. Results of Tenability Analysis for Scenario 10. .......................................................... 16 

Table 11. Results of Tenability Analysis for Scenario 11. .......................................................... 18 

Table 12. Results of Tenability Analysis for Scenario 12. .......................................................... 20 

Table 13. Results of Tenability Analysis for Scenario 13. .......................................................... 23 

Table 14. Results of Tenability Analysis for Scenario 14. .......................................................... 25 

Table 15. Results of Tenability Analysis for Scenario 15. .......................................................... 35 

Table 16. Results of Tenability Analysis for Scenario 16. .......................................................... 45 

Table 17. Results of Tenability Analysis for Scenario 17. .......................................................... 55 

Table 18. Results of Tenability Analysis for Scenario 18. .......................................................... 65 

Table 19. Results of Tenability Analysis for Scenario 19. .......................................................... 68 

Table 20. Results of Tenability Analysis for Scenario 20. .......................................................... 73 

Table 21. Results of Tenability Analysis for Scenario 21. .......................................................... 79 

Table 22. Results of Tenability Analysis for Scenario 22. .......................................................... 84 

Table 23. Results of Tenability Analysis for Scenario 23. .......................................................... 92 

Table 24. Results of Tenability Analysis for Scenario 24. .......................................................... 93 

Table 25. Results of Tenability Analysis for Scenario 25. ........................................................ 108 

Table 26. Results of Tenability Analysis for Scenario 26. ........................................................ 123 

Table 27. Results of Tenability Analysis for Scenario 27. ........................................................ 138 
1 

Hazards Due To Smoke Migration Through Elevator 

Shafts – Volume II: Results of Tenability Calculations

1. Introduction 

This project looks at the hazard to life due to smoke migration through elevator hoistways and the 

effectiveness of methods to reduce that hazard. This report of this project is in two volumes. The first 

volume presents the analysis and discusses the results of that analysis (Klote, 2003). The second volume 

consists of the complete results of the tenability calculations. The results of the tenability calculations are 

listed in Tables 1 through 27. 

2. Key to Tables 

CONTAMW limits the length of names of zones (or rooms) to 4 characters. The following symbols are 

used in the zone names of this project. 

EL Elevator 

ELME Elevator Mechanical Room 

EL-S Service Elevator 

LOBY Passenger Elevator Lobby 

L-SR Service Elevator Lobby 

MECH Mechanical Space 

OPEN Open Plan Office Space 

SW Stairwell 

T Toilet 

 

3. Reference 

Klote, J. H. 2003. Hazards Due to Smoke Migration through Elevator Shafts – Vol. I: Analysis and 

Discussion, John H. Klote, Inc., Leesburg, VA. 
2 

Table 01. Results of Tenability Analysis for Scenario 01. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 2.9 3.9 5.6 ****   

 2 LOBY 11.3 17.0 28.6 ** **   

 2 EL01 22.6 52.1 ** **   ** ** 

 2 SW2 30.9   ** **   ** ** 

 2 SW1 11.7 18.8 43.9   ** ** 

 

 2 TO-2 45.0 86.6   ** **   

 3 EL01 32.5 87.1 ** **   ** ** 

 3 SW2 46.8   ** **   ** ** 

 3 SW1 25.7 41.8   ** **   

 4 EL01 41.6 ** **   ** **   

 

 4 SW2 64.6 ** **   ** **   

 4 SW1 41.5 70.4 ** **   ** ** 

 5 EL01 49.7   ** **   ** ** 

 5 SW2 88.9   ** **   ** ** 

 5 SW1 56.0 93.0   ** **   

 

 6 EL01 56.5 ** **   ** **   

 6 SW1 71.8 ** **   ** **   

 R SW1 98.5 ** **   ** **   

 R EL1 56.6 ** **   ** **   

 
3 

Table 02. Results of Tenability Analysis for Scenario 02. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 LOBY 6.3 8.6 12.0 47.1 61.4 

 2 EL01 17.8 24.0 33.0 97.5 ** ** 

 2 TO-1 1.0 1.0 1.0 3.6 4.9 

 2 SW2 5.4 7.5 10.7 48.0 65.6 

 2 C-Rm 1.0 1.0 1.0 0.0 0.0 

 

 3 LOBY 69.0 99.9   ** **   

 3 EL01 23.3 30.6 41.2 ** **   

 3 TO-1 8.5 11.7 16.3 54.8 69.9 

 3 SW2 10.5 13.6 18.0 58.1 76.6 

 4 LOBY 98.4 ** **   ** **   

 

 4 EL01 28.0 36.2 48.1 ** **   

 4 TO-1 87.6 ** **   ** **   

 4 SW2 16.9 21.1 26.6 69.5 89.1 

 5 LOBY 111.8 ** **   ** **   

 5 EL01 32.1 40.9 54.0 ** **   

 

 5 SW2 25.6 30.9 37.8 84.2 ** ** 

 6 EL01 35.5 44.8 58.7   ** ** 

 6 SW2 39.2 46.3 55.3   ** ** 

 R EL1 35.6 44.9 58.9   ** ** 
4 

Table 03. Results of Tenability Analysis for Scenario 03. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 G LOBY 15.8 18.3 21.0 41.0 47.0 

 G EL01 24.9 27.9 31.4 58.6 67.8 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 LOBY 1.0 1.0 1.6 8.1 9.8 

 2 EL01 1.8 2.2 2.9 11.3 13.3 

 

 2 SW1 2.2 2.9 3.8 14.4 16.7 

 2 TO-2 5.1 6.6 8.2 22.0 24.9 

 3 LOBY 14.3 16.7 19.3 37.8 43.1 

 3 EL01 2.8 3.6 4.4 13.6 15.7 

 3 SW1 6.0 7.3 8.9 21.5 24.0 

 

 4 EL01 4.0 4.8 5.8 15.7 17.9 

 4 SW1 10.8 12.6 14.6 27.7 30.3 

 5 EL01 5.2 6.1 7.2 17.6 19.9 

 5 SW1 15.9 17.9 19.9 33.4 36.2 

 6 OPEN 51.4 56.4 62.2   ** ** 

 

 6 LOBY 75.6 84.5 96.3   ** ** 

 6 EL01 6.4 7.4 8.6 19.4 21.6 

 6 SW1 21.0 23.0 25.0 39.1 42.3 

 6 TO-2 47.7 52.0 57.1 92.7   

 R SW1 27.2 29.2 31.4 47.1 50.8 

 

 R EL1 6.5 7.5 8.7 19.4 21.7 
5 

Table 04. Results of Tenability Analysis for Scenario 04. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.1 1.7 9.0 11.0 

 2 SW1 2.5 3.2 4.2 15.2 17.5 

 2 TO-2 6.0 7.7 9.6 23.9 26.9 

 3 OPEN 12.3 14.7 17.4 36.5 42.1 

 

 3 EL01 1.6 1.9 2.6 10.9 13.0 

 3 SW1 6.5 7.9 9.5 22.3 24.8 

 3 TO-2 35.6 40.9 47.6 90.4 ** ** 

 4 OPEN 76.0 98.3   ** **   

 4 EL01 2.1 2.8 3.5 12.5 14.6 

 

 4 SW1 11.9 13.7 15.7 29.0 31.6 

 5 OPEN 61.5 69.1 80.3 ** **   

 5 EL01 2.9 3.6 4.4 13.8 16.0 

 5 SW1 17.7 19.7 21.7 35.4 38.4 

 5 TO-2 55.4 61.6 69.2 ** **   

 

 6 OPEN 18.7 21.1 23.7 42.8 48.5 

 6 EL01 3.6 4.4 5.2 14.9 17.0 

 6 SW1 23.6 25.6 27.7 42.6 46.1 

 6 TO-2 21.9 24.5 27.3 50.5 58.2 

 R SW1 29.9 32.1 34.5 51.1 55.1 

 

 R EL1 3.7 4.4 5.3 15.0 17.1 
6 

Table 05. Results of Tenability Analysis for Scenario 05. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 G EL01 26.5 29.8 33.8 65.3 77.1 

 G LOBY 15.9 18.4 21.2 42.2 49.0 

 G EL02 28.4 32.0 36.5 72.8 88.8 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.7 2.0 2.7 10.8 12.7 

 

 2 LOBY 1.0 1.0 1.3 7.4 9.0 

 2 EL02 1.7 2.0 2.8 11.0 13.0 

 2 SW1 1.9 2.5 3.3 13.1 15.4 

 2 TO-2 4.4 5.7 7.2 20.4 23.2 

 3 EL01 2.8 3.5 4.3 13.5 15.6 

 

 3 LOBY 14.4 16.7 19.3 38.0 43.5 

 3 EL02 2.8 3.4 4.2 13.4 15.5 

 3 SW1 5.0 6.2 7.6 19.7 22.1 

 4 EL01 4.1 5.0 6.0 16.0 18.2 

 4 EL02 3.9 4.8 5.8 15.7 17.9 

 

 4 SW1 8.9 10.6 12.3 25.2 27.7 

 5 EL01 5.6 6.6 7.7 18.3 20.6 

 5 EL02 5.2 6.2 7.3 17.8 20.1 

 5 SW1 13.0 14.9 16.8 29.9 32.5 

 6 EL01 7.0 8.0 9.3 20.4 22.8 

 

 6 EL02 6.6 7.6 8.8 19.7 22.1 

 6 SW1 16.9 18.8 20.8 34.1 36.9 

 7 EL01 8.4 9.6 10.9 22.4 24.8 

 7 EL02 7.8 8.9 10.2 21.5 23.9 

 7 SW1 20.4 22.3 24.2 38.0 41.0 

 

 8 EL01 9.8 11.0 12.5 24.3 26.7 

 8 EL02 9.0 10.2 11.6 23.2 25.6 

 8 SW1 23.6 25.4 27.4 41.6 44.8 

 9 EL01 11.0 12.5 13.9 26.0 28.5 

 9 EL02 10.2 11.5 12.9 24.8 27.3 

 

 9 SW1 26.4 28.3 30.3 45.0 48.5 

 10 EL01 12.4 13.8 15.4 27.7 30.2 

 10 EL02 11.4 12.7 14.2 26.3 28.8 

 10 SW1 29.1 31.0 33.1 48.3 51.9 

 11 OPEN 68.1 75.6 86.8 ** **   

 

 11 EL01 13.6 15.1 16.7 29.3 31.8 

 11 LOBY 89.0 ** **   ** **   

 11 EL02 12.5 13.9 15.5 27.7 30.3 

 11 SW1 31.8 33.8 35.9 51.5 55.2 

 11 TO-2 62.5 68.1 75.6 ** **   
7 

Table 05. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 12 OPEN 67.2 73.6 82.3 ** **   

 12 EL01 14.8 16.4 18.0 30.7 33.4 

 12 LOBY 24.6 26.8 29.1 45.5 49.3 

 12 EL02 13.6 15.0 16.7 29.1 31.7 

 12 SW1 34.8 36.8 39.0 55.2 59.0 

 

 12 TO-2 62.8 67.9 74.5 ** **   

 13 OPEN 71.3 78.2 87.8 ** **   

 13 EL01 16.0 17.6 19.3 32.2 34.8 

 13 LOBY 23.7 25.8 27.9 43.4 46.8 

 13 EL02 14.7 16.2 17.8 30.4 33.1 

 

 13 SW1 38.5 40.7 43.0 59.9 63.9 

 13 TO-2 66.7 72.1 79.3 ** **   

 R SW1 43.8 46.2 48.8 67.1 72.0 

 R EL01 16.0 17.6 19.3 32.2 34.9 

 R EL02 14.8 16.3 17.9 30.5 33.1 

 
8 

Table 06. Results of Tenability Analysis for Scenario 06. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.2 1.8 9.3 11.3 

 2 EL02 1.0 1.3 1.8 9.4 11.4 

 2 SW1 2.7 3.5 4.5 15.7 18.1 

 2 TO-2 6.7 8.4 10.4 25.1 28.3 

 

 3 OPEN 14.2 16.8 19.6 41.1 48.1 

 3 EL01 1.8 2.1 2.8 11.5 13.6 

 3 EL02 1.8 2.1 2.8 11.5 13.7 

 3 SW1 7.0 8.6 10.3 23.4 25.9 

 3 TO-2 41.4 48.3 57.2 ** **   

 

 4 EL01 2.6 3.1 3.9 13.4 15.6 

 4 EL02 2.6 3.1 3.9 13.4 15.6 

 4 SW1 12.9 14.8 16.8 30.4 33.2 

 5 EL01 3.4 4.1 5.0 15.1 17.3 

 5 EL02 3.4 4.1 5.0 15.0 17.3 

 

 5 SW1 18.9 20.9 23.0 37.3 40.5 

 6 EL01 4.2 5.0 6.0 16.5 18.8 

 6 EL02 4.2 5.0 6.0 16.5 18.8 

 6 SW1 24.5 26.6 28.7 44.2 47.9 

 7 EL01 5.0 5.9 7.0 17.8 20.2 

 

 7 EL02 5.0 5.9 7.0 17.8 20.2 

 7 SW1 29.7 31.9 34.2 51.1 55.1 

 8 EL01 5.9 6.8 7.9 19.1 21.4 

 8 EL02 5.8 6.8 7.9 19.0 21.4 

 8 SW1 34.9 37.3 39.8 58.0 62.3 

 

 9 EL01 6.7 7.7 8.9 20.2 22.6 

 9 EL02 6.6 7.6 8.8 20.1 22.5 

 9 SW1 40.2 42.7 45.6 64.8 69.8 

 10 EL01 7.4 8.5 9.7 21.2 23.7 

 10 EL02 7.3 8.4 9.6 21.1 23.6 

 

 10 SW1 45.5 48.3 51.3 72.3 78.4 

 11 EL01 8.0 9.2 10.5 22.1 24.6 

 11 EL02 8.0 9.1 10.4 22.1 24.5 

 11 SW1 51.0 54.0 57.3 81.1 89.0 

 12 OPEN 27.3 30.2 33.3 56.9 64.3 

 

 12 EL01 8.8 9.9 11.2 23.0 25.5 

 12 EL02 8.7 9.8 11.1 22.9 25.4 

 12 SW1 56.9 60.1 63.7 92.7 ** ** 

 12 TO-2 33.7 37.3 41.5 74.8 87.5 

 13 OPEN 24.9 27.5 30.3 50.6 56.3 
9 

Table 06. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL01 9.5 10.7 12.0 23.9 26.4 

 13 EL02 9.4 10.6 11.9 23.7 26.3 

 13 TO-1 45.7 52.0 60.6   ** ** 

 13 SW1 63.4 67.2 72.0   ** ** 

 13 TO-2 30.9 34.1 37.6 65.0 74.3 

 

 R SW1 71.7 77.0 84.0   ** ** 

 R EL01 9.5 10.7 12.0 23.9 26.4 

 R EL02 9.4 10.6 11.9 23.8 26.3 
10 

Table 07. Results of Tenability Analysis for Scenario 07. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.3 1.8 9.4 11.5 

 2 EL02 1.0 1.3 1.8 9.4 11.5 

 2 SW1 3.5 4.5 5.8 18.1 20.7 

 2 TO-2 8.9 10.9 13.2 29.2 33.0 

 

 3 OPEN 18.1 21.1 24.3 52.0 62.0 

 3 EL01 1.8 2.1 2.8 11.5 13.7 

 3 EL02 1.8 2.1 2.8 11.5 13.7 

 3 SW1 9.5 11.3 13.3 27.2 30.0 

 3 TO-2 63.7 78.2   ** **   

 

 4 EL01 2.5 3.0 3.9 13.4 15.6 

 4 EL02 2.5 3.0 3.9 13.4 15.6 

 4 SW1 16.9 19.0 21.2 36.1 39.5 

 5 EL01 3.3 4.0 4.9 15.0 17.2 

 5 EL02 3.3 4.0 4.9 15.0 17.2 

 

 5 SW1 24.0 26.2 28.5 45.3 49.4 

 6 EL01 4.1 4.9 5.9 16.4 18.7 

 6 EL02 4.1 4.9 5.9 16.3 18.7 

 6 SW1 30.8 33.2 35.8 54.7 59.4 

 7 EL01 4.9 5.8 6.9 17.6 20.0 

 

 7 EL02 4.9 5.8 6.9 17.6 20.0 

 7 SW1 37.6 40.3 43.4 64.2 69.8 

 8 EL01 5.7 6.7 7.8 18.8 21.2 

 8 EL02 5.7 6.7 7.8 18.8 21.2 

 8 SW1 44.6 47.7 51.2 74.8 82.3 

 

 9 EL01 6.5 7.5 8.7 19.9 22.4 

 9 EL02 6.5 7.5 8.6 19.9 22.3 

 9 SW1 51.8 55.3 59.0 87.9 98.3 

 10 EL01 7.1 8.2 9.5 20.9 23.4 

 10 EL02 7.1 8.2 9.5 20.9 23.3 

 

 10 SW1 59.1 62.9 67.6 ** **   

 11 EL01 7.8 8.9 10.2 21.8 24.3 

 11 EL02 7.8 8.9 10.2 21.8 24.3 

 11 SW1 37.7 42.5 49.0 ** **   

 12 OPEN 26.3 29.1 32.2 54.9 61.9 

 

 12 EL01 8.5 9.7 10.9 22.7 25.2 

 12 EL02 8.5 9.6 10.9 22.6 25.1 

 12 SW1 33.8 37.4 41.7 80.2 ** ** 

 12 TO-2 37.7 42.0 47.6 89.9   

 13 OPEN 24.2 26.8 29.6 49.5 55.1 
11 

Table 07. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL01 9.2 10.4 11.7 23.5 26.1 

 13 EL02 9.1 10.3 11.7 23.5 26.0 

 13 TO-1 51.4 60.0 72.5 ** **   

 13 SW1 32.4 35.7 39.4 70.6 85.0 

 13 TO-2 33.8 37.3 41.5 73.9 86.0 

 

 R SW1 39.8 43.6 48.1 85.7 ** ** 

 R EL01 9.2 10.4 11.8 23.6 26.1 

 R EL02 9.2 10.4 11.7 23.5 26.1 
12 

Table 08. Results of Tenability Analysis for Scenario 08. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.3 1.8 9.3 11.3 

 2 EL02 1.0 1.3 1.8 9.4 11.4 

 2 SW1 2.7 3.5 4.5 15.7 18.1 

 2 TO-2 6.7 8.4 10.4 25.1 28.3 

 

 3 OPEN 14.1 16.7 19.6 41.0 47.9 

 3 EL01 1.8 2.1 2.8 11.5 13.6 

 3 EL02 1.8 2.1 2.8 11.5 13.7 

 3 SW1 7.0 8.6 10.3 23.3 25.9 

 3 TO-2 41.3 48.2 57.0   ** ** 

 

 4 EL01 2.6 3.1 3.9 13.4 15.6 

 4 EL02 2.6 3.1 3.9 13.4 15.6 

 4 SW1 12.9 14.8 16.8 30.4 33.2 

 5 EL01 3.4 4.1 5.0 15.1 17.3 

 5 EL02 3.4 4.1 5.0 15.0 17.3 

 

 5 SW1 18.9 20.9 23.0 37.3 40.5 

 6 EL01 4.2 5.0 6.0 16.5 18.8 

 6 EL02 4.2 5.0 6.0 16.5 18.8 

 6 SW1 24.5 26.5 28.6 44.1 47.8 

 7 EL01 5.0 5.9 7.0 17.8 20.2 

 

 7 EL02 5.0 5.9 7.0 17.8 20.2 

 7 SW1 29.7 31.8 34.2 51.0 55.0 

 8 EL01 5.9 6.8 7.9 19.1 21.4 

 8 EL02 5.8 6.8 7.9 19.0 21.4 

 8 SW1 34.9 37.2 39.8 57.9 62.2 

 

 9 EL01 6.7 7.7 8.9 20.2 22.6 

 9 EL02 6.6 7.6 8.8 20.1 22.5 

 9 SW1 40.1 42.7 45.5 64.7 69.7 

 10 EL01 7.4 8.5 9.7 21.2 23.7 

 10 EL02 7.3 8.4 9.6 21.1 23.6 

 

 10 SW1 45.5 48.2 51.3 72.2 78.3 

 11 EL01 8.0 9.2 10.5 22.1 24.6 

 11 EL02 8.0 9.1 10.4 22.1 24.5 

 11 SW1 50.9 53.9 57.2 81.0 88.8 

 12 OPEN 27.3 30.2 33.3 56.9 64.3 

 

 12 EL01 8.8 9.9 11.2 23.0 25.5 

 12 EL02 8.7 9.8 11.1 22.9 25.4 

 12 SW1 56.8 60.0 63.6 92.5   

 12 TO-2 33.7 37.3 41.5 74.8 87.5 

 13 OPEN 24.9 27.5 30.4 50.6 56.3 
13 

Table 08. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL01 9.5 10.7 12.0 23.9 26.4 

 13 EL02 9.4 10.6 11.9 23.8 26.3 

 13 TO-1 45.7 52.0 60.7 ** **   

 13 SW1 63.3 67.1 71.8 ** **   

 13 TO-2 30.9 34.1 37.6 65.0 74.3 

 

 R SW1 71.6 76.9 83.8 ** **   

 R EL01 9.5 10.7 12.0 23.9 26.4 

 R EL02 9.4 10.6 11.9 23.8 26.3 
14 

Table 09. Results of Tenability Analysis for Scenario 09. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 G EL01 25.7 28.9 32.7 63.5 75.1 

 G LOBY 15.4 17.9 20.7 41.3 48.0 

 G EL02 27.4 30.9 35.2 70.6 86.0 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.6 1.9 2.6 10.5 12.4 

 

 2 LOBY 1.0 1.0 1.2 7.2 8.9 

 2 EL02 1.6 2.0 2.7 10.7 12.6 

 2 SW1 1.8 2.4 3.0 12.8 15.0 

 2 TO-2 4.3 5.5 6.9 20.1 22.8 

 3 EL01 2.7 3.3 4.0 13.1 15.1 

 

 3 LOBY 13.9 16.2 18.8 37.2 42.7 

 3 EL02 2.6 3.2 3.9 13.0 15.1 

 3 SW1 4.7 5.8 7.1 19.0 21.4 

 4 EL01 3.9 4.7 5.7 15.4 17.5 

 4 EL02 3.7 4.5 5.4 15.1 17.3 

 

 4 SW1 8.3 9.8 11.5 24.2 26.7 

 5 EL01 5.2 6.1 7.2 17.5 19.8 

 5 EL02 4.9 5.8 6.8 17.1 19.3 

 5 SW1 12.0 13.8 15.7 28.6 31.2 

 6 EL01 6.5 7.6 8.7 19.5 21.8 

 

 6 EL02 6.0 7.0 8.2 18.9 21.2 

 6 SW1 15.6 17.4 19.4 32.5 35.2 

 7 EL01 7.8 8.9 10.2 21.4 23.8 

 7 EL02 7.2 8.3 9.5 20.6 22.9 

 7 SW1 18.8 20.7 22.6 36.0 38.9 

 

 8 EL01 9.0 10.2 11.6 23.1 25.5 

 8 EL02 8.3 9.5 10.8 22.1 24.5 

 8 SW1 21.8 23.6 25.5 39.2 42.3 

 9 EL01 10.2 11.5 12.9 24.8 27.2 

 9 EL02 9.4 10.6 11.9 23.6 26.0 

 

 9 SW1 24.4 26.2 28.1 42.3 45.5 

 10 EL01 11.4 12.8 14.2 26.3 28.8 

 10 EL02 10.4 11.7 13.1 25.0 27.4 

 10 SW1 26.8 28.6 30.6 45.2 48.6 

 11 EL01 12.6 13.9 15.5 27.8 30.3 

 

 11 EL02 11.5 12.8 14.2 26.3 28.8 

 11 SW1 29.0 30.9 32.9 47.9 51.4 

 12 EL01 13.7 15.1 16.7 29.1 31.7 

 12 EL02 12.4 13.8 15.3 27.5 30.1 

 12 SW1 31.2 33.1 35.2 50.6 54.2 
15 

Table 09. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 OPEN 71.2 79.8 93.3 ** **   

 13 EL01 14.7 16.2 17.8 30.5 33.1 

 13 LOBY 92.5 ** **   ** **   

 13 EL02 13.4 14.8 16.4 28.7 31.3 

 13 SW1 33.4 35.3 37.5 53.1 56.7 

 

 13 TO-2 64.6 70.6 78.8 ** **   

 14 OPEN 68.1 74.7 84.0 ** **   

 14 EL01 15.7 17.3 18.9 31.7 34.4 

 14 LOBY 26.7 29.0 31.5 48.8 53.0 

 14 EL02 14.3 15.8 17.4 29.9 32.4 

 

 14 SW1 35.7 37.7 39.9 55.8 59.6 

 14 TO-2 63.6 68.8 75.6 ** **   

 15 OPEN 70.0 76.6 85.8 ** **   

 15 EL01 16.7 18.3 20.0 32.9 35.6 

 15 LOBY 24.8 26.9 29.2 45.0 48.6 

 

 15 EL02 15.2 16.7 18.4 31.0 33.6 

 15 SW1 38.5 40.5 42.8 59.1 63.0 

 15 TO-2 65.6 70.8 77.7 ** **   

 16 OPEN 54.1 59.5 65.9 ** **   

 16 EL01 17.7 19.3 21.0 34.1 36.8 

 

 16 LOBY 24.2 26.2 28.3 43.4 46.7 

 16 EL02 16.1 17.7 19.3 32.1 34.7 

 16 SW1 41.9 44.1 46.5 63.5 67.7 

 16 TO-2 43.4 47.2 51.6 82.6 93.3 

 R SW1 46.9 49.3 51.9 70.6 75.8 

 

 R EL01 17.8 19.4 21.1 34.1 36.8 

 R EL02 16.2 17.7 19.4 32.1 34.7 
16 

Table 10. Results of Tenability Analysis for Scenario 10. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.2 1.8 9.2 11.2 

 2 EL02 1.0 1.2 1.8 9.2 11.2 

 2 SW1 2.6 3.3 4.3 15.3 17.7 

 2 TO-2 6.5 8.1 10.1 24.7 27.9 

 

 3 OPEN 14.0 16.6 19.5 40.8 47.7 

 3 EL01 1.7 2.0 2.8 11.3 13.4 

 3 EL02 1.7 2.0 2.8 11.3 13.4 

 3 SW1 6.8 8.2 9.9 22.9 25.4 

 3 TO-2 40.2 46.9 55.4 ** **   

 

 4 EL01 2.4 3.0 3.8 13.1 15.3 

 4 EL02 2.4 3.0 3.8 13.1 15.3 

 4 SW1 12.4 14.3 16.2 29.7 32.4 

 5 EL01 3.2 3.9 4.8 14.7 16.9 

 5 EL02 3.1 3.9 4.8 14.6 16.9 

 

 5 SW1 18.1 20.2 22.2 36.3 39.4 

 6 EL01 3.9 4.8 5.8 16.1 18.4 

 6 EL02 3.9 4.8 5.7 16.0 18.3 

 6 SW1 23.6 25.6 27.6 42.7 46.2 

 7 EL01 4.8 5.7 6.7 17.3 19.7 

 

 7 EL02 4.7 5.6 6.7 17.3 19.6 

 7 SW1 28.5 30.6 32.8 49.2 53.0 

 8 EL01 5.5 6.5 7.6 18.4 20.9 

 8 EL02 5.5 6.4 7.5 18.4 20.8 

 8 SW1 33.3 35.6 38.0 55.5 59.6 

 

 9 EL01 6.2 7.2 8.4 19.5 22.0 

 9 EL02 6.1 7.1 8.3 19.4 21.9 

 9 SW1 38.1 40.6 43.2 61.7 66.2 

 10 EL01 6.9 7.9 9.1 20.5 23.0 

 10 EL02 6.8 7.8 9.0 20.4 22.9 

 

 10 SW1 42.9 45.5 48.4 68.0 73.3 

 11 EL01 7.5 8.6 9.8 21.4 23.9 

 11 EL02 7.5 8.5 9.8 21.3 23.8 

 11 SW1 47.7 50.6 53.6 75.0 81.5 

 12 EL01 8.1 9.3 10.6 22.2 24.8 

 

 12 EL02 8.0 9.2 10.5 22.1 24.7 

 12 SW1 52.6 55.6 58.8 83.0 91.1 

 13 EL01 8.7 9.9 11.2 23.0 25.5 

 13 EL02 8.7 9.8 11.1 22.9 25.4 

 13 SW1 57.5 60.7 64.1 92.7 ** ** 
17 

Table 10. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 14 OPEN 28.2 31.1 34.3 58.7 66.5 

 14 EL01 9.3 10.5 11.8 23.7 26.3 

 14 EL02 9.2 10.4 11.7 23.6 26.2 

 14 SW1 62.7 66.3 70.7   ** ** 

 14 TO-2 34.7 38.4 42.8 77.6 91.4 

 

 15 OPEN 26.0 28.8 31.7 52.9 59.1 

 15 EL01 9.9 11.0 12.5 24.4 27.0 

 15 EL02 9.8 11.0 12.4 24.3 26.9 

 15 TO-1 48.6 55.9 66.4   ** ** 

 15 SW1 68.9 73.5 79.2   ** ** 

 

 15 TO-2 32.4 35.7 39.4 68.9 79.4 

 16 OPEN 25.2 27.8 30.6 50.4 55.9 

 16 EL01 10.5 11.7 13.1 25.2 27.7 

 16 EL02 10.4 11.6 13.0 25.1 27.6 

 16 TO-1 45.2 51.1 59.1   ** ** 

 

 16 SW1 77.0 83.1 91.3   ** ** 

 16 TO-2 31.1 34.2 37.7 64.2 73.1 

 R SW1 88.7 96.0   ** **   

 R EL01 10.5 11.8 13.1 25.2 27.8 

 R EL02 10.4 11.7 13.0 25.1 27.6 

 
18 

Table 11. Results of Tenability Analysis for Scenario 11. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.2 1.8 9.3 11.3 

 2 EL02 1.0 1.2 1.8 9.3 11.4 

 2 SW1 2.8 3.6 4.7 16.1 18.5 

 2 TO-2 6.6 8.3 10.3 25.0 28.2 

 

 3 OPEN 13.7 16.3 19.1 40.0 46.7 

 3 EL01 1.7 2.0 2.7 11.3 13.4 

 3 EL02 1.7 2.0 2.7 11.3 13.4 

 3 SW1 7.5 9.0 10.8 24.1 26.7 

 3 TO-2 40.0 46.7 55.1 ** **   

 

 4 EL01 2.3 2.9 3.7 13.0 15.2 

 4 EL02 2.3 2.9 3.7 13.0 15.2 

 4 SW1 13.8 15.8 17.9 31.7 34.6 

 5 EL01 3.0 3.8 4.7 14.5 16.7 

 5 EL02 3.0 3.8 4.6 14.4 16.7 

 

 5 SW1 20.5 22.6 24.7 39.6 43.0 

 6 OPEN 90.1 ** **   ** **   

 6 EL01 3.8 4.7 5.6 15.8 18.1 

 6 EL02 3.8 4.6 5.5 15.7 18.0 

 6 SW1 26.8 28.9 31.2 47.9 51.9 

 

 6 TO-2 76.5 88.3 ** **   ** ** 

 7 OPEN 100.9   ** **   ** ** 

 7 EL01 4.6 5.4 6.5 17.0 19.3 

 7 EL02 4.5 5.4 6.4 16.9 19.2 

 7 SW1 33.7 36.1 38.7 57.4 62.0 

 

 7 TO-2 87.7   ** **   ** ** 

 8 EL01 5.3 6.2 7.3 18.1 20.4 

 8 EL02 5.2 6.1 7.1 18.0 20.3 

 8 SW1 41.9 44.8 47.9 69.3 75.5 

 8 TO-2 110.2   ** **   ** ** 

 

 9 EL01 5.9 6.9 8.0 19.1 21.5 

 9 EL02 5.9 6.8 7.9 19.0 21.4 

 9 SW1 52.7 56.1 59.9 89.7   

 10 EL01 6.7 7.7 8.8 20.0 22.5 

 10 EL02 6.6 7.6 8.7 19.9 22.3 

 

 10 SW1 70.1 76.6 86.1 ** **   

 11 EL01 7.3 8.4 9.6 21.0 23.4 

 11 EL02 7.1 8.2 9.5 20.8 23.2 

 12 EL01 7.9 9.0 10.3 21.8 24.3 

 12 EL02 7.8 8.9 10.1 21.6 24.1 
19 

Table 11. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL01 8.6 9.7 11.0 22.6 25.1 

 13 EL02 8.4 9.6 10.8 22.4 25.0 

 14 OPEN 45.1 51.5 60.4 ** **   

 14 EL01 9.2 10.4 11.7 23.4 26.0 

 14 EL02 9.0 10.2 11.5 23.2 25.7 

 

 15 OPEN 33.0 36.4 40.3 70.9 82.1 

 15 EL01 9.8 11.0 12.4 24.2 26.7 

 15 EL02 9.6 10.8 12.1 24.0 26.5 

 15 TO-2 39.2 43.7 49.3 92.8 ** ** 

 16 OPEN 32.8 36.1 39.8 68.9 79.2 

 

 16 EL01 10.4 11.7 13.0 25.0 27.5 

 16 EL02 10.2 11.5 12.8 24.7 27.2 

 16 TO-2 47.2 53.8 63.0   ** ** 

 R EL01 10.5 11.7 13.0 25.0 27.5 

 R EL02 10.3 11.5 12.8 24.7 27.3 

 
20 

Table 12. Results of Tenability Analysis for Scenario 12. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.3 1.8 9.3 11.2 

 2 EL02 1.0 1.3 1.8 9.4 11.4 

 2 TO-1 11.7 14.0 16.6 34.5 39.6 

 2 SW2 2.2 2.9 3.8 15.0 17.4 

 

 2 SW1 1.8 2.2 2.9 12.3 14.5 

 2 TO-2 4.2 5.4 6.9 19.9 22.6 

 3 OPEN 10.2 12.5 14.9 32.4 37.2 

 3 EL01 1.8 2.3 2.9 11.7 13.8 

 3 EL02 1.8 2.3 2.9 11.8 13.9 

 

 3 TO-1 43.3 50.9 60.6   ** ** 

 3 SW2 3.9 4.9 6.1 18.0 20.4 

 3 SW1 4.3 5.4 6.6 18.0 20.4 

 3 TO-2 26.4 29.8 33.9 64.3 74.2 

 4 OPEN 58.6 71.2 91.2   ** ** 

 

 4 EL01 2.8 3.4 4.2 13.8 16.0 

 4 EL02 2.7 3.4 4.1 13.8 16.0 

 4 SW2 5.9 7.1 8.6 20.8 23.3 

 4 SW1 7.8 9.2 10.8 23.1 25.5 

 4 TO-2 111.5   ** **   ** ** 

 

 5 OPEN 38.2 43.2 49.9   ** ** 

 5 EL01 3.7 4.5 5.4 15.6 17.9 

 5 EL02 3.7 4.4 5.4 15.5 17.8 

 5 TO-1 34.7 38.8 43.8 84.8   

 5 SW2 8.0 9.5 11.0 23.5 25.9 

 

 5 SW1 11.6 13.3 15.0 27.6 30.1 

 5 TO-2 93.1 ** **   ** **   

 6 OPEN 38.2 42.5 48.0 92.1 ** ** 

 6 EL01 4.7 5.6 6.6 17.2 19.5 

 6 EL02 4.6 5.4 6.5 17.1 19.4 

 

 6 TO-1 35.1 38.7 43.1 78.5 93.7 

 6 SW2 10.5 11.9 13.7 26.1 28.5 

 6 SW1 15.4 17.2 19.0 31.7 34.3 

 6 TO-2 85.5   ** **   ** ** 

 7 OPEN 39.7 43.8 48.9 89.6   

 

 7 EL01 5.6 6.6 7.7 18.7 21.1 

 7 EL02 5.4 6.4 7.5 18.5 20.9 

 7 TO-1 36.6 40.1 44.3 77.5 91.1 

 7 SW2 12.9 14.6 16.3 28.7 31.1 

 7 SW1 19.0 20.8 22.7 35.5 38.3 
21 

Table 12. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 7 TO-2 84.9 ** **   ** **   

 8 OPEN 41.7 45.7 50.7 89.7 ** ** 

 8 EL01 6.5 7.5 8.7 20.0 22.4 

 8 EL02 6.2 7.3 8.5 19.8 22.2 

 8 TO-1 38.7 42.1 46.3 78.4 91.2 

 

 8 SW2 15.6 17.3 19.0 31.3 33.8 

 8 SW1 22.4 24.1 26.0 39.2 42.1 

 8 TO-2 86.8   ** **   ** ** 

 9 OPEN 44.1 48.1 53.0 91.3   

 9 EL01 7.3 8.4 9.6 21.2 23.7 

 

 9 EL02 7.0 8.1 9.4 20.9 23.4 

 9 TO-1 41.0 44.5 48.7 80.3 92.8 

 9 SW2 18.3 20.0 21.8 34.1 36.6 

 9 SW1 25.4 27.2 29.0 42.8 45.8 

 9 TO-2 90.2 ** **   ** **   

 

 10 OPEN 46.8 50.9 55.8 94.0 ** ** 

 10 EL01 8.0 9.2 10.6 22.3 24.8 

 10 EL02 7.8 8.9 10.2 22.0 24.5 

 10 TO-1 43.8 47.3 51.5 83.1 95.6 

 10 SW2 21.1 22.8 24.6 37.0 39.7 

 

 10 SW1 28.3 30.1 32.0 46.2 49.4 

 10 TO-2 95.3   ** **   ** ** 

 11 OPEN 49.9 54.1 59.0 97.9   

 11 EL01 8.8 10.0 11.4 23.4 25.9 

 11 EL02 8.6 9.7 11.0 23.0 25.6 

 

 11 TO-1 46.8 50.5 54.7 86.8 99.5 

 11 SW2 24.0 25.7 27.4 40.2 43.0 

 11 SW1 31.1 33.0 35.0 49.6 52.9 

 11 TO-2 102.8 ** **   ** **   

 12 OPEN 53.4 57.6 62.6 ** **   

 

 12 EL01 9.6 10.8 12.2 24.3 26.9 

 12 EL02 9.2 10.5 11.8 24.0 26.5 

 12 TO-1 50.4 54.1 58.5 91.7 ** ** 

 12 SW2 27.0 28.7 30.5 43.8 46.7 

 12 SW1 33.9 35.8 37.9 52.9 56.3 

 

 12 TO-2 69.6 76.2 85.4   ** ** 

 13 OPEN 57.3 61.6 66.7   ** ** 

 13 EL01 10.3 11.6 13.0 25.3 27.9 

 13 EL02 9.9 11.1 12.6 24.8 27.4 

 13 TO-1 54.4 58.3 62.8 98.0   
22 

Table 12. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 SW2 30.3 32.1 34.0 47.9 51.0 

 13 SW1 36.8 38.8 40.9 56.4 59.9 

 13 TO-2 69.2 75.1 82.9 ** **   

 14 OPEN 34.6 38.1 42.2 73.2 83.9 

 14 EL01 10.9 12.3 13.7 26.1 28.7 

 

 14 EL02 10.6 11.8 13.3 25.6 28.2 

 14 TO-1 59.3 63.4 68.3 ** **   

 14 SW2 34.2 36.1 38.1 52.8 56.1 

 14 SW1 40.0 42.1 44.4 60.3 63.9 

 14 TO-2 33.4 36.8 40.6 70.1 80.3 

 

 15 OPEN 30.4 33.3 36.6 60.7 68.2 

 15 EL01 11.6 12.9 14.4 26.9 29.5 

 15 EL02 11.1 12.5 13.9 26.3 29.0 

 15 TO-1 48.9 55.0 62.5 ** **   

 15 SW2 39.0 41.0 43.3 59.1 62.7 

 

 15 SW1 43.6 45.8 48.2 64.8 68.8 

 15 TO-2 30.5 33.5 36.7 61.2 68.9 

 16 OPEN 29.0 31.8 34.8 56.6 63.0 

 16 EL01 12.2 13.6 15.1 27.6 30.3 

 16 EL02 11.8 13.1 14.7 27.1 29.8 

 

 16 TO-1 43.4 48.2 54.2 97.1 ** ** 

 16 SW2 45.8 48.2 50.7 68.8 73.6 

 16 SW1 47.9 50.2 52.8 70.5 75.2 

 16 TO-2 29.7 32.5 35.6 58.4 65.2 

 R SW1 53.2 55.8 58.5 78.9 85.0 

 

 R EL01 12.3 13.7 15.2 27.7 30.3 

 R EL02 11.8 13.2 14.7 27.2 29.8 
23 

Table 13. Results of Tenability Analysis for Scenario 13. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 2 OPEN 1.0 1.0 1.0 4.9 6.2 

 2 EL01 1.0 1.2 1.8 9.2 11.2 

 2 EL02 1.0 1.2 1.8 9.2 11.2 

 2 SW1 2.6 3.3 4.3 15.3 17.7 

 2 TO-2 6.5 8.1 10.1 24.7 27.9 

 

 3 OPEN 13.9 16.6 19.4 40.7 47.6 

 3 EL01 1.7 2.0 2.8 11.3 13.4 

 3 EL02 1.7 2.0 2.8 11.3 13.4 

 3 SW1 6.8 8.2 9.9 22.9 25.4 

 3 TO-2 40.1 46.7 55.2   ** ** 

 

 4 EL01 2.4 3.0 3.8 13.1 15.3 

 4 EL02 2.4 3.0 3.8 13.1 15.3 

 4 SW1 12.3 14.2 16.2 29.7 32.4 

 5 EL01 3.2 3.9 4.8 14.7 16.9 

 5 EL02 3.1 3.9 4.8 14.6 16.9 

 

 5 SW1 18.1 20.1 22.2 36.2 39.3 

 6 EL01 3.9 4.8 5.8 16.1 18.4 

 6 EL02 3.9 4.8 5.7 16.0 18.3 

 6 SW1 23.5 25.5 27.6 42.7 46.2 

 7 EL01 4.8 5.7 6.7 17.3 19.7 

 

 7 EL02 4.7 5.6 6.7 17.3 19.6 

 7 SW1 28.5 30.5 32.8 49.1 52.9 

 8 EL01 5.5 6.5 7.6 18.4 20.9 

 8 EL02 5.5 6.4 7.5 18.4 20.8 

 8 SW1 33.3 35.5 37.9 55.4 59.5 

 

 9 EL01 6.2 7.2 8.4 19.5 22.0 

 9 EL02 6.1 7.1 8.3 19.4 21.9 

 9 SW1 38.0 40.5 43.1 61.6 66.1 

 10 EL01 6.9 7.9 9.1 20.5 23.0 

 10 EL02 6.8 7.8 9.0 20.4 22.9 

 

 10 SW1 42.8 45.5 48.3 67.9 73.2 

 11 EL01 7.5 8.6 9.8 21.4 23.9 

 11 EL02 7.5 8.5 9.8 21.3 23.8 

 11 SW1 47.7 50.5 53.5 74.8 81.3 

 12 EL01 8.1 9.3 10.6 22.2 24.8 

 

 12 EL02 8.0 9.2 10.5 22.1 24.7 

 12 SW1 52.5 55.5 58.7 82.8 90.9 

 13 EL01 8.7 9.9 11.2 23.0 25.6 

 13 EL02 8.7 9.8 11.1 22.9 25.4 

 13 SW1 57.4 60.6 64.0 92.4   
24 

Table 13. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 14 OPEN 28.2 31.1 34.3 58.7 66.5 

 14 EL01 9.3 10.5 11.8 23.7 26.3 

 14 EL02 9.2 10.4 11.7 23.6 26.2 

 14 SW1 62.6 66.2 70.6 ** **   

 14 TO-2 34.7 38.4 42.8 77.6 91.4 

 

 15 OPEN 26.1 28.8 31.7 52.9 59.1 

 15 EL01 9.9 11.0 12.5 24.4 27.0 

 15 EL02 9.8 11.0 12.4 24.3 26.9 

 15 TO-1 48.6 55.9 66.4 ** **   

 15 SW1 68.8 73.3 79.0 ** **   

 

 15 TO-2 32.4 35.7 39.4 68.9 79.4 

 16 OPEN 25.2 27.8 30.6 50.4 55.9 

 16 EL01 10.5 11.7 13.1 25.2 27.7 

 16 EL02 10.4 11.6 13.0 25.1 27.6 

 16 TO-1 45.2 51.1 59.1 ** **   

 

 16 SW1 76.8 82.9 91.1 ** **   

 16 TO-2 31.1 34.2 37.7 64.3 73.1 

 R SW1 88.4 95.8 ** **   ** ** 

 R EL01 10.5 11.8 13.1 25.2 27.8 

 R EL02 10.4 11.7 13.0 25.1 27.6 

 
25 

Table 14. Results of Tenability Analysis for Scenario 14. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 40.6 47.8 57.1   ** ** 

 B L-SR 65.5 77.0 92.6   ** ** 

 B L-MR 64.9 76.0 90.7   ** ** 

 B L-HR 59.6 69.4 82.2   ** ** 

 B EL-S 91.7   ** **   ** ** 

 

 B EL01 59.2 69.0 81.8   ** ** 

 B EL02 70.4 82.7 99.3   ** ** 

 B EL03 63.6 74.1 87.9   ** ** 

 B EL04 54.5 63.3 74.7   ** ** 

 B SW2 72.2 85.3   ** **   

 

 G OPEN 10.3 12.6 15.0 32.7 37.6 

 G SW1 18.5 21.3 24.4 48.9 57.3 

 G L-SR 17.7 20.4 23.3 44.8 51.2 

 G L-MR 16.6 19.1 21.9 41.9 47.6 

 G L-HR 15.5 17.9 20.6 39.7 45.0 

 

 G EL-S 26.5 29.7 33.4 60.5 68.9 

 G EL01 17.6 20.3 23.2 44.9 51.5 

 G EL02 20.2 23.0 26.0 48.9 55.7 

 G EL03 19.8 22.6 25.6 48.5 55.5 

 G EL04 19.7 22.5 25.5 48.5 55.5 

 

 G T01 17.2 19.8 22.6 42.9 48.7 

 G T02 19.9 22.7 25.7 48.7 55.7 

 G SW2 18.9 21.7 24.7 47.4 54.3 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.7 2.0 10.6 12.7 

 

 2 L-SR 1.0 1.7 2.0 9.8 11.7 

 2 CR01 1.6 1.9 2.6 11.2 13.3 

 2 CR02 1.4 1.8 2.4 10.7 12.7 

 2 EL-S 3.8 4.7 5.8 17.0 19.4 

 2 EL01 1.2 1.8 2.2 10.6 12.7 

 

 2 EL02 1.9 2.6 3.3 13.2 15.5 

 2 EL03 1.8 2.4 3.0 13.0 15.2 

 2 EL04 1.8 2.4 3.0 13.0 15.2 

 2 T01 1.8 2.2 2.9 12.2 14.3 

 2 T02 2.2 2.9 3.8 14.1 16.4 

 

 2 SW2 1.0 1.5 1.9 9.5 11.4 

 3 SW1 2.0 2.7 3.5 13.0 15.1 

 3 L-SR 22.1 25.1 28.4 61.0 76.7 

 3 EL-S 5.9 7.1 8.5 20.6 23.2 

 3 EL01 2.8 3.5 4.4 14.5 16.7 
26 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL02 4.5 5.5 6.7 18.7 21.2 

 3 EL03 3.4 4.2 5.3 16.4 18.8 

 3 EL04 3.2 4.0 5.1 16.1 18.5 

 3 SW2 2.8 3.5 4.3 14.0 16.2 

 4 SW1 3.1 3.9 4.9 15.1 17.3 

 

 4 L-SR 24.4 27.3 30.8 65.5 83.9 

 4 EL-S 8.0 9.4 10.9 23.7 26.4 

 4 EL01 4.5 5.5 6.6 17.7 20.1 

 4 EL02 7.7 9.0 10.7 24.0 26.8 

 4 EL03 5.0 6.1 7.4 19.3 21.9 

 

 4 EL04 4.8 5.8 7.0 18.7 21.3 

 4 SW2 4.7 5.7 6.8 17.6 19.9 

 5 SW1 4.3 5.2 6.3 17.0 19.2 

 5 L-SR 26.3 29.3 33.0 69.6 91.3 

 5 EL-S 9.9 11.5 13.1 26.3 29.1 

 

 5 EL01 6.2 7.4 8.7 20.5 23.1 

 5 EL02 11.3 13.0 14.9 29.2 32.3 

 5 EL03 6.8 7.9 9.4 21.9 24.6 

 5 EL04 6.2 7.4 8.8 21.0 23.6 

 5 SW2 6.7 7.8 9.1 20.6 22.8 

 

 6 SW1 5.5 6.5 7.7 18.7 21.0 

 6 L-SR 28.0 31.2 35.0 73.5 99.4 

 6 EL-S 11.7 13.3 15.1 28.7 31.5 

 6 EL01 7.9 9.1 10.6 23.0 25.6 

 6 EL02 15.0 17.0 19.1 34.3 37.7 

 

 6 EL03 8.4 9.7 11.3 24.2 27.0 

 6 EL04 7.7 8.9 10.4 23.0 25.7 

 6 SW2 8.6 9.9 11.3 23.0 25.2 

 7 SW1 6.6 7.7 9.0 20.2 22.5 

 7 L-SR 29.7 32.9 37.0 77.5 ** ** 

 

 7 EL-S 13.4 15.0 16.9 30.7 33.6 

 7 EL01 9.5 10.8 12.4 25.2 28.0 

 7 EL02 18.8 20.9 23.3 39.4 43.0 

 7 EL03 9.9 11.4 13.0 26.3 29.1 

 7 EL04 8.9 10.3 11.9 24.8 27.5 

 

 7 SW2 10.3 11.7 13.3 25.1 27.3 

 8 SW1 7.7 8.9 10.3 21.7 24.0 

 8 L-SR 31.2 34.6 38.9 81.6   

 8 EL-S 14.9 16.6 18.6 32.6 35.5 

 8 EL01 10.9 12.5 14.1 27.3 30.1 
27 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL02 22.6 24.9 27.4 44.3 48.3 

 8 EL03 11.3 12.9 14.6 28.2 31.1 

 8 EL04 10.1 11.6 13.3 26.4 29.1 

 8 SW2 11.9 13.5 15.1 26.8 29.1 

 9 SW1 8.8 10.0 11.5 23.0 25.2 

 

 9 L-SR 32.7 36.2 40.7 86.2 ** ** 

 9 EL-S 16.3 18.1 20.1 34.3 37.3 

 9 EL01 12.4 13.9 15.7 29.1 32.0 

 9 EL02 26.3 28.8 31.4 49.2 53.5 

 9 EL03 12.7 14.3 16.1 30.0 32.9 

 

 9 EL04 11.3 12.8 14.5 27.8 30.6 

 9 SW2 13.5 15.0 16.7 28.4 30.7 

 10 SW1 9.9 11.2 12.7 24.2 26.4 

 10 L-SR 34.2 37.9 42.7 91.6   

 10 EL-S 17.6 19.5 21.5 35.9 39.0 

 

 10 EL01 13.7 15.3 17.1 30.8 33.7 

 10 EL02 30.0 32.6 35.4 54.1 58.6 

 10 EL03 13.9 15.6 17.5 31.6 34.6 

 10 EL04 12.4 13.9 15.7 29.1 31.9 

 10 SW2 14.9 16.5 18.1 29.8 32.1 

 

 11 SW1 10.9 12.3 13.8 25.4 27.7 

 11 L-SR 36.1 40.0 45.1 98.5 ** ** 

 11 EL-S 18.8 20.7 22.8 37.3 40.5 

 11 EL01 14.9 16.6 18.5 32.4 35.3 

 11 EL02 33.7 36.4 39.3 58.8 63.6 

 

 11 EL03 15.1 16.8 18.8 33.1 36.2 

 11 EL04 13.4 15.0 16.8 30.3 33.2 

 11 SW2 16.2 17.8 19.6 31.4 33.8 

 12 SW1 11.9 13.3 14.9 26.7 29.0 

 12 L-SR 38.1 42.3 47.9   ** ** 

 

 12 EL-S 20.0 21.9 24.0 38.7 41.9 

 12 EL01 16.1 17.9 19.8 33.9 36.9 

 12 EL02 37.3 40.1 43.1 63.5 68.5 

 12 EL03 16.2 18.0 20.0 34.5 37.6 

 12 EL04 14.4 16.0 17.8 31.5 34.4 

 

 12 SW2 17.5 19.1 20.9 32.9 35.3 

 13 SW1 12.9 14.3 15.9 27.9 30.2 

 13 L-SR 40.3 44.8 51.1   ** ** 

 13 EL-S 21.1 23.1 25.2 40.0 43.3 

 13 EL01 17.3 19.0 21.0 35.3 38.3 
28 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL02 40.8 43.8 47.0 68.1 73.4 

 13 EL03 17.3 19.1 21.1 35.8 39.0 

 13 EL04 15.3 16.9 18.8 32.6 35.5 

 13 SW2 18.7 20.4 22.1 34.3 36.8 

 14 SW1 13.8 15.3 16.9 29.0 31.3 

 

 14 L-SR 42.3 47.1 53.9   ** ** 

 14 L-MR 28.1 30.6 33.2 51.4 55.8 

 14 EL-S 22.1 24.1 26.3 41.2 44.5 

 14 EL01 18.3 20.1 22.1 36.5 39.6 

 14 EL02 36.2 39.1 42.3 63.7 69.3 

 

 14 EL03 18.3 20.2 22.2 37.1 40.3 

 14 EL04 16.1 17.8 19.7 33.6 36.5 

 14 SW2 19.9 21.6 23.3 35.7 38.2 

 15 SW1 14.7 16.2 17.9 30.0 32.4 

 15 L-SR 42.1 46.5 52.4   ** ** 

 

 15 L-MR 28.4 30.8 33.4 51.2 55.5 

 15 EL-S 23.1 25.1 27.3 42.3 45.6 

 15 EL01 19.3 21.1 23.2 37.7 40.9 

 15 EL02 35.5 38.3 41.3 62.0 67.4 

 15 EL03 19.3 21.2 23.3 38.2 41.5 

 

 15 EL04 16.9 18.7 20.6 34.6 37.5 

 15 T01 37.1 40.4 44.4 78.6 94.1 

 15 SW2 20.9 22.6 24.4 36.9 39.5 

 16 SW1 15.6 17.1 18.8 31.1 33.5 

 16 L-SR 44.5 49.3 55.8   ** ** 

 

 16 L-MR 29.3 31.7 34.3 52.1 56.4 

 16 EL-S 24.0 26.0 28.2 43.4 46.7 

 16 EL01 20.3 22.2 24.2 38.9 42.1 

 16 EL02 35.8 38.5 41.5 61.7 67.0 

 16 EL03 20.2 22.1 24.3 39.3 42.7 

 

 16 EL04 17.8 19.5 21.5 35.5 38.5 

 16 SW2 21.9 23.7 25.5 38.1 40.7 

 17 SW1 16.5 18.0 19.7 32.1 34.5 

 17 L-SR 49.8 56.1 65.2   ** ** 

 17 L-MR 30.3 32.7 35.3 53.2 57.5 

 

 17 EL-S 24.9 27.0 29.2 44.4 47.8 

 17 EL01 21.4 23.2 25.3 40.1 43.3 

 17 EL02 36.3 39.0 42.0 62.1 67.2 

 17 EL03 21.1 23.0 25.2 40.4 43.8 

 17 EL04 18.5 20.3 22.2 36.3 39.4 
29 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 17 SW2 22.9 24.7 26.5 39.2 41.9 

 18 SW1 17.3 18.9 20.7 33.1 35.5 

 18 L-MR 31.3 33.8 36.4 54.4 58.7 

 18 EL-S 25.8 27.9 30.1 45.4 48.8 

 18 EL01 22.4 24.3 26.4 41.3 44.5 

 

 18 EL02 37.0 39.8 42.7 62.6 67.7 

 18 EL03 21.9 23.9 26.1 41.4 44.8 

 18 EL04 19.2 21.0 23.0 37.2 40.2 

 18 SW2 23.9 25.7 27.5 40.3 43.0 

 19 SW1 18.2 19.8 21.6 34.0 36.5 

 

 19 L-MR 32.3 34.8 37.4 55.5 59.9 

 19 EL-S 26.7 28.7 31.0 46.3 49.8 

 19 EL01 23.4 25.3 27.5 42.5 45.8 

 19 EL02 37.8 40.5 43.5 63.4 68.4 

 19 EL03 22.8 24.8 26.9 42.4 45.9 

 

 19 EL04 19.9 21.8 23.8 38.0 41.1 

 19 SW2 24.9 26.7 28.5 41.4 44.1 

 20 OPEN 65.0 72.0 81.6   ** ** 

 20 SW1 19.0 20.7 22.5 35.0 37.5 

 20 L-SR 41.4 44.3 47.4 69.0 74.7 

 

 20 L-MR 33.4 35.9 38.5 56.7 61.1 

 20 CR01 83.2 93.4   ** **   

 20 EL-S 27.5 29.6 31.8 47.3 50.7 

 20 EL01 24.4 26.4 28.6 43.7 47.0 

 20 EL02 38.7 41.4 44.3 64.2 69.2 

 

 20 EL03 23.6 25.6 27.8 43.4 46.8 

 20 EL04 20.6 22.5 24.5 38.8 41.9 

 20 T01 87.1 98.4 ** **   ** ** 

 20 T02 49.1 52.8 56.9 85.4 94.4 

 20 SW2 25.8 27.6 29.5 42.5 45.2 

 

 21 OPEN 47.9 51.9 56.9 93.5   

 21 SW1 19.9 21.6 23.3 36.0 38.5 

 21 L-SR 40.0 42.7 45.6 65.6 70.8 

 21 L-MR 34.4 36.9 39.6 57.9 62.3 

 21 CR01 61.3 67.0 74.1 ** **   

 

 21 EL-S 28.4 30.5 32.7 48.2 51.7 

 21 EL01 25.4 27.5 29.6 44.9 48.2 

 21 EL02 39.5 42.2 45.1 65.0 70.0 

 21 EL03 24.3 26.4 28.6 44.3 47.8 

 21 EL04 21.3 23.1 25.2 39.5 42.7 
30 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 21 T01 48.6 53.1 58.8 ** **   

 21 T02 44.5 47.8 51.5 77.0 84.5 

 21 SW2 26.8 28.6 30.5 43.5 46.3 

 22 OPEN 45.8 49.4 53.7 85.2 96.7 

 22 SW1 20.8 22.5 24.3 37.0 39.5 

 

 22 L-SR 39.4 42.0 44.8 64.0 68.8 

 22 L-MR 35.4 37.9 40.6 58.9 63.3 

 22 CR01 58.3 63.3 69.2 ** **   

 22 EL-S 29.2 31.4 33.6 49.2 52.7 

 22 EL01 26.5 28.5 30.7 46.1 49.5 

 

 22 EL02 40.3 43.0 46.0 65.8 70.8 

 22 EL03 25.0 27.1 29.4 45.2 48.7 

 22 EL04 21.9 23.8 25.8 40.3 43.4 

 22 T01 46.3 50.2 54.9 91.0 ** ** 

 22 T02 43.2 46.3 49.7 73.6 80.3 

 

 22 SW2 27.7 29.5 31.4 44.6 47.4 

 23 OPEN 45.2 48.6 52.5 81.6 91.5 

 23 SW1 21.7 23.4 25.2 38.0 40.6 

 23 L-SR 39.3 41.9 44.6 63.3 67.9 

 23 L-MR 36.3 38.8 41.5 59.8 64.2 

 

 23 CR01 57.3 61.9 67.4   ** ** 

 23 EL-S 30.1 32.2 34.5 50.2 53.7 

 23 EL01 27.5 29.6 31.8 47.3 50.7 

 23 EL02 41.1 43.8 46.8 66.6 71.6 

 23 EL03 25.8 27.9 30.1 46.0 49.6 

 

 23 EL04 22.6 24.5 26.5 41.0 44.2 

 23 T01 45.6 49.2 53.5 86.3 98.7 

 23 T02 42.8 45.8 49.0 71.9 78.2 

 23 SW2 28.7 30.5 32.4 45.7 48.5 

 24 OPEN 45.1 48.3 52.0 79.6 88.6 

 

 24 SW1 22.6 24.4 26.2 39.0 41.6 

 24 L-SR 39.5 42.0 44.7 63.1 67.5 

 24 L-MR 37.0 39.6 42.3 60.6 65.0 

 24 CR01 57.0 61.5 66.7   ** ** 

 24 EL-S 31.0 33.1 35.5 51.2 54.7 

 

 24 EL01 28.6 30.7 32.9 48.5 52.0 

 24 EL02 41.9 44.6 47.6 67.4 72.3 

 24 EL03 26.5 28.6 30.9 46.8 50.4 

 24 EL04 23.1 25.0 27.1 41.7 44.9 

 24 T01 45.5 48.9 52.9 83.6 94.7 
31 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 24 T02 42.8 45.7 48.8 71.0 77.0 

 24 SW2 29.7 31.5 33.4 46.8 49.7 

 25 OPEN 45.2 48.3 51.8 78.1 86.4 

 25 SW1 23.6 25.4 27.2 40.1 42.8 

 25 L-SR 39.7 42.2 44.9 63.0 67.3 

 

 25 L-MR 37.5 40.0 42.7 60.6 64.9 

 25 CR01 57.3 61.6 66.6 99.7   

 25 EL-S 31.9 34.1 36.4 52.2 55.8 

 25 EL01 29.6 31.7 34.0 49.7 53.2 

 25 EL02 42.6 45.4 48.3 68.1 73.0 

 

 25 EL03 27.1 29.3 31.6 47.6 51.2 

 25 EL04 23.7 25.7 27.7 42.3 45.5 

 25 T01 45.6 48.8 52.6 81.7 91.8 

 25 T02 43.0 45.8 48.9 70.4 76.2 

 25 SW2 30.7 32.6 34.5 48.0 50.9 

 

 26 OPEN 45.7 48.7 52.2 77.5 85.2 

 26 SW1 24.7 26.4 28.3 41.3 44.0 

 26 L-SR 40.3 42.8 45.5 63.5 67.7 

 26 L-MR 38.0 40.5 43.1 60.9 65.1 

 26 L-HR 56.6 60.6 65.3 96.1 ** ** 

 

 26 EL-S 32.9 35.1 37.4 53.3 56.9 

 26 EL01 30.7 32.8 35.1 50.9 54.4 

 26 EL02 43.4 46.1 49.1 68.8 73.6 

 26 EL03 27.8 29.9 32.3 48.4 52.1 

 26 EL04 24.3 26.2 28.3 43.0 46.2 

 

 26 T01 46.2 49.4 53.1 81.5 91.0 

 26 T02 43.6 46.4 49.4 70.7 76.3 

 26 SW2 31.8 33.6 35.6 49.2 52.1 

 27 OPEN 46.5 49.5 53.0 78.1 85.8 

 27 SW1 25.8 27.6 29.4 42.6 45.3 

 

 27 L-SR 40.8 43.3 45.9 63.8 68.0 

 27 L-HR 58.3 62.5 67.2 98.7   

 27 EL-S 33.9 36.1 38.5 54.4 58.0 

 27 EL03 28.4 30.6 32.9 49.2 52.8 

 27 EL04 24.8 26.8 28.9 43.6 46.8 

 

 27 T01 46.7 49.8 53.5 80.9 90.0 

 27 T02 44.1 46.8 49.8 70.7 76.1 

 27 SW2 32.9 34.8 36.7 50.5 53.4 

 28 OPEN 47.5 50.6 54.0 78.9 86.4 

 28 SW1 27.0 28.8 30.7 43.9 46.7 
32 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 28 L-SR 41.7 44.1 46.8 64.6 68.8 

 28 L-HR 60.1 64.3 69.2 ** **   

 28 EL-S 35.0 37.2 39.6 55.7 59.3 

 28 EL03 29.0 31.2 33.6 49.9 53.6 

 28 EL04 25.4 27.3 29.4 44.2 47.4 

 

 28 T01 47.8 50.9 54.5 81.7 90.6 

 28 T02 45.0 47.8 50.8 71.5 76.9 

 28 SW2 34.0 35.9 37.9 51.8 54.8 

 29 OPEN 48.8 51.9 55.4 80.2 87.6 

 29 SW1 28.3 30.1 32.0 45.5 48.3 

 

 29 L-SR 42.7 45.2 47.8 65.7 69.9 

 29 L-HR 62.4 66.7 71.7 ** **   

 29 EL-S 36.2 38.4 40.8 57.0 60.6 

 29 EL03 29.6 31.8 34.2 50.5 54.3 

 29 EL04 25.9 27.8 29.9 44.8 48.0 

 

 29 T01 49.1 52.3 55.9 82.9 91.7 

 29 T02 46.2 48.9 51.9 72.6 78.0 

 29 SW2 35.3 37.2 39.3 53.3 56.3 

 30 OPEN 50.4 53.5 57.0 81.8 89.1 

 30 SW1 29.8 31.7 33.6 47.2 50.1 

 

 30 L-SR 43.8 46.4 49.0 67.0 71.2 

 30 L-HR 44.3 47.5 51.0 76.6 84.4 

 30 EL-S 37.4 39.7 42.1 58.4 62.1 

 30 EL03 30.2 32.4 34.8 51.2 55.0 

 30 EL04 26.4 28.4 30.5 45.3 48.6 

 

 30 T01 50.7 53.9 57.6 84.6 93.4 

 30 T02 47.6 50.3 53.3 74.0 79.3 

 30 SW2 36.7 38.7 40.7 54.9 58.0 

 31 OPEN 52.2 55.4 58.9 83.7 91.1 

 31 SW1 31.5 33.4 35.4 49.2 52.1 

 

 31 L-SR 45.2 47.7 50.4 68.4 72.7 

 31 L-HR 41.3 44.1 47.2 69.3 75.6 

 31 EL-S 38.8 41.0 43.5 59.9 63.6 

 31 EL03 30.8 33.0 35.4 51.8 55.6 

 31 EL04 26.9 28.8 31.0 45.9 49.2 

 

 31 T01 52.6 55.9 59.6 86.8 95.5 

 31 T02 49.1 51.9 54.9 75.7 81.0 

 31 SW2 38.2 40.2 42.3 56.7 59.8 

 32 OPEN 54.5 57.7 61.3 86.3 93.6 

 32 SW1 33.6 35.5 37.5 51.6 54.6 
33 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 32 L-SR 46.7 49.2 51.9 70.1 74.3 

 32 L-HR 40.2 42.9 45.8 66.6 72.2 

 32 EL-S 40.3 42.6 45.0 61.6 65.4 

 32 EL03 31.3 33.5 35.9 52.4 56.2 

 32 EL04 27.4 29.4 31.5 46.4 49.7 

 

 32 T01 54.9 58.3 62.1 89.6 98.4 

 32 T02 50.9 53.7 56.8 77.6 82.9 

 32 SW2 39.9 41.9 44.0 58.7 61.9 

 33 OPEN 57.3 60.6 64.2 89.5 96.9 

 33 SW1 36.0 38.0 40.1 54.5 57.6 

 

 33 L-SR 48.4 50.9 53.7 72.0 76.3 

 33 L-HR 39.7 42.3 45.1 65.1 70.4 

 33 EL-S 42.0 44.3 46.8 63.6 67.4 

 33 EL03 31.8 34.0 36.5 53.1 56.9 

 33 EL04 27.8 29.8 32.0 47.0 50.3 

 

 33 T01 58.0 61.5 65.5 93.4 ** ** 

 33 T02 53.0 55.9 59.0 80.0 85.3 

 33 SW2 41.9 43.9 46.1 61.0 64.2 

 34 OPEN 60.8 64.2 68.0 93.8   

 34 SW1 39.3 41.4 43.5 58.5 61.8 

 

 34 L-SR 50.3 52.9 55.7 74.3 78.7 

 34 L-HR 39.4 42.0 44.8 64.3 69.3 

 34 EL-S 43.9 46.3 48.8 65.8 69.7 

 34 EL03 32.3 34.6 37.0 53.6 57.4 

 34 EL04 28.3 30.3 32.5 47.5 50.8 

 

 34 T01 52.7 56.5 60.8 89.3 97.9 

 34 T02 55.5 58.5 61.7 82.8 88.2 

 34 SW2 44.1 46.2 48.5 63.7 67.0 

 35 OPEN 66.0 69.7 73.7 ** **   

 35 SW1 44.2 46.4 48.8 64.9 68.5 

 

 35 L-SR 52.6 55.3 58.1 77.0 81.4 

 35 L-HR 40.1 42.7 45.5 65.2 70.3 

 35 EL-S 46.2 48.6 51.2 68.5 72.4 

 35 EL03 32.8 35.1 37.5 54.2 58.0 

 35 EL04 28.8 30.8 33.0 48.0 51.4 

 

 35 T01 62.0 66.7 72.0 ** **   

 35 T02 58.5 61.6 64.8 86.4 91.9 

 35 SW2 46.8 49.0 51.3 67.0 70.5 

 36 MECH 67.4 71.0 74.9 ** **   

 36 ELME 70.8 74.7 79.1 ** **   
34 

Table 14. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 36 EL-S 48.9 51.4 54.0 71.7 75.7 

 36 EL03 32.9 35.1 37.6 54.2 58.1 

 36 EL04 28.8 30.9 33.0 48.1 51.4 

 36 SW2 50.3 52.6 54.9 71.2 74.9 

 R SW2 54.9 57.3 59.8 77.1 81.0 

 
35 

Table 15. Results of Tenability Analysis for Scenario 15. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 53.4 65.1 83.5 ** **   

 B L-SR 83.2 ** **   ** **   

 B L-MR 47.9 57.6 71.1 ** **   

 B L-HR 40.2 47.5 57.4 ** **   

 B EL01 83.2 ** **   ** **   

 

 B EL02 81.6 99.5 ** **   ** ** 

 B EL03 61.9 73.1 88.9   ** ** 

 B EL04 65.1 77.6 96.5   ** ** 

 B SW2 91.2   ** **   ** ** 

 G OPEN 7.7 9.7 11.9 27.9 31.7 

 

 G SW1 22.4 25.6 29.2 60.3 72.3 

 G L-SR 16.7 19.3 22.1 42.3 48.1 

 G EL-S 29.8 33.3 37.5 67.5 77.1 

 G EL01 11.1 13.3 15.6 32.4 36.6 

 G EL02 11.1 13.2 15.6 32.3 36.5 

 

 G EL03 9.8 11.8 14.1 30.4 34.5 

 G EL04 9.8 11.9 14.2 30.6 34.7 

 G T01 16.3 18.8 21.5 40.9 46.3 

 G T02 19.0 21.7 24.6 46.3 52.6 

 G SW2 20.9 23.9 27.1 52.0 59.9 

 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.6 2.0 10.3 12.4 

 2 L-SR 1.0 1.7 2.0 9.9 11.8 

 2 CR01 1.7 2.0 2.8 11.7 13.7 

 2 CR02 1.5 1.9 2.6 11.1 13.1 

 

 2 EL-S 3.8 4.7 5.8 16.8 19.1 

 2 EL01 1.5 1.9 2.6 11.9 14.1 

 2 EL02 2.0 2.8 3.8 14.7 17.2 

 2 EL03 2.1 2.9 3.9 15.6 18.3 

 2 EL04 2.1 2.9 3.9 15.5 18.1 

 

 2 T01 1.8 2.4 3.0 12.5 14.7 

 2 T02 2.2 2.9 3.8 14.2 16.4 

 2 SW2 1.0 1.5 1.9 9.4 11.3 

 3 SW1 2.2 2.9 3.7 13.2 15.3 

 3 L-SR 21.0 23.8 26.8 54.1 65.1 

 

 3 CR02 33.3 38.7 46.0   ** ** 

 3 EL-S 6.4 7.6 9.0 21.2 23.8 

 3 EL01 2.6 3.2 4.0 14.4 16.7 

 3 EL02 3.7 4.7 5.8 17.7 20.3 

 3 EL03 3.0 3.9 5.0 17.1 19.8 
36 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL04 3.0 3.9 4.9 16.9 19.6 

 3 SW2 3.0 3.8 4.8 14.8 17.0 

 4 SW1 3.6 4.4 5.3 15.7 17.9 

 4 L-SR 23.6 26.4 29.6 58.8 71.2 

 4 EL-S 8.8 10.3 11.9 24.9 27.5 

 

 4 EL01 3.8 4.6 5.7 16.7 19.1 

 4 EL02 5.6 6.7 8.1 20.7 23.4 

 4 EL03 3.9 4.9 6.1 18.5 21.2 

 4 EL04 3.9 4.8 6.0 18.3 21.0 

 4 SW2 5.4 6.5 7.7 18.9 21.2 

 

 5 SW1 4.9 5.9 7.0 17.9 20.2 

 5 L-SR 25.9 28.8 32.1 63.2 77.2 

 5 EL-S 11.1 12.7 14.5 28.0 30.7 

 5 EL01 5.0 6.0 7.2 18.8 21.3 

 5 EL02 7.5 8.9 10.5 23.6 26.4 

 

 5 EL03 4.8 5.9 7.1 19.8 22.5 

 5 EL04 4.7 5.8 7.0 19.5 22.3 

 5 SW2 7.7 9.0 10.5 22.2 24.5 

 6 SW1 6.3 7.4 8.7 19.9 22.1 

 6 L-SR 27.9 30.9 34.4 67.3 83.6 

 

 6 EL-S 13.2 14.9 16.8 30.6 33.5 

 6 EL01 6.3 7.4 8.7 20.7 23.3 

 6 EL02 9.6 11.1 12.8 26.5 29.4 

 6 EL03 5.7 6.8 8.2 21.1 23.8 

 6 EL04 5.6 6.7 8.0 20.8 23.5 

 

 6 SW2 9.9 11.3 12.9 24.9 27.1 

 7 SW1 7.6 8.8 10.2 21.6 23.9 

 7 L-SR 29.8 32.8 36.6 71.5 90.6 

 7 EL-S 15.1 16.9 18.9 33.0 36.0 

 7 EL01 7.5 8.7 10.1 22.4 25.1 

 

 7 EL02 11.7 13.4 15.2 29.3 32.4 

 7 EL03 6.5 7.7 9.2 22.2 25.1 

 7 EL04 6.4 7.6 9.0 21.9 24.7 

 7 SW2 11.9 13.4 15.1 27.1 29.3 

 8 SW1 8.9 10.2 11.6 23.2 25.4 

 

 8 L-SR 31.5 34.7 38.6 75.7 98.8 

 8 EL-S 16.8 18.7 20.7 35.1 38.2 

 8 EL01 8.7 9.9 11.5 24.1 26.8 

 8 EL02 13.9 15.7 17.6 32.2 35.3 

 8 EL03 7.3 8.6 10.1 23.4 26.2 
37 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL04 7.1 8.4 9.9 23.0 25.8 

 8 SW2 13.7 15.3 17.0 29.0 31.3 

 9 SW1 10.1 11.5 13.0 24.6 26.8 

 9 L-SR 33.2 36.5 40.6 80.2   

 9 EL-S 18.4 20.4 22.4 37.1 40.2 

 

 9 EL01 9.8 11.2 12.8 25.7 28.4 

 9 EL02 16.0 17.9 20.0 34.9 38.2 

 9 EL03 8.1 9.5 11.0 24.5 27.3 

 9 EL04 7.9 9.3 10.8 24.0 26.9 

 9 SW2 15.3 16.9 18.7 30.6 33.0 

 

 10 SW1 11.3 12.7 14.3 25.9 28.1 

 10 L-SR 34.8 38.3 42.6 85.2 ** ** 

 10 EL-S 19.9 21.9 24.0 38.8 42.0 

 10 EL01 10.9 12.4 13.9 27.1 29.9 

 10 EL02 18.2 20.2 22.3 37.6 41.0 

 

 10 EL03 8.9 10.3 11.9 25.5 28.4 

 10 EL04 8.7 10.0 11.7 25.0 27.9 

 10 SW2 16.8 18.5 20.2 32.1 34.6 

 11 SW1 12.5 13.9 15.5 27.3 29.5 

 11 L-SR 36.7 40.4 45.1 91.6   

 

 11 EL-S 21.3 23.3 25.5 40.4 43.7 

 11 EL01 11.9 13.5 15.1 28.5 31.3 

 11 EL02 20.4 22.4 24.7 40.3 43.9 

 11 EL03 9.7 11.1 12.8 26.5 29.4 

 11 EL04 9.4 10.8 12.5 26.0 28.8 

 

 11 SW2 18.2 19.9 21.7 33.9 36.3 

 12 SW1 13.6 15.0 16.7 28.6 30.9 

 12 L-SR 38.7 42.7 47.8 99.6 ** ** 

 12 EL-S 22.6 24.6 26.8 42.0 45.3 

 12 EL01 12.9 14.5 16.3 29.8 32.7 

 

 12 EL02 22.5 24.6 26.9 43.0 46.6 

 12 EL03 10.4 11.9 13.6 27.4 30.4 

 12 EL04 10.1 11.6 13.2 26.9 29.7 

 12 SW2 19.6 21.3 23.0 35.4 38.0 

 13 SW1 14.6 16.1 17.8 29.8 32.2 

 

 13 L-SR 40.8 45.0 50.7   ** ** 

 13 EL-S 23.8 25.9 28.1 43.4 46.8 

 13 EL01 13.9 15.6 17.3 31.0 34.0 

 13 EL02 24.6 26.8 29.2 45.6 49.4 

 13 EL03 11.1 12.7 14.4 28.4 31.3 
38 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL04 10.8 12.3 14.0 27.7 30.6 

 13 SW2 20.8 22.6 24.4 36.9 39.6 

 14 SW1 15.6 17.1 18.8 31.0 33.3 

 14 L-SR 40.7 44.6 49.6 96.0   

 14 EL-S 24.9 27.0 29.2 44.7 48.1 

 

 14 EL01 15.5 17.2 19.1 33.4 36.4 

 14 EL02 28.2 30.6 33.2 51.2 55.5 

 14 EL03 11.8 13.4 15.2 29.2 32.2 

 14 EL04 11.5 12.9 14.7 28.5 31.5 

 14 SW2 21.9 23.7 25.5 38.3 41.0 

 

 15 MECH 40.4 43.8 48.0 80.1 92.5 

 15 SW1 16.4 18.0 19.7 31.9 34.3 

 15 L-SR 36.4 39.1 42.0 63.0 68.4 

 15 CR01 54.2 59.5 65.9 ** **   

 15 EL-S 25.8 27.9 30.2 45.7 49.2 

 

 15 EL01 16.2 17.9 19.9 34.3 37.4 

 15 EL02 29.6 32.1 34.8 53.1 57.6 

 15 EL03 12.5 14.1 15.9 30.1 33.1 

 15 EL04 12.0 13.6 15.4 29.3 32.2 

 15 T01 38.1 41.3 45.0 75.7 87.5 

 

 15 T02 39.1 42.3 45.9 71.9 79.7 

 15 SW2 22.9 24.7 26.6 39.4 42.1 

 16 OPEN 41.3 44.8 48.9 80.7 92.7 

 16 SW1 17.3 18.9 20.7 32.9 35.4 

 16 L-SR 37.1 39.8 42.7 63.2 68.5 

 

 16 CR01 55.1 60.4 66.7 ** **   

 16 EL-S 26.8 28.9 31.2 46.8 50.3 

 16 EL01 16.9 18.7 20.6 35.1 38.3 

 16 EL02 30.9 33.4 36.1 54.7 59.4 

 16 EL03 13.1 14.8 16.6 30.8 33.9 

 

 16 EL04 12.7 14.3 16.0 30.0 33.0 

 16 T01 41.6 45.2 49.6 84.7 99.3 

 16 T02 40.0 43.1 46.7 72.3 79.8 

 16 SW2 23.9 25.7 27.6 40.5 43.3 

 17 OPEN 42.5 46.0 50.2 82.1 94.2 

 

 17 SW1 18.2 19.9 21.6 34.0 36.4 

 17 L-SR 38.1 40.8 43.8 64.2 69.4 

 17 CR01 56.5 61.7 68.1 ** **   

 17 EL-S 27.8 29.9 32.2 47.9 51.4 

 17 EL01 17.5 19.3 21.3 35.9 39.1 
39 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 17 EL02 32.0 34.6 37.4 56.2 61.0 

 17 EL03 13.8 15.4 17.3 31.6 34.7 

 17 EL04 13.3 14.9 16.7 30.7 33.7 

 17 T01 42.8 46.4 50.9 86.2 ** ** 

 17 T02 41.1 44.2 47.8 73.3 80.8 

 

 17 SW2 25.0 26.8 28.6 41.7 44.5 

 18 OPEN 43.7 47.3 51.5 83.6 95.7 

 18 SW1 19.2 20.8 22.6 35.0 37.5 

 18 L-SR 39.1 41.9 44.8 65.3 70.5 

 18 CR01 57.8 63.1 69.5   ** ** 

 

 18 EL-S 28.8 30.9 33.2 49.0 52.5 

 18 EL01 18.1 19.9 21.9 36.6 39.8 

 18 EL02 33.1 35.7 38.5 57.6 62.5 

 18 EL03 14.4 16.0 17.9 32.4 35.5 

 18 EL04 13.8 15.5 17.3 31.4 34.5 

 

 18 T01 44.0 47.7 52.2 87.8   

 18 T02 42.2 45.4 49.0 74.5 81.9 

 18 SW2 26.0 27.8 29.7 42.9 45.7 

 19 OPEN 45.0 48.6 52.9 85.1 97.3 

 19 SW1 20.1 21.8 23.6 36.1 38.7 

 

 19 L-SR 40.2 42.9 45.9 66.3 71.5 

 19 CR01 59.2 64.5 71.0 ** **   

 19 EL-S 29.8 31.9 34.2 50.1 53.6 

 19 EL01 18.7 20.5 22.5 37.3 40.5 

 19 EL02 34.1 36.7 39.6 58.9 63.9 

 

 19 EL03 15.0 16.7 18.6 33.1 36.2 

 19 EL04 14.4 16.1 17.9 32.1 35.2 

 19 T01 45.3 49.0 53.6 89.4 ** ** 

 19 T02 43.4 46.6 50.2 75.7 83.1 

 19 SW2 27.1 28.9 30.8 44.1 47.0 

 

 20 OPEN 46.3 49.9 54.3 86.7 99.0 

 20 SW1 21.1 22.8 24.7 37.3 39.8 

 20 L-SR 41.4 44.1 47.1 67.5 72.7 

 20 CR01 60.6 66.0 72.6   ** ** 

 20 EL-S 30.8 32.9 35.3 51.2 54.8 

 

 20 EL01 19.2 21.0 23.1 37.9 41.2 

 20 EL02 35.1 37.7 40.6 60.1 65.2 

 20 EL03 15.6 17.3 19.3 33.8 37.0 

 20 EL04 15.0 16.7 18.6 32.8 35.9 

 20 T01 46.6 50.4 55.1 91.1   
40 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 20 T02 44.6 47.8 51.5 76.9 84.3 

 20 SW2 28.2 30.0 31.9 45.4 48.2 

 21 OPEN 47.6 51.4 55.8 88.5 ** ** 

 21 SW1 22.2 23.9 25.7 38.4 41.0 

 21 L-SR 42.5 45.3 48.3 68.7 73.9 

 

 21 CR01 62.1 67.6 74.2   ** ** 

 21 EL-S 31.8 34.0 36.4 52.4 56.0 

 21 EL01 19.7 21.6 23.6 38.5 41.8 

 21 EL02 36.0 38.6 41.5 61.3 66.4 

 21 EL03 16.2 17.9 19.9 34.5 37.7 

 

 21 EL04 15.6 17.2 19.1 33.5 36.5 

 21 T01 47.9 51.9 56.6 92.9   

 21 T02 45.8 49.1 52.8 78.3 85.6 

 21 SW2 29.3 31.1 33.1 46.6 49.5 

 22 OPEN 44.5 48.0 52.2 82.2 92.4 

 

 22 SW1 23.3 25.0 26.8 39.6 42.3 

 22 L-SR 43.7 46.5 49.5 70.0 75.2 

 22 CR01 58.4 63.5 69.4 ** **   

 22 EL-S 32.9 35.1 37.4 53.5 57.2 

 22 EL01 20.2 22.1 24.2 39.1 42.3 

 

 22 EL02 36.8 39.5 42.4 62.4 67.6 

 22 EL03 16.8 18.5 20.5 35.2 38.4 

 22 EL04 16.0 17.8 19.7 34.1 37.2 

 22 T01 48.9 52.8 57.5 92.6 ** ** 

 22 T02 47.1 50.4 54.1 79.7 87.0 

 

 22 SW2 30.5 32.3 34.3 48.0 50.9 

 23 OPEN 42.4 45.8 49.7 77.6 86.6 

 23 SW1 24.4 26.1 27.9 40.9 43.5 

 23 L-SR 44.8 47.6 50.7 71.1 76.2 

 23 CR01 55.8 60.6 66.0   ** ** 

 

 23 EL-S 33.9 36.2 38.6 54.7 58.4 

 23 EL01 20.8 22.7 24.7 39.6 42.9 

 23 EL02 37.6 40.3 43.2 63.3 68.6 

 23 EL03 17.3 19.1 21.1 35.9 39.1 

 23 EL04 16.6 18.4 20.3 34.7 37.8 

 

 23 T01 49.6 53.5 58.0 91.6   

 23 T02 48.2 51.6 55.3 80.7 88.0 

 23 SW2 31.6 33.5 35.5 49.3 52.2 

 24 OPEN 40.8 44.0 47.7 73.6 81.7 

 24 SW1 25.5 27.3 29.1 42.2 44.9 
41 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 24 L-SR 45.8 48.6 51.6 71.8 76.9 

 24 CR01 53.7 58.1 63.2 96.3 ** ** 

 24 EL-S 35.0 37.3 39.7 56.0 59.7 

 24 EL01 21.3 23.2 25.3 40.2 43.5 

 24 EL02 38.2 40.9 43.9 64.1 69.4 

 

 24 EL03 17.9 19.7 21.7 36.5 39.8 

 24 EL04 17.1 18.9 20.8 35.3 38.5 

 24 T01 49.8 53.6 58.0 89.8   

 24 T02 49.1 52.4 56.1 81.2 88.3 

 24 SW2 32.8 34.7 36.7 50.6 53.6 

 

 25 OPEN 41.1 44.3 47.9 73.7 81.6 

 25 SW1 26.7 28.5 30.4 43.5 46.3 

 25 L-SR 47.0 49.8 52.8 73.1 78.2 

 25 CR01 54.0 58.3 63.3 96.0 ** ** 

 25 EL-S 36.1 38.4 40.8 57.2 60.9 

 

 25 EL01 21.8 23.8 25.8 40.9 44.2 

 25 EL02 38.8 41.6 44.5 64.8 70.1 

 25 EL03 18.4 20.2 22.3 37.2 40.4 

 25 EL04 17.7 19.4 21.4 36.0 39.1 

 25 T01 50.8 54.6 59.0 90.4   

 

 25 T02 50.4 53.7 57.3 82.4 89.5 

 25 SW2 33.9 35.9 37.9 52.0 55.1 

 26 OPEN 36.6 39.4 42.5 63.9 69.7 

 26 SW1 27.9 29.7 31.6 44.9 47.7 

 26 L-SR 45.3 47.9 50.7 69.6 74.2 

 

 26 EL-S 37.3 39.6 42.0 58.5 62.2 

 26 EL01 22.5 24.4 26.5 41.5 44.8 

 26 EL02 39.5 42.2 45.2 65.5 70.8 

 26 EL03 19.3 21.1 23.2 38.4 41.8 

 26 EL04 18.5 20.3 22.3 37.1 40.3 

 

 26 T01 48.0 51.3 55.0 81.6 89.9 

 26 T02 48.3 51.2 54.5 77.0 83.0 

 26 SW2 35.2 37.1 39.1 53.4 56.5 

 27 OPEN 50.4 53.6 57.2 82.9 90.6 

 27 SW1 29.2 31.0 33.0 46.4 49.2 

 

 27 L-SR 45.5 48.1 50.8 69.4 73.8 

 27 EL-S 38.5 40.8 43.2 59.9 63.6 

 27 EL03 19.7 21.6 23.7 39.0 42.4 

 27 EL04 18.9 20.7 22.8 37.6 40.9 

 27 T01 50.7 53.9 57.7 85.5 94.8 
42 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 27 T02 48.5 51.4 54.5 76.2 81.9 

 27 SW2 36.5 38.4 40.5 54.9 58.0 

 28 OPEN 52.2 55.4 59.1 85.0 92.8 

 28 SW1 30.7 32.5 34.5 48.1 50.9 

 28 L-SR 46.8 49.4 52.2 70.9 75.3 

 

 28 EL-S 39.8 42.1 44.6 61.3 65.1 

 28 EL03 20.2 22.0 24.2 39.5 42.9 

 28 EL04 19.3 21.1 23.2 38.1 41.3 

 28 T01 52.4 55.7 59.6 87.6 96.9 

 28 T02 50.0 52.9 56.1 77.9 83.6 

 

 28 SW2 37.8 39.8 41.9 56.4 59.6 

 29 OPEN 48.0 52.0 56.4 83.8 91.8 

 29 SW1 32.3 34.2 36.1 49.9 52.8 

 29 L-SR 48.3 50.9 53.7 72.5 77.0 

 29 EL-S 41.1 43.5 46.0 62.9 66.7 

 

 29 EL03 20.6 22.5 24.6 40.0 43.4 

 29 EL04 19.7 21.6 23.6 38.5 41.8 

 29 T01 44.3 48.1 52.5 81.3 90.1 

 29 T02 51.7 54.6 57.8 79.7 85.4 

 29 SW2 39.3 41.3 43.5 58.2 61.4 

 

 30 OPEN 46.8 50.9 55.5 84.0 92.2 

 30 SW1 34.1 36.0 38.0 52.0 55.0 

 30 L-SR 49.8 52.5 55.3 74.3 78.8 

 30 EL-S 42.6 45.0 47.5 64.5 68.4 

 30 EL03 21.0 22.9 25.0 40.4 43.9 

 

 30 EL04 20.0 21.9 24.0 39.0 42.2 

 30 T01 42.7 46.4 50.6 79.4 88.2 

 30 T02 53.5 56.5 59.8 81.8 87.5 

 30 SW2 40.9 43.0 45.1 60.1 63.4 

 31 OPEN 45.8 49.8 54.5 84.0 92.5 

 

 31 SW1 36.2 38.1 40.2 54.5 57.6 

 31 L-SR 51.5 54.2 57.1 76.2 80.8 

 31 EL-S 44.2 46.7 49.2 66.4 70.3 

 31 EL03 21.4 23.3 25.5 40.8 44.3 

 31 EL04 20.5 22.4 24.4 39.4 42.7 

 

 31 T01 42.7 46.4 50.6 79.7 88.7 

 31 T02 55.6 58.6 61.9 84.1 89.8 

 31 SW2 42.7 44.8 47.0 62.2 65.5 

 32 OPEN 44.5 48.4 52.9 83.1 91.9 

 32 SW1 38.6 40.6 42.8 57.4 60.6 
43 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 32 L-SR 53.4 56.1 59.0 78.3 82.9 

 32 EL-S 46.0 48.5 51.0 68.4 72.4 

 32 EL03 21.8 23.7 25.8 41.3 44.7 

 32 EL04 20.9 22.8 24.8 39.8 43.1 

 32 T01 42.3 45.9 50.0 79.2 88.2 

 

 32 T02 57.9 61.0 64.4 86.6 92.4 

 32 SW2 44.7 46.8 49.0 64.5 68.0 

 33 OPEN 43.8 47.5 51.8 82.1 91.3 

 33 SW1 41.6 43.7 45.9 61.1 64.4 

 33 L-SR 55.4 58.2 61.2 80.7 85.4 

 

 33 EL-S 48.0 50.5 53.1 70.7 74.8 

 33 EL03 22.2 24.1 26.3 41.7 45.2 

 33 EL04 21.3 23.2 25.2 40.3 43.6 

 33 T01 41.9 45.5 49.5 78.3 87.4 

 33 T02 60.5 63.7 67.1 89.6 95.4 

 

 33 SW2 46.9 49.1 51.4 67.2 70.7 

 34 OPEN 43.3 46.9 51.1 81.2 90.6 

 34 SW1 45.5 47.7 50.0 66.0 69.5 

 34 L-SR 57.8 60.6 63.6 83.4 88.1 

 34 EL-S 50.2 52.8 55.5 73.3 77.4 

 

 34 EL03 22.6 24.6 26.7 42.2 45.6 

 34 EL04 21.7 23.6 25.7 40.7 44.1 

 34 T01 41.7 45.1 49.0 77.4 86.5 

 34 T02 63.5 66.8 70.3 93.0 98.9 

 34 SW2 49.5 51.7 54.1 70.2 73.9 

 

 35 OPEN 42.6 46.1 50.0 79.1 88.5 

 35 SW1 51.3 53.7 56.2 73.6 77.6 

 35 L-SR 60.4 63.3 66.4 86.5 91.3 

 35 EL-S 52.8 55.4 58.1 76.3 80.5 

 35 EL03 23.0 24.9 27.1 42.6 46.1 

 

 35 EL04 22.1 24.0 26.1 41.2 44.5 

 35 T01 41.2 44.5 48.2 75.6 84.4 

 35 T02 66.9 70.3 73.9 97.0 ** ** 

 35 SW2 52.5 54.8 57.2 73.9 77.6 

 36 MECH 75.2 79.1 83.5   ** ** 

 

 36 ELME 79.3 83.6 88.3   ** ** 

 36 EL-S 55.8 58.4 61.3 79.9 84.2 

 36 EL03 23.0 25.0 27.1 42.6 46.1 

 36 EL04 22.1 24.0 26.1 41.2 44.5 

 36 SW2 56.1 58.5 61.0 78.4 82.3 
44 

Table 15. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 R SW2 60.8 63.4 66.1 84.4 88.6 
45 

Table 16. Results of Tenability Analysis for Scenario 16. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 38.5 45.0 53.7   ** ** 

 B L-SR 61.7 72.2 86.2   ** ** 

 B L-MR 41.3 48.6 58.3   ** ** 

 B L-HR 37.1 43.3 51.3   ** ** 

 B EL-S 83.7   ** **   ** ** 

 

 B EL01 61.3 71.5 84.9   ** ** 

 B EL02 57.6 67.1 79.4   ** ** 

 B EL03 52.2 60.5 70.9   ** ** 

 B EL04 50.4 58.4 68.5   ** ** 

 B SW2 66.6 78.2 93.8   ** ** 

 

 G OPEN 7.6 9.5 11.8 27.6 31.4 

 G SW1 17.2 19.9 22.9 45.5 52.8 

 G L-SR 15.2 17.6 20.3 39.2 44.4 

 G EL-S 25.4 28.5 31.9 57.3 65.0 

 G EL01 12.1 14.4 16.8 34.0 38.3 

 

 G EL02 12.3 14.5 16.9 34.2 38.7 

 G EL03 11.4 13.5 15.9 32.8 37.1 

 G EL04 11.5 13.7 16.0 33.1 37.5 

 G T01 15.5 17.9 20.5 39.4 44.5 

 G T02 17.8 20.4 23.2 43.9 49.8 

 

 G SW2 17.6 20.3 23.2 44.4 50.6 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.6 2.0 10.2 12.2 

 2 L-SR 1.0 1.6 2.0 9.6 11.5 

 2 CR01 1.6 1.9 2.7 11.2 13.3 

 

 2 CR02 1.4 1.9 2.4 10.7 12.7 

 2 EL-S 3.6 4.4 5.5 16.3 18.6 

 2 EL01 1.3 1.8 2.3 11.0 13.1 

 2 EL02 1.9 2.6 3.4 13.6 16.0 

 2 EL03 1.9 2.5 3.3 13.8 16.2 

 

 2 EL04 1.9 2.5 3.3 13.7 16.1 

 2 T01 1.8 2.2 2.9 12.2 14.3 

 2 T02 2.0 2.8 3.7 13.8 16.1 

 2 SW2 1.0 1.4 1.9 9.2 11.1 

 3 SW1 2.0 2.7 3.4 12.7 14.9 

 

 3 L-SR 21.0 23.8 26.9 56.2 68.9 

 3 EL-S 5.8 6.9 8.3 20.2 22.7 

 3 EL01 2.7 3.3 4.1 14.2 16.5 

 3 EL02 3.8 4.8 5.9 17.5 20.1 

 3 EL03 3.0 3.9 4.9 16.2 18.6 
46 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL04 3.0 3.8 4.8 16.0 18.4 

 3 SW2 2.8 3.5 4.4 14.1 16.2 

 4 SW1 3.2 3.9 4.9 15.0 17.2 

 4 L-SR 23.5 26.3 29.5 61.0 75.8 

 4 EL-S 7.9 9.3 10.8 23.5 26.1 

 

 4 EL01 4.0 4.9 6.0 17.0 19.4 

 4 EL02 6.0 7.3 8.8 21.4 24.1 

 4 EL03 4.3 5.3 6.5 18.3 20.9 

 4 EL04 4.2 5.1 6.3 18.0 20.6 

 4 SW2 4.8 5.8 6.9 17.8 20.1 

 

 5 SW1 4.4 5.3 6.4 17.0 19.3 

 5 L-SR 25.6 28.5 31.9 65.5 82.9 

 5 EL-S 9.9 11.4 13.1 26.2 29.0 

 5 EL01 5.6 6.6 7.8 19.5 22.0 

 5 EL02 8.6 10.0 11.7 25.1 27.9 

 

 5 EL03 5.6 6.7 8.0 20.3 23.0 

 5 EL04 5.4 6.5 7.7 19.8 22.4 

 5 SW2 6.8 8.0 9.4 20.8 23.1 

 6 SW1 5.6 6.7 7.8 18.8 21.1 

 6 L-SR 27.5 30.4 34.0 69.8 91.0 

 

 6 EL-S 11.8 13.4 15.1 28.6 31.4 

 6 EL01 7.0 8.2 9.6 21.7 24.3 

 6 EL02 11.2 12.8 14.7 28.7 31.7 

 6 EL03 6.8 8.0 9.5 22.1 24.8 

 6 EL04 6.5 7.7 9.0 21.5 24.2 

 

 6 SW2 8.7 10.0 11.6 23.3 25.5 

 7 SW1 6.8 7.9 9.2 20.4 22.7 

 7 L-SR 29.2 32.3 36.1 74.3   

 7 EL-S 13.4 15.1 16.9 30.7 33.6 

 7 EL01 8.4 9.7 11.2 23.7 26.4 

 

 7 EL02 13.8 15.6 17.6 32.2 35.3 

 7 EL03 8.0 9.3 10.8 23.8 26.5 

 7 EL04 7.6 8.8 10.3 23.0 25.7 

 7 SW2 10.5 11.9 13.5 25.3 27.5 

 8 SW1 7.9 9.1 10.5 21.9 24.1 

 

 8 L-SR 30.8 34.0 38.1 79.1 ** ** 

 8 EL-S 14.9 16.7 18.6 32.6 35.5 

 8 EL01 9.8 11.1 12.7 25.6 28.3 

 8 EL02 16.4 18.4 20.5 35.6 38.9 

 8 EL03 9.1 10.5 12.1 25.3 28.1 
47 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL04 8.6 9.9 11.5 24.4 27.1 

 8 SW2 12.0 13.6 15.2 27.1 29.3 

 9 SW1 9.0 10.3 11.7 23.2 25.4 

 9 L-SR 32.4 35.8 40.1 84.6   

 9 EL-S 16.4 18.2 20.1 34.3 37.3 

 

 9 EL01 11.0 12.5 14.1 27.3 30.1 

 9 EL02 19.0 21.0 23.3 38.9 42.4 

 9 EL03 10.2 11.7 13.3 26.7 29.6 

 9 EL04 9.6 11.0 12.6 25.7 28.4 

 9 SW2 13.6 15.1 16.8 28.6 30.9 

 

 10 SW1 10.0 11.4 12.8 24.4 26.6 

 10 L-SR 33.9 37.5 42.2 91.4 ** ** 

 10 EL-S 17.7 19.5 21.6 35.9 39.0 

 10 EL01 12.2 13.8 15.5 28.9 31.7 

 10 EL02 21.6 23.7 26.0 42.1 45.8 

 

 10 EL03 11.2 12.8 14.5 28.1 31.0 

 10 EL04 10.6 12.0 13.6 26.9 29.7 

 10 SW2 14.9 16.5 18.2 30.0 32.3 

 11 SW1 11.0 12.4 13.9 25.6 27.9 

 11 L-SR 35.9 39.8 44.9   ** ** 

 

 11 EL-S 18.9 20.8 22.8 37.3 40.5 

 11 EL01 13.4 15.0 16.7 30.3 33.2 

 11 EL02 24.0 26.3 28.7 45.3 49.1 

 11 EL03 12.2 13.8 15.6 29.4 32.3 

 11 EL04 11.4 12.9 14.6 28.0 30.8 

 

 11 SW2 16.2 17.8 19.5 31.5 33.9 

 12 SW1 12.0 13.4 15.0 26.8 29.1 

 12 L-SR 38.0 42.2 47.9   ** ** 

 12 EL-S 20.0 21.9 24.0 38.7 41.9 

 12 EL01 14.5 16.1 17.9 31.7 34.7 

 

 12 EL02 26.5 28.8 31.3 48.4 52.3 

 12 EL03 13.1 14.8 16.6 30.6 33.5 

 12 EL04 12.3 13.8 15.6 29.1 31.9 

 12 SW2 17.4 19.0 20.8 32.9 35.4 

 13 SW1 12.9 14.4 16.0 28.0 30.3 

 

 13 L-SR 40.4 45.0 51.6   ** ** 

 13 EL-S 21.1 23.0 25.2 40.0 43.2 

 13 EL01 15.5 17.2 19.0 33.0 36.0 

 13 EL02 28.9 31.3 33.9 51.4 55.5 

 13 EL03 14.0 15.7 17.6 31.7 34.7 
48 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL04 13.0 14.7 16.4 30.1 33.0 

 13 SW2 18.5 20.2 21.9 34.2 36.8 

 14 SW1 13.8 15.3 16.9 29.0 31.3 

 14 L-SR 39.6 43.6 49.0   ** ** 

 14 EL-S 22.1 24.0 26.2 41.1 44.4 

 

 14 EL01 16.7 18.4 20.3 34.6 37.6 

 14 EL02 31.8 34.4 37.0 55.5 59.9 

 14 EL03 14.9 16.6 18.5 32.8 35.8 

 14 EL04 13.8 15.5 17.3 31.0 33.9 

 14 SW2 19.6 21.2 23.0 35.4 38.0 

 

 15 MECH 54.4 63.5 79.3   ** ** 

 15 SW1 14.6 16.0 17.7 29.9 32.2 

 15 L-SR 38.9 42.6 47.1 85.9   

 15 CR01 76.8 92.6 ** **   ** ** 

 15 EL-S 22.9 24.9 27.1 42.1 45.4 

 

 15 EL01 17.6 19.4 21.3 35.7 38.8 

 15 EL02 33.9 36.5 39.3 58.3 62.9 

 15 EL03 15.7 17.5 19.4 33.7 36.9 

 15 EL04 14.6 16.2 18.0 31.9 34.8 

 15 T01 35.9 39.0 42.7 74.2 87.3 

 

 15 T02 45.7 51.2 58.8   ** ** 

 15 SW2 20.5 22.2 23.9 36.5 39.1 

 16 OPEN 41.6 45.4 50.1 87.4   

 16 SW1 15.4 16.9 18.6 30.7 33.2 

 16 L-SR 39.8 43.3 47.6 79.8 91.2 

 

 16 CR01 55.2 61.0 68.2 ** **   

 16 EL-S 23.8 25.8 27.9 43.0 46.3 

 16 EL01 18.4 20.2 22.2 36.7 39.9 

 16 EL02 35.8 38.4 41.3 60.7 65.5 

 16 EL03 16.5 18.3 20.2 34.7 37.8 

 

 16 EL04 15.3 16.9 18.8 32.7 35.7 

 16 T01 40.7 44.5 49.3 88.7 ** ** 

 16 T02 41.1 44.8 49.4 84.1 97.8 

 16 SW2 21.4 23.0 24.9 37.5 40.1 

 17 OPEN 41.7 45.4 49.9 84.9 99.3 

 

 17 SW1 16.1 17.7 19.4 31.6 34.1 

 17 L-SR 36.5 39.3 42.2 63.2 68.7 

 17 CR01 55.0 60.5 67.2   ** ** 

 17 EL-S 24.6 26.7 28.8 44.0 47.3 

 17 EL01 19.2 21.0 23.0 37.7 40.9 
49 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 17 EL02 37.4 40.1 43.0 62.8 67.8 

 17 EL03 17.3 19.0 21.0 35.6 38.8 

 17 EL04 15.9 17.7 19.5 33.5 36.5 

 17 T01 41.2 45.0 49.7 87.6   

 17 T02 40.0 43.2 46.9 73.6 81.7 

 

 17 SW2 22.3 24.0 25.8 38.5 41.1 

 18 OPEN 42.0 45.6 49.9 83.3 96.4 

 18 SW1 17.0 18.6 20.3 32.6 35.0 

 18 L-SR 36.6 39.2 42.1 62.0 67.2 

 18 CR01 55.1 60.3 66.8 ** **   

 

 18 EL-S 25.5 27.5 29.7 44.9 48.2 

 18 EL01 20.0 21.8 23.9 38.6 41.8 

 18 EL02 38.8 41.6 44.6 64.8 69.9 

 18 EL03 18.0 19.8 21.8 36.5 39.7 

 18 EL04 16.6 18.3 20.2 34.3 37.3 

 

 18 T01 41.8 45.5 50.0 86.7 ** ** 

 18 T02 40.0 43.1 46.7 71.9 79.4 

 18 SW2 23.2 24.9 26.8 39.5 42.2 

 19 OPEN 42.4 45.9 50.1 82.3 94.5 

 19 SW1 17.8 19.4 21.1 33.5 36.0 

 

 19 L-SR 37.0 39.6 42.4 61.9 66.8 

 19 CR01 55.3 60.4 66.6   ** ** 

 19 EL-S 26.3 28.4 30.6 45.8 49.2 

 19 EL01 20.7 22.6 24.7 39.5 42.7 

 19 EL02 40.1 42.9 46.0 66.6 71.9 

 

 19 EL03 18.8 20.6 22.6 37.4 40.6 

 19 EL04 17.3 19.0 20.9 35.1 38.1 

 19 T01 42.4 46.0 50.5 86.0   

 19 T02 40.4 43.4 46.8 71.3 78.3 

 19 SW2 24.1 25.9 27.7 40.6 43.3 

 

 20 OPEN 43.0 46.4 50.5 81.8 93.3 

 20 SW1 18.7 20.3 22.0 34.5 37.0 

 20 L-SR 37.7 40.3 43.0 62.2 67.0 

 20 CR01 55.8 60.8 66.8 ** **   

 20 EL-S 27.2 29.3 31.5 46.8 50.2 

 

 20 EL01 21.4 23.3 25.4 40.3 43.5 

 20 EL02 41.4 44.2 47.3 68.2 73.6 

 20 EL03 19.5 21.3 23.4 38.2 41.5 

 20 EL04 17.9 19.7 21.6 35.8 38.8 

 20 T01 43.0 46.6 51.0 85.7 99.8 
50 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 20 T02 40.8 43.8 47.2 71.1 78.0 

 20 SW2 25.0 26.8 28.7 41.6 44.4 

 21 OPEN 43.7 47.1 51.1 81.8 92.9 

 21 SW1 19.6 21.2 22.9 35.5 38.0 

 21 L-SR 38.2 40.8 43.6 62.5 67.2 

 

 21 CR01 56.4 61.3 67.2 ** **   

 21 EL-S 28.1 30.2 32.4 47.8 51.2 

 21 EL01 22.1 24.0 26.1 41.1 44.3 

 21 EL02 42.5 45.4 48.5 69.8 75.3 

 21 EL03 20.1 22.0 24.0 39.1 42.3 

 

 21 EL04 18.5 20.3 22.2 36.5 39.5 

 21 T01 43.8 47.4 51.7 85.8 99.3 

 21 T02 41.5 44.5 47.8 71.4 78.0 

 21 SW2 26.0 27.8 29.7 42.7 45.5 

 22 OPEN 44.3 47.8 51.7 81.7 92.3 

 

 22 SW1 20.5 22.1 23.9 36.5 39.1 

 22 L-SR 38.9 41.5 44.3 63.2 67.9 

 22 CR01 57.0 61.9 67.6 ** **   

 22 EL-S 29.0 31.1 33.3 48.8 52.2 

 22 EL01 22.7 24.7 26.7 41.8 45.1 

 

 22 EL02 43.6 46.5 49.7 71.2 76.8 

 22 EL03 20.8 22.7 24.8 39.8 43.2 

 22 EL04 19.1 20.9 22.9 37.2 40.3 

 22 T01 44.7 48.3 52.6 86.3 99.5 

 22 T02 42.3 45.3 48.6 72.0 78.6 

 

 22 SW2 27.0 28.8 30.7 43.9 46.6 

 23 OPEN 43.5 46.7 50.4 77.6 86.4 

 23 SW1 21.5 23.1 24.9 37.6 40.2 

 23 L-SR 39.5 42.1 44.8 63.6 68.3 

 23 CR01 55.7 60.1 65.2 99.4 ** ** 

 

 23 EL-S 29.9 32.0 34.3 49.8 53.3 

 23 EL01 23.4 25.3 27.4 42.5 45.8 

 23 EL02 44.5 47.4 50.7 72.5 78.2 

 23 EL03 21.4 23.4 25.5 40.6 44.0 

 23 EL04 19.7 21.5 23.5 37.9 41.0 

 

 23 T01 45.3 48.8 53.0 85.2 97.0 

 23 T02 42.9 45.9 49.2 72.3 78.7 

 23 SW2 28.0 29.8 31.7 45.0 47.8 

 24 OPEN 42.6 45.7 49.1 74.2 81.8 

 24 SW1 22.4 24.1 25.9 38.7 41.3 
51 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 24 L-SR 39.7 42.2 44.9 63.4 67.9 

 24 CR01 54.5 58.6 63.4 94.9   

 24 EL-S 30.8 33.0 35.2 50.9 54.3 

 24 EL01 24.0 25.9 28.0 43.2 46.5 

 24 EL02 45.3 48.3 51.5 73.5 79.3 

 

 24 EL03 22.0 24.0 26.1 41.3 44.7 

 24 EL04 20.3 22.1 24.1 38.5 41.6 

 24 T01 45.4 48.7 52.7 82.8 93.2 

 24 T02 43.0 45.9 49.1 71.6 77.7 

 24 SW2 29.0 30.9 32.8 46.2 49.0 

 

 25 OPEN 42.6 45.7 49.0 73.2 80.4 

 25 SW1 23.5 25.2 27.0 39.9 42.5 

 25 L-SR 40.2 42.7 45.4 63.7 68.1 

 25 CR01 54.6 58.6 63.1 93.7 ** ** 

 25 EL-S 31.8 33.9 36.2 52.0 55.4 

 

 25 EL01 24.7 26.6 28.8 43.9 47.3 

 25 EL02 46.1 49.1 52.4 74.5 80.3 

 25 EL03 22.7 24.6 26.8 42.1 45.5 

 25 EL04 20.8 22.7 24.7 39.2 42.3 

 25 T01 45.8 49.2 53.0 82.0 91.8 

 

 25 T02 43.5 46.4 49.5 71.5 77.5 

 25 SW2 30.1 31.9 33.9 47.3 50.2 

 26 OPEN 41.9 44.9 48.0 70.8 77.3 

 26 SW1 24.5 26.3 28.1 41.1 43.7 

 26 L-SR 40.2 42.7 45.3 63.2 67.4 

 

 26 EL-S 32.8 34.9 37.3 53.1 56.6 

 26 EL01 25.4 27.4 29.5 44.7 48.1 

 26 EL02 47.0 50.1 53.4 75.5 81.4 

 26 EL03 23.4 25.4 27.5 43.0 46.4 

 26 EL04 21.5 23.3 25.4 40.0 43.1 

 

 26 T01 45.6 48.8 52.4 79.6 88.4 

 26 T02 43.4 46.1 49.1 70.3 75.8 

 26 SW2 31.2 33.0 35.0 48.6 51.5 

 27 OPEN 45.9 48.8 52.2 76.7 84.1 

 27 SW1 25.7 27.5 29.3 42.4 45.1 

 

 27 L-SR 40.5 42.9 45.5 63.2 67.3 

 27 EL-S 33.8 36.0 38.4 54.2 57.8 

 27 EL03 23.9 26.0 28.2 43.7 47.2 

 27 EL04 22.0 23.9 25.9 40.6 43.8 

 27 T01 46.1 49.2 52.7 79.4 88.2 
52 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 27 T02 43.6 46.3 49.3 69.8 75.1 

 27 SW2 32.3 34.2 36.1 49.9 52.8 

 28 OPEN 47.1 50.1 53.5 78.0 85.3 

 28 SW1 26.9 28.7 30.6 43.8 46.6 

 28 L-SR 41.5 43.9 46.6 64.2 68.4 

 

 28 EL-S 35.0 37.2 39.5 55.5 59.1 

 28 EL03 24.5 26.5 28.7 44.3 47.8 

 28 EL04 22.5 24.4 26.5 41.2 44.4 

 28 T01 47.4 50.5 54.1 80.7 89.5 

 28 T02 44.8 47.5 50.4 70.9 76.2 

 

 28 SW2 33.6 35.4 37.4 51.3 54.3 

 29 OPEN 48.7 51.8 55.2 79.8 87.1 

 29 SW1 28.4 30.2 32.1 45.4 48.2 

 29 L-SR 42.7 45.2 47.8 65.6 69.7 

 29 EL-S 36.2 38.4 40.8 56.9 60.5 

 

 29 EL03 25.0 27.0 29.3 44.9 48.5 

 29 EL04 22.9 24.9 26.9 41.7 44.9 

 29 T01 49.0 52.2 55.8 82.6 91.4 

 29 T02 46.1 48.9 51.8 72.4 77.7 

 29 SW2 34.9 36.8 38.8 52.8 55.9 

 

 30 OPEN 50.5 53.6 57.1 81.9 89.2 

 30 SW1 29.9 31.8 33.7 47.3 50.1 

 30 L-SR 44.0 46.5 49.2 67.1 71.3 

 30 EL-S 37.5 39.7 42.1 58.3 62.0 

 30 EL03 25.5 27.6 29.8 45.5 49.0 

 

 30 EL04 23.4 25.3 27.4 42.2 45.4 

 30 T01 50.9 54.1 57.8 84.9 93.8 

 30 T02 47.7 50.5 53.5 74.1 79.4 

 30 SW2 36.3 38.3 40.3 54.5 57.6 

 31 OPEN 50.2 53.5 57.2 82.5 89.9 

 

 31 SW1 31.8 33.7 35.7 49.4 52.3 

 31 L-SR 45.5 48.0 50.7 68.7 73.0 

 31 EL-S 38.9 41.2 43.6 60.0 63.7 

 31 EL03 26.0 28.0 30.3 46.1 49.6 

 31 EL04 23.8 25.8 27.9 42.7 45.9 

 

 31 T01 43.4 46.6 50.2 75.2 82.7 

 31 T02 49.5 52.3 55.3 76.1 81.4 

 31 SW2 37.9 39.9 41.9 56.4 59.5 

 32 OPEN 50.3 53.9 57.9 83.9 91.4 

 32 SW1 33.9 35.9 37.9 52.0 55.0 
53 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 32 L-SR 47.1 49.7 52.4 70.6 74.9 

 32 EL-S 40.5 42.8 45.3 61.8 65.5 

 32 EL03 26.5 28.6 30.8 46.6 50.2 

 32 EL04 24.3 26.2 28.3 43.2 46.4 

 32 T01 41.9 45.0 48.4 72.6 79.6 

 

 32 T02 51.5 54.3 57.4 78.3 83.6 

 32 SW2 39.7 41.7 43.8 58.5 61.7 

 33 OPEN 50.8 54.7 58.9 86.0 93.7 

 33 SW1 36.6 38.6 40.7 55.2 58.3 

 33 L-SR 48.9 51.5 54.3 72.7 77.0 

 

 33 EL-S 42.3 44.6 47.1 63.8 67.6 

 33 EL03 26.9 29.0 31.3 47.1 50.7 

 33 EL04 24.7 26.7 28.8 43.7 46.9 

 33 T01 41.7 44.8 48.1 72.0 78.9 

 33 T02 53.7 56.6 59.8 80.9 86.2 

 

 33 SW2 41.7 43.8 45.9 60.9 64.2 

 34 OPEN 50.8 54.8 59.3 87.8 95.9 

 34 SW1 40.0 42.1 44.3 59.4 62.8 

 34 L-SR 51.0 53.6 56.5 75.1 79.5 

 34 EL-S 44.3 46.7 49.2 66.2 70.0 

 

 34 EL03 27.4 29.5 31.7 47.6 51.2 

 34 EL04 25.1 27.1 29.2 44.2 47.4 

 34 T01 42.0 45.0 48.4 72.3 79.3 

 34 T02 56.4 59.3 62.6 83.9 89.3 

 34 SW2 44.1 46.2 48.4 63.7 67.1 

 

 35 OPEN 51.5 55.6 60.4 91.0 99.9 

 35 SW1 45.2 47.5 49.8 66.2 69.9 

 35 L-SR 53.4 56.1 58.9 77.8 82.3 

 35 EL-S 46.6 49.0 51.6 68.9 72.8 

 35 EL03 27.8 29.9 32.2 48.1 51.7 

 

 35 EL04 25.6 27.6 29.7 44.7 47.9 

 35 T01 42.5 45.5 48.9 73.0 80.2 

 35 T02 59.4 62.5 65.8 87.5 93.1 

 35 SW2 46.9 49.0 51.3 67.1 70.6 

 36 MECH 67.9 71.5 75.4   ** ** 

 

 36 ELME 71.4 75.3 79.7   ** ** 

 36 EL-S 49.4 51.9 54.5 72.2 76.2 

 36 EL03 27.9 29.9 32.2 48.1 51.7 

 36 EL04 25.7 27.6 29.7 44.7 48.0 

 36 SW2 50.3 52.6 55.0 71.4 75.1 
54 

Table 16. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 R SW2 54.9 57.3 59.9 77.2 81.2 
55 

Table 17. Results of Tenability Analysis for Scenario 17. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 53.5 65.2 83.6   ** ** 

 B L-SR 83.2   ** **   ** ** 

 B L-MR 48.0 57.6 71.1   ** ** 

 B L-HR 40.2 47.5 57.4   ** ** 

 B EL01 83.2   ** **   ** ** 

 

 B EL02 81.7 99.5   ** **   

 B EL03 61.9 73.1 88.9 ** **   

 B EL04 65.1 77.7 96.6 ** **   

 B SW2 91.3 ** **   ** **   

 G OPEN 7.7 9.7 11.9 27.9 31.7 

 

 G SW1 22.5 25.6 29.2 60.4 72.3 

 G L-SR 16.7 19.3 22.1 42.3 48.1 

 G EL-S 29.8 33.4 37.5 67.5 77.1 

 G EL01 11.1 13.3 15.6 32.4 36.6 

 G EL02 11.1 13.2 15.6 32.3 36.6 

 

 G EL03 9.8 11.8 14.1 30.4 34.5 

 G EL04 9.8 11.9 14.2 30.6 34.7 

 G T01 16.3 18.8 21.5 40.9 46.3 

 G T02 19.0 21.7 24.6 46.3 52.6 

 G SW2 21.0 23.9 27.1 52.1 59.9 

 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.6 2.0 10.3 12.4 

 2 L-SR 1.0 1.7 2.0 9.9 11.8 

 2 CR01 1.7 2.0 2.8 11.7 13.7 

 2 CR02 1.5 1.9 2.6 11.1 13.1 

 

 2 EL-S 3.8 4.7 5.8 16.8 19.2 

 2 EL01 1.5 1.9 2.6 11.9 14.1 

 2 EL02 2.0 2.8 3.8 14.7 17.2 

 2 EL03 2.1 2.9 3.9 15.6 18.3 

 2 EL04 2.1 2.9 3.9 15.5 18.1 

 

 2 T01 1.8 2.4 3.0 12.5 14.7 

 2 T02 2.2 2.9 3.8 14.2 16.4 

 2 SW2 1.0 1.5 1.9 9.4 11.3 

 3 SW1 2.2 2.9 3.7 13.2 15.3 

 3 L-SR 21.0 23.8 26.8 54.1 65.1 

 

 3 EL-S 6.4 7.6 9.0 21.2 23.8 

 3 EL01 2.6 3.2 4.0 14.4 16.7 

 3 EL02 3.7 4.7 5.8 17.7 20.3 

 3 EL03 3.0 3.9 5.0 17.1 19.8 

 3 EL04 3.0 3.9 4.9 16.9 19.6 
56 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 SW2 3.0 3.8 4.8 14.8 17.0 

 4 SW1 3.6 4.4 5.3 15.7 17.9 

 4 L-SR 23.7 26.4 29.6 58.8 71.2 

 4 EL-S 8.8 10.3 11.9 24.9 27.5 

 4 EL01 3.8 4.6 5.7 16.7 19.1 

 

 4 EL02 5.6 6.7 8.1 20.7 23.4 

 4 EL03 3.9 4.9 6.1 18.5 21.2 

 4 EL04 3.9 4.8 6.0 18.3 21.0 

 4 SW2 5.4 6.5 7.7 18.9 21.2 

 5 SW1 4.9 5.9 7.0 17.9 20.2 

 

 5 L-SR 25.9 28.8 32.1 63.2 77.2 

 5 EL-S 11.1 12.7 14.5 28.0 30.7 

 5 EL01 5.0 6.0 7.2 18.8 21.3 

 5 EL02 7.5 8.9 10.5 23.6 26.4 

 5 EL03 4.8 5.9 7.1 19.8 22.5 

 

 5 EL04 4.7 5.8 7.0 19.5 22.3 

 5 SW2 7.7 9.0 10.5 22.2 24.5 

 6 SW1 6.3 7.4 8.7 19.9 22.1 

 6 L-SR 27.9 30.9 34.4 67.3 83.6 

 6 EL-S 13.2 14.9 16.8 30.6 33.5 

 

 6 EL01 6.3 7.4 8.7 20.7 23.3 

 6 EL02 9.6 11.1 12.8 26.5 29.4 

 6 EL03 5.7 6.8 8.2 21.1 23.8 

 6 EL04 5.6 6.7 8.0 20.8 23.5 

 6 SW2 9.9 11.3 12.9 24.9 27.1 

 

 7 SW1 7.6 8.8 10.2 21.6 23.9 

 7 L-SR 29.8 32.9 36.6 71.5 90.6 

 7 EL-S 15.1 16.9 18.9 33.0 36.0 

 7 EL01 7.5 8.7 10.1 22.5 25.1 

 7 EL02 11.7 13.4 15.2 29.4 32.4 

 

 7 EL03 6.5 7.7 9.2 22.2 25.1 

 7 EL04 6.4 7.6 9.0 21.9 24.7 

 7 SW2 11.9 13.4 15.1 27.1 29.3 

 8 SW1 8.9 10.2 11.6 23.2 25.4 

 8 L-SR 31.5 34.7 38.6 75.7 98.8 

 

 8 EL-S 16.8 18.7 20.7 35.1 38.2 

 8 EL01 8.7 9.9 11.5 24.1 26.8 

 8 EL02 13.9 15.7 17.6 32.2 35.3 

 8 EL03 7.3 8.6 10.1 23.4 26.2 

 8 EL04 7.1 8.4 9.9 23.0 25.8 
57 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 SW2 13.7 15.3 17.0 29.0 31.3 

 9 SW1 10.1 11.5 13.0 24.6 26.8 

 9 L-SR 33.2 36.5 40.6 80.2 ** ** 

 9 EL-S 18.4 20.4 22.5 37.1 40.2 

 9 EL01 9.8 11.2 12.8 25.7 28.4 

 

 9 EL02 16.0 17.9 20.0 34.9 38.2 

 9 EL03 8.1 9.5 11.0 24.5 27.3 

 9 EL04 7.9 9.3 10.8 24.0 26.9 

 9 SW2 15.4 16.9 18.7 30.6 33.0 

 10 SW1 11.3 12.7 14.3 25.9 28.1 

 

 10 L-SR 34.8 38.3 42.6 85.3   

 10 EL-S 19.9 21.9 24.0 38.8 42.0 

 10 EL01 10.9 12.4 13.9 27.1 29.9 

 10 EL02 18.2 20.2 22.3 37.6 41.0 

 10 EL03 8.9 10.3 11.9 25.5 28.4 

 

 10 EL04 8.7 10.0 11.7 25.0 27.9 

 10 SW2 16.8 18.5 20.2 32.2 34.6 

 11 SW1 12.5 13.9 15.5 27.3 29.5 

 11 L-SR 36.7 40.4 45.1 91.7 ** ** 

 11 EL-S 21.3 23.3 25.5 40.4 43.7 

 

 11 EL01 11.9 13.5 15.1 28.5 31.3 

 11 EL02 20.4 22.4 24.7 40.3 43.9 

 11 EL03 9.7 11.1 12.8 26.5 29.4 

 11 EL04 9.4 10.8 12.5 26.0 28.8 

 11 SW2 18.2 19.9 21.7 33.9 36.3 

 

 12 SW1 13.6 15.0 16.7 28.6 30.9 

 12 L-SR 38.7 42.7 47.8 99.7   

 12 EL-S 22.6 24.6 26.8 42.0 45.3 

 12 EL01 13.0 14.5 16.3 29.8 32.7 

 12 EL02 22.5 24.6 26.9 43.0 46.6 

 

 12 EL03 10.4 11.9 13.6 27.4 30.4 

 12 EL04 10.1 11.6 13.2 26.9 29.7 

 12 SW2 19.6 21.3 23.0 35.4 38.0 

 13 SW1 14.6 16.1 17.8 29.8 32.2 

 13 L-SR 40.8 45.0 50.7 ** **   

 

 13 EL-S 23.8 25.9 28.1 43.4 46.8 

 13 EL01 13.9 15.6 17.3 31.0 34.0 

 13 EL02 24.6 26.8 29.2 45.6 49.4 

 13 EL03 11.1 12.7 14.4 28.4 31.3 

 13 EL04 10.8 12.3 14.0 27.7 30.6 
58 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 SW2 20.8 22.6 24.4 36.9 39.6 

 14 SW1 15.6 17.1 18.8 31.0 33.3 

 14 L-SR 40.7 44.6 49.6 96.0 ** ** 

 14 EL-S 24.9 27.0 29.2 44.7 48.1 

 14 EL01 15.5 17.2 19.1 33.4 36.4 

 

 14 EL02 28.2 30.6 33.2 51.2 55.5 

 14 EL03 11.8 13.4 15.2 29.2 32.2 

 14 EL04 11.5 12.9 14.7 28.5 31.5 

 14 SW2 21.9 23.7 25.5 38.3 41.0 

 15 MECH 40.4 43.8 48.0 80.1 92.5 

 

 15 SW1 16.4 18.0 19.7 31.9 34.3 

 15 L-SR 36.4 39.1 42.1 63.0 68.4 

 15 CR01 54.2 59.5 65.9   ** ** 

 15 EL-S 25.8 27.9 30.2 45.7 49.2 

 15 EL01 16.2 17.9 19.9 34.3 37.4 

 

 15 EL02 29.7 32.1 34.8 53.1 57.6 

 15 EL03 12.5 14.1 15.9 30.1 33.1 

 15 EL04 12.0 13.6 15.4 29.3 32.2 

 15 T01 38.1 41.3 45.0 75.7 87.5 

 15 T02 39.2 42.3 45.9 71.9 79.7 

 

 15 SW2 22.9 24.7 26.6 39.4 42.1 

 16 OPEN 41.3 44.8 48.9 80.7 92.7 

 16 SW1 17.3 18.9 20.7 32.9 35.4 

 16 L-SR 37.1 39.8 42.7 63.2 68.5 

 16 CR01 55.1 60.4 66.7   ** ** 

 

 16 EL-S 26.8 28.9 31.2 46.8 50.3 

 16 EL01 16.9 18.7 20.6 35.1 38.3 

 16 EL02 30.9 33.4 36.1 54.7 59.4 

 16 EL03 13.1 14.8 16.6 30.8 33.9 

 16 EL04 12.7 14.3 16.0 30.0 33.0 

 

 16 T01 41.6 45.2 49.6 84.7 99.3 

 16 T02 40.0 43.1 46.7 72.3 79.8 

 16 SW2 23.9 25.7 27.6 40.5 43.3 

 17 OPEN 42.5 46.0 50.2 82.1 94.2 

 17 SW1 18.2 19.9 21.6 34.0 36.4 

 

 17 L-SR 38.1 40.8 43.8 64.2 69.4 

 17 CR01 56.5 61.7 68.1   ** ** 

 17 EL-S 27.8 29.9 32.2 47.9 51.4 

 17 EL01 17.5 19.3 21.3 35.9 39.1 

 17 EL02 32.0 34.6 37.4 56.2 61.0 
59 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 17 EL03 13.8 15.4 17.3 31.6 34.7 

 17 EL04 13.3 14.9 16.7 30.7 33.7 

 17 T01 42.8 46.4 50.9 86.2   

 17 T02 41.1 44.2 47.8 73.3 80.8 

 17 SW2 25.0 26.8 28.6 41.7 44.5 

 

 18 OPEN 43.7 47.3 51.5 83.6 95.7 

 18 SW1 19.2 20.8 22.6 35.0 37.5 

 18 L-SR 39.1 41.9 44.8 65.3 70.5 

 18 CR01 57.8 63.1 69.6 ** **   

 18 EL-S 28.8 30.9 33.2 49.0 52.5 

 

 18 EL01 18.1 19.9 21.9 36.6 39.8 

 18 EL02 33.1 35.7 38.5 57.6 62.5 

 18 EL03 14.4 16.0 17.9 32.4 35.5 

 18 EL04 13.8 15.5 17.3 31.4 34.5 

 18 T01 44.0 47.7 52.2 87.8 ** ** 

 

 18 T02 42.2 45.4 49.0 74.5 81.9 

 18 SW2 26.0 27.8 29.7 42.9 45.7 

 19 OPEN 45.0 48.6 52.9 85.1 97.3 

 19 SW1 20.1 21.8 23.6 36.1 38.7 

 19 L-SR 40.2 43.0 45.9 66.4 71.5 

 

 19 CR01 59.2 64.5 71.0   ** ** 

 19 EL-S 29.8 31.9 34.2 50.1 53.6 

 19 EL01 18.7 20.5 22.5 37.3 40.5 

 19 EL02 34.1 36.8 39.6 58.9 63.9 

 19 EL03 15.0 16.7 18.6 33.1 36.2 

 

 19 EL04 14.4 16.1 17.9 32.1 35.2 

 19 T01 45.3 49.0 53.6 89.4   

 19 T02 43.4 46.6 50.2 75.7 83.1 

 19 SW2 27.1 28.9 30.8 44.1 47.0 

 20 OPEN 46.3 49.9 54.3 86.7 99.0 

 

 20 SW1 21.2 22.8 24.7 37.3 39.8 

 20 L-SR 41.4 44.1 47.1 67.5 72.7 

 20 CR01 60.6 66.0 72.6 ** **   

 20 EL-S 30.8 32.9 35.3 51.2 54.8 

 20 EL01 19.2 21.0 23.1 37.9 41.2 

 

 20 EL02 35.1 37.7 40.6 60.2 65.2 

 20 EL03 15.6 17.3 19.3 33.8 37.0 

 20 EL04 15.0 16.7 18.6 32.8 35.9 

 20 T01 46.6 50.4 55.1 91.1 ** ** 

 20 T02 44.6 47.8 51.5 76.9 84.3 
60 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 20 SW2 28.2 30.0 31.9 45.4 48.2 

 21 OPEN 47.7 51.4 55.8 88.5   

 21 SW1 22.2 23.9 25.7 38.4 41.0 

 21 L-SR 42.5 45.3 48.3 68.7 73.9 

 21 CR01 62.1 67.6 74.2 ** **   

 

 21 EL-S 31.8 34.0 36.4 52.4 56.0 

 21 EL01 19.7 21.6 23.7 38.5 41.8 

 21 EL02 36.0 38.6 41.5 61.3 66.4 

 21 EL03 16.2 17.9 19.9 34.5 37.7 

 21 EL04 15.6 17.2 19.1 33.5 36.5 

 

 21 T01 48.0 51.9 56.6 92.9 ** ** 

 21 T02 45.8 49.1 52.8 78.3 85.7 

 21 SW2 29.3 31.2 33.1 46.6 49.6 

 22 OPEN 44.5 48.1 52.2 82.2 92.4 

 22 SW1 23.3 25.0 26.8 39.6 42.3 

 

 22 L-SR 43.7 46.5 49.5 70.0 75.2 

 22 CR01 58.4 63.5 69.5   ** ** 

 22 EL-S 32.9 35.1 37.5 53.5 57.2 

 22 EL01 20.3 22.1 24.2 39.1 42.3 

 22 EL02 36.8 39.5 42.4 62.4 67.6 

 

 22 EL03 16.8 18.5 20.5 35.2 38.4 

 22 EL04 16.0 17.8 19.7 34.1 37.2 

 22 T01 48.9 52.8 57.5 92.6   

 22 T02 47.1 50.4 54.1 79.7 87.0 

 22 SW2 30.5 32.3 34.3 48.0 50.9 

 

 23 OPEN 42.4 45.9 49.7 77.6 86.6 

 23 SW1 24.4 26.1 27.9 40.9 43.5 

 23 L-SR 44.8 47.6 50.7 71.1 76.3 

 23 CR01 55.8 60.6 66.1 ** **   

 23 EL-S 33.9 36.2 38.6 54.8 58.4 

 

 23 EL01 20.8 22.7 24.7 39.6 42.9 

 23 EL02 37.6 40.3 43.2 63.3 68.6 

 23 EL03 17.3 19.1 21.1 35.9 39.1 

 23 EL04 16.6 18.4 20.3 34.7 37.9 

 23 T01 49.6 53.5 58.0 91.6 ** ** 

 

 23 T02 48.3 51.6 55.3 80.7 88.0 

 23 SW2 31.6 33.5 35.5 49.3 52.2 

 24 OPEN 40.8 44.0 47.7 73.6 81.7 

 24 SW1 25.5 27.3 29.1 42.2 44.9 

 24 L-SR 45.8 48.6 51.6 71.8 76.9 
61 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 24 CR01 53.7 58.1 63.2 96.3   

 24 EL-S 35.0 37.3 39.7 56.0 59.7 

 24 EL01 21.3 23.2 25.3 40.2 43.5 

 24 EL02 38.2 40.9 43.9 64.1 69.4 

 24 EL03 17.9 19.7 21.7 36.5 39.8 

 

 24 EL04 17.1 18.9 20.8 35.3 38.5 

 24 T01 49.9 53.6 58.0 89.8 ** ** 

 24 T02 49.1 52.4 56.1 81.2 88.3 

 24 SW2 32.8 34.7 36.7 50.6 53.6 

 25 OPEN 41.1 44.3 47.9 73.7 81.6 

 

 25 SW1 26.7 28.5 30.4 43.5 46.3 

 25 L-SR 47.0 49.8 52.8 73.1 78.2 

 25 CR01 54.0 58.3 63.3 96.0   

 25 EL-S 36.1 38.4 40.8 57.2 60.9 

 25 EL01 21.9 23.8 25.8 40.9 44.2 

 

 25 EL02 38.8 41.6 44.5 64.8 70.1 

 25 EL03 18.4 20.2 22.3 37.2 40.5 

 25 EL04 17.7 19.4 21.4 36.0 39.1 

 25 T01 50.8 54.6 59.0 90.4 ** ** 

 25 T02 50.4 53.7 57.4 82.4 89.5 

 

 25 SW2 33.9 35.9 37.9 52.0 55.1 

 26 OPEN 36.6 39.4 42.5 63.9 69.7 

 26 SW1 27.9 29.7 31.6 44.9 47.7 

 26 L-SR 45.3 47.9 50.7 69.6 74.2 

 26 EL-S 37.3 39.6 42.0 58.5 62.2 

 

 26 EL01 22.5 24.4 26.5 41.5 44.8 

 26 EL02 39.5 42.2 45.2 65.5 70.8 

 26 EL03 19.3 21.1 23.2 38.4 41.8 

 26 EL04 18.5 20.3 22.3 37.1 40.4 

 26 T01 48.0 51.3 55.0 81.6 89.9 

 

 26 T02 48.3 51.3 54.5 77.0 83.0 

 26 SW2 35.2 37.1 39.1 53.4 56.5 

 27 OPEN 50.4 53.6 57.2 82.9 90.7 

 27 SW1 29.2 31.0 33.0 46.4 49.2 

 27 L-SR 45.5 48.1 50.8 69.4 73.8 

 

 27 EL-S 38.5 40.8 43.2 59.9 63.6 

 27 EL03 19.7 21.6 23.7 39.0 42.4 

 27 EL04 18.9 20.7 22.8 37.6 40.9 

 27 T01 50.7 54.0 57.7 85.5 94.8 

 27 T02 48.5 51.4 54.5 76.2 81.9 
62 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 27 SW2 36.5 38.4 40.5 54.9 58.0 

 28 OPEN 52.2 55.4 59.1 85.0 92.8 

 28 SW1 30.7 32.5 34.5 48.1 50.9 

 28 L-SR 46.8 49.4 52.2 70.9 75.4 

 28 EL-S 39.8 42.1 44.6 61.3 65.1 

 

 28 EL03 20.2 22.0 24.2 39.5 42.9 

 28 EL04 19.3 21.1 23.2 38.1 41.3 

 28 T01 52.4 55.8 59.6 87.6 96.9 

 28 T02 50.0 52.9 56.1 77.9 83.6 

 28 SW2 37.8 39.8 41.9 56.4 59.6 

 

 29 OPEN 48.0 52.0 56.4 83.8 91.8 

 29 SW1 32.3 34.2 36.1 49.9 52.9 

 29 L-SR 48.3 50.9 53.7 72.5 77.0 

 29 EL-S 41.1 43.5 46.0 62.9 66.7 

 29 EL03 20.6 22.5 24.6 40.0 43.4 

 

 29 EL04 19.7 21.6 23.6 38.5 41.8 

 29 T01 44.3 48.1 52.5 81.3 90.1 

 29 T02 51.7 54.6 57.8 79.7 85.4 

 29 SW2 39.3 41.3 43.5 58.2 61.4 

 30 OPEN 46.8 50.9 55.5 84.0 92.2 

 

 30 SW1 34.1 36.0 38.0 52.1 55.0 

 30 L-SR 49.8 52.5 55.3 74.3 78.8 

 30 EL-S 42.6 45.0 47.5 64.5 68.4 

 30 EL03 21.0 22.9 25.0 40.4 43.9 

 30 EL04 20.0 21.9 24.0 39.0 42.2 

 

 30 T01 42.7 46.4 50.6 79.4 88.2 

 30 T02 53.5 56.5 59.8 81.8 87.5 

 30 SW2 40.9 43.0 45.1 60.1 63.4 

 31 OPEN 45.8 49.8 54.5 84.0 92.5 

 31 SW1 36.2 38.1 40.2 54.5 57.6 

 

 31 L-SR 51.5 54.2 57.1 76.2 80.8 

 31 EL-S 44.2 46.7 49.2 66.4 70.3 

 31 EL03 21.4 23.3 25.5 40.8 44.3 

 31 EL04 20.5 22.4 24.4 39.4 42.7 

 31 T01 42.7 46.4 50.6 79.7 88.7 

 

 31 T02 55.6 58.6 61.9 84.1 89.8 

 31 SW2 42.7 44.8 47.0 62.2 65.5 

 32 OPEN 44.5 48.4 52.9 83.1 91.9 

 32 SW1 38.6 40.6 42.8 57.4 60.6 

 32 L-SR 53.4 56.1 59.0 78.3 83.0 
63 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 32 EL-S 46.0 48.5 51.0 68.4 72.4 

 32 EL03 21.8 23.7 25.9 41.3 44.7 

 32 EL04 20.9 22.8 24.8 39.8 43.1 

 32 T01 42.3 45.9 50.0 79.2 88.2 

 32 T02 57.9 61.0 64.4 86.6 92.4 

 

 32 SW2 44.7 46.8 49.0 64.5 68.0 

 33 OPEN 43.8 47.5 51.8 82.1 91.3 

 33 SW1 41.6 43.7 45.9 61.1 64.4 

 33 L-SR 55.4 58.2 61.2 80.7 85.4 

 33 EL-S 48.0 50.5 53.1 70.7 74.8 

 

 33 EL03 22.2 24.1 26.3 41.7 45.2 

 33 EL04 21.3 23.2 25.2 40.3 43.6 

 33 T01 41.9 45.5 49.5 78.3 87.4 

 33 T02 60.5 63.7 67.1 89.6 95.4 

 33 SW2 46.9 49.1 51.4 67.2 70.7 

 

 34 OPEN 43.3 46.9 51.1 81.2 90.6 

 34 SW1 45.5 47.7 50.0 66.0 69.5 

 34 L-SR 57.8 60.6 63.6 83.4 88.2 

 34 EL-S 50.2 52.8 55.5 73.3 77.4 

 34 EL03 22.6 24.6 26.7 42.2 45.6 

 

 34 EL04 21.7 23.6 25.7 40.7 44.1 

 34 T01 41.7 45.1 49.0 77.4 86.5 

 34 T02 63.5 66.8 70.3 93.0 98.9 

 34 SW2 49.5 51.7 54.1 70.2 73.9 

 35 OPEN 42.6 46.1 50.0 79.1 88.5 

 

 35 SW1 51.3 53.7 56.2 73.6 77.6 

 35 L-SR 60.4 63.3 66.4 86.5 91.3 

 35 EL-S 52.8 55.4 58.1 76.3 80.5 

 35 EL03 23.0 24.9 27.1 42.6 46.1 

 35 EL04 22.1 24.0 26.1 41.2 44.5 

 

 35 T01 41.2 44.5 48.2 75.6 84.4 

 35 T02 66.9 70.3 73.9 97.0   

 35 SW2 52.5 54.8 57.2 73.9 77.6 

 36 MECH 75.2 79.2 83.5 ** **   

 36 ELME 79.3 83.6 88.3 ** **   

 

 36 EL-S 55.8 58.4 61.3 79.9 84.2 

 36 EL03 23.0 25.0 27.1 42.6 46.1 

 36 EL04 22.1 24.0 26.1 41.2 44.5 

 36 SW2 56.1 58.5 61.1 78.4 82.3 

 R SW2 60.8 63.4 66.1 84.4 88.6 
64 

Table 17. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 
65 

Table 18. Results of Tenability Analysis for Scenario 18. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 G L-HR 4.0 5.6 8.2 58.3 ** ** 

 G EL03 16.0 23.6 39.3   ** ** 

 G EL04 18.3 28.3   ** **   

 2 F-RM 1.0 1.0 1.0 1.6 2.1 

 2 CR02 10.2 16.7 30.1 ** **   

 

 2 EL03 1.0 1.0 1.0 5.3 7.0 

 2 EL04 1.0 1.0 1.0 5.4 7.1 

 3 EL03 1.2 1.7 1.9 8.3 10.5 

 3 EL04 1.1 1.6 1.9 8.2 10.4 

 4 EL03 2.0 2.5 2.9 11.1 13.8 

 

 4 EL04 1.9 2.4 2.9 10.9 13.6 

 5 EL03 2.9 3.5 4.1 13.8 16.9 

 5 EL04 2.8 3.3 3.9 13.3 16.4 

 6 EL03 3.9 4.6 5.4 16.2 19.7 

 6 EL04 3.7 4.3 5.0 15.6 19.1 

 

 7 EL03 4.9 5.7 6.7 18.5 22.3 

 7 EL04 4.6 5.3 6.2 17.7 21.5 

 8 EL03 5.9 6.9 7.9 20.6 24.7 

 8 EL04 5.5 6.3 7.3 19.7 23.7 

 9 EL03 6.9 7.9 9.1 22.6 26.9 

 

 9 EL04 6.4 7.3 8.4 21.5 25.8 

 10 EL03 7.9 9.0 10.3 24.5 29.0 

 10 EL04 7.2 8.3 9.5 23.2 27.7 

 11 EL03 8.9 10.0 11.5 26.2 31.0 

 11 EL04 8.1 9.2 10.5 24.8 29.6 

 

 12 EL03 9.9 11.1 12.6 27.8 32.8 

 12 EL04 8.9 10.1 11.5 26.3 31.3 

 13 EL03 10.8 12.0 13.6 29.4 34.6 

 13 EL04 9.8 10.9 12.4 27.7 32.9 

 14 EL03 11.7 13.0 14.6 30.9 36.2 

 

 14 EL04 10.6 11.8 13.3 29.1 34.5 

 15 EL03 12.5 13.9 15.6 32.2 37.8 

 15 EL04 11.3 12.6 14.1 30.4 35.9 

 16 EL03 13.3 14.8 16.5 33.6 39.3 

 16 EL04 12.0 13.4 15.0 31.6 37.3 

 

 17 EL03 14.1 15.6 17.4 34.8 40.7 

 17 EL04 12.7 14.1 15.8 32.7 38.7 

 18 EL03 14.9 16.5 18.2 36.1 42.1 

 18 EL04 13.4 14.9 16.6 33.9 40.0 

 19 EL03 15.6 17.2 19.1 37.2 43.4 
66 

Table 18. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 19 EL04 14.0 15.6 17.3 35.0 41.2 

 20 EL03 16.4 18.0 19.9 38.4 44.7 

 20 EL04 14.7 16.3 18.0 36.0 42.4 

 21 EL03 17.0 18.7 20.7 39.5 46.0 

 21 EL04 15.4 16.9 18.8 37.0 43.6 

 

 22 EL03 17.7 19.5 21.5 40.5 47.2 

 22 EL04 15.9 17.6 19.5 38.0 44.7 

 23 EL03 18.4 20.2 22.2 41.5 48.4 

 23 EL04 16.6 18.2 20.1 39.0 45.8 

 24 EL03 19.0 20.8 22.9 42.5 49.5 

 

 24 EL04 17.1 18.8 20.8 39.9 46.9 

 25 EL03 19.7 21.5 23.6 43.5 50.6 

 25 EL04 17.7 19.4 21.4 40.7 47.9 

 26 EL03 20.3 22.2 24.3 44.5 51.7 

 26 EL04 18.3 20.0 22.0 41.6 48.8 

 

 27 EL03 20.9 22.8 24.9 45.4 52.7 

 27 EL04 18.8 20.6 22.6 42.3 49.7 

 28 EL03 21.5 23.4 25.6 46.2 53.7 

 28 EL04 19.3 21.1 23.1 43.1 50.5 

 29 EL03 22.0 24.0 26.2 47.0 54.6 

 

 29 EL04 19.8 21.6 23.7 43.8 51.3 

 30 L-HR 42.2 49.1 60.1 ** **   

 30 EL03 22.6 24.6 26.8 47.8 55.5 

 30 EL04 20.3 22.1 24.2 44.4 52.0 

 31 L-HR 37.0 41.7 48.0 ** **   

 

 31 EL03 23.1 25.1 27.4 48.6 56.3 

 31 EL04 20.8 22.6 24.8 45.1 52.8 

 32 L-HR 35.3 39.3 44.5 92.0 ** ** 

 32 EL03 23.7 25.7 28.0 49.3 57.1 

 32 EL04 21.3 23.1 25.3 45.7 53.4 

 

 33 L-HR 34.5 38.1 42.8 84.7   

 33 EL03 24.2 26.2 28.6 50.0 57.8 

 33 EL04 21.8 23.6 25.8 46.4 54.1 

 34 L-HR 34.0 37.5 41.8 80.2 99.5 

 34 EL03 24.7 26.7 29.1 50.6 58.5 

 

 34 EL04 22.2 24.1 26.3 47.0 54.7 

 34 T01 59.1 75.9 ** **   ** ** 

 35 L-HR 34.8 38.3 42.8 81.9   

 35 EL03 25.2 27.3 29.6 51.2 59.2 

 35 EL04 22.7 24.6 26.8 47.6 55.4 
67 

Table 18. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 35 T01 70.7 ** **   ** **   

 36 EL03 25.2 27.3 29.7 51.3 59.3 

 36 EL04 22.8 24.7 26.9 47.6 55.4 
68 

Table 19. Results of Tenability Analysis for Scenario 19. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B L-HR 96.5 ** **   ** **   

 G OPEN 3.0 4.3 5.0 31.1 44.0 

 G SW1 19.5 30.6 56.0 ** **   

 G L-SR 12.1 16.1 21.9 69.6 90.7 

 G EL-S 35.1 45.8 60.9 ** **   

 

 G EL01 5.4 6.7 8.7 38.0 51.6 

 G EL02 5.4 6.7 8.6 37.8 51.4 

 G EL03 4.6 5.7 7.1 34.9 48.2 

 G EL04 4.7 5.7 7.2 35.6 49.4 

 G T01 13.1 17.5 23.9 74.1 96.6 

 

 G T02 22.3 31.0 44.0 ** **   

 G SW2 15.6 21.1 29.5 87.7 ** ** 

 2 F-RM 1.0 1.0 1.0 0.0 0.0 

 2 SW1 27.4 42.9 84.7   ** ** 

 2 EL-S 53.0 68.5 91.8   ** ** 

 

 2 EL01 7.7 9.5 12.1 44.8 60.0 

 2 EL02 7.7 9.6 12.1 44.0 58.6 

 2 EL03 1.0 1.0 1.0 0.4 0.7 

 2 EL04 1.0 1.0 1.0 0.4 0.7 

 2 SW2 49.4 68.4   ** **   

 

 3 SW1 33.6 53.6 ** **   ** ** 

 3 EL-S 66.6 86.2   ** **   

 3 EL01 10.0 12.3 15.3 50.8 67.6 

 3 EL02 10.5 12.7 15.8 50.1 65.8 

 3 EL03 1.0 1.0 1.0 1.0 1.3 

 

 3 EL04 1.0 1.0 1.0 1.0 1.3 

 3 SW2 74.1 ** **   ** **   

 4 SW1 39.4 68.4 ** **   ** ** 

 4 EL-S 77.8   ** **   ** ** 

 4 EL01 12.3 14.9 18.3 56.3 74.6 

 

 4 EL02 13.3 16.0 19.5 56.1 73.0 

 4 EL03 1.0 1.0 1.0 1.4 2.1 

 4 EL04 1.0 1.0 1.0 1.4 2.1 

 4 SW2 98.9   ** **   ** ** 

 5 SW1 45.3 93.5   ** **   

 

 5 EL-S 87.6 ** **   ** **   

 5 EL01 14.5 17.3 21.1 61.3 81.1 

 5 EL02 16.3 19.3 23.3 62.0 80.2 

 5 EL03 1.0 1.0 1.0 2.1 2.7 

 5 EL04 1.0 1.0 1.0 2.1 2.7 
69 

Table 19. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 5 SW2 116.6 ** **   ** **   

 6 SW1 51.0 ** **   ** **   

 6 EL-S 96.4 ** **   ** **   

 6 EL01 16.5 19.6 23.8 66.0 87.2 

 6 EL02 19.3 22.7 27.1 67.9 87.3 

 

 6 EL03 1.0 1.0 1.0 2.7 3.4 

 6 EL04 1.0 1.0 1.0 2.7 3.4 

 7 SW1 56.8 ** **   ** **   

 7 EL-S 104.4 ** **   ** **   

 7 EL01 18.4 21.8 26.2 70.4 93.0 

 

 7 EL02 22.4 26.1 30.9 73.7 94.4 

 7 EL03 1.0 1.0 1.0 3.4 4.2 

 7 EL04 1.0 1.0 1.0 3.3 4.1 

 8 SW1 63.0 ** **   ** **   

 8 EL-S 111.8 ** **   ** **   

 

 8 EL01 20.3 23.8 28.6 74.5 98.5 

 8 EL02 25.5 29.5 34.7 79.4 ** ** 

 8 EL03 1.0 1.0 1.0 4.1 4.9 

 8 EL04 1.0 1.0 1.0 4.0 4.8 

 9 SW1 93.1   ** **   ** ** 

 

 9 EL-S 118.8   ** **   ** ** 

 9 EL01 22.0 25.7 30.8 78.5   

 9 EL02 28.5 32.9 38.5 85.2 ** ** 

 9 EL03 1.0 1.0 1.0 4.7 5.5 

 9 EL04 1.0 1.0 1.0 4.6 5.4 

 

 10 SW1 98.8   ** **   ** ** 

 10 EL01 23.6 27.5 32.8 82.2   

 10 EL02 31.6 36.2 42.3 90.8 ** ** 

 10 EL03 1.0 1.0 1.5 5.3 6.2 

 10 EL04 1.0 1.0 1.4 5.2 6.1 

 

 11 SW1 104.4   ** **   ** ** 

 11 EL01 25.2 29.3 34.8 85.8   

 11 EL02 34.6 39.6 46.0 96.5 ** ** 

 11 EL03 1.0 1.5 1.8 5.9 6.8 

 11 EL04 1.0 1.4 1.8 5.7 6.6 

 

 12 SW1 110.5   ** **   ** ** 

 12 EL01 26.7 30.9 36.7 89.2   

 12 EL02 37.7 42.9 49.7 ** **   

 12 EL03 1.5 1.8 2.0 6.5 7.4 

 12 EL04 1.4 1.8 2.0 6.3 7.2 
70 

Table 19. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 SW1 117.8 ** **   ** **   

 13 EL01 28.1 32.5 38.5 92.5 ** ** 

 13 EL02 40.6 46.1 53.4   ** ** 

 13 EL03 1.8 2.0 2.5 7.1 8.1 

 13 EL04 1.7 1.9 2.4 6.9 7.8 

 

 14 EL01 31.2 36.5 44.1   ** ** 

 14 EL02 48.3 56.0 67.1   ** ** 

 14 EL03 2.0 2.5 2.9 7.6 8.6 

 14 EL04 1.9 2.2 2.8 7.4 8.3 

 15 EL01 32.4 37.8 45.8   ** ** 

 

 15 EL02 50.9 59.1 71.5   ** ** 

 15 EL03 2.4 2.8 3.2 8.2 9.2 

 15 EL04 2.1 2.7 3.0 7.9 8.9 

 16 EL01 33.4 38.9 47.3   ** ** 

 16 EL02 53.2 61.9 75.5   ** ** 

 

 16 EL03 2.7 3.0 3.6 8.7 9.7 

 16 EL04 2.6 2.9 3.4 8.4 9.4 

 17 EL01 34.3 40.0 48.5   ** ** 

 17 EL02 55.3 64.5 79.2   ** ** 

 17 EL03 2.9 3.5 3.9 9.2 10.3 

 

 17 EL04 2.8 3.2 3.8 8.9 10.0 

 18 EL01 35.1 41.0 49.7   ** ** 

 18 EL02 57.2 66.9 82.8   ** ** 

 18 EL03 3.3 3.8 4.4 9.8 10.9 

 18 EL04 3.0 3.6 4.0 9.4 10.5 

 

 19 EL01 35.9 41.9 50.8   ** ** 

 19 EL02 59.0 69.2 86.3   ** ** 

 19 EL03 3.7 4.1 4.8 10.3 11.4 

 19 EL04 3.5 3.9 4.5 9.9 11.0 

 20 EL01 36.7 42.7 51.7   ** ** 

 

 20 EL02 60.7 71.4 89.6   ** ** 

 20 EL03 3.9 4.6 5.0 10.8 12.0 

 20 EL04 3.8 4.2 4.8 10.3 11.5 

 21 EL01 37.3 43.3 52.4   ** ** 

 21 EL02 62.3 73.5 92.9   ** ** 

 

 21 EL03 4.3 4.9 5.5 11.3 12.4 

 21 EL04 4.0 4.6 5.1 10.9 12.0 

 22 EL01 37.9 43.9 53.0   ** ** 

 22 EL02 63.8 75.4 96.2   ** ** 

 22 EL03 4.7 5.2 5.9 11.8 13.0 
71 

Table 19. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 22 EL04 4.4 4.9 5.6 11.3 12.5 

 23 EL01 38.6 44.6 53.7   ** ** 

 23 EL02 65.2 77.2 99.0   ** ** 

 23 EL03 4.9 5.6 6.2 12.2 13.5 

 23 EL04 4.7 5.2 5.9 11.8 13.0 

 

 24 EL01 39.2 45.3 54.4   ** ** 

 24 EL02 66.1 78.2   ** **   

 24 EL03 5.4 5.9 6.6 12.7 14.0 

 24 EL04 4.9 5.6 6.2 12.2 13.4 

 25 EL01 39.9 46.0 55.1 ** **   

 

 25 EL02 66.8 78.9 ** **   ** ** 

 25 EL03 5.7 6.3 6.9 13.2 14.4 

 25 EL04 5.3 5.9 6.6 12.7 13.9 

 26 OPEN 85.1   ** **   ** ** 

 26 EL01 40.6 46.7 55.8   ** ** 

 

 26 EL02 67.6 79.7   ** **   

 26 EL03 6.0 6.8 7.5 13.9 15.2 

 26 EL04 5.7 6.3 7.0 13.3 14.6 

 27 EL03 6.4 7.0 7.8 14.3 15.6 

 27 EL04 5.9 6.7 7.3 13.7 15.0 

 

 28 EL03 6.7 7.4 8.0 14.7 16.0 

 28 EL04 6.2 6.9 7.6 14.1 15.4 

 29 OPEN 18.9 20.8 23.2 47.3 56.6 

 29 EL03 6.9 7.7 8.4 15.1 16.4 

 29 EL04 6.6 7.1 7.9 14.4 15.7 

 

 29 T01 16.9 18.6 20.5 39.4 45.9 

 30 OPEN 18.2 20.0 22.1 43.4 51.1 

 30 EL03 7.2 7.9 8.7 15.4 16.8 

 30 EL04 6.8 7.5 8.1 14.8 16.1 

 30 T01 16.4 17.9 19.7 36.8 42.2 

 

 31 OPEN 17.9 19.6 21.5 40.6 47.1 

 31 EL03 7.6 8.2 8.9 15.8 17.2 

 31 EL04 7.0 7.8 8.5 15.1 16.5 

 31 T01 16.6 18.0 19.8 36.5 41.8 

 32 OPEN 17.5 19.0 20.9 38.3 43.9 

 

 32 EL03 7.8 8.5 9.3 16.2 17.5 

 32 EL04 7.4 8.0 8.8 15.5 16.9 

 32 T01 16.6 18.0 19.8 35.8 40.8 

 33 OPEN 17.4 18.9 20.7 37.1 42.2 

 33 EL03 8.0 8.8 9.6 16.5 17.9 
72 

Table 19. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 33 EL04 7.7 8.3 9.0 15.9 17.2 

 33 T01 16.6 18.0 19.7 35.3 39.9 

 34 OPEN 17.4 18.9 20.6 36.4 41.2 

 34 EL03 8.4 9.0 9.9 16.9 18.3 

 34 EL04 7.9 8.7 9.4 16.2 17.6 

 

 34 T01 16.7 18.1 19.7 34.9 39.3 

 35 OPEN 17.3 18.7 20.4 35.5 39.8 

 35 EL03 8.7 9.4 10.2 17.3 18.7 

 35 EL04 8.2 8.9 9.7 16.6 18.1 

 35 T01 16.7 18.0 19.6 34.2 38.3 

 

 36 MECH 54.7 65.8 81.8 ** **   

 36 ELME 82.8 ** **   ** **   

 36 EL03 8.7 9.5 10.2 17.3 18.7 

 36 EL04 8.2 8.9 9.7 16.6 18.1 
73 

Table 20. Results of Tenability Analysis for Scenario 20. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 77.2 ** **   ** **   

 B L-MR 89.2 ** **   ** **   

 B L-HR 70.3 ** **   ** **   

 B EL02 118.4 ** **   ** **   

 B EL03 100.1 ** **   ** **   

 

 B EL04 96.8 ** **   ** **   

 G OPEN 3.0 4.3 5.1 31.7 44.4 

 G SW1 10.8 15.0 22.4 89.0 ** ** 

 G L-SR 9.7 12.8 17.2 58.2 75.4 

 G EL-S 24.5 31.5 41.2 99.4   

 

 G EL01 6.1 7.8 10.2 41.8 55.6 

 G EL02 6.2 7.9 10.4 43.1 57.7 

 G EL03 5.6 7.0 9.2 40.4 54.5 

 G EL04 5.7 7.1 9.4 42.1 57.2 

 G T01 12.0 16.0 21.8 68.5 88.5 

 

 G T02 17.0 23.2 32.3 89.6 ** ** 

 G SW2 11.4 15.1 20.7 66.7 86.7 

 2 F-RM 1.0 1.0 1.0 0.0 0.0 

 2 SW1 15.3 20.9 30.6   ** ** 

 2 EL-S 36.1 45.7 59.2   ** ** 

 

 2 EL01 9.8 12.4 15.8 53.0 69.7 

 2 EL02 10.0 12.5 16.0 53.3 70.1 

 2 EL03 1.0 1.0 1.0 0.3 0.5 

 2 EL04 1.0 1.0 1.0 0.3 0.5 

 2 SW2 29.7 39.3 53.5   ** ** 

 

 3 SW1 19.2 25.4 37.2   ** ** 

 3 EL-S 45.2 56.8 73.6   ** ** 

 3 EL01 13.5 16.6 20.9 62.5 81.7 

 3 EL02 14.3 17.5 22.0 63.4 82.3 

 3 EL03 1.0 1.0 1.0 1.0 1.4 

 

 3 EL04 1.0 1.0 1.0 1.0 1.4 

 3 SW2 41.8 55.1 80.4   ** ** 

 4 SW1 22.5 29.4 43.8   ** ** 

 4 EL-S 52.7 66.1 86.0   ** ** 

 4 EL01 16.8 20.5 25.5 70.7 92.2 

 

 4 EL02 18.7 22.7 28.0 73.2 94.4 

 4 EL03 1.0 1.0 1.0 1.8 2.4 

 4 EL04 1.0 1.0 1.0 1.8 2.3 

 4 SW2 51.3 71.1   ** **   

 5 SW1 25.3 33.4 50.2 ** **   
74 

Table 20. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 5 EL-S 59.0 74.1 97.0 ** **   

 5 EL01 19.8 23.9 29.6 78.0 ** ** 

 5 EL02 23.3 27.8 34.0 82.7   

 5 EL03 1.0 1.0 1.0 2.7 3.4 

 5 EL04 1.0 1.0 1.0 2.6 3.3 

 

 5 SW2 59.4 92.3 ** **   ** ** 

 6 SW1 27.9 37.1 56.6   ** ** 

 6 EL-S 64.6 81.3   ** **   

 6 EL01 22.6 27.1 33.3 84.6 ** ** 

 6 EL02 27.8 32.9 39.9 92.1   

 

 6 EL03 1.0 1.0 1.0 3.6 4.4 

 6 EL04 1.0 1.0 1.0 3.5 4.3 

 6 SW2 69.0 ** **   ** **   

 7 SW1 30.2 40.7 63.9 ** **   

 7 EL-S 69.7 87.9 ** **   ** ** 

 

 7 EL01 25.2 30.0 36.8 90.7   

 7 EL02 32.3 38.0 45.8 ** **   

 7 EL03 1.0 1.0 1.0 4.5 5.4 

 7 EL04 1.0 1.0 1.0 4.3 5.2 

 7 SW2 84.9 ** **   ** **   

 

 8 SW1 32.6 44.3 90.3 ** **   

 8 EL-S 74.3 94.1 ** **   ** ** 

 8 EL01 27.6 32.7 39.9 96.3   

 8 EL02 36.7 43.0 51.5 ** **   

 8 EL03 1.0 1.0 1.5 5.4 6.3 

 

 8 EL04 1.0 1.0 1.3 5.2 6.1 

 8 SW2 95.5 ** **   ** **   

 9 SW1 34.8 47.9 95.7 ** **   

 9 EL-S 78.6 99.8 ** **   ** ** 

 9 EL01 29.7 35.2 42.9   ** ** 

 

 9 EL02 41.0 47.8 57.2   ** ** 

 9 EL03 1.2 1.7 1.9 6.3 7.2 

 9 EL04 1.0 1.5 1.8 6.0 6.9 

 9 SW2 101.6   ** **   ** ** 

 10 SW1 36.9 51.3   ** **   

 

 10 EL-S 82.6 ** **   ** **   

 10 EL01 31.8 37.6 45.7 ** **   

 10 EL02 45.3 52.6 62.8 ** **   

 10 EL03 1.8 2.0 2.4 7.1 8.1 

 10 EL04 1.6 1.9 2.1 6.7 7.7 
75 

Table 20. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 10 SW2 107.1 ** **   ** **   

 11 SW1 39.5 55.3 ** **   ** ** 

 11 EL-S 86.4   ** **   ** ** 

 11 EL01 33.7 39.7 48.4   ** ** 

 11 EL02 49.4 57.3 68.3   ** ** 

 

 11 EL03 2.0 2.5 2.9 7.9 9.0 

 11 EL04 1.9 2.1 2.7 7.4 8.4 

 11 SW2 112.5   ** **   ** ** 

 12 SW1 42.0 59.2   ** **   

 12 EL-S 90.0 ** **   ** **   

 

 12 EL01 35.5 41.8 50.8 ** **   

 12 EL02 53.5 61.9 73.7 ** **   

 12 EL03 2.6 2.9 3.5 8.6 9.7 

 12 EL04 2.1 2.7 3.0 8.2 9.2 

 12 SW2 117.6 ** **   ** **   

 

 13 SW1 44.4 63.1 ** **   ** ** 

 13 EL-S 93.3   ** **   ** ** 

 13 EL01 37.2 43.8 53.2   ** ** 

 13 EL02 57.5 66.4 79.1   ** ** 

 13 EL03 2.9 3.4 3.9 9.4 10.5 

 

 13 EL04 2.7 3.0 3.6 8.9 10.0 

 14 SW1 46.4 66.6   ** **   

 14 EL-S 96.1 ** **   ** **   

 14 EL01 39.6 46.7 57.2 ** **   

 14 EL02 64.2 74.9 91.2 ** **   

 

 14 EL03 3.4 3.9 4.5 10.1 11.3 

 14 EL04 2.9 3.5 4.0 9.5 10.6 

 15 SW1 47.6 67.9 ** **   ** ** 

 15 EL-S 97.6   ** **   ** ** 

 15 EL01 41.1 48.4 59.4   ** ** 

 

 15 EL02 68.5 80.4 99.1   ** ** 

 15 EL03 3.8 4.4 4.9 10.8 12.0 

 15 EL04 3.4 3.9 4.5 10.1 11.3 

 16 SW1 48.7 69.2   ** **   

 16 EL-S 98.7 ** **   ** **   

 

 16 EL01 42.5 50.0 61.5 ** **   

 16 EL02 72.5 85.5 ** **   ** ** 

 16 EL03 4.2 4.8 5.5 11.5 12.7 

 16 EL04 3.8 4.4 4.9 10.7 11.9 

 17 SW1 49.9 70.5   ** **   
76 

Table 20. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 17 EL-S 99.9 ** **   ** **   

 17 EL01 43.8 51.5 63.3 ** **   

 17 EL02 76.2 90.2 ** **   ** ** 

 17 EL03 4.7 5.3 5.9 12.1 13.4 

 17 EL04 4.1 4.8 5.4 11.3 12.5 

 

 18 SW1 51.1 71.8   ** **   

 18 EL-S 101.0 ** **   ** **   

 18 EL01 45.0 52.9 65.1 ** **   

 18 EL02 79.6 94.8 ** **   ** ** 

 18 EL03 5.1 5.8 6.5 12.8 14.1 

 

 18 EL04 4.6 5.1 5.8 11.9 13.2 

 19 SW1 52.4 73.2   ** **   

 19 EL-S 102.2 ** **   ** **   

 19 EL01 46.1 54.2 66.7 ** **   

 19 EL02 82.8 99.1 ** **   ** ** 

 

 19 EL03 5.6 6.2 6.9 13.4 14.7 

 19 EL04 4.9 5.6 6.2 12.5 13.8 

 20 SW1 53.7 74.6   ** **   

 20 EL-S 103.4 ** **   ** **   

 20 EL01 47.2 55.4 68.0 ** **   

 

 20 EL02 85.8 ** **   ** **   

 20 EL03 6.0 6.7 7.4 14.0 15.3 

 20 EL04 5.4 5.9 6.7 13.1 14.3 

 21 SW1 55.0 76.1 ** **   ** ** 

 21 EL-S 104.5   ** **   ** ** 

 

 21 EL01 48.1 56.4 69.2   ** ** 

 21 EL02 88.7   ** **   ** ** 

 21 EL03 6.5 7.1 7.9 14.6 16.0 

 21 EL04 5.8 6.4 7.0 13.6 14.9 

 22 SW1 56.3 77.6   ** **   

 

 22 EL-S 105.7 ** **   ** **   

 22 EL01 48.9 57.2 70.1 ** **   

 22 EL02 91.4 ** **   ** **   

 22 EL03 6.9 7.6 8.3 15.2 16.6 

 22 EL04 6.1 6.8 7.6 14.1 15.5 

 

 23 SW1 57.7 79.2 ** **   ** ** 

 23 EL-S 106.9   ** **   ** ** 

 23 EL01 49.7 58.0 70.9   ** ** 

 23 EL02 93.9   ** **   ** ** 

 23 EL03 7.3 7.9 8.8 15.8 17.2 
77 

Table 20. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 23 EL04 6.6 7.2 7.9 14.6 16.1 

 24 SW1 59.2 80.8   ** **   

 24 EL-S 108.2 ** **   ** **   

 24 EL01 50.5 58.9 71.7 ** **   

 24 EL02 95.9 ** **   ** **   

 

 24 EL03 7.7 8.5 9.2 16.3 17.8 

 24 EL04 6.9 7.6 8.4 15.2 16.6 

 25 SW1 60.7 82.6 ** **   ** ** 

 25 EL-S 109.5   ** **   ** ** 

 25 EL01 51.3 59.7 72.6   ** ** 

 

 25 EL02 97.3   ** **   ** ** 

 25 EL03 8.0 8.8 9.7 16.9 18.3 

 25 EL04 7.3 7.9 8.8 15.7 17.1 

 26 SW1 62.3 84.4   ** **   

 26 EL-S 110.9 ** **   ** **   

 

 26 EL01 52.2 60.6 73.6 ** **   

 26 EL02 98.4 ** **   ** **   

 26 EL03 8.6 9.3 10.1 17.5 19.0 

 26 EL04 7.7 8.4 9.1 16.2 17.7 

 27 SW1 64.1 86.3 ** **   ** ** 

 

 27 EL-S 112.3   ** **   ** ** 

 27 EL03 8.9 9.7 10.6 18.1 19.5 

 27 EL04 8.0 8.8 9.6 16.7 18.2 

 28 SW1 66.0 88.6   ** **   

 28 EL-S 113.8 ** **   ** **   

 

 28 EL03 9.3 10.0 10.9 18.5 20.1 

 28 EL04 8.4 9.0 9.9 17.2 18.7 

 29 SW1 68.2 91.1 ** **   ** ** 

 29 EL-S 115.5   ** **   ** ** 

 29 EL03 9.7 10.5 11.3 19.0 20.5 

 

 29 EL04 8.7 9.5 10.3 17.6 19.1 

 30 SW1 70.8 94.0   ** **   

 30 EL-S 117.3 ** **   ** **   

 30 EL03 10.0 10.8 11.7 19.4 21.1 

 30 EL04 9.0 9.8 10.6 18.1 19.5 

 

 31 OPEN 24.2 26.5 29.3 55.5 65.5 

 31 SW1 73.8 97.6 ** **   ** ** 

 31 EL-S 119.3   ** **   ** ** 

 31 EL03 10.4 11.2 12.0 19.9 21.5 

 31 EL04 9.3 10.0 10.9 18.4 20.0 
78 

Table 20. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 31 T01 18.9 20.5 22.3 38.2 42.7 

 32 OPEN 23.3 25.4 27.9 50.9 59.0 

 32 SW1 77.6   ** **   ** ** 

 32 EL03 10.7 11.6 12.5 20.3 22.0 

 32 EL04 9.7 10.5 11.3 18.9 20.4 

 

 32 T01 18.4 19.8 21.5 36.1 40.1 

 33 OPEN 23.2 25.3 27.7 49.7 57.3 

 33 SW1 82.6   ** **   ** ** 

 33 EL03 11.0 11.9 12.8 20.8 22.4 

 33 EL04 9.9 10.8 11.7 19.3 20.8 

 

 33 T01 18.4 19.9 21.5 35.7 39.5 

 34 OPEN 23.0 25.0 27.2 47.5 54.1 

 34 SW1 89.9   ** **   ** ** 

 34 EL03 11.4 12.2 13.1 21.2 22.8 

 34 EL04 10.3 11.1 12.0 19.7 21.3 

 

 34 T01 18.7 20.1 21.8 35.9 39.7 

 35 OPEN 23.4 25.4 27.6 47.8 54.3 

 35 SW1 103.5   ** **   ** ** 

 35 EL03 11.7 12.6 13.6 21.6 23.3 

 35 EL04 10.7 11.5 12.4 20.1 21.7 

 

 35 T01 19.1 20.6 22.2 36.4 40.1 

 36 EL03 11.8 12.7 13.6 21.6 23.3 

 36 EL04 10.7 11.5 12.4 20.2 21.7 
79 

Table 21. Results of Tenability Analysis for Scenario 21. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B L-HR 96.5   ** **   ** ** 

 G OPEN 3.0 4.3 5.0 31.1 44.0 

 G SW1 19.5 30.7 56.2   ** ** 

 G L-SR 12.1 16.1 21.9 69.7 90.8 

 G EL-S 35.2 45.8 61.0   ** ** 

 

 G EL01 5.4 6.7 8.7 38.0 51.6 

 G EL02 5.4 6.7 8.6 37.8 51.4 

 G EL03 4.6 5.7 7.1 34.9 48.2 

 G EL04 4.7 5.7 7.2 35.6 49.4 

 G T01 13.1 17.5 23.9 74.1 96.6 

 

 G T02 22.3 31.0 44.0   ** ** 

 G SW2 15.6 21.1 29.6 87.8   

 2 F-RM 1.0 1.0 1.0 0.0 0.0 

 2 SW1 27.5 43.0 85.0 ** **   

 2 EL-S 53.0 68.5 91.9 ** **   

 

 2 EL01 7.7 9.5 12.1 44.8 60.0 

 2 EL02 7.7 9.6 12.1 44.0 58.6 

 2 EL03 1.0 1.0 1.0 0.4 0.7 

 2 EL04 1.0 1.0 1.0 0.4 0.7 

 2 SW2 49.5 68.5 ** **   ** ** 

 

 3 SW1 33.6 53.7   ** **   

 3 EL-S 66.6 86.2 ** **   ** ** 

 3 EL01 10.0 12.3 15.3 50.8 67.6 

 3 EL02 10.5 12.7 15.8 50.1 65.8 

 3 EL03 1.0 1.0 1.0 1.0 1.3 

 

 3 EL04 1.0 1.0 1.0 1.0 1.3 

 3 SW2 74.2   ** **   ** ** 

 4 SW1 39.4 68.9   ** **   

 4 EL-S 77.8 ** **   ** **   

 4 EL01 12.3 14.9 18.3 56.3 74.6 

 

 4 EL02 13.3 16.0 19.6 56.1 73.0 

 4 EL03 1.0 1.0 1.0 1.4 2.1 

 4 EL04 1.0 1.0 1.0 1.4 2.1 

 4 SW2 99.0 ** **   ** **   

 5 SW1 45.4 93.7 ** **   ** ** 

 

 5 EL-S 87.6   ** **   ** ** 

 5 EL01 14.5 17.3 21.1 61.3 81.2 

 5 EL02 16.3 19.4 23.3 62.0 80.2 

 5 EL03 1.0 1.0 1.0 2.1 2.7 

 5 EL04 1.0 1.0 1.0 2.1 2.7 
80 

Table 21. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 5 SW2 116.7   ** **   ** ** 

 6 SW1 51.1   ** **   ** ** 

 6 EL-S 96.4   ** **   ** ** 

 6 EL01 16.5 19.6 23.8 66.0 87.3 

 6 EL02 19.3 22.7 27.1 67.9 87.3 

 

 6 EL03 1.0 1.0 1.0 2.8 3.4 

 6 EL04 1.0 1.0 1.0 2.7 3.4 

 7 SW1 56.9   ** **   ** ** 

 7 EL-S 104.4   ** **   ** ** 

 7 EL01 18.4 21.8 26.3 70.4 93.0 

 

 7 EL02 22.4 26.1 30.9 73.7 94.4 

 7 EL03 1.0 1.0 1.0 3.4 4.2 

 7 EL04 1.0 1.0 1.0 3.3 4.1 

 8 SW1 63.3   ** **   ** ** 

 8 EL-S 111.8   ** **   ** ** 

 

 8 EL01 20.3 23.8 28.6 74.5 98.5 

 8 EL02 25.5 29.5 34.7 79.5   

 8 EL03 1.0 1.0 1.0 4.1 4.9 

 8 EL04 1.0 1.0 1.0 4.0 4.8 

 9 SW1 93.2 ** **   ** **   

 

 9 EL-S 118.8 ** **   ** **   

 9 EL01 22.0 25.7 30.8 78.5 ** ** 

 9 EL02 28.5 32.9 38.5 85.2   

 9 EL03 1.0 1.0 1.0 4.7 5.5 

 9 EL04 1.0 1.0 1.0 4.6 5.4 

 

 10 SW1 99.0 ** **   ** **   

 10 EL01 23.6 27.5 32.8 82.2 ** ** 

 10 EL02 31.6 36.2 42.3 90.9   

 10 EL03 1.0 1.0 1.5 5.3 6.2 

 10 EL04 1.0 1.0 1.4 5.2 6.1 

 

 11 SW1 104.6 ** **   ** **   

 11 EL01 25.2 29.3 34.8 85.8 ** ** 

 11 EL02 34.6 39.6 46.0 96.5   

 11 EL03 1.0 1.5 1.8 5.9 6.8 

 11 EL04 1.0 1.4 1.8 5.7 6.6 

 

 12 SW1 110.7 ** **   ** **   

 12 EL01 26.7 30.9 36.7 89.2 ** ** 

 12 EL02 37.7 42.9 49.7   ** ** 

 12 EL03 1.5 1.8 2.0 6.5 7.4 

 12 EL04 1.4 1.8 2.0 6.3 7.2 
81 

Table 21. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 SW1 118.1   ** **   ** ** 

 13 EL01 28.1 32.5 38.5 92.5   

 13 EL02 40.7 46.1 53.4 ** **   

 13 EL03 1.8 2.0 2.5 7.1 8.1 

 13 EL04 1.7 1.9 2.4 6.9 7.8 

 

 14 EL01 31.2 36.5 44.1 ** **   

 14 EL02 48.4 56.0 67.2 ** **   

 14 EL03 2.0 2.5 2.9 7.6 8.6 

 14 EL04 1.9 2.2 2.8 7.4 8.3 

 15 EL01 32.4 37.8 45.8 ** **   

 

 15 EL02 50.9 59.2 71.6 ** **   

 15 EL03 2.4 2.8 3.2 8.2 9.2 

 15 EL04 2.1 2.7 3.0 7.9 8.9 

 16 EL01 33.4 39.0 47.3 ** **   

 16 EL02 53.2 61.9 75.5 ** **   

 

 16 EL03 2.7 3.0 3.6 8.7 9.7 

 16 EL04 2.6 2.9 3.4 8.4 9.4 

 17 EL01 34.3 40.0 48.6 ** **   

 17 EL02 55.3 64.5 79.2 ** **   

 17 EL03 2.9 3.5 3.9 9.2 10.3 

 

 17 EL04 2.8 3.2 3.8 8.9 10.0 

 18 EL01 35.2 41.0 49.7 ** **   

 18 EL02 57.2 67.0 82.8 ** **   

 18 EL03 3.3 3.8 4.4 9.8 10.9 

 18 EL04 3.0 3.6 4.0 9.4 10.5 

 

 19 EL01 35.9 41.9 50.8 ** **   

 19 EL02 59.0 69.3 86.3 ** **   

 19 EL03 3.7 4.1 4.8 10.3 11.4 

 19 EL04 3.5 3.9 4.5 9.9 11.0 

 20 EL01 36.7 42.7 51.7 ** **   

 

 20 EL02 60.7 71.4 89.7 ** **   

 20 EL03 3.9 4.6 5.0 10.8 12.0 

 20 EL04 3.8 4.2 4.8 10.3 11.5 

 21 EL01 37.3 43.3 52.4 ** **   

 21 EL02 62.3 73.5 93.0 ** **   

 

 21 EL03 4.3 4.9 5.5 11.3 12.4 

 21 EL04 4.0 4.6 5.1 10.9 12.0 

 22 EL01 37.9 44.0 53.0 ** **   

 22 EL02 63.9 75.5 96.2 ** **   

 22 EL03 4.7 5.2 5.9 11.8 13.0 
82 

Table 21. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 22 EL04 4.4 4.9 5.6 11.3 12.5 

 23 EL01 38.6 44.6 53.7 ** **   

 23 EL02 65.2 77.2 99.1 ** **   

 23 EL03 4.9 5.6 6.2 12.2 13.5 

 23 EL04 4.7 5.2 5.9 11.8 13.0 

 

 24 EL01 39.2 45.3 54.4 ** **   

 24 EL02 66.1 78.2 ** **   ** ** 

 24 EL03 5.4 5.9 6.6 12.7 14.0 

 24 EL04 4.9 5.6 6.2 12.2 13.4 

 25 EL01 39.9 46.0 55.1   ** ** 

 

 25 EL02 66.9 79.0   ** **   

 25 EL03 5.7 6.3 6.9 13.2 14.4 

 25 EL04 5.3 5.9 6.6 12.7 13.9 

 26 OPEN 85.1 ** **   ** **   

 26 EL01 40.6 46.7 55.9 ** **   

 

 26 EL02 67.6 79.8 ** **   ** ** 

 26 EL03 6.0 6.8 7.5 13.9 15.2 

 26 EL04 5.7 6.3 7.0 13.3 14.6 

 27 EL03 6.4 7.0 7.8 14.3 15.6 

 27 EL04 5.9 6.7 7.3 13.7 15.0 

 

 28 EL03 6.7 7.4 8.0 14.7 16.0 

 28 EL04 6.2 6.9 7.6 14.1 15.4 

 29 OPEN 18.9 20.8 23.2 47.3 56.6 

 29 EL03 6.9 7.7 8.4 15.1 16.4 

 29 EL04 6.6 7.1 7.9 14.4 15.7 

 

 29 T01 16.9 18.6 20.5 39.4 45.9 

 30 OPEN 18.2 20.0 22.1 43.4 51.1 

 30 EL03 7.2 7.9 8.7 15.4 16.8 

 30 EL04 6.8 7.5 8.1 14.8 16.1 

 30 T01 16.4 17.9 19.7 36.8 42.2 

 

 31 OPEN 17.9 19.6 21.5 40.6 47.1 

 31 EL03 7.6 8.2 8.9 15.8 17.2 

 31 EL04 7.0 7.8 8.5 15.1 16.5 

 31 T01 16.6 18.0 19.8 36.5 41.8 

 32 OPEN 17.5 19.0 20.9 38.3 43.9 

 

 32 EL03 7.8 8.5 9.3 16.2 17.5 

 32 EL04 7.4 8.0 8.8 15.5 16.9 

 32 T01 16.6 18.0 19.8 35.8 40.8 

 33 OPEN 17.4 18.9 20.7 37.1 42.2 

 33 EL03 8.0 8.8 9.6 16.5 17.9 
83 

Table 21. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 33 EL04 7.7 8.3 9.0 15.9 17.2 

 33 T01 16.6 18.0 19.7 35.3 39.9 

 34 OPEN 17.4 18.9 20.6 36.4 41.2 

 34 EL03 8.4 9.0 9.9 16.9 18.3 

 34 EL04 7.9 8.7 9.4 16.2 17.6 

 

 34 T01 16.7 18.1 19.7 34.9 39.3 

 35 OPEN 17.3 18.7 20.4 35.5 39.8 

 35 EL03 8.7 9.4 10.2 17.3 18.7 

 35 EL04 8.2 8.9 9.7 16.6 18.1 

 35 T01 16.7 18.0 19.6 34.2 38.3 

 

 36 MECH 54.7 65.8 81.8   ** ** 

 36 ELME 82.8   ** **   ** ** 

 36 EL03 8.7 9.5 10.2 17.3 18.7 

 36 EL04 8.2 8.9 9.7 16.6 18.1 
84 

Table 22. Results of Tenability Analysis for Scenario 22. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B EL-S 105.6   ** **   ** ** 

 B EL04 107.9   ** **   ** ** 

 G SW1 83.0 88.0 93.7   ** ** 

 G L-SR 103.3   ** **   ** ** 

 G EL-S 89.6 93.4 97.6   ** ** 

 

 G EL04 90.4 97.3   ** **   

 G T01 119.8 ** **   ** **   

 G T02 113.7 ** **   ** **   

 G EL05 110.9 ** **   ** **   

 G SW2 102.2 ** **   ** **   

 

 2 SW1 75.9 80.6 85.9 ** **   

 2 L-SR 91.4 95.3 99.6 ** **   

 2 CR02 102.6 ** **   ** **   

 2 EL-S 79.9 83.3 87.0 ** **   

 2 EL04 79.2 85.1 92.2 ** **   

 

 2 T01 104.1 ** **   ** **   

 2 T02 101.3 ** **   ** **   

 2 EL05 100.3 ** **   ** **   

 2 SW2 84.7 89.7 95.0 ** **   

 3 OPEN 114.0 ** **   ** **   

 

 3 SW1 71.3 75.8 80.9 ** **   

 3 L-SR 84.9 88.7 92.7 ** **   

 3 CR02 99.7 ** **   ** **   

 3 EL-S 73.9 77.2 80.7 ** **   

 3 EL04 73.0 78.4 85.0 ** **   

 

 3 T01 96.8 ** **   ** **   

 3 T02 94.3 98.8 ** **   ** ** 

 3 EL05 93.5 98.0   ** **   

 3 SW2 75.3 79.6 84.5 ** **   

 4 OPEN 107.9 ** **   ** **   

 

 4 SW1 68.1 72.3 77.0 ** **   

 4 L-SR 79.8 83.4 87.3 ** **   

 4 CR02 93.8 ** **   ** **   

 4 EL-S 69.1 72.2 75.6 96.4 ** ** 

 4 EL04 68.0 73.1 79.3   ** ** 

 

 4 T01 91.1 99.6   ** **   

 4 T02 88.8 93.1 97.8 ** **   

 4 EL05 88.1 92.4 97.1 ** **   

 4 SW2 69.6 73.3 77.4 ** **   

 5 OPEN 102.8 ** **   ** **   
85 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 5 SW1 65.4 69.4 73.7 99.3 ** ** 

 5 L-SR 75.6 79.1 82.8   ** ** 

 5 CR02 88.9 98.3   ** **   

 5 EL-S 65.0 68.0 71.3 91.6 96.4 

 5 EL04 63.8 68.7 74.6 ** **   

 

 5 T01 86.3 94.6 ** **   ** ** 

 5 T02 84.3 88.5 93.0   ** ** 

 5 EL05 83.6 87.8 92.4   ** ** 

 5 SW2 65.5 68.7 72.4 96.6   

 6 OPEN 98.4 ** **   ** **   

 

 6 SW1 63.1 66.8 71.0 95.7 ** ** 

 6 L-SR 72.0 75.4 79.0   ** ** 

 6 CR02 84.8 94.0   ** **   

 6 EL-S 61.5 64.5 67.6 87.4 92.1 

 6 L-LR 117.8 ** **   ** **   

 

 6 EL04 60.2 64.9 70.5 ** **   

 6 T01 82.3 90.5 ** **   ** ** 

 6 T02 80.5 84.6 89.0   ** ** 

 6 EL05 79.8 83.8 88.2   ** ** 

 6 SW2 62.2 65.2 68.6 91.3 96.8 

 

 7 OPEN 94.5   ** **   ** ** 

 7 SW1 61.2 64.7 68.6 92.4 97.8 

 7 L-SR 68.8 72.1 75.7 97.8   

 7 CR02 81.2 90.2 ** **   ** ** 

 7 EL-S 58.4 61.3 64.3 83.8 88.3 

 

 7 L-LR 113.6   ** **   ** ** 

 7 EL04 57.0 61.5 67.0   ** ** 

 7 T01 78.8 86.8 97.1   ** ** 

 7 T02 77.2 81.1 85.5   ** ** 

 7 EL05 76.4 80.3 84.6   ** ** 

 

 7 SW2 59.6 62.4 65.5 86.8 92.2 

 8 OPEN 91.0 96.6   ** **   

 8 SW1 59.4 62.8 66.5 89.3 94.7 

 8 L-SR 65.9 69.2 72.7 94.6 ** ** 

 8 CR02 78.0 86.9 99.4   ** ** 

 

 8 EL-S 55.6 58.4 61.4 80.5 85.0 

 8 L-LR 109.8   ** **   ** ** 

 8 EL04 54.1 58.5 63.8   ** ** 

 8 T01 75.7 83.6 93.8   ** ** 

 8 T02 74.2 78.1 82.3   ** ** 
86 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL05 73.3 77.2 81.4   ** ** 

 8 EL06 119.9   ** **   ** ** 

 8 SW2 57.3 60.0 62.9 83.2 88.1 

 9 OPEN 87.9 93.5 99.3   ** ** 

 9 SW1 57.8 61.1 64.6 86.5 91.8 

 

 9 L-SR 63.4 66.6 70.0 91.7 97.0 

 9 CR02 75.1 83.9 96.3   ** ** 

 9 EL-S 53.0 55.8 58.7 77.6 81.9 

 9 L-LR 106.3   ** **   ** ** 

 9 EL04 51.5 55.8 60.9   ** ** 

 

 9 T01 72.9 80.7 90.9   ** ** 

 9 T02 71.6 75.4 79.5   ** ** 

 9 EL05 70.6 74.4 78.5   ** ** 

 9 EL06 116.4   ** **   ** ** 

 9 SW2 55.1 57.8 60.7 80.1 84.7 

 

 10 OPEN 85.2 90.6 96.3   ** ** 

 10 SW1 56.3 59.5 62.9 84.1 89.1 

 10 L-SR 61.0 64.2 67.6 89.0 94.3 

 10 CR02 72.5 81.2 93.6   ** ** 

 10 EL-S 50.7 53.4 56.3 74.9 79.2 

 

 10 L-LR 103.2   ** **   ** ** 

 10 EL04 49.1 53.3 58.3 99.3   

 10 T01 70.4 78.1 88.2 ** **   

 10 T02 69.1 72.9 77.0 ** **   

 10 EL05 68.0 71.8 75.9 ** **   

 

 10 EL06 113.1 ** **   ** **   

 10 SW2 53.2 55.9 58.7 77.4 81.8 

 11 OPEN 82.9 87.9 93.6 ** **   

 11 SW1 54.9 58.1 61.5 81.9 86.6 

 11 L-SR 58.9 62.0 65.3 86.6 91.8 

 

 11 CR02 70.1 78.8 91.1 ** **   

 11 EL-S 48.5 51.2 54.0 72.3 76.6 

 11 L-LR 100.4 ** **   ** **   

 11 EL04 47.0 51.0 55.9 96.5 ** ** 

 11 T01 68.0 75.7 85.8   ** ** 

 

 11 T02 66.9 70.6 74.7   ** ** 

 11 EL05 65.7 69.4 73.4 98.6   

 11 EL06 110.2 ** **   ** **   

 11 SW2 51.4 54.0 56.9 75.1 79.2 

 12 OPEN 80.5 85.5 91.1 ** **   
87 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 12 SW1 52.9 56.0 59.3 79.5 84.2 

 12 L-SR 56.9 59.9 63.3 84.4 89.6 

 12 CR02 67.9 76.5 88.8 ** **   

 12 EL-S 46.5 49.1 51.9 70.0 74.2 

 12 L-LR 97.7 ** **   ** **   

 

 12 EL04 44.9 48.9 53.7 94.0 ** ** 

 12 T01 65.8 73.5 83.6   ** ** 

 12 T02 64.9 68.6 72.6 97.8   

 12 EL05 63.5 67.2 71.1 96.1 ** ** 

 12 EL06 107.5   ** **   ** ** 

 

 12 SW2 49.0 51.6 54.4 72.4 76.4 

 13 OPEN 78.3 83.3 88.8   ** ** 

 13 SW1 50.9 54.0 57.3 77.2 81.8 

 13 L-SR 55.1 58.1 61.4 82.5 87.6 

 13 CR02 65.9 74.5 86.8   ** ** 

 

 13 EL-S 44.6 47.1 49.9 67.8 72.0 

 13 L-LR 95.3   ** **   ** ** 

 13 EL04 43.0 46.9 51.6 91.6   

 13 T01 63.9 71.5 81.6 ** **   

 13 T02 63.0 66.7 70.7 95.9 ** ** 

 

 13 EL05 61.5 65.0 68.9 93.8   

 13 EL06 105.1 ** **   ** **   

 13 SW2 46.8 49.4 52.1 69.8 73.8 

 14 OPEN 76.6 81.6 87.3 ** **   

 14 SW1 49.1 52.1 55.3 75.0 79.6 

 

 14 L-SR 53.6 56.6 59.9 81.0 86.2 

 14 CR02 64.2 72.8 85.2 ** **   

 14 EL-S 42.8 45.3 48.0 65.8 69.8 

 14 L-LR 93.5 99.7 ** **   ** ** 

 14 EL04 41.3 45.1 49.6 89.4   

 

 14 T01 62.2 69.8 80.2 ** **   

 14 T02 61.5 65.2 69.2 94.6 ** ** 

 14 EL05 59.5 63.1 66.9 91.6 98.3 

 14 EL06 103.0   ** **   ** ** 

 14 SW2 44.7 47.2 49.9 67.4 71.3 

 

 15 MECH 77.3 82.7 88.9   ** ** 

 15 SW1 47.4 50.3 53.4 72.9 77.4 

 15 L-SR 53.8 56.9 60.3 82.3 87.8 

 15 CR01 63.2 72.0 84.9   ** ** 

 15 EL-S 41.0 43.5 46.2 63.8 67.8 
88 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 15 EL04 39.6 43.3 47.8 87.3   

 15 T01 61.1 69.0 80.1 ** **   

 15 T02 62.1 65.9 70.2 97.1 ** ** 

 15 SW2 42.7 45.2 47.8 65.1 69.0 

 16 OPEN 77.0 82.7 89.2   ** ** 

 

 16 SW1 45.6 48.5 51.6 70.8 75.2 

 16 L-SR 53.2 56.4 59.8 82.2 88.0 

 16 CR01 61.6 70.5 83.5   ** ** 

 16 EL-S 39.4 41.8 44.5 61.9 65.9 

 16 EL04 38.0 41.7 46.0 85.3   

 

 16 T01 58.3 65.8 75.8 ** **   

 16 T02 61.5 65.5 69.8 97.4 ** ** 

 16 SW2 40.7 43.2 45.8 62.9 66.7 

 17 OPEN 76.6 82.5 89.2   ** ** 

 17 SW1 43.9 46.7 49.7 68.7 73.1 

 

 17 L-SR 52.5 55.7 59.2 82.1 88.1 

 17 CR01 60.0 68.9 81.9   ** ** 

 17 EL-S 37.7 40.1 42.7 60.0 64.0 

 17 EL04 36.5 40.1 44.4 83.4   

 17 T01 56.7 64.2 74.3 ** **   

 

 17 T02 61.0 65.0 69.5 97.9 ** ** 

 17 SW2 38.8 41.2 43.8 60.7 64.5 

 18 OPEN 76.8 83.0 90.3   ** ** 

 18 SW1 42.2 45.0 47.9 66.7 71.0 

 18 L-SR 52.3 55.7 59.3 83.0 89.3 

 

 18 CR01 58.4 67.3 80.4   ** ** 

 18 EL-S 36.1 38.5 41.0 58.2 62.1 

 18 EL04 35.0 38.6 42.8 81.6   

 18 T01 55.2 62.7 72.9 ** **   

 18 T02 61.1 65.3 70.0 99.8 ** ** 

 

 18 SW2 36.9 39.3 41.8 58.5 62.3 

 19 OPEN 79.1 86.0 94.4   ** ** 

 19 SW1 40.5 43.2 46.1 64.7 68.9 

 19 L-SR 54.7 58.4 62.4 88.8 96.2 

 19 CR01 56.9 65.8 78.9   ** ** 

 

 19 EL-S 34.5 36.9 39.4 56.3 60.2 

 19 EL04 33.7 37.1 41.3 79.9   

 19 T01 53.7 61.2 71.5 ** **   

 19 T02 64.3 69.1 74.6 ** **   

 19 SW2 35.1 37.4 39.9 56.4 60.1 
89 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 20 OPEN 95.8 ** **   ** **   

 20 SW1 38.8 41.5 44.3 62.6 66.8 

 20 L-SR 87.7 95.4 ** **   ** ** 

 20 CR01 55.5 64.3 77.4   ** ** 

 20 EL-S 32.9 35.3 37.8 54.5 58.3 

 

 20 EL04 32.3 35.8 39.8 78.3   

 20 T01 52.3 59.7 70.1 ** **   

 20 T02 96.4 ** **   ** **   

 20 SW2 33.3 35.6 38.0 54.3 58.0 

 21 SW1 37.1 39.7 42.5 60.6 64.7 

 

 21 L-SR 84.1 91.6 ** **   ** ** 

 21 CR01 54.1 62.9 76.0   ** ** 

 21 EL-S 31.3 33.6 36.1 52.7 56.5 

 21 EL04 31.0 34.5 38.4 76.7   

 21 T01 50.9 58.4 69.0 ** **   

 

 21 SW2 31.5 33.7 36.1 52.3 55.8 

 22 SW1 35.4 37.9 40.7 58.5 62.6 

 22 L-SR 80.9 88.2 97.1 ** **   

 22 CR01 52.8 61.7 74.8 ** **   

 22 EL-S 29.7 31.9 34.4 50.8 54.5 

 

 22 EL04 29.8 33.2 37.1 75.2 ** ** 

 22 T01 49.7 57.2 67.8   ** ** 

 22 SW2 29.6 31.8 34.2 50.2 53.7 

 23 SW1 33.6 36.1 38.7 56.3 60.3 

 23 L-SR 77.9 85.1 93.7   ** ** 

 

 23 CR01 51.7 60.7 73.9   ** ** 

 23 EL-S 28.0 30.3 32.7 48.9 52.6 

 23 EL04 28.7 31.9 35.8 73.8   

 23 T01 48.6 56.1 66.8 ** **   

 23 SW2 27.8 29.9 32.3 48.0 51.4 

 

 24 SW1 31.7 34.2 36.8 54.0 58.0 

 24 L-SR 75.0 82.0 90.5 ** **   

 24 CR01 50.8 59.9 73.4 ** **   

 24 EL-S 26.3 28.6 30.9 47.0 50.5 

 24 EL04 27.5 30.8 34.6 72.4 ** ** 

 

 24 T01 47.6 55.3 66.2   ** ** 

 24 SW2 25.9 28.0 30.3 45.8 49.2 

 25 SW1 29.8 32.1 34.7 51.7 55.5 

 25 L-SR 72.3 79.2 87.6   ** ** 

 25 CR01 50.3 59.6 73.7   ** ** 
90 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 25 EL-S 24.6 26.8 29.1 44.9 48.4 

 25 EL04 26.4 29.6 33.4 71.0   

 25 T01 47.0 54.8 66.1 ** **   

 25 SW2 23.9 26.0 28.3 43.5 46.8 

 26 SW1 27.7 30.0 32.5 49.1 52.9 

 

 26 L-SR 69.4 76.1 84.3 ** **   

 26 L-HR 50.7 60.9 77.4 ** **   

 26 EL-S 22.8 24.9 27.2 42.8 46.3 

 26 EL04 25.3 28.5 32.2 69.7 99.8 

 26 T01 46.5 54.6 66.3 ** **   

 

 26 SW2 21.9 24.0 26.2 41.2 44.4 

 27 SW1 25.5 27.8 30.2 46.5 50.1 

 27 L-SR 66.8 73.5 81.7 ** **   

 27 L-HR 54.6 67.2 ** **   ** ** 

 27 EL-S 20.9 23.0 25.3 40.6 44.0 

 

 27 EL04 24.3 27.4 31.0 68.4 98.4 

 27 T01 47.1 55.9 68.8   ** ** 

 27 SW2 19.9 21.9 24.0 38.7 41.8 

 28 SW1 23.1 25.4 27.7 43.5 47.1 

 28 L-SR 63.4 70.0 77.9   ** ** 

 

 28 L-HR 60.7 79.0   ** **   

 28 EL-S 19.0 21.0 23.2 38.3 41.5 

 28 EL04 23.2 26.4 29.9 67.2 97.0 

 28 T01 47.6 57.1 71.2 ** **   

 28 SW2 17.8 19.7 21.7 36.1 39.1 

 

 29 SW1 20.6 22.7 25.0 40.4 43.8 

 29 L-SR 59.6 65.9 73.6 ** **   

 29 EL-S 16.9 18.9 21.0 35.8 39.0 

 29 EL04 22.2 25.4 28.9 65.9 95.6 

 29 T01 48.4 58.7 74.8 ** **   

 

 29 SW2 15.5 17.3 19.3 33.3 36.3 

 30 SW1 17.8 19.9 22.0 37.0 40.2 

 30 L-SR 55.4 61.4 68.6 ** **   

 30 EL-S 14.8 16.7 18.7 33.2 36.2 

 30 EL04 21.2 24.4 27.8 64.7 94.3 

 

 30 T01 49.8 61.2 82.3 ** **   

 30 SW2 13.2 14.9 16.7 30.4 33.2 

 31 SW1 14.8 16.7 18.8 33.2 36.2 

 31 L-SR 50.5 56.1 62.9 ** **   

 31 EL-S 12.6 14.3 16.3 30.4 33.3 
91 

Table 22. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 31 EL04 20.2 23.4 26.7 63.5 92.8 

 31 T01 52.5 65.7 ** **   ** ** 

 31 SW2 10.8 12.3 14.0 27.3 30.0 

 32 SW1 11.6 13.3 15.2 29.0 31.8 

 32 L-SR 45.0 50.1 56.3 97.1   

 

 32 EL-S 10.2 11.8 13.7 27.4 30.2 

 32 EL04 19.2 22.4 25.7 62.3 91.1 

 32 T01 58.1 76.9 ** **   ** ** 

 32 SW2 8.3 9.7 11.2 23.9 26.4 

 33 SW1 8.0 9.5 11.1 24.1 26.7 

 

 33 L-SR 38.6 43.0 48.5 85.6   

 33 EL-S 7.8 9.2 10.9 24.2 26.9 

 33 EL04 18.2 21.4 24.6 61.0 89.2 

 33 T01 76.8 ** **   ** **   

 33 SW2 5.8 6.9 8.2 20.2 22.6 

 

 34 SW1 4.5 5.6 6.8 18.3 20.8 

 34 L-SR 31.0 34.7 39.0 71.3 83.0 

 34 EL-S 5.3 6.5 7.9 20.6 23.2 

 34 EL04 17.2 20.4 23.6 59.7 87.1 

 34 SW2 3.5 4.3 5.3 16.1 18.4 

 

 35 OPEN 1.0 1.0 1.0 5.0 6.3 

 35 SW1 1.5 1.9 2.6 11.2 13.2 

 35 L-SR 1.7 2.0 2.8 11.6 13.7 

 35 EL-S 2.9 3.9 4.9 16.7 19.2 

 35 EL04 16.2 19.3 22.6 58.4 85.0 

 

 35 T01 6.0 7.7 9.6 23.9 26.9 

 35 T02 3.0 4.0 5.1 16.9 19.3 

 35 SW2 1.6 1.9 2.7 11.6 13.7 

 36 MECH 10.7 13.0 15.5 33.1 37.9 

 36 ELME 33.9 38.8 44.9 84.6 ** ** 

 

 36 EL-S 15.1 17.6 20.3 39.3 44.6 

 36 SW2 19.6 22.5 25.5 48.8 56.1 
92 

Table 23. Results of Tenability Analysis for Scenario 23. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 35 OPEN 1.0 1.0 1.0 5.0 6.3 

 36 MECH 10.5 12.7 15.2 32.8 37.6 

 36 ELME 19.0 22.0 25.3 54.5 65.2 
93 

Table 24. Results of Tenability Analysis for Scenario 24. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 38.5 45.1 53.9   ** ** 

 B L-SR 57.4 67.0 79.7   ** ** 

 B L-MR 57.9 67.5 79.9   ** ** 

 B L-HR 54.4 63.2 74.6   ** ** 

 B EL-S 50.9 57.5 65.6   ** ** 

 

 B EL01 53.1 61.8 72.9   ** ** 

 B EL02 62.4 72.9 86.5   ** ** 

 B EL03 57.8 67.2 79.2   ** ** 

 B EL04 50.0 58.0 68.3   ** ** 

 B SW2 30.1 33.7 38.0 68.1 77.6 

 

 G OPEN 9.9 12.1 14.6 32.2 37.0 

 G SW1 17.6 20.4 23.4 47.4 55.6 

 G L-SR 16.6 19.2 22.0 42.8 48.9 

 G L-MR 15.2 17.7 20.3 39.5 44.9 

 G L-HR 12.5 14.7 17.1 34.3 38.7 

 

 G EL-S 24.4 27.4 30.8 56.5 64.5 

 G EL01 16.5 19.0 21.9 43.0 49.4 

 G EL02 18.6 21.3 24.2 45.8 52.2 

 G EL03 17.8 20.4 23.3 44.2 50.4 

 G EL04 17.9 20.6 23.4 44.7 51.0 

 

 G T01 15.9 18.4 21.1 40.7 46.2 

 G T02 18.7 21.4 24.3 46.3 52.8 

 G SW2 17.9 20.6 23.5 45.4 52.0 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.6 2.0 10.3 12.4 

 

 2 L-SR 1.0 1.5 1.9 9.3 11.2 

 2 CR01 1.4 1.8 2.4 10.6 12.6 

 2 CR02 1.0 1.4 1.9 9.1 11.0 

 2 EL-S 3.3 4.1 5.1 15.9 18.2 

 2 EL01 1.0 1.6 2.0 10.1 12.2 

 

 2 EL02 1.8 2.3 3.0 12.7 14.9 

 2 EL03 1.7 2.0 2.8 12.1 14.3 

 2 EL04 1.7 2.0 2.8 12.2 14.4 

 2 T01 1.6 2.0 2.8 11.6 13.7 

 2 T02 2.0 2.7 3.5 13.5 15.8 

 

 2 SW2 1.0 1.4 1.8 9.1 10.9 

 3 SW1 1.9 2.6 3.2 12.5 14.7 

 3 L-SR 18.2 20.9 23.8 49.1 59.4 

 3 CR02 12.9 15.2 17.7 35.3 40.0 

 3 EL-S 5.0 6.0 7.3 19.0 21.4 
94 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL01 2.4 3.0 3.9 13.5 15.7 

 3 EL02 3.8 4.7 5.8 17.2 19.7 

 3 EL03 2.9 3.7 4.6 15.0 17.3 

 3 EL04 2.8 3.6 4.5 14.8 17.1 

 3 SW2 2.8 3.5 4.3 14.0 16.1 

 

 4 SW1 2.9 3.6 4.5 14.5 16.7 

 4 L-SR 20.3 23.0 25.9 52.7 64.0 

 4 EL-S 6.7 7.9 9.3 21.5 24.1 

 4 EL01 3.8 4.7 5.7 16.3 18.7 

 4 EL02 6.3 7.6 9.0 21.6 24.3 

 

 4 EL03 4.2 5.1 6.3 17.4 19.9 

 4 EL04 3.9 4.9 5.9 17.0 19.4 

 4 SW2 4.8 5.7 6.9 17.8 20.0 

 5 SW1 3.9 4.8 5.7 16.2 18.5 

 5 L-SR 22.1 24.8 27.8 56.0 68.4 

 

 5 EL-S 8.2 9.6 11.1 23.7 26.4 

 5 EL01 5.2 6.2 7.4 18.7 21.2 

 5 EL02 9.1 10.6 12.3 25.8 28.7 

 5 EL03 5.6 6.6 7.9 19.6 22.1 

 5 EL04 5.1 6.2 7.4 18.9 21.4 

 

 5 SW2 6.8 7.9 9.3 20.8 23.1 

 6 SW1 4.9 5.8 6.9 17.8 20.1 

 6 L-SR 23.8 26.5 29.5 59.0 72.5 

 6 EL-S 9.7 11.1 12.7 25.7 28.3 

 6 EL01 6.6 7.7 8.9 20.8 23.3 

 

 6 EL02 12.0 13.7 15.6 29.8 32.9 

 6 EL03 6.8 8.0 9.4 21.5 24.1 

 6 EL04 6.3 7.4 8.7 20.6 23.1 

 6 SW2 8.7 9.9 11.5 23.3 25.5 

 7 SW1 5.9 6.9 8.1 19.3 21.6 

 

 7 L-SR 25.2 27.9 31.0 61.9 76.7 

 7 EL-S 10.9 12.5 14.2 27.4 30.1 

 7 EL01 7.8 9.0 10.4 22.7 25.3 

 7 EL02 14.9 16.8 18.8 33.7 37.0 

 7 EL03 8.0 9.3 10.8 23.2 25.9 

 

 7 EL04 7.3 8.5 9.9 22.1 24.6 

 7 SW2 10.4 11.8 13.4 25.3 27.6 

 8 SW1 6.9 7.9 9.3 20.6 22.9 

 8 L-SR 26.5 29.3 32.5 64.6 81.0 

 8 EL-S 12.2 13.8 15.5 28.9 31.7 
95 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL01 8.9 10.3 11.8 24.3 27.0 

 8 EL02 17.7 19.7 21.9 37.5 40.9 

 8 EL03 9.1 10.5 12.0 24.8 27.5 

 8 EL04 8.3 9.6 10.9 23.4 26.0 

 8 SW2 12.0 13.5 15.1 27.1 29.3 

 

 9 SW1 7.8 9.0 10.3 21.8 24.1 

 9 L-SR 27.7 30.6 33.9 67.2 85.5 

 9 EL-S 13.3 14.9 16.8 30.3 33.2 

 9 EL01 10.0 11.5 13.0 25.9 28.6 

 9 EL02 20.5 22.7 24.9 41.1 44.8 

 

 9 EL03 10.2 11.6 13.2 26.2 29.0 

 9 EL04 9.1 10.5 12.0 24.6 27.3 

 9 SW2 13.5 15.0 16.7 28.6 30.9 

 10 SW1 8.8 9.9 11.4 22.9 25.1 

 10 L-SR 28.9 31.7 35.2 69.8 90.3 

 

 10 EL-S 14.4 16.0 17.9 31.6 34.5 

 10 EL01 11.1 12.6 14.2 27.3 30.1 

 10 EL02 23.3 25.5 27.9 44.6 48.5 

 10 EL03 11.2 12.7 14.3 27.5 30.3 

 10 EL04 10.0 11.4 12.9 25.8 28.4 

 

 10 SW2 14.8 16.4 18.1 30.0 32.3 

 11 SW1 9.6 10.9 12.3 23.9 26.2 

 11 L-SR 29.9 32.9 36.5 72.4 95.7 

 11 EL-S 15.3 17.0 18.9 32.8 35.8 

 11 EL01 12.1 13.6 15.3 28.6 31.4 

 

 11 EL02 25.9 28.3 30.8 48.0 52.1 

 11 EL03 12.1 13.7 15.4 28.8 31.6 

 11 EL04 10.8 12.3 13.9 26.8 29.5 

 11 SW2 16.0 17.7 19.4 31.2 33.6 

 12 SW1 10.5 11.8 13.2 24.8 27.1 

 

 12 L-SR 31.0 34.0 37.7 75.1   

 12 EL-S 16.2 18.0 19.9 34.0 36.9 

 12 EL01 13.0 14.6 16.3 29.8 32.6 

 12 EL02 28.5 30.9 33.6 51.3 55.6 

 12 EL03 13.0 14.6 16.4 30.0 32.8 

 

 12 EL04 11.6 13.0 14.7 27.8 30.5 

 12 SW2 17.2 18.8 20.5 32.4 34.8 

 13 SW1 11.3 12.6 14.1 25.7 28.0 

 13 L-SR 32.0 35.1 38.9 77.9 ** ** 

 13 EL-S 17.1 18.9 20.9 35.0 38.0 
96 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL01 13.9 15.5 17.2 30.9 33.8 

 13 EL02 31.0 33.6 36.2 54.6 59.0 

 13 EL03 13.9 15.5 17.3 31.0 34.0 

 13 EL04 12.3 13.8 15.5 28.7 31.4 

 13 SW2 18.2 19.8 21.6 33.4 35.9 

 

 14 SW1 12.0 13.5 14.9 26.5 28.8 

 14 L-SR 33.0 36.1 40.1 80.9   

 14 EL-S 17.9 19.8 21.7 36.0 39.0 

 14 EL01 14.7 16.4 18.1 32.0 34.9 

 14 EL02 33.5 36.1 38.9 57.7 62.3 

 

 14 EL03 14.7 16.4 18.2 32.1 35.0 

 14 EL04 13.0 14.6 16.3 29.5 32.3 

 14 SW2 19.2 20.8 22.5 34.4 37.0 

 15 SW1 12.8 14.2 15.7 27.3 29.6 

 15 L-SR 33.9 37.2 41.3 84.1 ** ** 

 

 15 EL-S 18.7 20.6 22.6 36.9 40.0 

 15 EL01 15.5 17.2 19.0 33.0 35.9 

 15 EL02 35.9 38.6 41.5 60.8 65.5 

 15 EL03 15.5 17.1 19.0 33.0 36.0 

 15 EL04 13.7 15.2 16.9 30.3 33.1 

 

 15 SW2 20.1 21.7 23.4 35.4 37.9 

 16 SW1 13.5 14.9 16.5 28.1 30.3 

 16 L-SR 34.9 38.3 42.5 87.7   

 16 EL-S 19.5 21.3 23.4 37.8 40.9 

 16 EL01 16.3 17.9 19.8 33.9 36.9 

 

 16 EL02 38.3 41.0 44.0 63.8 68.7 

 16 EL03 16.2 17.9 19.8 33.9 37.0 

 16 EL04 14.3 15.9 17.7 31.1 33.9 

 16 SW2 20.9 22.5 24.2 36.3 38.8 

 17 SW1 14.2 15.7 17.2 28.7 31.0 

 

 17 L-SR 35.9 39.4 43.8 92.0 ** ** 

 17 EL-S 20.1 22.0 24.1 38.6 41.7 

 17 EL01 17.0 18.7 20.6 34.8 37.9 

 17 EL02 40.6 43.4 46.4 66.7 71.8 

 17 EL03 16.9 18.7 20.6 34.8 37.9 

 

 17 EL04 14.9 16.5 18.3 31.8 34.7 

 17 SW2 21.7 23.3 24.9 37.1 39.7 

 18 SW1 14.9 16.3 17.9 29.4 31.7 

 18 L-SR 36.9 40.5 45.2 97.2   

 18 EL-S 20.8 22.7 24.8 39.4 42.5 
97 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 18 EL01 17.7 19.5 21.4 35.6 38.7 

 18 EL02 42.9 45.7 48.8 69.5 74.8 

 18 EL03 17.6 19.4 21.3 35.6 38.7 

 18 EL04 15.5 17.1 18.9 32.5 35.4 

 18 SW2 22.4 24.0 25.7 37.9 40.5 

 

 19 SW1 15.5 16.9 18.6 30.1 32.4 

 19 L-SR 38.0 41.8 46.7 ** **   

 19 EL-S 21.5 23.4 25.5 40.2 43.3 

 19 EL01 18.4 20.1 22.0 36.5 39.6 

 19 EL02 45.1 48.0 51.2 72.3 77.7 

 

 19 EL03 18.2 20.0 22.0 36.4 39.5 

 19 EL04 16.0 17.7 19.5 33.2 36.1 

 19 SW2 23.1 24.7 26.3 38.6 41.3 

 20 SW1 16.1 17.6 19.2 30.6 33.0 

 20 L-SR 39.3 43.2 48.5 ** **   

 

 20 EL-S 22.1 24.0 26.1 40.9 44.1 

 20 EL01 19.0 20.8 22.8 37.3 40.4 

 20 EL02 47.3 50.3 53.6 75.1 80.6 

 20 EL03 18.8 20.7 22.7 37.2 40.3 

 20 EL04 16.6 18.2 20.1 33.8 36.7 

 

 20 SW2 23.8 25.3 27.0 39.3 42.0 

 21 SW1 16.8 18.2 19.8 31.4 33.8 

 21 L-SR 41.0 45.2 51.2 ** **   

 21 EL-S 22.7 24.7 26.8 41.6 44.8 

 21 EL01 19.6 21.4 23.4 38.0 41.2 

 

 21 EL02 49.4 52.5 55.8 77.8 83.4 

 21 EL03 19.5 21.3 23.3 37.9 41.1 

 21 EL04 17.0 18.8 20.6 34.4 37.3 

 21 SW2 24.5 26.0 27.8 40.2 42.9 

 22 SW1 17.4 18.9 20.5 32.1 34.5 

 

 22 L-SR 43.3 48.1 55.2 ** **   

 22 EL-S 23.3 25.2 27.4 42.2 45.5 

 22 EL01 20.2 22.0 24.0 38.7 41.9 

 22 EL02 51.5 54.7 58.1 80.4 86.2 

 22 EL03 20.0 21.9 23.9 38.6 41.8 

 

 22 EL04 17.6 19.3 21.1 35.0 37.9 

 22 SW2 25.2 26.8 28.5 41.1 43.8 

 23 SW1 17.9 19.5 21.1 32.8 35.2 

 23 L-SR 48.1 54.9 66.4 ** **   

 23 EL-S 23.8 25.8 27.9 42.9 46.2 
98 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 23 EL01 20.8 22.6 24.7 39.4 42.6 

 23 EL02 53.6 56.8 60.3 83.0 88.9 

 23 EL03 20.6 22.5 24.5 39.3 42.5 

 23 EL04 18.0 19.8 21.7 35.5 38.5 

 23 SW2 25.9 27.5 29.2 41.9 44.7 

 

 24 SW1 18.6 20.1 21.7 33.5 36.0 

 24 L-MR 30.1 32.5 35.1 53.3 57.8 

 24 EL-S 24.4 26.4 28.5 43.5 46.8 

 24 EL01 21.3 23.2 25.2 40.1 43.3 

 24 EL02 39.0 42.1 45.5 69.6 76.5 

 

 24 EL03 21.1 23.0 25.0 40.0 43.2 

 24 EL04 18.5 20.3 22.1 36.1 39.1 

 24 SW2 26.6 28.1 29.9 42.7 45.5 

 25 SW1 19.1 20.7 22.3 34.2 36.6 

 25 L-MR 30.0 32.4 35.0 52.9 57.3 

 

 25 EL-S 24.8 26.9 29.0 44.1 47.4 

 25 EL01 21.8 23.7 25.8 40.7 43.9 

 25 EL02 37.3 40.2 43.3 65.4 71.6 

 25 EL03 21.7 23.6 25.6 40.6 43.9 

 25 EL04 18.9 20.7 22.6 36.6 39.6 

 

 25 T01 40.4 43.8 48.2 88.3 ** ** 

 25 SW2 27.1 28.8 30.5 43.4 46.3 

 26 SW1 19.7 21.2 22.8 34.8 37.3 

 26 L-MR 30.5 32.9 35.5 53.3 57.7 

 26 EL-S 25.3 27.4 29.5 44.6 47.9 

 

 26 EL01 22.4 24.2 26.3 41.3 44.5 

 26 EL02 36.8 39.6 42.6 63.8 69.6 

 26 EL03 22.1 24.0 26.1 41.2 44.5 

 26 EL04 19.4 21.1 23.1 37.1 40.1 

 26 T01 40.7 44.0 48.3 87.1   

 

 26 SW2 27.8 29.4 31.1 44.1 47.0 

 27 SW1 20.2 21.7 23.4 35.4 37.9 

 27 L-MR 30.9 33.4 35.9 53.8 58.2 

 27 EL-S 25.8 27.8 30.0 45.1 48.5 

 27 EL01 22.9 24.8 26.9 41.9 45.2 

 

 27 EL02 36.8 39.5 42.5 63.1 68.7 

 27 EL03 22.6 24.6 26.7 41.8 45.1 

 27 EL04 19.8 21.6 23.5 37.6 40.6 

 27 T01 41.2 44.6 48.8 87.3 ** ** 

 27 SW2 28.4 30.0 31.8 44.8 47.7 
99 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 28 SW1 20.7 22.3 23.9 36.0 38.5 

 28 L-MR 31.5 33.8 36.4 54.4 58.8 

 28 EL-S 26.2 28.3 30.5 45.6 49.0 

 28 EL01 23.4 25.3 27.4 42.5 45.8 

 28 EL02 36.9 39.6 42.5 62.9 68.3 

 

 28 EL03 23.1 25.0 27.2 42.4 45.7 

 28 EL04 20.2 22.0 23.9 38.1 41.1 

 28 T01 41.7 45.1 49.4 87.8   

 28 SW2 28.9 30.6 32.4 45.5 48.4 

 29 SW1 21.2 22.8 24.5 36.6 39.1 

 

 29 L-MR 31.9 34.4 36.9 54.9 59.3 

 29 EL-S 26.7 28.7 30.9 46.1 49.5 

 29 EL01 23.9 25.8 27.9 43.1 46.4 

 29 EL02 37.1 39.8 42.7 62.9 68.2 

 29 EL03 23.6 25.5 27.7 42.9 46.3 

 

 29 EL04 20.6 22.4 24.4 38.5 41.5 

 29 T01 42.3 45.8 50.0 88.5 ** ** 

 29 SW2 29.5 31.2 32.9 46.2 49.1 

 30 SW1 21.8 23.4 25.0 37.2 39.8 

 30 L-MR 32.5 34.9 37.5 55.5 59.9 

 

 30 EL-S 27.1 29.2 31.4 46.6 50.0 

 30 EL01 24.4 26.4 28.5 43.7 47.0 

 30 EL02 37.4 40.1 43.0 63.0 68.2 

 30 EL03 24.0 26.0 28.1 43.4 46.8 

 30 EL04 21.0 22.8 24.8 39.0 42.0 

 

 30 T01 42.9 46.4 50.7 89.3   

 30 SW2 30.0 31.8 33.6 46.8 49.8 

 31 OPEN 82.0 94.5 ** **   ** ** 

 31 SW1 22.3 23.9 25.6 37.8 40.4 

 31 L-SR 40.6 43.3 46.3 67.4 73.1 

 

 31 L-MR 32.9 35.4 38.0 56.1 60.5 

 31 CR01 102.4   ** **   ** ** 

 31 EL-S 27.6 29.6 31.8 47.1 50.4 

 31 EL01 24.9 26.9 29.0 44.3 47.6 

 31 EL02 37.8 40.4 43.3 63.2 68.4 

 

 31 EL03 24.5 26.5 28.6 44.0 47.4 

 31 EL04 21.4 23.2 25.2 39.4 42.5 

 31 T01 43.6 47.1 51.4 89.9   

 31 T02 48.0 51.6 55.5 83.9 93.3 

 31 SW2 30.6 32.3 34.1 47.5 50.4 
100 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 32 OPEN 64.6 71.0 79.7 ** **   

 32 SW1 22.8 24.4 26.1 38.4 41.0 

 32 L-SR 39.1 41.7 44.6 64.2 69.4 

 32 L-MR 33.5 35.9 38.5 56.6 61.1 

 32 CR01 79.8 88.7 ** **   ** ** 

 

 32 EL-S 28.0 30.0 32.2 47.5 50.9 

 32 EL01 25.5 27.4 29.6 44.9 48.2 

 32 EL02 38.1 40.8 43.7 63.5 68.6 

 32 EL03 24.9 26.9 29.0 44.5 47.9 

 32 EL04 21.8 23.6 25.6 39.8 42.9 

 

 32 T01 44.3 47.8 52.2 90.6   

 32 T02 46.0 49.2 52.8 78.4 86.2 

 32 SW2 31.2 32.9 34.7 48.1 51.1 

 33 OPEN 59.9 65.0 71.3 ** **   

 33 SW1 23.3 24.9 26.7 39.0 41.6 

 

 33 L-SR 38.3 40.9 43.6 62.5 67.3 

 33 L-MR 33.9 36.4 39.0 57.1 61.6 

 33 CR01 73.4 80.2 89.1 ** **   

 33 EL-S 28.4 30.5 32.7 48.0 51.4 

 33 EL01 25.9 27.9 30.1 45.5 48.9 

 

 33 EL02 38.5 41.1 44.0 63.8 68.9 

 33 EL03 25.3 27.3 29.5 45.0 48.4 

 33 EL04 22.1 23.9 25.9 40.2 43.3 

 33 T01 75.7 83.0 92.6 ** **   

 33 T02 45.0 48.1 51.5 75.5 82.7 

 

 33 SW2 31.7 33.4 35.3 48.7 51.7 

 34 OPEN 58.7 63.3 68.9 ** **   

 34 SW1 23.8 25.5 27.2 39.6 42.2 

 34 L-SR 38.0 40.6 43.2 61.8 66.4 

 34 L-MR 34.4 36.9 39.5 57.7 62.1 

 

 34 CR01 71.5 77.8 85.6 ** **   

 34 EL-S 28.8 30.9 33.1 48.5 51.9 

 34 EL01 26.5 28.5 30.7 46.1 49.5 

 34 EL02 38.9 41.5 44.4 64.1 69.2 

 34 EL03 25.7 27.8 29.9 45.5 49.0 

 

 34 EL04 22.5 24.3 26.3 40.7 43.8 

 34 T01 73.7 80.3 88.8 ** **   

 34 T02 44.6 47.6 50.8 74.1 80.8 

 34 SW2 32.2 34.0 35.8 49.4 52.4 

 35 OPEN 58.1 62.5 67.8 ** **   
101 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 35 SW1 24.3 25.9 27.7 40.1 42.8 

 35 L-SR 38.0 40.5 43.1 61.4 65.9 

 35 L-MR 34.9 37.4 40.0 58.2 62.6 

 35 CR01 70.6 76.5 83.8 ** **   

 35 EL-S 29.3 31.4 33.6 49.0 52.4 

 

 35 EL01 27.0 29.0 31.2 46.7 50.1 

 35 EL02 39.3 41.9 44.8 64.4 69.5 

 35 EL03 26.1 28.1 30.4 46.0 49.4 

 35 EL04 22.8 24.7 26.7 41.1 44.2 

 35 T01 72.6 78.8 86.7 ** **   

 

 35 T02 44.4 47.4 50.6 73.3 79.7 

 35 SW2 32.8 34.6 36.4 50.0 53.0 

 36 OPEN 52.6 56.8 61.9 98.8 ** ** 

 36 SW1 24.8 26.5 28.2 40.7 43.4 

 36 L-SR 38.1 40.6 43.2 61.3 65.7 

 

 36 L-MR 35.4 37.8 40.5 58.7 63.1 

 36 CR01 65.0 70.6 77.4   ** ** 

 36 EL-S 29.7 31.8 34.0 49.4 52.9 

 36 EL01 27.6 29.6 31.8 47.3 50.7 

 36 EL02 39.6 42.3 45.1 64.8 69.8 

 

 36 EL03 26.5 28.6 30.8 46.4 49.9 

 36 EL04 23.2 25.0 27.0 41.5 44.6 

 36 T01 54.7 60.1 67.2   ** ** 

 36 T02 44.5 47.4 50.5 72.9 79.2 

 36 SW2 33.3 35.1 36.9 50.6 53.7 

 

 37 OPEN 50.3 54.1 58.8 93.1   

 37 SW1 25.4 27.0 28.7 41.3 43.9 

 37 L-SR 38.2 40.6 43.2 61.2 65.5 

 37 L-MR 35.8 38.3 40.9 59.1 63.5 

 37 CR01 62.2 67.5 73.8 ** **   

 

 37 EL-S 30.2 32.3 34.5 49.9 53.4 

 37 EL01 28.0 30.1 32.3 47.9 51.3 

 37 EL02 40.0 42.7 45.5 65.1 70.1 

 37 EL03 26.9 28.9 31.2 46.9 50.4 

 37 EL04 23.5 25.4 27.4 41.9 45.0 

 

 37 T01 51.2 55.6 61.2 ** **   

 37 T02 43.8 46.7 49.8 71.8 77.9 

 37 SW2 33.9 35.7 37.6 51.3 54.4 

 38 OPEN 49.3 52.9 57.3 89.8 ** ** 

 38 SW1 25.8 27.5 29.3 41.8 44.5 
102 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 38 L-SR 38.3 40.7 43.3 61.1 65.4 

 38 L-MR 36.3 38.7 41.4 59.5 63.9 

 38 CR01 61.0 65.9 71.9   ** ** 

 38 EL-S 30.7 32.8 35.0 50.4 53.9 

 38 EL01 28.6 30.6 32.8 48.5 52.0 

 

 38 EL02 40.4 43.0 45.9 65.4 70.4 

 38 EL03 27.3 29.3 31.6 47.3 50.9 

 38 EL04 23.8 25.7 27.8 42.2 45.4 

 38 T01 49.9 53.9 58.8 97.7   

 38 T02 43.6 46.4 49.5 71.1 77.1 

 

 38 SW2 34.5 36.2 38.1 52.0 55.0 

 39 OPEN 48.8 52.3 56.4 87.4 98.6 

 39 SW1 26.4 28.0 29.8 42.4 45.1 

 39 L-SR 38.4 40.8 43.4 61.0 65.3 

 39 L-MR 36.6 39.1 41.7 59.8 64.2 

 

 39 CR01 60.3 65.1 70.8 ** **   

 39 EL-S 31.1 33.2 35.5 51.0 54.4 

 39 EL01 29.1 31.2 33.4 49.1 52.6 

 39 EL02 40.7 43.4 46.2 65.8 70.8 

 39 EL03 27.7 29.7 31.9 47.7 51.3 

 

 39 EL04 24.2 26.0 28.1 42.6 45.8 

 39 T01 49.2 53.0 57.6 93.9 ** ** 

 39 T02 43.6 46.3 49.3 70.6 76.4 

 39 SW2 35.0 36.8 38.7 52.6 55.7 

 40 OPEN 48.5 51.9 55.8 85.6 96.0 

 

 40 SW1 26.9 28.6 30.4 43.0 45.7 

 40 L-SR 38.6 40.9 43.5 61.0 65.2 

 40 L-MR 36.9 39.4 42.0 60.0 64.3 

 40 CR01 60.0 64.6 70.1   ** ** 

 40 EL-S 31.6 33.7 36.0 51.5 55.0 

 

 40 EL01 29.7 31.7 33.9 49.7 53.2 

 40 EL02 41.1 43.7 46.6 66.1 71.0 

 40 EL03 28.0 30.1 32.3 48.2 51.7 

 40 EL04 24.5 26.4 28.4 43.0 46.2 

 40 T01 48.9 52.4 56.8 91.1   

 

 40 T02 43.5 46.3 49.2 70.2 75.9 

 40 SW2 35.6 37.4 39.3 53.3 56.4 

 41 OPEN 48.3 51.6 55.4 84.2 94.0 

 41 SW1 27.5 29.1 30.9 43.6 46.4 

 41 L-SR 38.7 41.1 43.7 61.1 65.2 
103 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 41 L-MR 37.0 39.4 42.0 59.7 64.0 

 41 CR01 59.9 64.5 69.8 ** **   

 41 EL-S 32.1 34.2 36.5 52.0 55.5 

 41 EL01 30.2 32.2 34.5 50.2 53.8 

 41 EL02 41.4 44.0 46.9 66.3 71.2 

 

 41 EL03 28.4 30.5 32.7 48.6 52.2 

 41 EL04 24.8 26.7 28.7 43.3 46.5 

 41 T01 48.7 52.1 56.2 89.0 ** ** 

 41 T02 43.6 46.3 49.2 69.9 75.5 

 41 SW2 36.2 38.0 39.9 54.0 57.1 

 

 42 OPEN 48.4 51.6 55.3 83.0 92.0 

 42 SW1 28.0 29.7 31.5 44.3 47.1 

 42 L-SR 39.1 41.5 44.0 61.4 65.5 

 42 L-MR 37.1 39.6 42.1 59.7 63.9 

 42 CR01 60.0 64.4 69.5   ** ** 

 

 42 EL-S 32.6 34.7 37.0 52.6 56.1 

 42 EL01 30.7 32.8 35.0 50.8 54.4 

 42 EL02 41.7 44.4 47.2 66.6 71.5 

 42 EL03 28.7 30.8 33.0 49.0 52.6 

 42 EL04 25.1 27.0 29.0 43.6 46.9 

 

 42 T01 49.0 52.4 56.5 88.5   

 42 T02 43.9 46.7 49.6 70.2 75.6 

 42 SW2 36.8 38.6 40.6 54.7 57.8 

 43 OPEN 48.5 51.7 55.3 82.2 90.8 

 43 SW1 28.7 30.3 32.1 45.0 47.7 

 

 43 L-SR 39.5 41.8 44.4 61.7 65.8 

 43 L-MR 37.6 40.0 42.6 60.1 64.2 

 43 L-HR 59.0 63.1 67.9 ** **   

 43 EL-S 33.1 35.3 37.6 53.2 56.7 

 43 EL01 31.3 33.4 35.6 51.4 55.0 

 

 43 EL02 42.1 44.7 47.6 66.9 71.7 

 43 EL03 29.0 31.1 33.4 49.4 53.0 

 43 EL04 25.4 27.3 29.4 44.0 47.2 

 43 T01 49.3 52.6 56.6 87.8 99.3 

 43 T02 44.3 46.9 49.8 70.3 75.7 

 

 43 SW2 37.4 39.2 41.2 55.4 58.6 

 44 OPEN 49.1 52.3 55.9 83.1 92.0 

 44 SW1 29.3 30.9 32.8 45.7 48.4 

 44 L-SR 39.7 42.0 44.6 61.7 65.8 

 44 L-HR 60.4 64.7 69.7 ** **   
104 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 44 EL-S 33.7 35.8 38.1 53.8 57.3 

 44 EL03 29.4 31.5 33.8 49.8 53.4 

 44 EL04 25.7 27.6 29.7 44.3 47.5 

 44 T01 49.3 52.5 56.3 86.7 97.9 

 44 T02 44.4 47.0 49.9 70.0 75.3 

 

 44 SW2 38.0 39.9 41.9 56.2 59.4 

 45 OPEN 49.6 52.7 56.3 83.3 92.0 

 45 SW1 29.9 31.6 33.5 46.4 49.2 

 45 L-SR 40.1 42.5 45.0 62.2 66.2 

 45 L-HR 61.4 65.8 70.8 ** **   

 

 45 EL-S 34.3 36.4 38.7 54.4 57.9 

 45 EL03 29.7 31.8 34.1 50.2 53.8 

 45 EL04 25.9 27.9 29.9 44.6 47.9 

 45 T01 49.7 53.0 56.8 86.7 97.6 

 45 T02 44.8 47.4 50.3 70.3 75.6 

 

 45 SW2 38.7 40.6 42.6 57.0 60.2 

 46 OPEN 50.2 53.3 56.9 83.7 92.2 

 46 SW1 30.6 32.4 34.1 47.2 50.0 

 46 L-SR 40.6 43.0 45.5 62.7 66.7 

 46 L-HR 62.6 67.0 72.1 ** **   

 

 46 EL-S 34.9 37.0 39.3 55.1 58.6 

 46 EL03 30.0 32.1 34.5 50.5 54.2 

 46 EL04 26.2 28.1 30.2 44.9 48.2 

 46 T01 50.3 53.6 57.3 87.0 97.8 

 46 T02 45.3 47.9 50.8 70.8 76.0 

 

 46 SW2 39.4 41.3 43.3 57.8 61.0 

 47 OPEN 50.9 54.0 57.6 84.2 92.7 

 47 SW1 31.4 33.1 34.9 48.1 50.9 

 47 L-SR 41.2 43.6 46.1 63.3 67.3 

 47 L-HR 48.5 52.1 56.4 87.5 98.1 

 

 47 EL-S 35.5 37.7 40.0 55.8 59.3 

 47 EL03 30.3 32.5 34.8 50.9 54.6 

 47 EL04 26.5 28.4 30.5 45.2 48.5 

 47 T01 51.0 54.3 58.0 87.5 98.2 

 47 T02 45.9 48.6 51.4 71.4 76.6 

 

 47 SW2 40.1 42.0 44.1 58.6 61.9 

 48 OPEN 51.7 54.8 58.4 84.9 93.3 

 48 SW1 32.1 33.9 35.7 49.0 51.8 

 48 L-SR 41.8 44.2 46.7 63.9 67.9 

 48 L-HR 42.5 45.4 48.7 72.9 80.3 
105 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 48 EL-S 36.2 38.4 40.7 56.5 60.1 

 48 EL03 30.6 32.8 35.1 51.3 54.9 

 48 EL04 26.7 28.7 30.8 45.5 48.8 

 48 T01 51.8 55.1 58.8 88.2 98.8 

 48 T02 46.6 49.2 52.1 72.0 77.2 

 

 48 SW2 40.8 42.8 44.9 59.6 62.9 

 49 OPEN 52.6 55.7 59.3 85.7 94.1 

 49 SW1 33.0 34.8 36.6 49.9 52.8 

 49 L-SR 42.5 44.8 47.4 64.6 68.6 

 49 L-HR 40.7 43.4 46.5 68.5 74.9 

 

 49 EL-S 36.9 39.1 41.4 57.3 60.9 

 49 EL03 30.9 33.1 35.4 51.6 55.3 

 49 EL04 27.0 28.9 31.0 45.8 49.1 

 49 T01 52.7 56.0 59.8 89.1 99.6 

 49 T02 47.3 49.9 52.8 72.8 77.9 

 

 49 SW2 41.7 43.7 45.7 60.5 63.9 

 50 OPEN 53.5 56.7 60.3 86.7 95.0 

 50 SW1 33.9 35.7 37.6 51.0 54.0 

 50 L-SR 43.2 45.6 48.1 65.4 69.4 

 50 L-HR 39.7 42.4 45.3 66.2 72.0 

 

 50 EL-S 37.7 39.8 42.2 58.1 61.7 

 50 EL03 31.2 33.4 35.7 51.9 55.6 

 50 EL04 27.2 29.2 31.3 46.1 49.4 

 50 T01 53.8 57.0 60.8 90.1 ** ** 

 50 T02 48.1 50.7 53.6 73.6 78.7 

 

 50 SW2 42.5 44.6 46.7 61.6 65.0 

 51 OPEN 54.6 57.8 61.4 87.8 96.1 

 51 SW1 35.0 36.8 38.7 52.2 55.2 

 51 L-SR 44.0 46.4 48.9 66.3 70.3 

 51 L-HR 39.1 41.7 44.5 64.7 70.2 

 

 51 EL-S 38.5 40.7 43.0 59.1 62.6 

 51 EL03 31.5 33.7 36.0 52.2 56.0 

 51 EL04 27.5 29.5 31.6 46.4 49.6 

 51 T01 54.9 58.2 62.0 91.4   

 51 T02 48.9 51.6 54.5 74.5 79.7 

 

 51 SW2 43.5 45.5 47.7 62.7 66.1 

 52 OPEN 55.9 59.1 62.8 89.2 97.4 

 52 SW1 36.1 37.9 39.9 53.5 56.5 

 52 L-SR 44.9 47.3 49.8 67.2 71.3 

 52 L-HR 38.7 41.3 44.0 63.6 68.9 
106 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 52 EL-S 39.4 41.6 43.9 60.0 63.6 

 52 EL03 31.8 33.9 36.3 52.6 56.3 

 52 EL04 27.8 29.7 31.8 46.6 49.9 

 52 T01 56.2 59.6 63.4 92.9 ** ** 

 52 T02 49.9 52.6 55.5 75.6 80.7 

 

 52 SW2 44.5 46.5 48.7 64.0 67.4 

 53 OPEN 57.4 60.6 64.3 90.8 99.0 

 53 SW1 37.5 39.3 41.2 55.1 58.1 

 53 L-SR 45.8 48.3 50.8 68.3 72.4 

 53 L-HR 38.4 40.9 43.6 62.8 67.9 

 

 53 EL-S 40.3 42.6 44.9 61.1 64.8 

 53 EL03 32.0 34.2 36.6 52.9 56.6 

 53 EL04 28.0 29.9 32.1 46.9 50.2 

 53 T01 57.8 61.1 65.1 94.7   

 53 T02 51.0 53.7 56.6 76.7 81.9 

 

 53 SW2 45.6 47.7 49.9 65.3 68.8 

 54 OPEN 58.4 61.7 65.5 92.1 ** ** 

 54 SW1 38.9 40.8 42.8 56.9 60.0 

 54 L-SR 46.9 49.4 51.9 69.5 73.6 

 54 L-HR 38.1 40.6 43.2 62.0 66.8 

 

 54 EL-S 41.4 43.7 46.0 62.3 66.0 

 54 EL03 32.3 34.5 36.8 53.2 56.9 

 54 EL04 28.3 30.2 32.3 47.2 50.5 

 54 T01 47.5 50.7 54.4 80.4 88.4 

 54 T02 52.2 54.9 57.9 78.1 83.3 

 

 54 SW2 46.8 48.9 51.2 66.8 70.3 

 55 OPEN 59.2 62.7 66.7 93.4   

 55 SW1 40.8 42.7 44.7 59.0 62.2 

 55 L-SR 48.1 50.6 53.2 70.9 75.0 

 55 L-HR 38.1 40.6 43.2 61.8 66.6 

 

 55 EL-S 42.6 44.9 47.3 63.6 67.3 

 55 EL03 32.6 34.8 37.1 53.4 57.2 

 55 EL04 28.5 30.5 32.6 47.5 50.8 

 55 T01 44.7 47.7 51.0 74.9 82.0 

 55 T02 53.6 56.3 59.3 79.6 84.8 

 

 55 SW2 48.1 50.3 52.6 68.5 72.1 

 56 OPEN 60.1 63.9 68.1 95.3 ** ** 

 56 SW1 43.0 44.9 47.0 61.7 65.1 

 56 L-SR 49.5 51.9 54.6 72.4 76.6 

 56 L-HR 38.2 40.7 43.3 61.8 66.6 
107 

Table 24. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 56 EL-S 43.9 46.2 48.7 65.2 68.9 

 56 EL03 32.8 35.0 37.4 53.7 57.5 

 56 EL04 28.8 30.7 32.8 47.7 51.1 

 56 T01 43.7 46.6 49.8 72.7 79.3 

 56 T02 55.0 57.9 60.9 81.3 86.6 

 

 56 SW2 49.7 51.9 54.3 70.4 74.0 

 57 OPEN 61.4 65.6 70.1 98.0   

 57 SW1 45.9 48.0 50.1 65.4 68.9 

 57 L-SR 51.0 53.6 56.2 74.2 78.4 

 57 L-HR 38.4 40.9 43.5 62.0 66.8 

 

 57 EL-S 45.5 47.8 50.3 66.9 70.7 

 57 EL03 33.1 35.3 37.7 54.0 57.8 

 57 EL04 29.0 31.0 33.1 48.0 51.3 

 57 T01 43.6 46.5 49.6 72.3 78.8 

 57 T02 56.8 59.7 62.8 83.4 88.7 

 

 57 SW2 51.5 53.8 56.2 72.6 76.3 

 58 OPEN 63.6 68.2 73.2 ** **   

 58 SW1 50.4 52.6 55.0 71.4 75.3 

 58 L-SR 52.9 55.4 58.1 76.3 80.6 

 58 L-HR 38.8 41.2 43.8 62.5 67.2 

 

 58 EL-S 47.3 49.6 52.1 69.0 72.8 

 58 EL03 33.4 35.6 37.9 54.3 58.1 

 58 EL04 29.3 31.2 33.4 48.3 51.6 

 58 T01 44.3 47.2 50.4 73.5 80.3 

 58 T02 58.9 61.8 65.0 86.0 91.3 

 

 58 SW2 53.6 55.9 58.5 75.3 79.2 

 59 MECH 66.9 70.3 74.1 99.0 ** ** 

 59 ELME 69.6 73.3 77.4   ** ** 

 59 EL-S 49.5 51.9 54.4 71.6 75.5 

 59 EL03 33.4 35.6 37.9 54.3 58.1 

 

 59 EL04 29.3 31.3 33.4 48.3 51.6 

 59 SW2 56.2 58.7 61.3 78.7 82.7 

 R SW2 60.4 63.0 65.7 83.9 88.2 
108 

Table 25. Results of Tenability Analysis for Scenario 25. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 41.5 46.3 52.0 88.8   

 B L-SR 61.6 68.8 77.5 ** **   

 B L-MR 44.1 52.0 61.7 ** **   

 B L-HR 37.1 43.4 51.5 97.9 ** ** 

 B EL-S 20.7 23.1 25.7 43.5 47.8 

 

 B EL01 55.8 62.4 70.2   ** ** 

 B EL02 61.3 69.2 78.6   ** ** 

 B EL03 51.8 58.8 67.1   ** ** 

 B EL04 50.6 56.6 63.6   ** ** 

 B SW2 9.6 11.2 13.0 26.6 29.4 

 

 G OPEN 7.1 9.0 11.2 26.9 30.6 

 G SW1 46.9 52.1 58.2 95.9   

 G L-SR 16.8 19.4 22.2 42.8 48.9 

 G EL-S 11.6 13.5 15.5 30.2 33.3 

 G EL01 9.7 11.7 13.9 30.1 34.1 

 

 G EL02 9.6 11.6 13.9 30.1 34.0 

 G EL03 8.5 10.5 12.7 28.6 32.4 

 G EL04 8.6 10.5 12.8 28.7 32.6 

 G T01 14.8 17.2 19.8 38.2 43.2 

 G T02 17.2 19.7 22.4 41.6 46.9 

 

 G SW2 3.7 4.5 5.6 16.2 18.4 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.5 1.9 9.7 11.7 

 2 L-SR 1.0 1.5 1.9 9.4 11.3 

 2 CR01 1.5 1.9 2.6 11.1 13.1 

 

 2 CR02 1.0 1.5 1.9 9.4 11.3 

 2 EL-S 3.3 4.0 5.0 15.6 17.9 

 2 EL01 1.4 1.9 2.5 11.9 14.2 

 2 EL02 2.0 2.8 3.6 14.7 17.2 

 2 EL03 2.0 2.9 3.8 15.5 18.2 

 

 2 EL04 2.0 2.8 3.8 15.3 17.9 

 2 T01 1.7 2.1 2.9 11.9 14.0 

 2 T02 2.0 2.8 3.6 13.6 15.8 

 2 SW2 1.0 1.4 1.9 9.0 10.9 

 3 SW1 2.1 2.8 3.6 12.8 15.0 

 

 3 L-SR 18.4 21.0 23.8 46.5 54.8 

 3 CR02 13.6 15.9 18.5 36.5 41.4 

 3 EL-S 5.5 6.6 7.9 19.6 22.1 

 3 EL01 2.1 2.8 3.6 13.8 16.1 

 3 EL02 3.2 4.0 5.1 16.9 19.5 
109 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL03 2.8 3.6 4.6 16.5 19.2 

 3 EL04 2.7 3.5 4.6 16.3 18.9 

 3 SW2 4.5 5.5 6.8 18.4 20.9 

 4 SW1 3.6 4.4 5.3 15.5 17.7 

 4 L-SR 21.3 23.9 26.7 51.1 60.5 

 

 4 EL-S 7.6 8.9 10.4 22.9 25.5 

 4 EL01 3.0 3.8 4.8 15.4 17.9 

 4 EL02 4.5 5.5 6.8 19.0 21.7 

 4 EL03 3.3 4.2 5.3 17.4 20.1 

 4 EL04 3.3 4.1 5.3 17.2 19.9 

 

 4 SW2 8.0 9.6 11.3 24.0 26.5 

 5 SW1 4.9 5.9 7.0 17.9 20.1 

 5 L-SR 23.7 26.3 29.2 55.3 65.6 

 5 EL-S 9.6 11.0 12.7 25.7 28.4 

 5 EL01 3.9 4.8 5.9 17.0 19.5 

 

 5 EL02 5.8 7.0 8.4 21.1 23.8 

 5 EL03 3.9 4.9 6.0 18.3 21.1 

 5 EL04 3.8 4.8 5.9 18.1 20.8 

 5 SW2 11.4 13.0 14.9 27.9 30.5 

 6 SW1 6.4 7.5 8.7 19.9 22.1 

 

 6 L-SR 25.7 28.4 31.4 59.0 70.6 

 6 EL-S 11.3 12.9 14.7 28.1 30.8 

 6 EL01 4.8 5.8 6.9 18.4 21.0 

 6 EL02 7.3 8.6 10.0 23.1 26.0 

 6 EL03 4.5 5.5 6.8 19.2 21.9 

 

 6 EL04 4.4 5.5 6.7 19.0 21.7 

 6 SW2 14.2 15.9 17.9 31.0 33.8 

 7 SW1 7.7 8.9 10.3 21.7 23.9 

 7 L-SR 27.6 30.3 33.4 62.5 75.4 

 7 EL-S 12.9 14.6 16.4 30.1 33.0 

 

 7 EL01 5.7 6.8 7.9 19.8 22.4 

 7 EL02 8.7 10.1 11.8 25.2 28.0 

 7 EL03 5.0 6.1 7.4 20.1 22.8 

 7 EL04 4.9 6.0 7.3 19.8 22.5 

 7 SW2 16.6 18.4 20.4 33.6 36.5 

 

 8 SW1 9.0 10.3 11.7 23.2 25.5 

 8 L-SR 29.2 31.9 35.2 65.9 80.3 

 8 EL-S 14.4 16.1 18.0 32.0 35.0 

 8 EL01 6.6 7.7 8.9 21.1 23.7 

 8 EL02 10.2 11.7 13.4 27.1 30.1 
110 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL03 5.6 6.8 8.0 20.8 23.6 

 8 EL04 5.6 6.7 7.9 20.6 23.3 

 8 SW2 18.6 20.5 22.4 35.9 38.9 

 9 SW1 10.2 11.6 13.0 24.7 26.9 

 9 L-SR 30.7 33.5 36.9 69.1 85.6 

 

 9 EL-S 15.7 17.5 19.5 33.7 36.7 

 9 EL01 7.4 8.6 9.9 22.2 24.9 

 9 EL02 11.7 13.3 15.1 29.1 32.1 

 9 EL03 6.1 7.3 8.7 21.6 24.4 

 9 EL04 6.0 7.2 8.6 21.3 24.1 

 

 9 SW2 20.4 22.2 24.1 37.8 41.0 

 10 SW1 11.4 12.8 14.3 25.9 28.2 

 10 L-SR 32.0 35.0 38.6 72.3 91.3 

 10 EL-S 17.0 18.8 20.8 35.3 38.3 

 10 EL01 8.2 9.4 10.8 23.3 26.1 

 

 10 EL02 13.2 14.9 16.7 31.0 34.1 

 10 EL03 6.7 7.9 9.4 22.3 25.1 

 10 EL04 6.6 7.8 9.2 22.1 24.8 

 10 SW2 21.9 23.7 25.6 39.6 42.8 

 11 SW1 12.5 13.9 15.5 27.1 29.3 

 

 11 L-SR 33.3 36.4 40.1 75.6 97.7 

 11 EL-S 18.1 20.0 22.1 36.7 39.8 

 11 EL01 8.9 10.2 11.7 24.4 27.1 

 11 EL02 14.7 16.4 18.4 32.9 36.1 

 11 EL03 7.2 8.5 9.9 23.1 25.9 

 

 11 EL04 7.0 8.3 9.8 22.7 25.5 

 11 SW2 23.3 25.1 27.0 41.2 44.5 

 12 SW1 13.5 14.9 16.6 28.2 30.4 

 12 L-SR 34.6 37.7 41.6 79.0 ** ** 

 12 EL-S 19.2 21.1 23.2 38.0 41.2 

 

 12 EL01 9.7 11.0 12.5 25.4 28.2 

 12 EL02 16.2 18.0 20.0 34.8 38.0 

 12 EL03 7.7 9.0 10.5 23.7 26.6 

 12 EL04 7.6 8.8 10.3 23.4 26.2 

 12 SW2 24.5 26.3 28.2 42.6 46.1 

 

 13 SW1 14.5 15.9 17.6 29.2 31.4 

 13 L-SR 35.8 39.0 43.0 82.6   

 13 EL-S 20.2 22.2 24.3 39.3 42.5 

 13 EL01 10.4 11.8 13.3 26.4 29.2 

 13 EL02 17.7 19.5 21.6 36.6 39.9 
111 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL03 8.2 9.6 11.1 24.4 27.3 

 13 EL04 8.0 9.3 10.8 24.1 26.9 

 13 SW2 25.6 27.4 29.3 44.0 47.5 

 14 SW1 15.4 16.8 18.5 30.1 32.4 

 14 L-SR 36.9 40.3 44.5 86.5 ** ** 

 

 14 EL-S 21.2 23.2 25.3 40.4 43.7 

 14 EL01 11.0 12.5 14.1 27.3 30.1 

 14 EL02 19.1 21.0 23.1 38.4 41.8 

 14 EL03 8.7 10.0 11.6 25.1 27.9 

 14 EL04 8.5 9.8 11.4 24.7 27.5 

 

 14 SW2 26.6 28.4 30.4 45.2 48.9 

 15 SW1 16.2 17.7 19.4 31.0 33.3 

 15 L-SR 38.0 41.5 45.9 90.9   

 15 EL-S 22.1 24.1 26.3 41.5 44.9 

 15 EL01 11.8 13.2 14.8 28.1 31.0 

 

 15 EL02 20.6 22.6 24.7 40.2 43.7 

 15 EL03 9.2 10.6 12.1 25.7 28.6 

 15 EL04 8.9 10.3 11.9 25.2 28.1 

 15 SW2 27.5 29.4 31.3 46.4 50.1 

 16 SW1 17.0 18.6 20.2 31.8 34.1 

 

 16 L-SR 39.2 42.8 47.4 96.2 ** ** 

 16 EL-S 22.9 25.0 27.2 42.5 46.0 

 16 EL01 12.4 13.9 15.6 29.0 31.8 

 16 EL02 22.0 24.0 26.2 42.0 45.5 

 16 EL03 9.7 11.0 12.7 26.3 29.2 

 

 16 EL04 9.4 10.8 12.4 25.8 28.7 

 16 SW2 28.4 30.2 32.2 47.5 51.3 

 17 SW1 17.8 19.3 20.9 32.5 34.9 

 17 L-SR 40.3 44.0 48.9   ** ** 

 17 EL-S 23.8 25.8 28.0 43.5 47.0 

 

 17 EL01 13.0 14.5 16.2 29.8 32.7 

 17 EL02 23.4 25.5 27.8 43.7 47.3 

 17 EL03 10.1 11.5 13.2 26.8 29.8 

 17 EL04 9.8 11.2 12.8 26.4 29.3 

 17 SW2 29.2 31.0 33.1 48.5 52.4 

 

 18 SW1 18.5 20.0 21.7 33.3 35.7 

 18 L-SR 41.5 45.4 50.6   ** ** 

 18 EL-S 24.5 26.6 28.9 44.5 48.0 

 18 EL01 13.6 15.1 16.9 30.5 33.5 

 18 EL02 24.8 26.9 29.3 45.4 49.1 
112 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 18 EL03 10.6 12.0 13.7 27.4 30.4 

 18 EL04 10.2 11.7 13.3 26.9 29.8 

 18 SW2 29.9 31.8 33.9 49.5 53.5 

 19 SW1 19.2 20.7 22.3 34.0 36.4 

 19 L-SR 42.8 46.9 52.5   ** ** 

 

 19 EL-S 25.3 27.4 29.6 45.3 48.9 

 19 EL01 14.2 15.8 17.5 31.3 34.2 

 19 EL02 26.2 28.4 30.7 47.1 50.9 

 19 EL03 10.9 12.5 14.1 28.0 30.9 

 19 EL04 10.6 12.1 13.8 27.4 30.4 

 

 19 SW2 30.7 32.6 34.7 50.4 54.4 

 20 SW1 19.8 21.4 22.9 34.6 37.1 

 20 L-SR 44.3 48.7 54.7   ** ** 

 20 EL-S 25.9 28.1 30.4 46.2 49.8 

 20 EL01 14.8 16.4 18.1 32.0 35.0 

 

 20 EL02 27.6 29.8 32.2 48.8 52.6 

 20 EL03 11.4 12.9 14.6 28.5 31.5 

 20 EL04 11.0 12.5 14.2 28.0 30.9 

 20 SW2 31.3 33.3 35.4 51.3 55.4 

 21 SW1 20.5 22.0 23.7 35.5 38.0 

 

 21 L-SR 46.3 51.2 58.2   ** ** 

 21 EL-S 26.6 28.8 31.1 47.0 50.6 

 21 EL01 15.3 16.9 18.7 32.7 35.7 

 21 EL02 28.9 31.2 33.6 50.4 54.4 

 21 EL03 11.8 13.3 15.0 29.0 32.0 

 

 21 EL04 11.4 12.9 14.6 28.4 31.4 

 21 SW2 32.2 34.1 36.2 52.4 56.6 

 22 SW1 21.1 22.7 24.3 36.3 38.8 

 22 L-SR 49.5 55.4 64.4   ** ** 

 22 EL-S 27.3 29.5 31.8 47.8 51.4 

 

 22 EL01 15.8 17.5 19.3 33.3 36.3 

 22 EL02 30.3 32.6 35.0 52.1 56.1 

 22 EL03 12.2 13.7 15.5 29.5 32.5 

 22 EL04 11.8 13.3 15.0 28.9 31.9 

 22 SW2 32.9 34.9 37.1 53.5 57.7 

 

 23 SW1 21.8 23.4 25.0 37.0 39.6 

 23 EL-S 27.9 30.1 32.4 48.5 52.2 

 23 EL01 16.4 18.0 19.9 34.0 37.0 

 23 EL02 31.6 33.9 36.5 53.7 57.7 

 23 EL03 12.6 14.1 15.9 30.0 33.1 
113 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 23 EL04 12.1 13.7 15.5 29.4 32.4 

 23 SW2 33.7 35.7 37.9 54.5 58.8 

 24 SW1 22.4 23.9 25.6 37.7 40.3 

 24 L-SR 54.1 61.3 74.1   ** ** 

 24 EL-S 28.5 30.7 33.0 49.2 52.9 

 

 24 EL01 17.5 19.2 21.1 35.7 39.0 

 24 EL02 34.7 37.2 39.9 58.7 63.5 

 24 EL03 12.9 14.6 16.3 30.5 33.5 

 24 EL04 12.5 14.0 15.8 29.8 32.8 

 24 SW2 34.4 36.4 38.6 55.4 59.7 

 

 25 OPEN 45.6 49.4 54.0 91.8   

 25 SW1 22.9 24.5 26.1 38.3 40.9 

 25 L-SR 38.1 40.8 43.6 63.1 68.1 

 25 CR01 58.9 64.6 71.7 ** **   

 25 EL-S 28.9 31.1 33.5 49.7 53.4 

 

 25 EL01 17.9 19.7 21.6 36.3 39.5 

 25 EL02 35.7 38.2 41.0 60.0 64.9 

 25 EL03 13.3 14.9 16.7 30.9 34.0 

 25 EL04 12.8 14.4 16.2 30.2 33.2 

 25 T01 43.5 46.9 51.0 85.8 ** ** 

 

 25 T02 42.4 45.5 48.9 73.6 80.7 

 25 SW2 35.0 37.0 39.2 56.1 60.4 

 26 OPEN 46.3 50.1 54.8 92.8   

 26 SW1 23.4 24.9 26.7 38.9 41.5 

 26 L-SR 38.7 41.4 44.2 63.7 68.6 

 

 26 CR01 59.7 65.4 72.6 ** **   

 26 EL-S 29.5 31.7 34.0 50.3 54.0 

 26 EL01 18.3 20.0 22.0 36.8 40.1 

 26 EL02 36.5 39.1 41.9 61.2 66.2 

 26 EL03 13.7 15.3 17.1 31.3 34.4 

 

 26 EL04 13.2 14.8 16.6 30.6 33.6 

 26 T01 44.2 47.6 51.8 86.6 ** ** 

 26 T02 42.9 46.0 49.5 74.0 81.1 

 26 SW2 35.6 37.7 39.9 56.8 61.1 

 27 OPEN 47.2 51.0 55.8 94.2   

 

 27 SW1 23.9 25.5 27.2 39.5 42.1 

 27 L-SR 39.2 41.8 44.7 64.2 69.1 

 27 CR01 60.7 66.5 73.8 ** **   

 27 EL-S 29.9 32.1 34.5 50.8 54.5 

 27 EL01 18.7 20.4 22.4 37.2 40.5 
114 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 27 EL02 37.3 39.9 42.7 62.3 67.4 

 27 EL03 14.0 15.7 17.5 31.8 34.9 

 27 EL04 13.5 15.1 16.9 31.0 34.1 

 27 T01 44.9 48.4 52.6 87.7 ** ** 

 27 T02 43.6 46.7 50.2 74.7 81.8 

 

 27 SW2 36.2 38.3 40.5 57.5 61.9 

 28 OPEN 48.1 52.0 56.9 95.8   

 28 SW1 24.5 26.0 27.8 40.1 42.7 

 28 L-SR 39.7 42.4 45.2 64.7 69.6 

 28 CR01 61.8 67.6 75.1 ** **   

 

 28 EL-S 30.4 32.7 35.0 51.3 55.1 

 28 EL01 19.0 20.8 22.8 37.7 41.0 

 28 EL02 38.0 40.7 43.5 63.3 68.5 

 28 EL03 14.4 16.0 17.9 32.2 35.3 

 28 EL04 13.8 15.5 17.3 31.4 34.5 

 

 28 T01 45.6 49.1 53.4 88.8 ** ** 

 28 T02 44.3 47.4 50.8 75.4 82.4 

 28 SW2 36.9 38.9 41.2 58.2 62.6 

 29 OPEN 49.0 53.0 58.0 97.4   

 29 SW1 25.0 26.6 28.3 40.7 43.4 

 

 29 L-SR 40.2 42.8 45.7 65.3 70.2 

 29 CR01 62.9 68.8 76.4 ** **   

 29 EL-S 30.9 33.2 35.6 51.9 55.6 

 29 EL01 19.3 21.1 23.2 38.1 41.4 

 29 EL02 38.7 41.4 44.3 64.2 69.5 

 

 29 EL03 14.7 16.4 18.2 32.6 35.7 

 29 EL04 14.1 15.8 17.6 31.8 34.9 

 29 T01 46.4 49.9 54.2 89.9 ** ** 

 29 T02 44.9 48.0 51.6 76.1 83.1 

 29 SW2 37.5 39.6 41.8 59.0 63.4 

 

 30 OPEN 50.0 54.1 59.2 99.0   

 30 SW1 25.6 27.2 28.9 41.4 44.1 

 30 L-SR 40.7 43.4 46.2 65.8 70.7 

 30 CR01 64.0 70.0 77.7 ** **   

 30 EL-S 31.5 33.7 36.0 52.4 56.2 

 

 30 EL01 19.7 21.5 23.5 38.5 41.8 

 30 EL02 39.4 42.0 44.9 65.1 70.5 

 30 EL03 15.0 16.7 18.6 33.0 36.2 

 30 EL04 14.5 16.1 17.9 32.2 35.2 

 30 T01 47.2 50.7 55.1 91.1 ** ** 
115 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 30 T02 45.6 48.8 52.3 76.8 83.8 

 30 SW2 38.2 40.3 42.5 59.7 64.2 

 31 OPEN 51.0 55.2 60.4   ** ** 

 31 SW1 26.2 27.8 29.5 42.0 44.7 

 31 L-SR 41.2 43.9 46.7 66.3 71.2 

 

 31 CR01 65.2 71.3 79.2   ** ** 

 31 EL-S 31.9 34.2 36.6 53.0 56.8 

 31 EL01 20.0 21.8 23.8 38.9 42.2 

 31 EL02 40.0 42.7 45.6 66.0 71.4 

 31 EL03 15.4 17.0 18.9 33.4 36.6 

 

 31 EL04 14.8 16.4 18.3 32.5 35.6 

 31 T01 47.9 51.6 56.0 92.3   

 31 T02 46.3 49.5 53.0 77.5 84.5 

 31 SW2 38.8 40.9 43.2 60.5 64.9 

 32 OPEN 52.1 56.3 61.6 ** **   

 

 32 SW1 26.8 28.4 30.1 42.7 45.4 

 32 L-SR 41.7 44.4 47.3 66.9 71.8 

 32 CR01 66.4 72.7 80.7 ** **   

 32 EL-S 32.5 34.7 37.1 53.6 57.3 

 32 EL01 20.3 22.1 24.2 39.2 42.6 

 

 32 EL02 40.6 43.3 46.3 66.8 72.3 

 32 EL03 15.7 17.4 19.3 33.8 37.0 

 32 EL04 15.0 16.7 18.6 32.9 36.0 

 32 T01 48.8 52.5 56.9 93.6 ** ** 

 32 T02 47.0 50.2 53.7 78.2 85.3 

 

 32 SW2 39.5 41.6 43.9 61.2 65.7 

 33 OPEN 53.2 57.6 63.0   ** ** 

 33 SW1 27.4 29.0 30.7 43.4 46.1 

 33 L-SR 42.2 44.9 47.8 67.4 72.4 

 33 CR01 67.7 74.1 82.3   ** ** 

 

 33 EL-S 33.0 35.3 37.7 54.2 57.9 

 33 EL01 20.6 22.4 24.5 39.6 42.9 

 33 EL02 41.1 43.9 46.8 67.5 73.1 

 33 EL03 16.0 17.7 19.7 34.2 37.4 

 33 EL04 15.4 17.0 18.9 33.3 36.4 

 

 33 T01 53.2 57.7 63.3   ** ** 

 33 T02 47.8 51.0 54.5 79.1 86.2 

 33 SW2 40.1 42.3 44.6 62.0 66.5 

 34 OPEN 54.4 58.9 64.4   ** ** 

 34 SW1 28.0 29.6 31.4 44.1 46.9 
116 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 34 L-SR 42.8 45.5 48.4 68.0 73.0 

 34 CR01 69.1 75.7 84.0   ** ** 

 34 EL-S 33.5 35.8 38.2 54.7 58.5 

 34 EL01 20.8 22.7 24.8 39.9 43.3 

 34 EL02 41.7 44.4 47.4 68.3 74.0 

 

 34 EL03 16.4 18.0 20.0 34.6 37.8 

 34 EL04 15.7 17.4 19.2 33.6 36.7 

 34 T01 54.5 59.1 64.9   ** ** 

 34 T02 48.6 51.8 55.3 79.9 86.9 

 34 SW2 40.8 42.9 45.3 62.7 67.2 

 

 35 OPEN 53.0 57.6 63.1   ** ** 

 35 SW1 28.6 30.3 32.0 44.8 47.6 

 35 L-SR 43.3 46.0 48.9 68.6 73.6 

 35 CR01 67.8 74.3 82.5   ** ** 

 35 EL-S 34.1 36.4 38.8 55.3 59.1 

 

 35 EL01 21.1 23.0 25.0 40.2 43.5 

 35 EL02 42.2 44.9 48.0 69.0 74.7 

 35 EL03 16.7 18.4 20.3 35.0 38.2 

 35 EL04 15.9 17.7 19.6 34.0 37.1 

 35 T01 55.6 60.3 66.3   ** ** 

 

 35 T02 49.3 52.6 56.1 80.7 87.8 

 35 SW2 41.4 43.6 45.9 63.5 68.0 

 36 OPEN 47.0 51.1 56.1 91.9   

 36 SW1 29.3 30.9 32.7 45.5 48.3 

 36 L-SR 43.9 46.6 49.5 69.2 74.2 

 

 36 CR01 60.9 66.6 73.7 ** **   

 36 EL-S 34.6 36.9 39.3 56.0 59.7 

 36 EL01 21.4 23.2 25.3 40.5 43.9 

 36 EL02 42.6 45.4 48.5 69.6 75.4 

 36 EL03 16.9 18.7 20.7 35.3 38.5 

 

 36 EL04 16.3 17.9 19.9 34.3 37.5 

 36 T01 55.6 60.2 66.0 ** **   

 36 T02 50.1 53.4 56.9 81.6 88.6 

 36 SW2 42.0 44.3 46.7 64.3 68.8 

 37 OPEN 44.5 48.2 52.7 85.5 97.6 

 

 37 SW1 29.9 31.6 33.4 46.3 49.1 

 37 L-SR 44.5 47.2 50.1 69.8 74.8 

 37 CR01 57.6 62.8 69.2 ** **   

 37 EL-S 35.2 37.5 39.9 56.6 60.4 

 37 EL01 21.7 23.5 25.6 40.8 44.1 
117 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 37 EL02 43.0 45.8 48.9 70.2 76.1 

 37 EL03 17.3 19.0 21.0 35.7 38.9 

 37 EL04 16.6 18.3 20.2 34.7 37.8 

 37 T01 55.4 60.0 65.6 ** **   

 37 T02 50.9 54.2 57.8 82.4 89.4 

 

 37 SW2 42.7 44.9 47.3 65.0 69.6 

 38 OPEN 42.6 46.2 50.3 80.7 91.3 

 38 SW1 30.6 32.3 34.0 47.0 49.9 

 38 L-SR 45.0 47.7 50.6 70.4 75.4 

 38 CR01 55.2 60.0 65.8 ** **   

 

 38 EL-S 35.8 38.0 40.5 57.2 61.0 

 38 EL01 21.9 23.8 25.9 41.1 44.4 

 38 EL02 43.3 46.2 49.3 70.7 76.6 

 38 EL03 17.6 19.3 21.3 36.1 39.3 

 38 EL04 16.8 18.6 20.5 35.0 38.2 

 

 38 T01 54.8 59.3 64.7 ** **   

 38 T02 51.7 55.0 58.6 83.2 90.2 

 38 SW2 43.4 45.6 48.0 65.8 70.4 

 39 OPEN 41.0 44.3 48.1 76.1 85.5 

 39 SW1 31.2 32.9 34.7 47.8 50.6 

 

 39 L-SR 45.5 48.2 51.1 70.9 75.8 

 39 CR01 53.0 57.5 62.7 97.7 ** ** 

 39 EL-S 36.4 38.7 41.1 57.8 61.7 

 39 EL01 22.2 24.0 26.1 41.3 44.8 

 39 EL02 43.6 46.5 49.6 71.1 77.1 

 

 39 EL03 17.9 19.7 21.6 36.4 39.7 

 39 EL04 17.1 18.8 20.8 35.3 38.5 

 39 T01 53.6 57.9 63.0 98.8   

 39 T02 52.3 55.5 59.1 83.7 90.7 

 39 SW2 44.0 46.3 48.7 66.6 71.1 

 

 40 OPEN 41.1 44.4 48.2 76.0 85.3 

 40 SW1 31.9 33.6 35.4 48.6 51.4 

 40 L-SR 46.1 48.8 51.8 71.5 76.5 

 40 CR01 53.0 57.5 62.7 97.5 ** ** 

 40 EL-S 36.9 39.3 41.7 58.5 62.3 

 

 40 EL01 22.5 24.4 26.5 41.7 45.1 

 40 EL02 43.9 46.8 49.9 71.4 77.4 

 40 EL03 18.2 19.9 21.9 36.8 40.0 

 40 EL04 17.4 19.1 21.0 35.7 38.8 

 40 T01 54.1 58.5 63.7 99.5   
118 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 40 T02 53.2 56.5 60.2 84.7 91.7 

 40 SW2 44.7 46.9 49.4 67.3 71.9 

 41 OPEN 41.4 44.7 48.4 76.3 85.6 

 41 SW1 32.6 34.3 36.1 49.4 52.3 

 41 L-SR 46.7 49.5 52.4 72.2 77.2 

 

 41 CR01 53.3 57.7 63.0 97.8 ** ** 

 41 EL-S 37.6 39.9 42.3 59.1 63.0 

 41 EL01 22.8 24.7 26.8 42.0 45.4 

 41 EL02 44.3 47.1 50.3 71.8 77.8 

 41 EL03 18.5 20.2 22.2 37.1 40.4 

 

 41 EL04 17.7 19.4 21.4 36.0 39.2 

 41 T01 54.8 59.3 64.6   ** ** 

 41 T02 53.9 57.2 60.8 85.4 92.4 

 41 SW2 45.3 47.6 50.1 68.1 72.7 

 42 OPEN 41.3 44.6 48.3 75.7 84.8 

 

 42 SW1 33.3 35.0 36.9 50.2 53.1 

 42 L-SR 47.3 50.0 53.0 72.8 77.8 

 42 CR01 53.1 57.5 62.6 96.9   

 42 EL-S 38.2 40.5 43.0 59.8 63.7 

 42 EL01 23.0 25.0 27.1 42.3 45.7 

 

 42 EL02 44.6 47.5 50.6 72.2 78.2 

 42 EL03 18.7 20.6 22.6 37.4 40.7 

 42 EL04 17.9 19.7 21.7 36.3 39.5 

 42 T01 54.9 59.5 64.9 ** **   

 42 T02 54.5 57.8 61.4 86.0 92.9 

 

 42 SW2 45.9 48.3 50.8 68.9 73.5 

 43 OPEN 35.7 38.5 41.5 62.7 68.6 

 43 SW1 34.0 35.8 37.6 51.0 53.9 

 43 L-SR 46.0 48.6 51.4 70.3 74.9 

 43 EL-S 38.8 41.1 43.6 60.5 64.4 

 

 43 EL01 23.4 25.3 27.4 42.7 46.1 

 43 EL02 45.0 47.8 51.0 72.5 78.5 

 43 EL03 19.3 21.2 23.2 38.3 41.7 

 43 EL04 18.5 20.3 22.3 37.2 40.4 

 43 T01 48.9 52.4 56.3 83.6 92.3 

 

 43 T02 51.2 54.2 57.5 80.0 86.1 

 43 SW2 46.6 49.0 51.5 69.7 74.3 

 44 OPEN 55.1 58.6 62.6 92.0 ** ** 

 44 SW1 34.8 36.5 38.4 51.8 54.8 

 44 L-SR 45.8 48.4 51.2 69.8 74.2 
119 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 44 EL-S 39.5 41.8 44.3 61.2 65.1 

 44 EL03 19.6 21.4 23.5 38.6 42.1 

 44 EL04 18.7 20.5 22.6 37.4 40.7 

 44 T01 55.5 58.9 62.9 93.7   

 44 T02 50.8 53.7 56.8 78.6 84.4 

 

 44 SW2 47.3 49.7 52.2 70.5 75.1 

 45 OPEN 56.5 60.0 64.0 93.7 ** ** 

 45 SW1 35.6 37.3 39.2 52.7 55.7 

 45 L-SR 46.5 49.1 51.9 70.5 75.0 

 45 EL-S 40.1 42.5 45.0 62.0 65.9 

 

 45 EL03 19.8 21.7 23.7 38.9 42.3 

 45 EL04 18.9 20.8 22.8 37.7 41.0 

 45 T01 56.4 59.9 63.9 94.9   

 45 T02 51.6 54.5 57.6 79.4 85.2 

 45 SW2 48.0 50.4 53.0 71.3 75.9 

 

 46 OPEN 55.3 59.2 63.6 93.6 ** ** 

 46 SW1 36.4 38.2 40.0 53.7 56.7 

 46 L-SR 47.3 49.9 52.7 71.3 75.8 

 46 EL-S 40.9 43.2 45.8 62.8 66.7 

 46 EL03 20.0 21.9 23.9 39.2 42.6 

 

 46 EL04 19.1 20.9 23.0 37.9 41.2 

 46 T01 56.1 59.8 64.1 95.3   

 46 T02 52.4 55.3 58.5 80.3 86.1 

 46 SW2 48.7 51.2 53.8 72.2 76.8 

 47 OPEN 48.0 52.6 57.8 89.2 99.5 

 

 47 SW1 37.3 39.1 41.0 54.7 57.8 

 47 L-SR 48.0 50.7 53.5 72.2 76.7 

 47 EL-S 41.7 44.0 46.6 63.6 67.6 

 47 EL03 20.3 22.1 24.2 39.4 42.9 

 47 EL04 19.4 21.2 23.2 38.2 41.4 

 

 47 T01 45.2 49.4 54.3 86.1 96.6 

 47 T02 53.2 56.2 59.4 81.3 87.1 

 47 SW2 49.5 52.0 54.6 73.1 77.8 

 48 OPEN 46.0 50.4 55.5 87.5 97.7 

 48 SW1 38.3 40.1 42.0 55.9 58.9 

 

 48 L-SR 48.9 51.5 54.3 73.1 77.6 

 48 EL-S 42.5 44.8 47.4 64.5 68.5 

 48 EL03 20.5 22.4 24.4 39.7 43.1 

 48 EL04 19.6 21.4 23.4 38.4 41.7 

 48 T01 43.3 47.2 51.8 83.2 93.4 
120 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 48 T02 54.2 57.1 60.3 82.3 88.1 

 48 SW2 50.3 52.8 55.5 74.1 78.8 

 49 OPEN 45.4 49.6 54.7 87.0 97.2 

 49 SW1 39.4 41.2 43.1 57.1 60.2 

 49 L-SR 49.8 52.4 55.2 74.1 78.6 

 

 49 EL-S 43.3 45.7 48.3 65.5 69.5 

 49 EL03 20.7 22.6 24.7 39.9 43.3 

 49 EL04 19.8 21.6 23.6 38.6 41.9 

 49 T01 42.7 46.5 51.0 82.2 92.3 

 49 T02 55.1 58.1 61.4 83.3 89.2 

 

 49 SW2 51.2 53.8 56.5 75.1 79.8 

 50 OPEN 44.6 48.7 53.6 86.0 96.2 

 50 SW1 40.5 42.4 44.3 58.4 61.6 

 50 L-SR 50.7 53.4 56.2 75.1 79.7 

 50 EL-S 44.3 46.7 49.2 66.5 70.5 

 

 50 EL03 20.9 22.8 24.9 40.2 43.6 

 50 EL04 19.9 21.8 23.8 38.8 42.1 

 50 T01 42.7 46.5 50.9 82.3 92.5 

 50 T02 56.2 59.2 62.5 84.5 90.4 

 50 SW2 52.2 54.7 57.5 76.3 81.0 

 

 51 OPEN 43.5 47.4 51.9 84.0 94.1 

 51 SW1 41.8 43.7 45.7 60.0 63.1 

 51 L-SR 51.7 54.4 57.3 76.3 80.8 

 51 EL-S 45.2 47.7 50.3 67.6 71.6 

 51 EL03 21.1 23.0 25.1 40.4 43.8 

 

 51 EL04 20.2 22.0 24.0 39.1 42.4 

 51 T01 42.4 46.1 50.5 81.8 92.0 

 51 T02 57.4 60.4 63.6 85.8 91.6 

 51 SW2 53.2 55.8 58.6 77.5 82.2 

 52 OPEN 42.7 46.4 50.8 82.3 92.4 

 

 52 SW1 43.2 45.1 47.2 61.6 64.9 

 52 L-SR 52.8 55.5 58.4 77.5 82.1 

 52 EL-S 46.3 48.8 51.4 68.8 72.9 

 52 EL03 21.3 23.2 25.3 40.6 44.1 

 52 EL04 20.4 22.2 24.3 39.3 42.6 

 

 52 T01 42.1 45.7 50.0 81.0 91.2 

 52 T02 58.6 61.6 64.9 87.1 93.0 

 52 SW2 54.3 56.9 59.7 78.8 83.5 

 53 OPEN 42.1 45.8 50.0 80.9 91.0 

 53 SW1 44.8 46.8 48.9 63.6 66.9 
121 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 53 L-SR 54.0 56.7 59.6 78.8 83.4 

 53 EL-S 47.5 49.9 52.6 70.1 74.2 

 53 EL03 21.5 23.4 25.5 40.8 44.3 

 53 EL04 20.6 22.5 24.5 39.5 42.9 

 53 T01 41.8 45.4 49.5 80.2 90.3 

 

 53 T02 59.9 63.0 66.3 88.6 94.5 

 53 SW2 55.5 58.1 61.0 80.2 85.0 

 54 OPEN 41.7 45.3 49.4 79.8 89.8 

 54 SW1 46.7 48.7 50.8 65.8 69.2 

 54 L-SR 55.3 58.0 61.0 80.3 84.9 

 

 54 EL-S 48.8 51.2 53.9 71.5 75.7 

 54 EL03 21.7 23.7 25.7 41.1 44.5 

 54 EL04 20.8 22.7 24.7 39.8 43.1 

 54 T01 41.5 45.0 49.1 79.4 89.5 

 54 T02 61.4 64.5 67.9 90.3 96.2 

 

 54 SW2 56.8 59.5 62.4 81.8 86.6 

 55 OPEN 41.4 44.9 48.9 78.8 88.7 

 55 SW1 48.9 51.0 53.1 68.5 72.0 

 55 L-SR 56.8 59.5 62.5 81.9 86.6 

 55 EL-S 50.2 52.7 55.3 73.2 77.3 

 

 55 EL03 21.9 23.9 25.9 41.3 44.7 

 55 EL04 21.0 22.9 24.9 40.0 43.3 

 55 T01 41.3 44.8 48.8 78.7 88.7 

 55 T02 63.0 66.2 69.6 92.2 98.1 

 55 SW2 58.3 61.0 64.0 83.5 88.4 

 

 56 OPEN 41.2 44.6 48.6 77.9 87.7 

 56 SW1 51.7 53.8 56.0 71.9 75.5 

 56 L-SR 58.4 61.2 64.1 83.7 88.5 

 56 EL-S 51.7 54.3 57.0 74.9 79.1 

 56 EL03 22.2 24.1 26.2 41.5 45.0 

 

 56 EL04 21.2 23.1 25.2 40.2 43.6 

 56 T01 41.2 44.6 48.6 78.0 88.0 

 56 T02 64.9 68.0 71.5 94.3 ** ** 

 56 SW2 60.0 62.8 65.7 85.5 90.4 

 57 OPEN 41.0 44.4 48.3 77.1 86.8 

 

 57 SW1 55.2 57.5 59.9 76.5 80.3 

 57 L-SR 60.2 63.0 66.0 85.8 90.6 

 57 EL-S 53.5 56.1 58.8 77.0 81.2 

 57 EL03 22.4 24.3 26.4 41.8 45.2 

 57 EL04 21.5 23.3 25.4 40.5 43.8 
122 

Table 25. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 57 T01 41.0 44.4 48.3 77.3 87.1 

 57 T02 66.9 70.2 73.7 96.7   

 57 SW2 61.9 64.7 67.8 87.8 92.8 

 58 OPEN 40.5 43.8 47.5 75.4 84.7 

 58 SW1 60.7 63.1 65.7 83.7 88.0 

 

 58 L-SR 62.3 65.2 68.2 88.2 93.1 

 58 EL-S 55.6 58.2 61.0 79.4 83.7 

 58 EL03 22.6 24.5 26.6 42.0 45.5 

 58 EL04 21.7 23.6 25.7 40.7 44.1 

 58 T01 40.6 43.9 47.7 75.8 85.2 

 

 58 T02 69.3 72.6 76.2 99.6 ** ** 

 58 SW2 64.1 67.0 70.1 90.5 95.6 

 59 MECH 76.8 80.9 85.4   ** ** 

 59 ELME 80.4 84.7 89.5   ** ** 

 59 EL-S 58.0 60.7 63.6 82.3 86.7 

 

 59 EL03 22.6 24.6 26.7 42.0 45.5 

 59 EL04 21.7 23.6 25.7 40.8 44.1 

 59 SW2 66.9 69.8 73.0 93.8 99.0 

 R SW2 71.4 74.6 77.9 99.5   
123 

Table 26. Results of Tenability Analysis for Scenario 26. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 37.7 43.2 49.9 91.1 ** ** 

 B L-SR 55.0 62.9 72.5   ** ** 

 B L-MR 38.4 45.0 53.5   ** ** 

 B L-HR 34.6 40.2 47.5 93.5   

 B EL-S 22.6 25.1 27.9 47.0 52.0 

 

 B EL01 53.3 60.5 69.1 ** **   

 B EL02 52.0 59.8 69.2 ** **   

 B EL03 47.5 54.5 62.9 ** **   

 B EL04 46.6 53.0 60.8 ** **   

 B SW2 11.1 12.9 14.9 29.3 32.3 

 

 G OPEN 7.0 8.9 11.0 26.6 30.3 

 G SW1 18.0 20.8 23.8 48.0 56.3 

 G L-SR 14.2 16.6 19.1 37.5 42.5 

 G EL-S 13.3 15.4 17.6 33.3 36.9 

 G EL01 10.7 12.8 15.1 31.7 35.8 

 

 G EL02 10.8 12.8 15.2 31.8 35.9 

 G EL03 9.9 11.9 14.2 30.5 34.5 

 G EL04 10.0 12.1 14.4 30.9 35.0 

 G T01 14.1 16.5 19.0 37.0 41.8 

 G T02 16.6 19.1 21.9 41.7 47.3 

 

 G SW2 4.6 5.7 6.9 18.6 21.1 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.5 1.9 9.8 11.8 

 2 L-SR 1.0 1.4 1.9 9.2 11.0 

 2 CR01 1.4 1.9 2.4 10.7 12.7 

 

 2 CR02 1.0 1.4 1.9 9.2 11.0 

 2 EL-S 3.0 3.9 4.8 15.2 17.5 

 2 EL01 1.1 1.7 2.2 10.8 12.9 

 2 EL02 1.8 2.4 3.1 13.3 15.7 

 2 EL03 1.8 2.3 3.0 13.2 15.6 

 

 2 EL04 1.8 2.3 3.0 13.2 15.5 

 2 T01 1.6 2.0 2.8 11.6 13.7 

 2 T02 1.9 2.7 3.4 13.3 15.5 

 2 SW2 1.0 1.3 1.8 8.8 10.6 

 3 SW1 1.9 2.6 3.2 12.4 14.5 

 

 3 L-SR 17.6 20.2 23.0 46.1 55.0 

 3 CR02 13.0 15.2 17.7 35.4 40.2 

 3 EL-S 4.9 6.0 7.2 18.6 21.1 

 3 EL01 2.2 2.9 3.7 13.4 15.7 

 3 EL02 3.3 4.1 5.2 16.5 19.0 
124 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL03 2.7 3.4 4.3 15.1 17.5 

 3 EL04 2.7 3.3 4.2 14.9 17.3 

 3 SW2 3.0 3.9 4.8 15.1 17.2 

 4 SW1 3.0 3.8 4.7 14.6 16.8 

 4 L-SR 20.0 22.7 25.5 50.1 60.1 

 

 4 EL-S 6.8 7.9 9.4 21.5 24.0 

 4 EL01 3.4 4.1 5.1 15.7 18.0 

 4 EL02 5.0 6.1 7.5 19.6 22.2 

 4 EL03 3.6 4.5 5.5 16.7 19.2 

 4 EL04 3.5 4.4 5.4 16.5 19.0 

 

 4 SW2 5.6 6.7 7.9 19.4 21.7 

 5 SW1 4.2 5.0 6.1 16.6 18.9 

 5 L-SR 22.1 24.7 27.6 53.8 64.8 

 5 EL-S 8.4 9.7 11.3 23.9 26.5 

 5 EL01 4.6 5.5 6.6 17.7 20.1 

 

 5 EL02 7.0 8.3 9.8 22.5 25.3 

 5 EL03 4.5 5.5 6.7 18.2 20.8 

 5 EL04 4.4 5.3 6.5 17.9 20.4 

 5 SW2 7.9 9.2 10.8 22.8 25.1 

 6 SW1 5.4 6.3 7.5 18.4 20.6 

 

 6 L-SR 23.9 26.5 29.5 57.2 69.3 

 6 EL-S 9.9 11.4 12.9 25.9 28.6 

 6 EL01 5.7 6.7 7.9 19.5 22.0 

 6 EL02 8.9 10.4 12.0 25.4 28.2 

 6 EL03 5.4 6.5 7.7 19.6 22.2 

 

 6 EL04 5.2 6.2 7.5 19.2 21.8 

 6 SW2 10.0 11.6 13.2 25.4 27.7 

 7 SW1 6.5 7.6 8.8 20.0 22.2 

 7 L-SR 25.5 28.1 31.2 60.3 73.7 

 7 EL-S 11.3 12.8 14.5 27.7 30.5 

 

 7 EL01 6.8 7.9 9.2 21.1 23.7 

 7 EL02 11.0 12.6 14.4 28.2 31.1 

 7 EL03 6.3 7.4 8.8 21.0 23.6 

 7 EL04 6.0 7.1 8.4 20.4 23.1 

 7 SW2 12.0 13.6 15.3 27.5 29.9 

 

 8 SW1 7.5 8.7 10.0 21.4 23.6 

 8 L-SR 26.9 29.6 32.8 63.4 78.3 

 8 EL-S 12.6 14.1 15.9 29.4 32.2 

 8 EL01 7.8 9.0 10.4 22.6 25.3 

 8 EL02 13.0 14.7 16.6 30.9 33.9 
125 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL03 7.1 8.3 9.7 22.2 24.8 

 8 EL04 6.8 7.9 9.3 21.6 24.2 

 8 SW2 13.7 15.4 17.1 29.4 31.8 

 9 SW1 8.6 9.8 11.1 22.6 24.9 

 9 L-SR 28.2 31.0 34.2 66.3 83.3 

 

 9 EL-S 13.7 15.4 17.2 30.9 33.7 

 9 EL01 8.8 10.0 11.5 24.1 26.7 

 9 EL02 15.0 16.8 18.8 33.5 36.7 

 9 EL03 7.9 9.2 10.7 23.3 26.0 

 9 EL04 7.6 8.8 10.2 22.6 25.3 

 

 9 SW2 15.3 16.9 18.7 31.0 33.5 

 10 SW1 9.5 10.8 12.2 23.8 26.0 

 10 L-SR 29.4 32.3 35.6 69.2 88.7 

 10 EL-S 14.8 16.5 18.4 32.2 35.1 

 10 EL01 9.7 11.0 12.6 25.3 28.1 

 

 10 EL02 17.0 18.9 21.0 36.0 39.3 

 10 EL03 8.7 10.0 11.5 24.3 27.1 

 10 EL04 8.3 9.5 11.0 23.6 26.3 

 10 SW2 16.7 18.4 20.1 32.4 35.0 

 11 SW1 10.5 11.8 13.2 24.8 27.1 

 

 11 L-SR 30.6 33.5 37.0 72.2 95.0 

 11 EL-S 15.8 17.5 19.5 33.4 36.4 

 11 EL01 10.6 12.0 13.6 26.5 29.3 

 11 EL02 18.9 20.9 23.1 38.5 41.9 

 11 EL03 9.5 10.8 12.4 25.3 28.1 

 

 11 EL04 8.9 10.2 11.8 24.5 27.2 

 11 SW2 17.9 19.6 21.4 33.8 36.4 

 12 SW1 11.3 12.7 14.2 25.8 28.1 

 12 L-SR 31.7 34.7 38.3 75.3 ** ** 

 12 EL-S 16.7 18.5 20.5 34.6 37.6 

 

 12 EL01 11.5 12.9 14.5 27.6 30.5 

 12 EL02 20.9 22.9 25.2 40.9 44.4 

 12 EL03 10.2 11.6 13.2 26.3 29.1 

 12 EL04 9.6 10.9 12.5 25.4 28.1 

 12 SW2 19.0 20.8 22.5 35.0 37.6 

 

 13 SW1 12.1 13.6 15.1 26.7 29.0 

 13 L-SR 32.7 35.8 39.6 78.6   

 13 EL-S 17.6 19.4 21.4 35.7 38.7 

 13 EL01 12.3 13.7 15.4 28.7 31.6 

 13 EL02 22.8 24.9 27.2 43.3 46.9 
126 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL03 10.9 12.3 13.9 27.2 30.1 

 13 EL04 10.2 11.6 13.2 26.2 29.0 

 13 SW2 20.1 21.8 23.5 36.1 38.8 

 14 SW1 12.9 14.4 15.9 27.5 29.8 

 14 L-SR 33.7 36.9 40.8 82.1 ** ** 

 

 14 EL-S 18.4 20.3 22.3 36.7 39.8 

 14 EL01 13.0 14.6 16.2 29.7 32.6 

 14 EL02 24.6 26.8 29.1 45.5 49.3 

 14 EL03 11.5 13.0 14.7 28.1 30.9 

 14 EL04 10.8 12.2 13.8 27.0 29.8 

 

 14 SW2 21.0 22.7 24.5 37.1 39.9 

 15 SW1 13.7 15.1 16.7 28.3 30.6 

 15 L-SR 34.7 38.0 42.1 86.2   

 15 EL-S 19.2 21.1 23.1 37.6 40.8 

 15 EL01 13.8 15.3 17.0 30.7 33.6 

 

 15 EL02 26.4 28.6 31.0 47.8 51.7 

 15 EL03 12.1 13.7 15.4 28.9 31.8 

 15 EL04 11.4 12.8 14.5 27.7 30.5 

 15 SW2 21.9 23.6 25.3 38.1 40.9 

 16 SW1 14.4 15.9 17.5 29.1 31.3 

 

 16 L-SR 35.7 39.1 43.4 90.9 ** ** 

 16 EL-S 19.9 21.9 23.9 38.5 41.7 

 16 EL01 14.5 16.0 17.8 31.6 34.5 

 16 EL02 28.1 30.5 32.9 50.0 54.0 

 16 EL03 12.8 14.3 16.0 29.7 32.6 

 

 16 EL04 11.9 13.4 15.1 28.4 31.2 

 16 SW2 22.7 24.4 26.1 39.0 41.8 

 17 SW1 15.1 16.6 18.1 29.7 32.1 

 17 L-SR 36.8 40.3 44.8 96.9   

 17 EL-S 20.7 22.6 24.7 39.4 42.6 

 

 17 EL01 15.1 16.8 18.6 32.4 35.4 

 17 EL02 29.9 32.2 34.8 52.1 56.2 

 17 EL03 13.4 14.9 16.7 30.4 33.3 

 17 EL04 12.5 14.0 15.7 29.1 32.0 

 17 SW2 23.5 25.1 26.8 39.8 42.7 

 

 18 SW1 15.8 17.2 18.8 30.4 32.7 

 18 L-SR 37.8 41.5 46.3 ** **   

 18 EL-S 21.4 23.3 25.4 40.2 43.4 

 18 EL01 15.8 17.5 19.3 33.2 36.3 

 18 EL02 31.6 33.9 36.5 54.2 58.4 
127 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 18 EL03 13.9 15.5 17.3 31.1 34.1 

 18 EL04 13.0 14.5 16.2 29.7 32.6 

 18 SW2 24.1 25.8 27.6 40.6 43.5 

 19 SW1 16.4 17.9 19.5 31.0 33.4 

 19 L-SR 39.0 42.8 48.0 ** **   

 

 19 EL-S 22.0 23.9 26.1 41.0 44.2 

 19 EL01 16.5 18.1 19.9 34.0 37.1 

 19 EL02 33.2 35.7 38.3 56.2 60.5 

 19 EL03 14.5 16.0 17.9 31.8 34.8 

 19 EL04 13.5 15.0 16.8 30.4 33.2 

 

 19 SW2 24.8 26.5 28.2 41.3 44.3 

 20 SW1 16.9 18.5 20.1 31.6 34.0 

 20 L-SR 40.3 44.4 50.0 ** **   

 20 EL-S 22.6 24.6 26.7 41.7 45.0 

 20 EL01 17.0 18.7 20.6 34.8 37.9 

 

 20 EL02 34.8 37.3 40.0 58.2 62.6 

 20 EL03 15.0 16.6 18.5 32.5 35.5 

 20 EL04 13.9 15.6 17.3 31.0 33.9 

 20 SW2 25.4 27.0 28.8 42.1 45.1 

 21 SW1 17.6 19.1 20.7 32.4 34.8 

 

 21 L-SR 42.2 46.7 53.2 ** **   

 21 EL-S 23.2 25.2 27.4 42.4 45.7 

 21 EL01 17.6 19.4 21.2 35.5 38.6 

 21 EL02 36.4 38.9 41.7 60.2 64.7 

 21 EL03 15.5 17.1 19.0 33.1 36.2 

 

 21 EL04 14.4 16.0 17.8 31.5 34.4 

 21 SW2 26.1 27.8 29.6 43.0 46.0 

 22 SW1 18.1 19.7 21.3 33.1 35.5 

 22 L-SR 44.9 50.4 58.8 ** **   

 22 EL-S 23.8 25.8 27.9 43.1 46.4 

 

 22 EL01 18.2 19.9 21.8 36.2 39.3 

 22 EL02 37.9 40.6 43.3 62.1 66.7 

 22 EL03 16.0 17.7 19.6 33.7 36.8 

 22 EL04 14.9 16.5 18.3 32.1 35.0 

 22 SW2 26.8 28.5 30.2 43.8 47.0 

 

 23 SW1 18.7 20.3 21.9 33.7 36.2 

 23 L-SR 56.3 70.5 ** **   ** ** 

 23 EL-S 24.3 26.4 28.5 43.7 47.1 

 23 EL01 18.7 20.5 22.4 36.9 40.0 

 23 EL02 39.5 42.1 44.9 64.0 68.7 
128 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 23 EL03 16.5 18.2 20.0 34.3 37.4 

 23 EL04 15.3 16.9 18.8 32.6 35.6 

 23 SW2 27.4 29.1 30.9 44.6 47.8 

 24 SW1 19.2 20.8 22.5 34.3 36.9 

 24 L-SR 51.8 60.0 78.8   ** ** 

 

 24 EL-S 24.8 26.9 29.0 44.3 47.7 

 24 EL01 19.4 21.2 23.2 37.8 41.1 

 24 EL02 41.7 44.4 47.3 67.2 72.2 

 24 EL03 16.9 18.7 20.6 34.9 38.0 

 24 EL04 15.7 17.4 19.2 33.1 36.1 

 

 24 SW2 28.0 29.7 31.6 45.3 48.6 

 25 OPEN 44.9 49.0 54.3 96.1   

 25 SW1 19.7 21.3 22.9 34.9 37.4 

 25 L-SR 36.4 39.0 41.9 61.9 67.2 

 25 CR01 57.7 63.7 71.2 ** **   

 

 25 EL-S 25.2 27.3 29.5 44.8 48.2 

 25 EL01 19.9 21.8 23.8 38.5 41.7 

 25 EL02 42.9 45.7 48.7 69.1 74.3 

 25 EL03 17.4 19.1 21.0 35.4 38.6 

 25 EL04 16.1 17.8 19.6 33.6 36.6 

 

 25 T01 40.0 43.3 47.3 82.7 99.2 

 25 T02 41.1 44.3 47.8 73.8 81.7 

 25 SW2 28.5 30.2 32.1 46.0 49.2 

 26 OPEN 44.1 48.0 52.9 91.2 ** ** 

 26 SW1 20.1 21.7 23.4 35.4 37.9 

 

 26 L-SR 35.6 38.1 40.8 59.8 64.6 

 26 CR01 56.5 62.1 69.0   ** ** 

 26 EL-S 25.7 27.7 29.9 45.3 48.7 

 26 EL01 20.4 22.2 24.3 39.1 42.3 

 26 EL02 43.8 46.7 49.8 70.7 76.1 

 

 26 EL03 17.8 19.6 21.5 36.0 39.1 

 26 EL04 16.5 18.2 20.0 34.1 37.0 

 26 T01 40.4 43.7 47.7 82.3 97.8 

 26 T02 40.1 43.1 46.5 70.6 77.7 

 26 SW2 29.0 30.8 32.6 46.5 49.8 

 

 27 OPEN 44.7 48.6 53.4 91.5   

 27 SW1 20.6 22.2 23.9 35.9 38.4 

 27 L-SR 35.6 38.2 40.9 59.6 64.4 

 27 CR01 57.1 62.7 69.6 ** **   

 27 EL-S 26.1 28.2 30.4 45.7 49.2 
129 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 27 EL01 20.9 22.7 24.8 39.6 42.9 

 27 EL02 44.7 47.6 50.8 72.2 77.8 

 27 EL03 18.2 20.0 21.9 36.5 39.6 

 27 EL04 16.9 18.6 20.5 34.5 37.5 

 27 T01 41.0 44.3 48.3 83.0 98.4 

 

 27 T02 40.4 43.4 46.7 70.4 77.3 

 27 SW2 29.6 31.3 33.2 47.2 50.4 

 28 OPEN 45.4 49.3 54.1 92.1 ** ** 

 28 SW1 21.1 22.7 24.4 36.4 39.0 

 28 L-SR 35.8 38.3 41.0 59.7 64.4 

 

 28 CR01 57.8 63.4 70.4   ** ** 

 28 EL-S 26.5 28.6 30.8 46.2 49.6 

 28 EL01 21.3 23.2 25.2 40.2 43.5 

 28 EL02 45.5 48.5 51.7 73.5 79.3 

 28 EL03 18.7 20.4 22.4 37.0 40.1 

 

 28 EL04 17.2 18.9 20.8 34.9 37.9 

 28 T01 41.6 44.9 48.9 83.7 99.2 

 28 T02 40.7 43.7 47.0 70.5 77.3 

 28 SW2 30.1 31.9 33.7 47.8 51.0 

 29 OPEN 46.0 50.0 54.9 92.8   

 

 29 SW1 21.6 23.2 24.8 37.0 39.5 

 29 L-SR 36.0 38.6 41.3 59.8 64.4 

 29 CR01 58.6 64.2 71.2 ** **   

 29 EL-S 26.9 29.0 31.3 46.7 50.1 

 29 EL01 21.7 23.6 25.7 40.7 44.0 

 

 29 EL02 46.2 49.2 52.6 74.8 80.7 

 29 EL03 19.0 20.8 22.8 37.4 40.6 

 29 EL04 17.6 19.3 21.2 35.3 38.4 

 29 T01 42.2 45.5 49.6 84.5 ** ** 

 29 T02 41.1 44.0 47.3 70.6 77.3 

 

 29 SW2 30.7 32.4 34.3 48.4 51.7 

 30 OPEN 46.7 50.7 55.6 93.4   

 30 SW1 22.0 23.7 25.4 37.5 40.1 

 30 L-SR 36.3 38.8 41.5 60.0 64.6 

 30 CR01 59.3 65.0 71.9 ** **   

 

 30 EL-S 27.4 29.5 31.7 47.2 50.6 

 30 EL01 22.1 24.0 26.1 41.2 44.5 

 30 EL02 46.8 50.0 53.4 76.0 82.0 

 30 EL03 19.5 21.2 23.2 37.9 41.1 

 30 EL04 17.9 19.7 21.6 35.8 38.8 
130 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 30 T01 42.8 46.2 50.3 85.3 ** ** 

 30 T02 41.5 44.4 47.7 70.8 77.4 

 30 SW2 31.2 33.0 34.9 49.1 52.3 

 31 OPEN 47.4 51.3 56.3 94.0   

 31 SW1 22.6 24.2 25.9 38.1 40.7 

 

 31 L-SR 36.6 39.1 41.8 60.2 64.8 

 31 CR01 60.0 65.7 72.7 ** **   

 31 EL-S 27.8 29.9 32.2 47.6 51.1 

 31 EL01 22.5 24.4 26.5 41.6 45.0 

 31 EL02 47.5 50.7 54.2 77.1 83.2 

 

 31 EL03 19.8 21.7 23.6 38.4 41.6 

 31 EL04 18.3 20.0 21.9 36.2 39.2 

 31 T01 43.4 46.8 50.9 86.1 ** ** 

 31 T02 41.9 44.8 48.0 71.0 77.6 

 31 SW2 31.8 33.6 35.5 49.7 53.0 

 

 32 OPEN 48.0 52.0 57.0 94.5   

 32 SW1 23.1 24.7 26.4 38.7 41.3 

 32 L-SR 36.9 39.4 42.1 60.5 65.0 

 32 CR01 60.8 66.4 73.4 ** **   

 32 EL-S 28.3 30.4 32.6 48.1 51.6 

 

 32 EL01 22.9 24.8 26.9 42.1 45.4 

 32 EL02 48.1 51.3 54.9 78.1 84.4 

 32 EL03 20.2 22.0 24.0 38.8 42.1 

 32 EL04 18.7 20.4 22.3 36.6 39.6 

 32 T01 44.1 47.5 51.7 87.0 ** ** 

 

 32 T02 42.3 45.2 48.5 71.3 77.8 

 32 SW2 32.4 34.1 36.0 50.3 53.7 

 33 OPEN 48.6 52.6 57.6 94.9   

 33 SW1 23.6 25.2 26.9 39.2 41.9 

 33 L-SR 37.3 39.8 42.4 60.7 65.3 

 

 33 CR01 61.4 67.1 74.1 ** **   

 33 EL-S 28.8 30.8 33.1 48.6 52.1 

 33 EL01 23.2 25.2 27.3 42.5 45.9 

 33 EL02 48.7 51.9 55.6 79.1 85.4 

 33 EL03 20.6 22.4 24.4 39.3 42.5 

 

 33 EL04 19.0 20.8 22.7 37.0 40.1 

 33 T01 48.7 52.9 58.4 ** **   

 33 T02 42.8 45.7 48.9 71.7 78.1 

 33 SW2 32.9 34.7 36.7 51.0 54.4 

 34 OPEN 49.4 53.4 58.4 95.7 ** ** 
131 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 34 SW1 24.1 25.8 27.5 39.8 42.5 

 34 L-SR 37.6 40.1 42.8 61.1 65.6 

 34 CR01 62.3 67.9 74.9   ** ** 

 34 EL-S 29.2 31.3 33.6 49.1 52.6 

 34 EL01 23.6 25.5 27.6 42.9 46.3 

 

 34 EL02 49.3 52.6 56.2 80.0 86.5 

 34 EL03 20.9 22.8 24.8 39.7 43.0 

 34 EL04 19.3 21.1 23.0 37.4 40.4 

 34 T01 49.4 53.8 59.3   ** ** 

 34 T02 43.3 46.2 49.4 72.1 78.5 

 

 34 SW2 33.5 35.3 37.3 51.7 55.1 

 35 OPEN 50.3 54.4 59.4 96.9   

 35 SW1 24.7 26.3 28.0 40.4 43.1 

 35 L-SR 38.0 40.5 43.2 61.5 66.0 

 35 CR01 63.3 69.0 76.1 ** **   

 

 35 EL-S 29.7 31.8 34.0 49.6 53.1 

 35 EL01 23.9 25.9 28.0 43.3 46.7 

 35 EL02 49.8 53.2 56.8 80.8 87.4 

 35 EL03 21.3 23.1 25.2 40.2 43.4 

 35 EL04 19.7 21.4 23.4 37.8 40.8 

 

 35 T01 50.4 54.8 60.4 ** **   

 35 T02 43.8 46.7 49.9 72.6 78.9 

 35 SW2 34.0 35.9 37.9 52.4 55.7 

 36 OPEN 49.2 53.1 57.8 92.4 ** ** 

 36 SW1 25.2 26.8 28.6 41.1 43.7 

 

 36 L-SR 38.5 41.0 43.7 62.0 66.5 

 36 CR01 61.7 67.1 73.6   ** ** 

 36 EL-S 30.1 32.3 34.5 50.2 53.6 

 36 EL01 24.2 26.2 28.3 43.6 47.0 

 36 EL02 50.3 53.7 57.4 81.6 88.3 

 

 36 EL03 21.7 23.5 25.6 40.6 43.9 

 36 EL04 19.9 21.8 23.7 38.1 41.2 

 36 T01 51.4 55.8 61.5   ** ** 

 36 T02 44.5 47.4 50.6 73.2 79.6 

 36 SW2 34.7 36.5 38.5 53.1 56.4 

 

 37 OPEN 47.5 51.1 55.4 87.1 98.5 

 37 SW1 25.8 27.4 29.1 41.7 44.3 

 37 L-SR 38.9 41.4 44.0 62.4 66.8 

 37 CR01 59.5 64.4 70.3   ** ** 

 37 EL-S 30.6 32.8 35.0 50.7 54.2 
132 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 37 EL01 24.6 26.5 28.6 44.0 47.4 

 37 EL02 50.6 54.0 57.8 82.3 89.1 

 37 EL03 22.0 23.9 25.9 41.0 44.3 

 37 EL04 20.3 22.1 24.0 38.5 41.6 

 37 T01 51.6 56.0 61.5   ** ** 

 

 37 T02 44.9 47.8 51.0 73.6 79.9 

 37 SW2 35.2 37.1 39.1 53.7 57.2 

 38 OPEN 46.2 49.7 53.7 83.2 93.4 

 38 SW1 26.3 28.0 29.7 42.3 45.0 

 38 L-SR 39.2 41.7 44.4 62.6 67.1 

 

 38 CR01 57.8 62.4 67.9   ** ** 

 38 EL-S 31.1 33.3 35.5 51.2 54.7 

 38 EL01 24.9 26.8 28.9 44.3 47.7 

 38 EL02 50.8 54.3 58.1 82.8 89.7 

 38 EL03 22.3 24.2 26.3 41.4 44.7 

 

 38 EL04 20.6 22.4 24.4 38.9 42.0 

 38 T01 51.4 55.5 60.6 98.3   

 38 T02 45.1 48.0 51.2 73.6 79.9 

 38 SW2 35.8 37.7 39.7 54.4 57.9 

 39 OPEN 44.9 48.2 52.0 79.5 88.6 

 

 39 SW1 26.9 28.6 30.3 43.0 45.6 

 39 L-SR 39.5 41.9 44.6 62.7 67.1 

 39 CR01 56.3 60.6 65.6 99.5 ** ** 

 39 EL-S 31.6 33.8 36.0 51.8 55.3 

 39 EL01 25.2 27.2 29.3 44.7 48.1 

 

 39 EL02 50.9 54.4 58.3 83.2 90.2 

 39 EL03 22.7 24.6 26.7 41.8 45.1 

 39 EL04 20.9 22.7 24.7 39.2 42.3 

 39 T01 50.5 54.4 59.0 94.0   

 39 T02 45.0 47.9 51.1 73.2 79.3 

 

 39 SW2 36.4 38.3 40.4 55.2 58.6 

 40 MECH 44.3 47.5 51.0 77.3 85.8 

 40 SW1 27.5 29.1 30.9 43.6 46.3 

 40 L-SR 39.7 42.2 44.8 62.8 67.2 

 40 CR01 55.5 59.6 64.4 96.9 ** ** 

 

 40 EL-S 32.1 34.3 36.6 52.3 55.9 

 40 EL01 25.6 27.5 29.7 45.0 48.5 

 40 EL02 51.1 54.6 58.5 83.6 90.6 

 40 EL03 23.0 24.9 27.0 42.2 45.5 

 40 EL04 21.2 23.0 25.0 39.6 42.7 
133 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 40 T01 50.1 53.8 58.1 91.2   

 40 T02 45.1 47.9 51.0 72.9 78.9 

 40 SW2 37.0 38.9 41.0 55.9 59.3 

 41 OPEN 44.4 47.6 51.1 77.1 85.4 

 41 SW1 28.0 29.8 31.5 44.3 47.0 

 

 41 L-SR 40.1 42.6 45.2 63.2 67.6 

 41 CR01 55.6 59.7 64.5 96.6 ** ** 

 41 EL-S 32.7 34.8 37.1 52.9 56.4 

 41 EL01 25.9 27.9 30.0 45.4 48.9 

 41 EL02 51.4 54.9 58.8 84.0 91.1 

 

 41 EL03 23.3 25.2 27.4 42.5 46.0 

 41 EL04 21.5 23.3 25.3 39.9 43.1 

 41 T01 50.5 54.1 58.4 91.0   

 41 T02 45.5 48.4 51.5 73.3 79.2 

 41 SW2 37.6 39.6 41.6 56.6 60.1 

 

 42 OPEN 44.7 47.9 51.4 77.3 85.4 

 42 SW1 28.7 30.4 32.1 45.0 47.7 

 42 L-SR 40.6 43.1 45.7 63.7 68.1 

 42 CR01 55.9 60.0 64.8 96.7 ** ** 

 42 EL-S 33.2 35.4 37.7 53.5 57.1 

 

 42 EL01 26.3 28.2 30.4 45.8 49.3 

 42 EL02 51.9 55.4 59.3 84.5 91.6 

 42 EL03 23.6 25.6 27.7 42.9 46.3 

 42 EL04 21.8 23.6 25.6 40.2 43.4 

 42 T01 51.0 54.7 59.0 91.3   

 

 42 T02 46.0 48.9 52.0 73.7 79.6 

 42 SW2 38.2 40.2 42.3 57.3 60.8 

 43 OPEN 42.9 45.9 49.2 72.8 79.8 

 43 SW1 29.3 31.0 32.8 45.7 48.4 

 43 L-SR 40.2 42.7 45.3 62.9 67.0 

 

 43 EL-S 33.8 35.9 38.2 54.1 57.7 

 43 EL01 26.7 28.6 30.8 46.2 49.7 

 43 EL02 52.4 55.9 59.8 85.0 92.1 

 43 EL03 24.0 26.0 28.1 43.5 46.9 

 43 EL04 22.1 24.0 26.0 40.7 43.9 

 

 43 T01 49.3 52.6 56.4 85.6 95.6 

 43 T02 45.1 47.9 50.8 71.7 77.2 

 43 SW2 38.9 40.8 42.9 58.1 61.6 

 44 OPEN 49.5 52.6 56.2 83.6 92.6 

 44 SW1 29.9 31.7 33.5 46.4 49.2 
134 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 44 L-SR 40.2 42.6 45.1 62.5 66.6 

 44 EL-S 34.4 36.5 38.8 54.7 58.3 

 44 EL03 24.4 26.3 28.5 43.9 47.3 

 44 EL04 22.5 24.3 26.4 41.1 44.3 

 44 T01 49.5 52.7 56.5 86.1 97.0 

 

 44 T02 44.8 47.5 50.4 70.7 76.0 

 44 SW2 39.5 41.5 43.7 58.9 62.4 

 45 OPEN 50.2 53.3 56.9 84.2 93.1 

 45 SW1 30.7 32.4 34.2 47.2 50.0 

 45 L-SR 40.7 43.1 45.7 63.0 67.1 

 

 45 EL-S 34.9 37.1 39.5 55.4 59.0 

 45 EL03 24.7 26.6 28.8 44.2 47.7 

 45 EL04 22.7 24.6 26.7 41.4 44.6 

 45 T01 50.2 53.4 57.1 86.6 97.5 

 45 T02 45.4 48.0 50.9 71.2 76.4 

 

 45 SW2 40.2 42.2 44.4 59.7 63.3 

 46 OPEN 51.0 54.1 57.8 85.0 93.9 

 46 SW1 31.4 33.1 34.9 48.1 50.9 

 46 L-SR 41.3 43.7 46.3 63.7 67.8 

 46 EL-S 35.6 37.8 40.1 56.1 59.7 

 

 46 EL03 24.9 26.9 29.1 44.6 48.1 

 46 EL04 22.9 24.8 26.9 41.7 44.9 

 46 T01 51.0 54.2 58.0 87.5 98.3 

 46 T02 46.1 48.8 51.7 71.9 77.2 

 46 SW2 40.9 42.9 45.1 60.5 64.1 

 

 47 OPEN 51.9 55.0 58.7 86.0 94.9 

 47 SW1 32.2 33.9 35.8 49.0 51.8 

 47 L-SR 42.0 44.4 47.0 64.4 68.5 

 47 EL-S 36.3 38.5 40.8 56.8 60.4 

 47 EL03 25.2 27.2 29.4 44.9 48.4 

 

 47 EL04 23.2 25.1 27.2 42.0 45.2 

 47 T01 51.9 55.2 58.9 88.5 99.4 

 47 T02 46.8 49.5 52.4 72.7 78.0 

 47 SW2 41.7 43.7 45.9 61.5 65.1 

 48 OPEN 52.8 56.0 59.7 87.0 95.9 

 

 48 SW1 33.0 34.8 36.7 50.0 52.8 

 48 L-SR 42.7 45.1 47.7 65.2 69.3 

 48 EL-S 37.0 39.2 41.6 57.6 61.3 

 48 EL03 25.5 27.5 29.7 45.2 48.7 

 48 EL04 23.5 25.4 27.4 42.2 45.5 
135 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 48 T01 52.9 56.2 60.0 89.7 ** ** 

 48 T02 47.6 50.3 53.2 73.5 78.8 

 48 SW2 42.5 44.6 46.8 62.4 66.1 

 49 OPEN 52.0 55.4 59.3 86.7 95.6 

 49 SW1 34.0 35.8 37.6 51.0 53.9 

 

 49 L-SR 43.5 45.9 48.5 66.1 70.2 

 49 EL-S 37.7 39.9 42.3 58.5 62.1 

 49 EL03 25.7 27.7 29.9 45.5 49.0 

 49 EL04 23.7 25.6 27.7 42.5 45.7 

 49 T01 46.6 50.0 53.9 81.8 91.0 

 

 49 T02 48.5 51.2 54.1 74.5 79.8 

 49 SW2 43.3 45.5 47.7 63.5 67.1 

 50 OPEN 50.5 54.1 58.2 85.9 94.6 

 50 SW1 35.0 36.8 38.7 52.2 55.2 

 50 L-SR 44.3 46.8 49.4 67.0 71.1 

 

 50 EL-S 38.6 40.8 43.1 59.4 63.0 

 50 EL03 26.0 28.0 30.2 45.8 49.3 

 50 EL04 23.9 25.8 27.9 42.7 46.0 

 50 T01 43.0 46.2 49.8 75.6 83.6 

 50 T02 49.4 52.1 55.0 75.5 80.8 

 

 50 SW2 44.2 46.4 48.7 64.6 68.3 

 51 OPEN 49.8 53.6 57.7 85.7 94.4 

 51 SW1 36.1 37.9 39.9 53.5 56.5 

 51 L-SR 45.2 47.7 50.3 68.0 72.1 

 51 EL-S 39.4 41.7 44.0 60.3 64.0 

 

 51 EL03 26.2 28.3 30.5 46.1 49.6 

 51 EL04 24.1 26.0 28.1 43.0 46.3 

 51 T01 41.8 44.9 48.4 73.2 80.8 

 51 T02 50.4 53.1 56.1 76.6 81.9 

 51 SW2 45.2 47.4 49.7 65.8 69.5 

 

 52 OPEN 49.6 53.4 57.7 86.0 94.8 

 52 SW1 37.4 39.2 41.2 55.0 58.0 

 52 L-SR 46.1 48.6 51.3 69.0 73.2 

 52 EL-S 40.4 42.6 45.0 61.4 65.1 

 52 EL03 26.5 28.5 30.7 46.3 49.9 

 

 52 EL04 24.4 26.3 28.4 43.2 46.5 

 52 T01 41.4 44.4 47.8 72.1 79.5 

 52 T02 51.4 54.2 57.2 77.7 83.1 

 52 SW2 46.3 48.5 50.8 67.1 70.8 

 53 OPEN 49.6 53.5 57.9 86.8 95.6 
136 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 53 SW1 38.8 40.7 42.7 56.7 59.8 

 53 L-SR 47.2 49.7 52.4 70.2 74.4 

 53 EL-S 41.4 43.7 46.1 62.5 66.3 

 53 EL03 26.7 28.7 30.9 46.6 50.1 

 53 EL04 24.6 26.5 28.6 43.5 46.8 

 

 53 T01 41.3 44.3 47.6 71.8 79.1 

 53 T02 52.6 55.4 58.4 79.1 84.4 

 53 SW2 47.4 49.7 52.0 68.5 72.3 

 54 OPEN 49.2 53.1 57.5 86.7 95.6 

 54 SW1 40.5 42.4 44.4 58.6 61.8 

 

 54 L-SR 48.4 50.9 53.6 71.5 75.7 

 54 EL-S 42.5 44.8 47.3 63.8 67.6 

 54 EL03 26.9 29.0 31.2 46.8 50.4 

 54 EL04 24.8 26.8 28.8 43.8 47.0 

 54 T01 41.4 44.4 47.7 71.9 79.2 

 

 54 T02 53.9 56.7 59.8 80.5 85.9 

 54 SW2 48.7 51.0 53.4 70.0 73.9 

 55 OPEN 48.7 52.5 56.9 86.5 95.5 

 55 SW1 42.5 44.4 46.5 61.0 64.2 

 55 L-SR 49.7 52.2 54.9 73.0 77.2 

 

 55 EL-S 43.8 46.1 48.6 65.2 69.0 

 55 EL03 27.2 29.2 31.4 47.1 50.6 

 55 EL04 25.0 27.0 29.1 44.0 47.3 

 55 T01 41.3 44.3 47.6 71.6 78.9 

 55 T02 55.4 58.2 61.3 82.2 87.6 

 

 55 SW2 50.1 52.5 54.9 71.8 75.7 

 56 OPEN 48.3 52.0 56.4 86.4 95.5 

 56 SW1 44.9 46.9 49.0 64.0 67.3 

 56 L-SR 51.1 53.7 56.4 74.6 78.9 

 56 EL-S 45.2 47.6 50.0 66.8 70.7 

 

 56 EL03 27.4 29.5 31.7 47.3 50.9 

 56 EL04 25.3 27.2 29.3 44.3 47.5 

 56 T01 41.3 44.2 47.5 71.3 78.4 

 56 T02 57.0 59.9 63.0 84.0 89.5 

 56 SW2 51.7 54.1 56.6 73.7 77.7 

 

 57 OPEN 48.2 51.9 56.2 86.5 96.1 

 57 SW1 48.0 50.1 52.4 68.0 71.6 

 57 L-SR 52.7 55.3 58.1 76.5 80.8 

 57 EL-S 46.8 49.2 51.7 68.7 72.6 

 57 EL03 27.7 29.7 31.9 47.6 51.2 
137 

Table 26. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 57 EL04 25.5 27.5 29.6 44.5 47.8 

 57 T01 41.3 44.2 47.5 71.1 78.2 

 57 T02 58.8 61.8 64.9 86.2 91.7 

 57 SW2 53.6 56.0 58.6 76.0 80.1 

 58 OPEN 48.5 52.3 56.6 87.8 98.0 

 

 58 SW1 52.9 55.2 57.6 74.5 78.4 

 58 L-SR 54.7 57.3 60.1 78.7 83.1 

 58 EL-S 48.7 51.1 53.7 70.9 74.8 

 58 EL03 27.9 29.9 32.1 47.9 51.4 

 58 EL04 25.8 27.7 29.8 44.8 48.1 

 

 58 T01 41.6 44.6 47.8 71.5 78.7 

 58 T02 61.0 64.0 67.2 88.8 94.4 

 58 SW2 55.7 58.2 60.9 78.7 83.0 

 59 MECH 68.9 72.4 76.3   ** ** 

 59 ELME 71.7 75.5 79.7   ** ** 

 

 59 EL-S 50.9 53.4 56.0 73.5 77.5 

 59 EL03 27.9 29.9 32.2 47.9 51.4 

 59 EL04 25.8 27.7 29.8 44.8 48.1 

 59 SW2 58.4 61.0 63.8 82.1 86.5 

 R SW2 62.7 65.4 68.3 87.5 92.1 

 
138 

Table 27. Results of Tenability Analysis for Scenario 27. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 B MECH 41.5 46.3 52.0 88.8   

 B L-SR 61.6 68.8 77.4 ** **   

 B L-MR 44.1 52.0 61.7 ** **   

 B L-HR 37.1 43.4 51.5 97.9 ** ** 

 B EL-S 20.7 23.1 25.7 43.5 47.8 

 

 B EL01 55.8 62.4 70.1   ** ** 

 B EL02 61.3 69.2 78.6   ** ** 

 B EL03 51.8 58.8 67.1   ** ** 

 B EL04 50.6 56.6 63.6   ** ** 

 B SW2 9.6 11.2 13.0 26.6 29.4 

 

 G OPEN 7.1 9.0 11.2 26.9 30.6 

 G SW1 46.9 52.1 58.2 95.9   

 G L-SR 16.8 19.4 22.2 42.8 48.9 

 G EL-S 11.6 13.5 15.5 30.2 33.3 

 G EL01 9.7 11.7 13.9 30.1 34.1 

 

 G EL02 9.6 11.6 13.9 30.1 34.0 

 G EL03 8.5 10.5 12.7 28.6 32.4 

 G EL04 8.6 10.5 12.8 28.7 32.6 

 G T01 14.8 17.2 19.8 38.2 43.2 

 G T02 17.2 19.7 22.4 41.6 46.9 

 

 G SW2 3.7 4.5 5.6 16.2 18.4 

 2 OPEN 1.0 1.0 1.0 4.8 6.1 

 2 SW1 1.0 1.5 1.9 9.7 11.7 

 2 L-SR 1.0 1.5 1.9 9.4 11.3 

 2 CR01 1.5 1.9 2.6 11.1 13.1 

 

 2 CR02 1.0 1.5 1.9 9.4 11.3 

 2 EL-S 3.3 4.0 5.0 15.6 17.9 

 2 EL01 1.4 1.9 2.5 11.9 14.2 

 2 EL02 2.0 2.8 3.6 14.7 17.2 

 2 EL03 2.0 2.9 3.8 15.5 18.2 

 

 2 EL04 2.0 2.8 3.8 15.3 17.9 

 2 T01 1.7 2.1 2.9 11.9 14.0 

 2 T02 2.0 2.8 3.6 13.6 15.8 

 2 SW2 1.0 1.4 1.9 9.0 10.9 

 3 SW1 2.1 2.8 3.6 12.8 15.0 

 

 3 L-SR 18.4 21.0 23.8 46.5 54.8 

 3 CR02 13.6 15.9 18.5 36.5 41.4 

 3 EL-S 5.5 6.6 7.9 19.6 22.1 

 3 EL01 2.1 2.8 3.6 13.8 16.1 

 3 EL02 3.2 4.0 5.1 16.9 19.5 
139 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 3 EL03 2.8 3.6 4.6 16.5 19.2 

 3 EL04 2.7 3.5 4.6 16.3 18.9 

 3 SW2 4.5 5.5 6.8 18.4 20.9 

 4 SW1 3.6 4.4 5.3 15.5 17.7 

 4 L-SR 21.3 23.9 26.7 51.1 60.5 

 

 4 EL-S 7.6 8.9 10.4 22.9 25.5 

 4 EL01 3.0 3.8 4.8 15.4 17.9 

 4 EL02 4.5 5.5 6.8 19.0 21.7 

 4 EL03 3.3 4.2 5.3 17.4 20.1 

 4 EL04 3.3 4.1 5.3 17.2 19.9 

 

 4 SW2 8.1 9.6 11.3 24.0 26.5 

 5 SW1 4.9 5.9 7.0 17.9 20.1 

 5 L-SR 23.7 26.3 29.2 55.3 65.7 

 5 EL-S 9.6 11.0 12.7 25.7 28.4 

 5 EL01 3.9 4.8 5.9 17.0 19.5 

 

 5 EL02 5.8 7.0 8.4 21.1 23.8 

 5 EL03 3.9 4.9 6.0 18.3 21.1 

 5 EL04 3.8 4.8 5.9 18.1 20.8 

 5 SW2 11.4 13.0 14.9 28.0 30.5 

 6 SW1 6.4 7.5 8.7 19.9 22.2 

 

 6 L-SR 25.7 28.4 31.4 59.0 70.6 

 6 EL-S 11.3 12.9 14.7 28.1 30.8 

 6 EL01 4.8 5.8 6.9 18.4 21.0 

 6 EL02 7.3 8.6 10.0 23.1 26.0 

 6 EL03 4.5 5.5 6.8 19.2 21.9 

 

 6 EL04 4.4 5.5 6.7 19.0 21.7 

 6 SW2 14.2 15.9 17.9 31.0 33.8 

 7 SW1 7.7 8.9 10.3 21.7 23.9 

 7 L-SR 27.6 30.3 33.4 62.6 75.4 

 7 EL-S 12.9 14.6 16.4 30.1 33.0 

 

 7 EL01 5.7 6.8 7.9 19.8 22.4 

 7 EL02 8.7 10.1 11.8 25.2 28.0 

 7 EL03 5.0 6.1 7.4 20.1 22.8 

 7 EL04 4.9 6.0 7.3 19.8 22.5 

 7 SW2 16.6 18.4 20.4 33.6 36.5 

 

 8 SW1 9.0 10.3 11.7 23.2 25.5 

 8 L-SR 29.2 31.9 35.2 65.9 80.3 

 8 EL-S 14.4 16.1 18.0 32.0 35.0 

 8 EL01 6.6 7.7 8.9 21.1 23.7 

 8 EL02 10.2 11.7 13.4 27.1 30.1 
140 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 8 EL03 5.6 6.8 8.0 20.8 23.6 

 8 EL04 5.6 6.7 7.9 20.6 23.3 

 8 SW2 18.6 20.5 22.4 35.9 38.9 

 9 SW1 10.2 11.6 13.0 24.7 26.9 

 9 L-SR 30.7 33.5 36.9 69.1 85.6 

 

 9 EL-S 15.7 17.5 19.5 33.7 36.7 

 9 EL01 7.4 8.6 9.9 22.2 24.9 

 9 EL02 11.7 13.3 15.1 29.1 32.1 

 9 EL03 6.1 7.3 8.7 21.6 24.4 

 9 EL04 6.0 7.2 8.6 21.3 24.1 

 

 9 SW2 20.4 22.2 24.1 37.8 41.0 

 10 SW1 11.4 12.8 14.3 26.0 28.2 

 10 L-SR 32.0 35.0 38.6 72.3 91.3 

 10 EL-S 17.0 18.8 20.8 35.3 38.3 

 10 EL01 8.2 9.4 10.8 23.3 26.1 

 

 10 EL02 13.2 14.9 16.8 31.0 34.1 

 10 EL03 6.7 7.9 9.4 22.3 25.1 

 10 EL04 6.6 7.8 9.2 22.1 24.8 

 10 SW2 21.9 23.7 25.7 39.6 42.8 

 11 SW1 12.5 13.9 15.5 27.1 29.3 

 

 11 L-SR 33.3 36.4 40.1 75.6 97.7 

 11 EL-S 18.1 20.0 22.1 36.7 39.8 

 11 EL01 8.9 10.2 11.7 24.4 27.1 

 11 EL02 14.7 16.5 18.4 32.9 36.1 

 11 EL03 7.2 8.5 9.9 23.1 25.9 

 

 11 EL04 7.0 8.3 9.8 22.7 25.5 

 11 SW2 23.3 25.1 27.0 41.2 44.5 

 12 SW1 13.5 14.9 16.6 28.2 30.4 

 12 L-SR 34.6 37.7 41.6 79.0 ** ** 

 12 EL-S 19.2 21.1 23.2 38.0 41.2 

 

 12 EL01 9.7 11.0 12.5 25.4 28.2 

 12 EL02 16.2 18.0 20.0 34.8 38.0 

 12 EL03 7.7 9.0 10.5 23.7 26.6 

 12 EL04 7.6 8.8 10.3 23.4 26.2 

 12 SW2 24.5 26.3 28.2 42.6 46.1 

 

 13 SW1 14.5 15.9 17.6 29.2 31.4 

 13 L-SR 35.8 39.0 43.0 82.6   

 13 EL-S 20.2 22.2 24.3 39.3 42.5 

 13 EL01 10.4 11.8 13.3 26.4 29.2 

 13 EL02 17.7 19.5 21.6 36.6 39.9 
141 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 13 EL03 8.2 9.6 11.1 24.4 27.3 

 13 EL04 8.0 9.3 10.8 24.1 26.9 

 13 SW2 25.6 27.4 29.3 44.0 47.5 

 14 SW1 15.4 16.8 18.5 30.1 32.4 

 14 L-SR 36.9 40.3 44.5 86.5 ** ** 

 

 14 EL-S 21.2 23.2 25.3 40.4 43.7 

 14 EL01 11.1 12.5 14.1 27.3 30.1 

 14 EL02 19.1 21.0 23.2 38.4 41.8 

 14 EL03 8.7 10.0 11.6 25.1 27.9 

 14 EL04 8.5 9.8 11.4 24.7 27.5 

 

 14 SW2 26.6 28.4 30.4 45.3 48.9 

 15 SW1 16.2 17.7 19.4 31.0 33.3 

 15 L-SR 38.0 41.5 45.9 91.0   

 15 EL-S 22.1 24.1 26.3 41.5 44.9 

 15 EL01 11.8 13.2 14.8 28.1 31.0 

 

 15 EL02 20.6 22.6 24.7 40.2 43.7 

 15 EL03 9.2 10.6 12.1 25.7 28.6 

 15 EL04 8.9 10.3 11.9 25.2 28.1 

 15 SW2 27.5 29.4 31.3 46.4 50.1 

 16 SW1 17.0 18.6 20.2 31.8 34.1 

 

 16 L-SR 39.2 42.8 47.4 96.2 ** ** 

 16 EL-S 22.9 25.0 27.2 42.6 46.0 

 16 EL01 12.4 13.9 15.6 29.0 31.9 

 16 EL02 22.0 24.0 26.3 42.0 45.5 

 16 EL03 9.7 11.0 12.7 26.3 29.2 

 

 16 EL04 9.4 10.8 12.4 25.8 28.7 

 16 SW2 28.4 30.2 32.2 47.5 51.3 

 17 SW1 17.8 19.3 20.9 32.5 34.9 

 17 L-SR 40.3 44.1 48.9   ** ** 

 17 EL-S 23.8 25.8 28.0 43.5 47.0 

 

 17 EL01 13.0 14.5 16.2 29.8 32.7 

 17 EL02 23.4 25.5 27.8 43.7 47.3 

 17 EL03 10.1 11.5 13.2 26.8 29.8 

 17 EL04 9.8 11.2 12.8 26.4 29.3 

 17 SW2 29.2 31.0 33.1 48.6 52.4 

 

 18 SW1 18.5 20.0 21.7 33.3 35.7 

 18 L-SR 41.5 45.4 50.6   ** ** 

 18 EL-S 24.5 26.6 28.9 44.5 48.0 

 18 EL01 13.6 15.1 16.9 30.5 33.5 

 18 EL02 24.8 26.9 29.3 45.4 49.1 
142 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 18 EL03 10.6 12.0 13.7 27.4 30.4 

 18 EL04 10.2 11.7 13.3 26.9 29.8 

 18 SW2 29.9 31.8 33.9 49.5 53.5 

 19 SW1 19.2 20.7 22.3 34.0 36.4 

 19 L-SR 42.8 46.9 52.5   ** ** 

 

 19 EL-S 25.3 27.4 29.7 45.4 48.9 

 19 EL01 14.2 15.8 17.5 31.3 34.2 

 19 EL02 26.2 28.4 30.7 47.1 50.9 

 19 EL03 10.9 12.5 14.1 28.0 30.9 

 19 EL04 10.7 12.1 13.8 27.4 30.4 

 

 19 SW2 30.7 32.6 34.7 50.5 54.5 

 20 SW1 19.8 21.4 22.9 34.6 37.1 

 20 L-SR 44.3 48.7 54.8   ** ** 

 20 EL-S 25.9 28.1 30.4 46.2 49.8 

 20 EL01 14.8 16.4 18.1 32.0 35.0 

 

 20 EL02 27.6 29.8 32.2 48.8 52.6 

 20 EL03 11.4 12.9 14.6 28.5 31.5 

 20 EL04 11.0 12.5 14.2 28.0 30.9 

 20 SW2 31.4 33.3 35.4 51.3 55.4 

 21 SW1 20.5 22.0 23.7 35.5 38.0 

 

 21 L-SR 46.4 51.2 58.2   ** ** 

 21 EL-S 26.7 28.8 31.1 47.0 50.6 

 21 EL01 15.3 16.9 18.7 32.7 35.7 

 21 EL02 28.9 31.2 33.6 50.4 54.4 

 21 EL03 11.8 13.3 15.0 29.0 32.0 

 

 21 EL04 11.4 12.9 14.6 28.4 31.4 

 21 SW2 32.2 34.1 36.2 52.4 56.6 

 22 SW1 21.1 22.7 24.3 36.3 38.8 

 22 L-SR 49.5 55.4 64.4   ** ** 

 22 EL-S 27.3 29.5 31.8 47.8 51.4 

 

 22 EL01 15.8 17.5 19.3 33.3 36.4 

 22 EL02 30.3 32.6 35.0 52.1 56.1 

 22 EL03 12.2 13.7 15.5 29.5 32.5 

 22 EL04 11.8 13.3 15.0 28.9 31.9 

 22 SW2 32.9 34.9 37.1 53.5 57.7 

 

 23 SW1 21.8 23.4 25.0 37.0 39.6 

 23 EL-S 27.9 30.1 32.4 48.5 52.2 

 23 EL01 16.4 18.0 19.9 34.0 37.0 

 23 EL02 31.6 33.9 36.5 53.7 57.8 

 23 EL03 12.6 14.1 15.9 30.0 33.1 
143 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 23 EL04 12.1 13.7 15.5 29.4 32.4 

 23 SW2 33.7 35.7 37.9 54.5 58.8 

 24 SW1 22.4 23.9 25.6 37.7 40.3 

 24 L-SR 54.2 61.3 74.2   ** ** 

 24 EL-S 28.5 30.7 33.0 49.2 52.9 

 

 24 EL01 17.5 19.2 21.1 35.7 39.0 

 24 EL02 34.7 37.3 40.0 58.7 63.5 

 24 EL03 12.9 14.6 16.3 30.5 33.5 

 24 EL04 12.5 14.0 15.8 29.8 32.8 

 24 SW2 34.4 36.4 38.6 55.4 59.7 

 

 25 OPEN 45.6 49.4 54.0 91.8   

 25 SW1 22.9 24.5 26.1 38.3 40.9 

 25 L-SR 38.1 40.8 43.6 63.2 68.1 

 25 CR01 58.9 64.6 71.7 ** **   

 25 EL-S 28.9 31.2 33.5 49.7 53.4 

 

 25 EL01 17.9 19.7 21.6 36.3 39.5 

 25 EL02 35.7 38.2 41.0 60.1 64.9 

 25 EL03 13.3 14.9 16.7 30.9 34.0 

 25 EL04 12.8 14.4 16.2 30.2 33.2 

 25 T01 43.5 46.9 51.1 85.8 ** ** 

 

 25 T02 42.4 45.5 49.0 73.6 80.8 

 25 SW2 35.0 37.0 39.2 56.1 60.4 

 26 OPEN 46.3 50.1 54.8 92.8   

 26 SW1 23.4 24.9 26.7 38.9 41.5 

 26 L-SR 38.7 41.4 44.2 63.7 68.6 

 

 26 CR01 59.7 65.4 72.6 ** **   

 26 EL-S 29.5 31.7 34.0 50.3 54.0 

 26 EL01 18.3 20.0 22.0 36.8 40.1 

 26 EL02 36.6 39.1 41.9 61.2 66.2 

 26 EL03 13.7 15.3 17.1 31.3 34.4 

 

 26 EL04 13.2 14.8 16.6 30.6 33.6 

 26 T01 44.2 47.6 51.8 86.6 ** ** 

 26 T02 42.9 46.0 49.5 74.0 81.1 

 26 SW2 35.6 37.7 39.9 56.8 61.2 

 27 OPEN 47.2 51.1 55.8 94.2   

 

 27 SW1 23.9 25.5 27.2 39.5 42.1 

 27 L-SR 39.2 41.9 44.7 64.2 69.1 

 27 CR01 60.7 66.5 73.8 ** **   

 27 EL-S 29.9 32.1 34.5 50.8 54.5 

 27 EL01 18.7 20.5 22.4 37.2 40.5 
144 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 27 EL02 37.3 39.9 42.8 62.3 67.4 

 27 EL03 14.0 15.7 17.5 31.8 34.9 

 27 EL04 13.5 15.1 16.9 31.0 34.1 

 27 T01 44.9 48.4 52.6 87.7 ** ** 

 27 T02 43.6 46.7 50.2 74.7 81.8 

 

 27 SW2 36.2 38.3 40.5 57.5 61.9 

 28 OPEN 48.1 52.0 56.9 95.8   

 28 SW1 24.5 26.0 27.8 40.1 42.8 

 28 L-SR 39.7 42.4 45.2 64.7 69.6 

 28 CR01 61.8 67.7 75.1 ** **   

 

 28 EL-S 30.5 32.7 35.0 51.4 55.1 

 28 EL01 19.0 20.8 22.8 37.7 41.0 

 28 EL02 38.0 40.7 43.5 63.3 68.5 

 28 EL03 14.4 16.0 17.9 32.2 35.3 

 28 EL04 13.8 15.5 17.3 31.4 34.5 

 

 28 T01 45.6 49.1 53.4 88.8 ** ** 

 28 T02 44.3 47.4 50.9 75.4 82.4 

 28 SW2 36.9 38.9 41.2 58.2 62.6 

 29 OPEN 49.0 53.0 58.0 97.4   

 29 SW1 25.0 26.6 28.3 40.7 43.4 

 

 29 L-SR 40.2 42.8 45.7 65.3 70.2 

 29 CR01 62.9 68.8 76.4 ** **   

 29 EL-S 30.9 33.2 35.6 51.9 55.6 

 29 EL01 19.3 21.1 23.2 38.1 41.4 

 29 EL02 38.7 41.4 44.3 64.2 69.5 

 

 29 EL03 14.7 16.4 18.2 32.6 35.7 

 29 EL04 14.1 15.8 17.6 31.8 34.9 

 29 T01 46.4 49.9 54.2 89.9 ** ** 

 29 T02 44.9 48.0 51.6 76.1 83.1 

 29 SW2 37.5 39.6 41.9 59.0 63.4 

 

 30 OPEN 50.0 54.1 59.2 99.0   

 30 SW1 25.6 27.2 28.9 41.4 44.1 

 30 L-SR 40.7 43.4 46.2 65.8 70.7 

 30 CR01 64.0 70.1 77.8 ** **   

 30 EL-S 31.5 33.7 36.0 52.5 56.2 

 

 30 EL01 19.7 21.5 23.5 38.5 41.8 

 30 EL02 39.4 42.1 45.0 65.1 70.5 

 30 EL03 15.0 16.7 18.6 33.0 36.2 

 30 EL04 14.5 16.1 17.9 32.2 35.2 

 30 T01 47.2 50.7 55.1 91.1 ** ** 
145 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 30 T02 45.6 48.8 52.3 76.8 83.8 

 30 SW2 38.2 40.3 42.6 59.7 64.2 

 31 OPEN 51.0 55.2 60.4   ** ** 

 31 SW1 26.2 27.8 29.5 42.0 44.7 

 31 L-SR 41.2 43.9 46.8 66.3 71.3 

 

 31 CR01 65.2 71.4 79.2   ** ** 

 31 EL-S 31.9 34.2 36.6 53.0 56.8 

 31 EL01 20.0 21.8 23.9 38.9 42.2 

 31 EL02 40.0 42.7 45.6 66.0 71.4 

 31 EL03 15.4 17.0 18.9 33.4 36.6 

 

 31 EL04 14.8 16.4 18.3 32.5 35.6 

 31 T01 47.9 51.6 56.0 92.3   

 31 T02 46.3 49.5 53.0 77.5 84.6 

 31 SW2 38.8 40.9 43.2 60.5 65.0 

 32 OPEN 52.1 56.3 61.6 ** **   

 

 32 SW1 26.8 28.4 30.1 42.7 45.4 

 32 L-SR 41.7 44.4 47.3 66.9 71.8 

 32 CR01 66.4 72.7 80.7 ** **   

 32 EL-S 32.5 34.7 37.1 53.6 57.4 

 32 EL01 20.3 22.1 24.2 39.2 42.6 

 

 32 EL02 40.6 43.3 46.3 66.8 72.3 

 32 EL03 15.7 17.4 19.3 33.8 37.0 

 32 EL04 15.0 16.7 18.6 32.9 36.0 

 32 T01 48.8 52.5 56.9 93.6 ** ** 

 32 T02 47.0 50.2 53.7 78.2 85.3 

 

 32 SW2 39.5 41.6 43.9 61.2 65.7 

 33 OPEN 53.2 57.6 63.0   ** ** 

 33 SW1 27.4 29.0 30.7 43.4 46.1 

 33 L-SR 42.2 44.9 47.8 67.4 72.4 

 33 CR01 67.7 74.1 82.3   ** ** 

 

 33 EL-S 33.0 35.3 37.7 54.2 58.0 

 33 EL01 20.6 22.4 24.5 39.6 43.0 

 33 EL02 41.1 43.9 46.9 67.5 73.2 

 33 EL03 16.0 17.7 19.7 34.2 37.4 

 33 EL04 15.4 17.0 18.9 33.3 36.4 

 

 33 T01 53.2 57.7 63.3   ** ** 

 33 T02 47.8 51.0 54.5 79.1 86.2 

 33 SW2 40.1 42.3 44.6 62.0 66.5 

 34 OPEN 54.4 58.9 64.5   ** ** 

 34 SW1 28.0 29.7 31.4 44.1 46.9 
146 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 34 L-SR 42.8 45.5 48.4 68.0 73.0 

 34 CR01 69.1 75.7 84.0   ** ** 

 34 EL-S 33.6 35.8 38.2 54.7 58.5 

 34 EL01 20.8 22.7 24.8 39.9 43.3 

 34 EL02 41.7 44.5 47.4 68.3 74.0 

 

 34 EL03 16.4 18.0 20.0 34.6 37.8 

 34 EL04 15.7 17.4 19.2 33.6 36.7 

 34 T01 54.5 59.1 64.9   ** ** 

 34 T02 48.6 51.8 55.3 79.9 87.0 

 34 SW2 40.8 42.9 45.3 62.8 67.3 

 

 35 OPEN 53.0 57.6 63.2   ** ** 

 35 SW1 28.6 30.3 32.0 44.8 47.6 

 35 L-SR 43.3 46.0 48.9 68.6 73.6 

 35 CR01 67.8 74.3 82.5   ** ** 

 35 EL-S 34.1 36.4 38.8 55.3 59.1 

 

 35 EL01 21.1 23.0 25.0 40.2 43.6 

 35 EL02 42.2 45.0 48.0 69.0 74.7 

 35 EL03 16.7 18.4 20.3 35.0 38.2 

 35 EL04 15.9 17.7 19.6 34.0 37.1 

 35 T01 55.6 60.3 66.3   ** ** 

 

 35 T02 49.3 52.6 56.1 80.7 87.8 

 35 SW2 41.4 43.6 45.9 63.5 68.0 

 36 OPEN 47.0 51.2 56.1 91.9   

 36 SW1 29.3 30.9 32.7 45.5 48.3 

 36 L-SR 43.9 46.6 49.5 69.2 74.2 

 

 36 CR01 60.9 66.6 73.7 ** **   

 36 EL-S 34.6 36.9 39.4 56.0 59.8 

 36 EL01 21.4 23.3 25.3 40.5 43.9 

 36 EL02 42.7 45.4 48.5 69.6 75.4 

 36 EL03 16.9 18.7 20.7 35.3 38.5 

 

 36 EL04 16.3 17.9 19.9 34.3 37.5 

 36 T01 55.6 60.2 66.0 ** **   

 36 T02 50.1 53.4 56.9 81.6 88.6 

 36 SW2 42.0 44.3 46.7 64.3 68.8 

 37 OPEN 44.5 48.3 52.7 85.6 97.7 

 

 37 SW1 29.9 31.6 33.4 46.3 49.1 

 37 L-SR 44.5 47.2 50.1 69.8 74.8 

 37 CR01 57.6 62.8 69.2 ** **   

 37 EL-S 35.2 37.5 39.9 56.6 60.4 

 37 EL01 21.7 23.5 25.6 40.8 44.2 
147 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 37 EL02 43.0 45.8 48.9 70.2 76.1 

 37 EL03 17.3 19.0 21.0 35.7 38.9 

 37 EL04 16.6 18.3 20.2 34.7 37.8 

 37 T01 55.4 60.0 65.6 ** **   

 37 T02 50.9 54.2 57.8 82.4 89.5 

 

 37 SW2 42.7 44.9 47.4 65.1 69.6 

 38 OPEN 42.7 46.2 50.3 80.7 91.3 

 38 SW1 30.6 32.3 34.0 47.0 49.9 

 38 L-SR 45.0 47.7 50.6 70.4 75.4 

 38 CR01 55.2 60.0 65.8 ** **   

 

 38 EL-S 35.8 38.0 40.5 57.2 61.0 

 38 EL01 21.9 23.8 25.9 41.1 44.4 

 38 EL02 43.4 46.2 49.3 70.7 76.6 

 38 EL03 17.6 19.3 21.3 36.1 39.3 

 38 EL04 16.8 18.6 20.5 35.0 38.2 

 

 38 T01 54.8 59.3 64.7 ** **   

 38 T02 51.7 55.0 58.6 83.2 90.2 

 38 SW2 43.4 45.6 48.0 65.8 70.4 

 39 OPEN 41.0 44.3 48.1 76.1 85.5 

 39 SW1 31.2 32.9 34.7 47.8 50.6 

 

 39 L-SR 45.5 48.2 51.1 70.9 75.9 

 39 CR01 53.0 57.5 62.7 97.7 ** ** 

 39 EL-S 36.4 38.7 41.1 57.8 61.7 

 39 EL01 22.2 24.1 26.1 41.3 44.8 

 39 EL02 43.7 46.5 49.6 71.1 77.1 

 

 39 EL03 17.9 19.7 21.6 36.4 39.7 

 39 EL04 17.1 18.8 20.8 35.3 38.5 

 39 T01 53.6 57.9 63.0 98.8   

 39 T02 52.3 55.6 59.1 83.7 90.7 

 39 SW2 44.0 46.3 48.7 66.6 71.2 

 

 40 MECH 41.1 44.4 48.2 76.0 85.3 

 40 SW1 31.9 33.6 35.5 48.6 51.4 

 40 L-SR 46.1 48.8 51.8 71.5 76.5 

 40 CR01 53.0 57.5 62.7 97.6 ** ** 

 40 EL-S 36.9 39.3 41.7 58.5 62.3 

 

 40 EL01 22.5 24.4 26.5 41.7 45.1 

 40 EL02 44.0 46.8 49.9 71.5 77.4 

 40 EL03 18.2 19.9 21.9 36.8 40.0 

 40 EL04 17.4 19.1 21.1 35.7 38.9 

 40 T01 54.1 58.5 63.7 99.5   
148 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 40 T02 53.3 56.6 60.2 84.7 91.7 

 40 SW2 44.7 46.9 49.4 67.4 71.9 

 41 OPEN 41.4 44.7 48.4 76.3 85.6 

 41 SW1 32.6 34.3 36.1 49.4 52.3 

 41 L-SR 46.7 49.5 52.4 72.2 77.2 

 

 41 CR01 53.3 57.7 63.0 97.8 ** ** 

 41 EL-S 37.6 39.9 42.4 59.1 63.0 

 41 EL01 22.8 24.7 26.8 42.0 45.4 

 41 EL02 44.3 47.2 50.3 71.8 77.8 

 41 EL03 18.5 20.2 22.2 37.1 40.4 

 

 41 EL04 17.7 19.4 21.4 36.0 39.2 

 41 T01 54.8 59.3 64.6   ** ** 

 41 T02 53.9 57.2 60.8 85.4 92.4 

 41 SW2 45.3 47.6 50.1 68.1 72.7 

 42 OPEN 41.3 44.6 48.3 75.7 84.8 

 

 42 SW1 33.3 35.0 36.9 50.2 53.1 

 42 L-SR 47.3 50.0 53.0 72.8 77.8 

 42 CR01 53.1 57.5 62.6 96.9   

 42 EL-S 38.2 40.5 43.0 59.8 63.7 

 42 EL01 23.0 25.0 27.1 42.3 45.7 

 

 42 EL02 44.6 47.5 50.6 72.2 78.2 

 42 EL03 18.7 20.6 22.6 37.4 40.7 

 42 EL04 17.9 19.7 21.7 36.3 39.5 

 42 T01 54.9 59.5 64.9 ** **   

 42 T02 54.5 57.8 61.4 86.0 92.9 

 

 42 SW2 45.9 48.3 50.8 68.9 73.5 

 43 OPEN 35.7 38.5 41.5 62.7 68.6 

 43 SW1 34.0 35.8 37.6 51.0 53.9 

 43 L-SR 46.0 48.6 51.4 70.3 74.9 

 43 EL-S 38.8 41.1 43.6 60.5 64.4 

 

 43 EL01 23.4 25.3 27.4 42.7 46.1 

 43 EL02 45.0 47.9 51.0 72.6 78.6 

 43 EL03 19.3 21.2 23.2 38.4 41.7 

 43 EL04 18.5 20.3 22.3 37.2 40.4 

 43 T01 48.9 52.4 56.3 83.6 92.3 

 

 43 T02 51.2 54.2 57.5 80.0 86.1 

 43 SW2 46.6 49.0 51.5 69.7 74.3 

 44 OPEN 55.1 58.6 62.6 92.0 ** ** 

 44 SW1 34.8 36.5 38.4 51.8 54.8 

 44 L-SR 45.8 48.4 51.2 69.8 74.2 
149 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 44 EL-S 39.5 41.8 44.3 61.2 65.1 

 44 EL03 19.6 21.4 23.5 38.6 42.1 

 44 EL04 18.7 20.5 22.6 37.4 40.7 

 44 T01 55.5 58.9 62.9 93.8   

 44 T02 50.8 53.7 56.8 78.6 84.4 

 

 44 SW2 47.3 49.7 52.3 70.5 75.1 

 45 OPEN 56.5 60.0 64.0 93.7 ** ** 

 45 SW1 35.6 37.3 39.2 52.7 55.7 

 45 L-SR 46.5 49.1 51.9 70.5 75.0 

 45 EL-S 40.1 42.5 45.0 62.0 65.9 

 

 45 EL03 19.8 21.7 23.7 38.9 42.3 

 45 EL04 18.9 20.8 22.8 37.7 41.0 

 45 T01 56.4 59.9 63.9 94.9   

 45 T02 51.6 54.5 57.6 79.4 85.2 

 45 SW2 48.0 50.4 53.0 71.3 76.0 

 

 46 OPEN 55.3 59.2 63.6 93.6 ** ** 

 46 SW1 36.4 38.2 40.0 53.7 56.7 

 46 L-SR 47.3 49.9 52.7 71.3 75.8 

 46 EL-S 40.9 43.2 45.8 62.8 66.7 

 46 EL03 20.0 21.9 24.0 39.2 42.6 

 

 46 EL04 19.1 20.9 23.0 37.9 41.2 

 46 T01 56.1 59.9 64.1 95.3   

 46 T02 52.4 55.3 58.5 80.3 86.1 

 46 SW2 48.7 51.2 53.8 72.2 76.8 

 47 OPEN 48.0 52.6 57.8 89.2 99.5 

 

 47 SW1 37.3 39.1 41.0 54.7 57.8 

 47 L-SR 48.0 50.7 53.5 72.2 76.7 

 47 EL-S 41.7 44.0 46.6 63.6 67.6 

 47 EL03 20.3 22.1 24.2 39.4 42.9 

 47 EL04 19.4 21.2 23.2 38.2 41.4 

 

 47 T01 45.2 49.4 54.3 86.1 96.6 

 47 T02 53.2 56.2 59.4 81.3 87.1 

 47 SW2 49.5 52.0 54.6 73.1 77.8 

 48 OPEN 46.0 50.4 55.5 87.5 97.7 

 48 SW1 38.3 40.1 42.0 55.9 58.9 

 

 48 L-SR 48.9 51.5 54.3 73.1 77.6 

 48 EL-S 42.5 44.8 47.4 64.5 68.5 

 48 EL03 20.5 22.4 24.4 39.7 43.1 

 48 EL04 19.6 21.4 23.4 38.4 41.7 

 48 T01 43.3 47.2 51.8 83.2 93.4 
150 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 48 T02 54.2 57.1 60.3 82.3 88.1 

 48 SW2 50.3 52.8 55.5 74.1 78.8 

 49 OPEN 45.4 49.6 54.7 87.0 97.2 

 49 SW1 39.4 41.2 43.1 57.1 60.2 

 49 L-SR 49.8 52.4 55.2 74.1 78.6 

 

 49 EL-S 43.3 45.7 48.3 65.5 69.5 

 49 EL03 20.7 22.6 24.7 39.9 43.3 

 49 EL04 19.8 21.6 23.6 38.6 41.9 

 49 T01 42.7 46.5 51.0 82.2 92.3 

 49 T02 55.1 58.1 61.4 83.3 89.2 

 

 49 SW2 51.2 53.8 56.5 75.2 79.9 

 50 OPEN 44.6 48.7 53.6 86.0 96.2 

 50 SW1 40.5 42.4 44.3 58.4 61.6 

 50 L-SR 50.7 53.4 56.2 75.1 79.7 

 50 EL-S 44.3 46.7 49.2 66.5 70.5 

 

 50 EL03 20.9 22.8 24.9 40.2 43.6 

 50 EL04 19.9 21.8 23.8 38.8 42.1 

 50 T01 42.7 46.5 50.9 82.3 92.5 

 50 T02 56.2 59.2 62.5 84.5 90.4 

 50 SW2 52.2 54.7 57.5 76.3 81.0 

 

 51 OPEN 43.5 47.4 51.9 84.0 94.1 

 51 SW1 41.8 43.7 45.7 60.0 63.1 

 51 L-SR 51.7 54.4 57.3 76.3 80.9 

 51 EL-S 45.3 47.7 50.3 67.6 71.7 

 51 EL03 21.1 23.0 25.1 40.4 43.8 

 

 51 EL04 20.2 22.0 24.0 39.1 42.4 

 51 T01 42.4 46.1 50.5 81.8 92.0 

 51 T02 57.4 60.4 63.6 85.8 91.6 

 51 SW2 53.2 55.8 58.6 77.5 82.2 

 52 OPEN 42.7 46.4 50.8 82.3 92.4 

 

 52 SW1 43.2 45.1 47.2 61.6 64.9 

 52 L-SR 52.8 55.5 58.4 77.5 82.1 

 52 EL-S 46.3 48.8 51.4 68.8 72.9 

 52 EL03 21.3 23.2 25.3 40.6 44.1 

 52 EL04 20.4 22.2 24.3 39.3 42.6 

 

 52 T01 42.1 45.7 50.0 81.0 91.2 

 52 T02 58.6 61.6 64.9 87.1 93.0 

 52 SW2 54.3 56.9 59.7 78.8 83.6 

 53 OPEN 42.1 45.8 50.0 80.9 91.0 

 53 SW1 44.8 46.8 48.9 63.6 66.9 
151 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 53 L-SR 54.0 56.7 59.6 78.8 83.4 

 53 EL-S 47.5 49.9 52.6 70.1 74.2 

 53 EL03 21.5 23.4 25.5 40.8 44.3 

 53 EL04 20.6 22.5 24.5 39.5 42.9 

 53 T01 41.8 45.4 49.5 80.2 90.3 

 

 53 T02 59.9 63.0 66.3 88.6 94.5 

 53 SW2 55.5 58.2 61.0 80.2 85.0 

 54 OPEN 41.7 45.3 49.4 79.8 89.8 

 54 SW1 46.7 48.7 50.8 65.8 69.2 

 54 L-SR 55.3 58.0 61.0 80.3 85.0 

 

 54 EL-S 48.8 51.2 53.9 71.6 75.7 

 54 EL03 21.7 23.7 25.7 41.1 44.5 

 54 EL04 20.8 22.7 24.7 39.8 43.1 

 54 T01 41.5 45.0 49.1 79.4 89.5 

 54 T02 61.4 64.5 67.9 90.3 96.2 

 

 54 SW2 56.8 59.5 62.4 81.8 86.6 

 55 OPEN 41.4 44.9 48.9 78.8 88.7 

 55 SW1 48.9 51.0 53.1 68.5 72.0 

 55 L-SR 56.8 59.5 62.5 81.9 86.6 

 55 EL-S 50.2 52.7 55.4 73.2 77.3 

 

 55 EL03 21.9 23.9 25.9 41.3 44.7 

 55 EL04 21.0 22.9 24.9 40.0 43.3 

 55 T01 41.3 44.8 48.8 78.7 88.7 

 55 T02 63.0 66.2 69.6 92.2 98.1 

 55 SW2 58.3 61.0 64.0 83.5 88.4 

 

 56 OPEN 41.2 44.6 48.6 77.9 87.7 

 56 SW1 51.7 53.8 56.0 71.9 75.5 

 56 L-SR 58.4 61.2 64.1 83.7 88.5 

 56 EL-S 51.7 54.3 57.0 75.0 79.1 

 56 EL03 22.2 24.1 26.2 41.5 45.0 

 

 56 EL04 21.2 23.1 25.2 40.2 43.6 

 56 T01 41.2 44.6 48.6 78.0 88.0 

 56 T02 64.9 68.0 71.5 94.3 ** ** 

 56 SW2 60.0 62.8 65.7 85.5 90.4 

 57 OPEN 41.0 44.4 48.3 77.1 86.8 

 

 57 SW1 55.3 57.5 59.9 76.5 80.3 

 57 L-SR 60.2 63.0 66.1 85.8 90.6 

 57 EL-S 53.5 56.1 58.8 77.0 81.2 

 57 EL03 22.4 24.3 26.4 41.8 45.2 

 57 EL04 21.5 23.3 25.4 40.5 43.8 
152 

Table 27. Continued. 

 Visibility of Visibility of Visibility of 

 30. m 15. m 8. m FED of FED of 

 (98 ft) (49 ft) (25 ft) 0.5 at 1.0 at 

 at Time at Time at Time Time Time 

Level Zone (min) (min) (min) (min) (min) 

 57 T01 41.0 44.4 48.3 77.3 87.2 

 57 T02 66.9 70.2 73.7 96.7   

 57 SW2 61.9 64.7 67.8 87.8 92.8 

 58 OPEN 40.5 43.8 47.6 75.4 84.7 

 58 SW1 60.7 63.1 65.7 83.7 88.0 

 

 58 L-SR 62.3 65.2 68.3 88.2 93.1 

 58 EL-S 55.6 58.2 61.0 79.4 83.7 

 58 EL03 22.6 24.5 26.6 42.0 45.5 

 58 EL04 21.7 23.6 25.7 40.7 44.1 

 58 T01 40.6 43.9 47.7 75.8 85.2 

 

 58 T02 69.3 72.6 76.2 99.6 ** ** 

 58 SW2 64.1 67.0 70.1 90.5 95.6 

 59 MECH 76.8 80.9 85.4   ** ** 

 59 ELME 80.4 84.7 89.5   ** ** 

 59 EL-S 58.0 60.7 63.6 82.3 86.7 

 

 59 EL03 22.6 24.6 26.7 42.0 45.5 

 59 EL04 21.7 23.6 25.7 40.8 44.1 

 59 SW2 66.9 69.8 73.0 93.8 99.0 

 R SW2 71.4 74.6 77.9 99.5 **** 
Appendix G

The Basis for Egress Provisions in U.S. Building Codes
InterFlam ’04 Page 1 of 15 4/28/2004 

The Basis for Egress Provisions in U.S. Building Codes 

Richard W. Bukowski, P.E., FSFPE and Erica Kuligowski 

NIST Building and Fire Research Laboratory 

Gaithersburg, Maryland 20899 USA 

Abstract

Some of the earliest public safety-from-fire regulations in the US are requirements for egress stairs adopted by New 

York City in 18601

. One of the first model regulations promulgated by the National Fire Protection Association 

(NFPA) was the 1927 Building Exits Code, predecessor of the Life Safety Code. Thus the need to move occupants out 

of harms’ way in building fires has long been central to fire safety regulations. 

The need to move occupants to a safe place was underscored in numerous historical fire disasters. Locked exits 

contributed to the high number of fatalities (150) in the 1911 Triangle Shirtwaist Factory fire and exit doors that 

opened inwards blocked by crowds was cited in the 492 fatalities of the Cocoanut Grove fire (1942)2

. Incidents like 

these resulted in public outcry for stronger code provisions but even today egress problems leading to high numbers of 

deaths persist. The 100 fatalities at the Station Club in Rhode Island in 2003 provide the most recent example. Since 

the Rhode Island fire, NFPA and other code authorities are reviewing current requirements for level of safety, 

especially for assembly spaces. 

These current prescriptive codes used for building design contain a list of egress specifications depending upon certain 

aspects of the building, such as the type of occupancy, the configuration of the space, the presence of sprinklers, and 

the type of construction of the building. These code specifications aid the designer in providing a certain level of life 

safety for their building, but little effort has been put into quantifying this level of life safety in terms of egress times. 

This paper attempts to describe the prescriptive design process for specific types of buildings. Secondly, by applying 

some assumptions to the egress specifications listed in the codes, an estimate of resulting egress times for maximum 

occupant loads were performed for specific occupancies. The egress times were obtained using multiple calculation 

methods and include estimates of pre-movement time, time to exit the occupied room, and time spent to travel one 

flight of stairs. Lastly, additional egress issues, such as merging flows and the use of elevators for occupant egress, are 

discussed. 

History of Egress Provisions in Regulations 

Some of the earliest public safety-from-fire regulations in the US are requirements for 

egress stairs adopted by New York City in 18601

. One of the first model regulations 

promulgated by the National Fire Protection Association (NFPA) was the 1927 Building 

Exits Code, predecessor of the Life Safety Code. Thus the need to move occupants out of 

harms’ way in building fires has long been central to fire safety regulations. 

The need to move occupants to a safe place was underscored in numerous historical fire 

disasters. Locked exits contributed to the high number of fatalities (150) in the 1911 

Triangle Shirtwaist Factory fire and exit doors that opened inwards blocked by crowds 

was cited in the 492 fatalities of the Cocoanut Grove fire (1942)2

. Incidents like these 

resulted in public outcry for stronger code provisions but even today egress problems 

leading to high number of deaths persist. The 100 fatalities at the Station Club in Rhode 

Island in 2003 provide the most recent example. 

Basic Principles of Egress Safety 

The basic concept of occupant egress implemented in building regulations involves the 

provision of a properly designed means of egress that is continuous and unobstructed 

from any point in the building to the outside. Proper design includes the width of the 

spaces and doors, direction of door swing, lighting and marking, protection from the fire 

and its effects, and geometry of stairs or ramps, among others. Limits on travel distances 
InterFlam ’04 Page 2 of 15 4/28/2004 

to reach a means of egress and on common paths of travel, dead ends, and the provision 

of alternate means of egress if the primary path is blocked by fire are also basic concepts 

of egress design. 

The means of egress described in building regulation consists of three parts. The exit 

access is the corridor, aisle, balcony, gallery, room, porch, or portion of a roof over 

which an occupant must travel to reach the exit. The exit is a door leading to the outside 

or through a protected passageway to the outside, a smokeproof tower, protected 

stairway, exit passageway, enclosed ramp, escalator, or moving walkway within a 

building. The exit discharge is the door to the outside, although some regulations allow 

not more than half the exits to discharge onto a floor with an unobstructed path to the 

outside, and is protected by sprinklers and a 2-hr separation from floors below. 

It must further be possible for all the occupants using the exit discharge to reach a safe 

place away from the building. Thus if exits discharge to a yard or alley these must lead 

to a safe place and have the capacity to carry all occupants and to protect them from the 

effects of the fire as they move away from the building. In Japanese building regulations3

 

the means of egress includes the entire path to a safe place of sufficient capacity to 

accommodate the entire population of all buildings intended to evacuate to that place. 

Thus Japanese cities are dotted with parks that serve as gathering places for occupants of 

multiple buildings. Those parks utilize perimeter trees intended to protect people in the 

park from thermal radiation from fires in surrounding buildings from which they 

evacuated. 

Designing an Egress System 

The objective of the egress system design is to allow the unimpeded evacuation of the 

building population without exposure to fire or smoke. Prescriptive building regulations 

address this by specifying a population density (people per unit floor area) for each 

building use group, called the occupant load factor. When multiplied by the floor area, 

the occupant load is obtained on which the egress system design is based (unless there is 

reason to believe that the actual load will be greater or the owner desires a greater 

allowance). 

The means of egress is then designed to accommodate that occupant load by specifying 

an egress width per occupant served. Values are specified for stairs and for other egress 

components, sprinklered and unsprinklered, and with special values for type-H (high 

hazard) and type-I (institutional) building uses to allow for higher egress speeds (high 

hazard) and greater number of wheelchairs or evacuation in patient beds (institutional), 

respectively. 

The width of the egress system at each floor is sized to accommodate the number of 

occupants on that floor only. There is an additional requirement that the egress system 

width cannot become narrower in the direction of egress travel and beyond any 

convergence of two or more egress systems from different directions, the capacity cannot 

be less than the sum of the capacities. These requirements are intended to account for the 
InterFlam ’04 Page 3 of 15 4/28/2004 

accumulation of flows from multiple floors. 

For very tall buildings, it was recognized that the accumulating flow from a large number 

of floors would result in congestion in the stairways and a reduction of flow speeds. 

Widening the stairway to increase the capacity has a serious economic impact that could 

make tall buildings impractical. Thus the concept of phased evacuation was developed 

where occupants are evacuated from the (3) floors closest to the fire first, while others 

wait their turn. Such systems require a voice communication system to manage the 

process by voice messages from a fire command center staffed by the fire service, and 

(e.g., in New York City) fire wardens on each floor directing the flow. 

Egress System Performance 

Egress systems designed in accordance with these rules are considered to allow all 

building occupants to get to a safe place, “in time.” Unfortunately, “in time” is not 

quantified. In the last 20 years, the engineering concept of Available Safe Egress Time

(or ASET) vs. Required Safe Egress Time (RSET) has become popular. ASET is defined 

as the time available for safe egress before conditions within a space or building become 

untenable4

. RSET is defined as the time required for the occupants in a structure to 

evacuate without harm. Time available is normally estimated by fire modeling and the 

application of tenability limits for human tolerance to fire effects. Time required is 

estimated by traffic flow calculations for speed of people movement through the egress 

system. 

With use, the ASET/RSET methodologies became more refined. The time required 

calculations began to include other, significant components such as pre-movement times 

and behavioral rules to account for many situations where people do not immediately 

evacuate. Human factors research documented large variability in movement speeds4

 and 

toxicology research showed large differences in individual tolerance to smoke depending 

on age and pre-existing physiological conditions. Recently questions have been raised 

about sub-lethal effects5

 that are difficult to estimate and unethical to measure, further 

clouding the picture. 

Because of the large variability in movement speeds, it is possible for individual designs 

to pass or fail by selection of a characteristic speed or by the application of an 

appropriately large factor of safety. A safety factor of 24

 is generally recommended in 

the fire protection engineering literature6

. Thus it would be of value to establish a 

benchmark for what might be considered adequate escape time. The prescriptive 

regulatory system for egress system design implies such a benchmark value as follows. 

Prescriptive Egress Specifications 

Traditional building codes specify the design of egress systems by first estimating the 

number of occupants in an area to be evacuated, second determining the (combined) 

width of the exit system needed for that number of occupants, and third dividing that 

width among the number of exits needed to achieve the travel distance limits. 

In current building codes, design occupant densities (called loads) range from 46.5 m2
InterFlam ’04 Page 4 of 15 4/28/2004 

(500 ft2) (gross13 – the area within the confining perimeter walls of the building) per 

occupant (aircraft hangers, warehouses) to 0.46 m2

 (5 ft2) (net13 – the actual occupied 

space only) per occupant (assembly, standing space). Common values are 9.3 m2

 (100 

ft2) (gross) per occupant (business, industrial) or 18.6 m2 (200 ft2) (gross) per occupant 

(residential). By multiplying these loads by the floor area, the number of people to be 

evacuated is obtained. 

With the exception of hazardous and health care occupancies, both the IBC7

 (without 

sprinkler protection) and NFPA 50008 (sprinklered or not) specify the same egress system 

width of 7.6 mm (0.3 in) per occupant in exit stairways and 5 mm (0.2 in) per occupant 

elsewhere. The IBC reduces egress capacity where sprinklered to 5 mm (0.2 in) per 

occupant in stairs and 3.8 mm (0.15 in) elsewhere. The egress capacity of the exit system 

is the smallest capacity of any component. For example, a 0.86 m (34 in) (clear width) 

door leading into a 1.1 m (44 in) (clear) stair have capacities of 170 (0.86 m/5 mm) and 

147 (1.1 m/7.6 mm) respectively. Thus the exit capacity is the smaller of the two, or 147. 

The minimum number of exits specified in both model codes is two for populations up to 

500, three from 501 to 1000, and four if over 1000. 

Finally, building codes specify maximum travel distances to an exit by occupancy. The 

IBC specifies 61 m (200 ft) (unsprinklered) and 76 m (250 ft) (sprinklered) for most 

occupancies, except for business which is allowed 91.4 m (300 ft) if sprinklered. NFPA 

5000 specifies travel distances without sprinklers of 30.5 m (100 ft) (hotels, apartments, 

mercantile), 45.7 m (150 ft) (health care, educational) or 61 m (200 ft) (business, 

industrial, assembly). When fully sprinklered, these increase to 61 m (200 ft) (hotel, 

apartments, educational), 76 m (250 ft) (mercantile, industrial, assembly) and 91.4 m 

(300 ft) (business). While most buildings will require two or more exits, the travel 

distance requirement only applies to the distance from any point to the closest (single) 

exit. The distance to any other exit(s) is unregulated. 

An unforeseen problem may exist involving travel distances of the occupants to the 

“main entrance” of assembly occupancies. For assembly occupancies, there exists a 

requirement that the “main entrance” of the building must be designed for half of the 

egress capacity. The travel distance requirement, however, applies only to the closest 

(single) exit from any point of occupancy in the building. The question that arises is 

whether or not a specific travel distance should be required for the “main entrance” of the 

building, especially since the exit is designed for use by half of the building population. 

For example, an assembly space with 650 m2

 (7,000 ft2) (net) will contain a design 

occupant load of 1000 people. The code requires 3 exits and sprinklers, which results in 

a travel distance limit of 76 m (250 ft). The “main entrance” is designed for half of the 

population (500 occupants), and the two other exits of the building include a larger exit 

designed for 400 occupants and a smaller exit designed for 100 occupants. If the smallest 

exit is 76 m (250 ft) away from the furthest occupied space in the building, the travel 

distance requirement for the building is met. The other two exits, the larger exit and the 

“main entrance” are not required to meet any travel distance requirements. In this 

example, 90% of the required egress capacity can be in exits that require excessively long 
InterFlam ’04 Page 5 of 15 4/28/2004 

travel distances to reach. 

Benchmarking the Intent of the Codes

By applying some assumptions to the specifications previously listed, it is possible to 

estimate the resulting egress times for maximum occupant loads by occupancy. In each 

case the occupant load can be estimated by assuming a square compartment with exits in 

opposite corners so that the diagonal dimension is the maximum travel distance. This 

establishes an area that, when multiplied by the occupant load, gives the number of 

occupants to be evacuated. 

Egress times are generally taken to be the time between notification of the occupants of 

the need to evacuate (initiation of the fire alarm system) and the time the occupants get 

into the stairway or a protected stairway access (this is not the normal exit access corridor 

but rather an extension of the stairway meeting the same fire and smoke protection 

requirements). 

The time required to evacuate these occupants is the pre-movement time plus the time 

required to move the (maximum) travel distance plus the time required to pass through 

the door. Table A9

 presents estimates of pre-movement times for various occupancies 

and type of warning system. Also, other references provide alternatives for premovement times, which were obtained from fire drills, experiments, and post-fire 

analysis10, , 11 12. 

Walking speeds on horizontal surfaces vary with density and fall within the range of 1.19 

m/s (235 ft/min) at 0.54 people/m2

 (0.05 people/ft2) to 0.63 m/s (125 ft/min) at 2.17 

people/m2

 (0.2 people/ft2)

4

. While walking speeds vary with exposure to smoke, it is 

reasonable to assume that codes would be based on no smoke exposure due to the limited 

data on this interaction. Travel speeds and flow rates are typically restricted by flow 

through doorways. The maximum rate of flow through doors is given in the literature as 

1.3 persons/s-m of effective width (24 people/min-ft)4

. 
InterFlam ’04 Page 6 of 15 4/28/2004 

Table A – Estimated Delay Time to Start Evacuation 

Occupancy Type W1 

(min) 

W2 

(min) 

W3 

(min)

Offices, commercial and industrial buildings, schools, colleges, 

and universities (Occupants awake and familiar with the building, 

the alarm system, and evacuation procedure) 

<1 3 >4 

Shops, museums, leisure-sport centers, and 

other assembly buildings (Occupants awake but may be 

unfamiliar with building, alarm system, evacuation procedure) 

<2 3 >6 

Dormitories, residential mid- and high-rise (Occupants may be 

asleep but are predominantly familiar with the building, alarm 

system, evacuation procedure) 

<2 4 >5 

Hotels and boarding houses (Occupants may be asleep and 

unfamiliar with building, alarm system, evacuation procedure) 

<2 4 >6 

Hospitals, nursing homes, and other institutional (A significant 

number of occupants may require assistance) 

<3 5 >8 

W1: live directives using voice communication system from a control room with closed-circuit television facility or 

live directives in conjunction with well-trained, uniformed staff that can be seen and heard by all occupants in the 

space. 

W2: nondirective voice messages (pre-recorded) and/or informative warning visual display with trained staff. 

W3: warning system using fire alarm signal and staff with no relevant training 

The building codes specify that egress doors cannot be less than 0.8 m (32 in) (clear) nor 

more than 1.2 m (48 in) (clear) in width (per leaf). Door capacities range from 160 

persons for a 0.8 m door to 240 persons for a 1.2 m door with a differential of 10 people 

per 51 mm (2 in) of width. 

Egress stairs cannot be less than 1.1 m (44 in) in width with no maximum. Design 

capacities for stairs range from 147 people for a 1.1 m (44 in) stair to 220 people for a 

1.67 m (66 in) stair with a differential of 13 people per 102 mm (4 in) of width. 

Horizontal Movement

Tables B1 and B2 show estimates of the worst-case egress times for each occupancy 

type; assembly without fixed seating, business, and residential (open space). Each egress 

time is the combination of the travel time to the stairwell door and the time for all of the 

occupants to go through the door into the stairwell. Prescriptive codes consider the 

occupant to reach safety as soon as they enter the stairwell. In the tables, egress times are 

separated first into occupancy type, and then second into whether or not the occupancy is 

sprinklered (S refers to sprinklered spaces and N refers to nonsprinklered (or 

unsprinklered) spaces in each table). Both designations ultimately affect the travel 

distances and number of occupants in a space, as shown in the table. 

For each occupancy type, a square room is configured so that the diagonal dimension is 

equivalent to the travel distance. Then, the dimensions of the compartment are used to 

calculate the number of occupants in the space according to the Life Safety Code13 (Table 

7.3.1.2). The “travel time” is used to represent the longest possible distance traveled by 
InterFlam ’04 Page 7 of 15 4/28/2004 

an occupant to reach the stairway door. As shown in Figure 1, this longest distance with 

all exits available is the distance along the side of the 

compartment (shown by the arrows in the figure). 

This provides a conservative estimate of travel time

for that space. The speeds used to calculate travel 

time for each occupancy reflect the actual density of 

the space and were obtained from Pauls’ density 

correlations in the SFPE handbook14. 

The next calculation in Table B1, specifically, shows 

the time for all of the distributed occupants to travel 

through their designated door. Each occupancy has a 

different number of exit doors depending upon the 

number of occupants in the space. The “through 

door” time is calculated by dividing the number of 

occupants through the door by the calculated flow 

(maximum specific flow x effective door width) in persons/minute. The door calculation 

takes into account that occupants will maintain a boundary layer of 150 mm (6 in) from

each side of the doorway. 

Figure 1: Square compartment 

Table B1 – Estimates of worst-case egress times using SFPE Handbook values 

Assembly Business Residential

Sb NSc S NS S NS

Travel distance 

(diagonal dimension– 

Fig. 1) in meters (ft) 

76 

(250) 

61 

(200) 

91.4 

(300) 

61 

(200) 

61a

(200) 

30.5a

(100) 

Compartment side 

dimensions in m (ft) 

54.3 

(178) 

43.6 

(143) 

65.2 

(214) 

43.6 

(143) 

43.6 

(143) 

21.6 

(71) 

Occupant # 

(load x area) 6336 4090 458 205 102 25

Travel time (s) 85 69 55 37 37 18 

Exit doors, # x width 

in m (people per set 

of doors) 

14x2.4 

(452) 

9x2.4 

(455) 

2x1.17 

(229) 

2x0.8 

(103) 

2x0.8 

(51) 

2x0.8 

(13) 

Through door (s) 162 163 202 155 77 20 a

Travel distance shown is from the door to any individual living unit to the exit. 

Additional travel time would be required for travel within the living unit. 

b

Refers to a Sprinklered space; cRefers to a Nonsprinklered space 

For Table B2, as a variation to the calculations made in Table B1, it is assumed that the 

doors act as turnstiles. From video tapes of egress through doors taken by Fruin15, it can

be seen that each exiting person places his/her hand on the door before leaving the 

building. Nelson16 speculates that this behavior limits the flow through each door to 

about 50 to 60 persons per minute. This applies to the full range of door widths from 0.8 

m (32 in) to 1.2 m (48 in). For the assembly space, a 2.4 m (96 in) door represents a twoleaf set of 1.2 m (48 in) wide doors, which would indicate a flow of 100 to 120 persons 
InterFlam ’04 Page 8 of 15 4/28/2004 

per minute. For all calculations in Table B2, a midrange value of 55 persons per minute 

per door was used to achieve times through the door. For example, in the assembly 

space, 452 people will pass through a two-leaf set of 1.2 m (48 in) doors, which 

corresponds to a flow of 110 people per minute. For sprinklered assembly spaces, the 

result is 247 seconds to flow 452 people through the 2-1.2 m (48 in) doors. 

 Table B2 – Estimates of worst-case egress times using Nelson and Fruin turnstile values 

(each door allows 55 persons/minute) 

Assembly Business Residential 

Sb NSc S NS S NS 

Travel distance in 

meters (ft) 

76 

(250) 

61 

(200) 

91.4 

(300) 

61 

(200) 

61a

(200) 

30.5a

(100) 

Compartment side 

dimensions in m (ft) 

54.3 

(178) 

43.6 

(143) 

65.2 

(214) 

43.6 

(143) 

43.6 

(143) 

21.6 

(71) 

Occupant # 

(load x area) 6336 4090 458 205 102 25 

Travel time (s) 85 69 55 37 37 18 

Exit doors, # x width 

in m (people per set 

of doors) 

14x2.4 

(452) 

9x2.4 

(455) 

2x1.17 

(229) 

2x0.8 

(103) 

2x0.8 

(51) 

2x0.8 

(13) 

Through door (s) 247 248 250 112 56 14 a

Travel distance shown is from the door to any individual living unit to the exit. 

Additional travel time would be required for travel within the living unit. 

b

Refers to a Sprinklered space; cRefers to a Nonsprinklered space 

By using the turnstile approach in Table B2, it can be seen that the flows become 

restricted in the larger density spaces. This causes a longer time through the door. 

Again, as with the calculations made in Table B1, these can be considered as 

conservative estimates of egress times for movement without the presence of fire effects. 

Assumptions lead to alternative approach to calculate egress times 

There are three assumptions made to calculate the horizontal travel time and time through 

the door shown in Tables B1 and B2. It should be understood that these calculations are 

approximations of general situations and certain assumptions needed to be made to 

complete the calculations for each case. The first assumption involves an even 

distribution of occupants to the doors leading to the stairwells. 

The second and third assumptions correspond to the addition of the “travel time” and the 

“through door” time to achieve the evacuation time for each room. There is an 

assumption made that “travel time” and “through door” time do not overlap. In the case 

where a queue forms after some period of time during the evacuation, the addition of 

these two values (travel and through door time) produces an evacuation time that is 

overly conservative. While the most remote occupant travels to the doorway, other 

occupants closer to the door leave the room. At some point, the remote occupant reaches 

a queue, meaning that they have not walked the entire travel distance. Once they reach 

the queue, the “through door” calculation dominates the evacuation time. Also, not all 
InterFlam ’04 Page 9 of 15 4/28/2004 

occupants are part of the queue, as was assumed in the “through door” calculation, since 

some leave while others join the queue. 

The third assumption made is that “travel” and “through door” times both have values 

that are nonzero. This is not always the case. For lower density spaces, such as the 

residential unsprinklered, if a queue never forms, the evacuation time should equal the 

“travel” time of the most remote occupant in the space. For the very high density spaces, 

such as the assembly spaces, a queue forms immediately. In the case of assembly spaces, 

the evacuation time is equivalent to the “through door” time only. 

Because of the previous assumptions made about the addition of travel time and time 

through the door, several evacuation simulations were run using the Simulex*

 model17 to 

correct these assumptions. The purpose of these evacuation simulations was to note how 

long occupants travel to the door unimpeded before a queue would form at the door, at 

which time the “through door” egress time dominates the total egress time from the room. 

Each occupancy (sprinklered and unsprinklered) was drawn using TurboCAD and 

imported into Simulex. The room for each occupancy was equipped with exits at 

opposing corners (except for the Assembly spaces which had doors all around the space) 

separated by the maximum travel distance along the diagonal. Simulex allows the user to 

input a travel speed and body size for each occupant in the simulation. For each run, all 

occupants moved at 1.2 m/s (235 ft/min) unimpeded and contained the “median” adult 

body size (average of men and women). The occupants were spaced evenly throughout 

the room and moved immediately with the start of the simulation. The model, Simulex, 

was used only to track the unimpeded movement of the occupants from their starting 

position to the doorway. Overall, these Simulex runs were used to obtain the amount of 

time that occupants walked through the door before a queue formed. The results were as 

follows: 

Table C - Simulated time before a queue developed at the doors 

Assembly Business Residential 

S NS S NS S NS 

Time (s) before queue at door !0 !0 12 12 16 "

A time of 0 seconds corresponds to a queue developing almost instantaneously in the 

assembly spaces. This was expected due to the fact that the assembly spaces were packed 

at an allowable density of 0.46 m2

/person (5 ft2/person). On the other hand, the 

unsprinklered residential space never formed a queue at the door, which is described as 

an infinite time in Table C. This was also expected due to the size of the space and the 

low number of occupants that needed to evacuate. For the business (sprinklered and 

unsprinklered) spaces and the sprinklered residential space, there was a recognized time 

 

*

 Certain commercial entities, equipment, or materials may be identified in this document in order to 

describe an experimental procedure or concept adequately. Such identification is not intended to imply 

recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended 

to imply that the entities, materials, or equipment are necessarily the best available for the purpose. 
InterFlam ’04 Page 10 of 15 4/28/2004 

before queuing began, and for the rest of the evacuation, the time through the door 

dominated. This shows that for these occupancies in this example, the evacuation time is 

a mix of the travel time and the time through the door. The appropriate evacuation time 

can be calculated, given the information in Table C. 

Since Table C displays the time before queuing begins for 

the three occupancies (Business Sprinklered, Business 

Unsprinklered, and Residential Sprinklered), the number of 

people that pass through the door in that amount of time 

can be calculated. The time before the queue forms and 

the speed of the occupants at the specific density is known, 

and from this information, the distance that the occupants 

traveled to evacuate before a queue formed can be 

calculated. As shown in Figure 2, an arc is drawn in front 

of each doorway, with the radius consisting of the distance 

traveled by the occupants before queuing. Essentially, this 

arc is drawn to show the position of the occupants that left 

before queuing began. By solving for the area of the arc, 

the number of occupants residing in this arc space (using 

the density of the space) can be found and used as the number of occupants evacuating 

during the pre-queuing time. These occupants are then subtracted out from the 

population. Lastly, the time for the rest of the occupants to move through the door is 

calculated using two different methods; the effective width method and the turnstile 

method. These values are shown in Table B3. 

Figure 2: Arc display of 

occupants who leave the

room before queuing occurs

Table B3 – Estimates of egress times without overlapping travel time and time through 

the doorway. 

Assembly Business Residential

S NS S NS S NS

Travel distance in meters (ft) 76 

(250) 

61 

(200) 

91.4 

(300)

61 

(200) 

61 

(200) 

30.5 

(100) 

Compartment side dimensions in m

(ft) 

54.3 

(178) 

43.6 

(143) 

65.2 

(214)

43.6 

(143) 

43.6 

(143) 

21.6 

(71) 

Occupant # (load x area) 6336 4090 458 205 102 25 

Time (s) before queue at door 0 0 12 12 16 ! (18) 

# of occupants evacuating during 

pre-queue per door 

(# of occupants left at time of queue) 

0 

(452) 

0 

(455) 

17 

(212)

17 

(86) 

15 

(36) 

13 

(0) 

Through door (s) for queuing 

occupants – effective width method 162 163 188 129 54 18a

Through door (s) for queuing 

occupants – turnstile method 247 248 231 94 39 18a

a

These values are equivalent to the travel time assuming that occupants are traveling at the 

unimpeded speed of 1.2 m/s (235 ft/min) (at least one traveling the entire “travel time” 

distance). 
InterFlam ’04 Page 11 of 15 4/28/2004 

For all occupancies, except for the residential unsprinklered, horizontal travel time was 

not explicitly included in the egress times from each space. This is because the egress 

times are dominated by the time through the door, as shown in the Simulex runs of each 

occupancy (except for residential unsprinklered). Because of this, the total egress time 

for the space is calculated by adding the “time before queue at door” and the “through 

door” time (depending upon the calculation method preferred). 

Overall 

If a more conservative evacuation time is preferred, it is recommended to add the travel 

time to the door and the time through the door for the business occupancy (sprinklered 

and unsprinklered) and the sprinklered residential occupancy. 

Stairs

While prescriptive codes generally designate occupants as safe when they enter the 

protected egress stair, evacuation often requires that the occupants travel down stairs to 

the level of exit discharge. From the literature, the maximum flow rate in a (7/11) egress 

stair is estimated to be 1 person/s-m (18.5 people/min-ft) of effective width. Thus 

typical/maximum flow rates for 1.1 m (44 in) to 1.67 m (66 in) egress stairs range from 

49 to 83 people per min. This does not include the effect of congestion in the stairs that 

results from accumulating flows from several floors accessing the stairs. 

Table D shows the time for travel on the stairs from one floor to another (including one 

landing in between flights). The times were obtained by assuming that the calculated 

flow (people/min) from one section of the building is equal to the calculated flow on the 

next section, except for the unsprinklered residential. For the unsprinklered residential 

occupancy, since no queue has formed at the door, unimpeded speed was used to 

calculate movement on the staircase. For all other occupancies, the occupants travel from 

the doorway into the stairwell with the same calculated flow, but different widths, and 

therefore, different specific flows. It is assumed that they travel from the room at a 

specific flow of 1.3 people/m-s (24 people/ft-min). The Life Safety code specifies 7.6 

mm/person (0.3 in/person) of stair width, which was used to calculate the appropriate 

stair width for each occupancy, sprinklered or unsprinklered. By solving for the specific 

flow for the staircase, the appropriate travel speed can be obtained from the SFPE 

handbook4

 in order to calculate the travel times for the section of stair. Stair travel 

distance was estimated by first, multiplying the vertical distance of the floor by the 

diagonal travel distance conversion factor found in Nelson’s chapter of the SFPE 

Handbook, Table 3-14.34

, and second, adding travel distance of the 2 landings. The 

calculated range of times for stair travel from one floor to another (assuming a 3.7 m (12 

ft) ceiling height – slab to slab and (7/11) stairs) was 12-25 seconds, depending upon the 

occupancy and method of calculation. 
InterFlam ’04 Page 12 of 15 4/28/2004 

Table D – Travel times on Stairs 

Assembly Business Residential 

S NS S NS S NS 

Travel distance in room (m) 76 61 91.4 61 61 30.5 

People per door/stair 452 455 229 103 51 13 

Stair width (m) 3.4 3.47 1.7 1.1 1.1 1.1 

Travel dist on Stairs (m) 20.5 20.5 13.7 11.2 11.2 11.2 

Time on each flight (s) – 

effective width method 25 25 16 13 13 12 

Time on each flight (s) – 

turnstile method 22 22 15 18 18 12 

Due to the number of occupants evacuating the three occupancies, especially in the case 

of the assembly space, the stairwells used in Table D are quite wide. The Life Safety 

Code specifies that handrails need to be placed 1.5 m (60 in) apart in order to provide 

support for occupants descending wider staircases. This handrail specification affects 

both the sprinklered and unsprinklered assembly spaces and the sprinklered business 

space. The calculations provided in Table D account for boundary layers (150 mm (6 in)) 

around the walls of the staircase, but not the handrails placed in the middle of the stair. 

Boundary layers from walls are used in evacuation calculations to account for lateral 

body sway in the stair9

. For this estimation of stair time, it is assumed that the occupants 

will allow their bodies to get within millimeters of the handrail, negating the need for 

additional boundary layers around handrails. It is possible that the presence of handrails 

in the center of a staircase can negatively affect the flow of occupants during egress, but 

there lacks a sufficient amount of data on this topic to include such in the estimation.

Thus the benchmark egress times on the initial floor implied in current building codes 

range from approximately 5.5 minutes (sprinklered assembly) to 0.3 min (unsprinklered 

residential), depending upon the method of calculation used and the type of occupancy. 

When added to the alarm time for the initial notification of the occupants (generally on 

the order of one minute from sustained ignition of the first item), estimated premovement times (Table A) and descent times (per floor times number of floors, Table D) 

as appropriate, these can be used to benchmark egress system performance for systems 

designed by calculation. 

Congestion and Merging Flows on Stairs 

Merging flows occur when occupants from a floor and the stairwell above enter the 

stairwell section simultaneously during downward flow. This can also occur during 

upward flow if occupants are traveling from basement levels of the building. In a highrise building, congestion points occur at each entrance into the stairway from all floors of 

the building. 

During merging flows, it is likely for researchers to witness the phenomenon of deference 

behavior. Deference behavior describes how occupants from the floors above yield to the 
InterFlam ’04 Page 13 of 15 4/28/2004 

occupants entering the stairwell from their floor. This behavior is often seen on airplanes 

where the rows leave before the passengers already waiting in the plane aisle. 

Merging flows and congestion frequently occur in high-rise buildings during full or total 

evacuation of the structure. Currently all US model building codes (International 

Building Code and NFPA5000) design tall buildings, particularly door and stair widths, 

based on a partial or phased evacuation plan for the building. The code specifies that the 

width of the stairs depends on the number of occupants on a particular floor, irrespective 

of building zones or the entire building population. This would result in congestion in 

high-rise buildings if the entire population evacuates simultaneously. Since 9/11, New 

York City has imposed a requirement for an evacuation drill (the entire population 

evacuating to the street) annually. It is reported that occupants of surrounding buildings 

seeing the evacuation themselves, then evacuate their buildings. Situations like this result 

in the opinion that the process for evacuation of tall buildings needs to be rethought. 

Elevators 

Currently there are no building codes that permit elevators to be used as a means of 

occupant egress, and ASME A17.118 requires signs at all elevators warning that they shall 

not be used in fires. NFPA 5000 permits protected elevators as a secondary means of 

egress for air traffic control towers and the City of Las Vegas accepted elevators as a 

primary means of occupant egress from Stratosphere Tower based on a performancebased design19. 

US codes require accessible elevators as part of a means of egress that may be used by 

the fire service to evacuate people with disabilities. These elevators must comply with 

the emergency operation requirements of ASME A17.1 (Phase II emergency operation by 

the fire service), be provided with emergency power, be accessible from an area of refuge 

or a horizontal exit (unless the building is fully sprinklered), and operate in a smoke 

protected hoistway. Phase II operation involves the use of an elevator by a firefighter for 

fire service access or for rescue of people with disabilities performed under manual 

control (with the use of a special key). 

According to a survey20 by the International Organization for Standardization technical 

committee on elevators (ISO TC178), there are twelve countries that require firefighter 

lifts, generally in buildings that exceed 30 m (98 ft) in height. Standards for firefighter 

lifts generally describe a firefighting shaft consisting of protected elevators, enclosed 

lobbies on each floor and an associated stairway, all of which have at least 1-hr fire 

resistance and smoke protection. Firefighters use the elevator to move their people and 

equipment to two floors below the fire, from which point they advance up the stairs, 

which contain a standpipe and provide a protected path for retreat. These firefighter lifts 

can be used to provide evacuation assistance for occupants with disabilities after 

suppression activities are underway. 

NIST studies have shown that the use of protected elevators to supplement stairs for 

occupant egress (not just for people with disabilities) can result in a significant reduction 
InterFlam ’04 Page 14 of 15 4/28/2004 

in total egress times, especially for taller buildings21. Given the observation that 

occupants may resist certain evacuation approaches, such as phased evacuation, protected 

elevators is clearly the most promising to address the problem without incurring huge 

penalties in decreased leasable space. 

Conclusions 

Based on the preceding analysis, the longest egress times expected in buildings designed 

in accordance with current (prescriptive) U.S. codes would occur in larger, assembly 

occupancies without fixed seating (the so-called festival seating) having the maximum 

occupant densities. Benchmark egress times would be approximately 4 minutes premovement, 5 minutes to get into the stairs, and 0.5 (25/60 s) minutes per floor to get to 

the level of exit discharge. 

In an office (business occupancy) egress times might be 3 minutes pre-movement, 5 

minutes to get into the stairs, and 0.3 minutes per floor to get to the level of exit 

discharge. In residential occupancies egress times might be 4 minutes pre-movement 

(but with much higher variability since there is likely additional delays to assist family 

members, obtain pets and valuables, etc.), 2 minutes to get into the stairs, and 0.3 minutes 

per floor to get to the level of exit discharge. These times attempt to account for queuing 

entering the stairs but do not include delays due to congestion within stairs that would be 

expected to increase with building height. 

These times represent estimates of the egress performance implied by egress system 

designs prescribed in current U.S. model building codes. These should not be taken as 

requirements nor even as the performance intended by the code developers, since this is 

the first attempt to quantify what might be expected from means of egress complying 

with the minimum requirements of the codes. The intent of this paper is simply to 

provide benchmarks that can be compared against performance-based egress analyses. 
InterFlam ’04 Page 15 of 15 4/28/2004 

References 

 

1

 1984 Fire Almanac, NFPA Quincy, MA 02269. 

2

Reily, E., “Third Code Revolution: A Brief History of US Building Codes,” Sprinkler Age, 10, 7, July 

1991. 

3 Building Standard Law of Japan, Official Translation by the Architectural Institute of Japan, Tokyo. 4 Nelson, H.E. and Mowrer, F.W. (2002), “Section 3, Chapter 14 Emergency Movement,” The SFPE 

Handbook of Fire Protection Engineering, 3 Edition, National Fire Protection Association, Quincy, MA. rd

5

 Gann, R.G., Averill, J.D., Johnsoon, E.L., Nyden, M.R., & Peacock, R.D., “Smoke Component Yields 

from Room-scale Fire Tests,” National Institute of Standards and Technology, NIST TN 1453, 159 pp., 

April 2003. 

6

 Bukowski, R. W., “Predicting the Fire Performance of Buildings: Establishing Appropriate Calculation 

Methods for Regulatory Applications,” Proc AsiaFlam ’95, International Conference on Fire Science and 

Engineering, March 15-16, 1995, Kowloon Hong Kong, pp 9-18. 

7

 International Building Code, 2003 edition, International Code Council, Inc., Falls Church, VA 22041. 8

 Building Construction and Safety Code (NFPA 5000-2003), National Fire Protection Assn., Quincy, MA 

02269. 

9

 Proulx, G. (2002), “Movement of People: The Evacuation Timing, Section 3 Chapter 13,” The SFPE 

Handbook of Fire Protection Engineering 3rd ed., P.J. DiNenno ed., NFPA, Quincy, MA. 10 Fahy, R.F. & Proulx, G., “Toward Creating a Database on Delay Times to Start Evacuation and Walking 

Speeds for Use in Evacuation Modeling,” Proceedings of the Second International Symposium on Human 

Behaviour in Fire, Boston, Mass., USA (2001). 

11 Brennan, P. “Timing Human Response in Real Fires,” Proceedings of the Fifth International Symposium 

on Fire Safety Science, Melbourne, Australia (1997). 12 Shields, T.J., Boyce, K.E., and Silcock, G.W.H., “Towards the Characterization of Large Retail Stores,” 

Proceedings of the First International Symposium on Human Behaviour in Fire, Belfast, UK (1998). 

13 Life Safety Code (NFPA 101-2003), National Fire Protection Assn., Quincy, MA 02269. 

14 Pauls, J. (1995), “Movement of People, Section 1 Chapter 15,” The SFPE Handbook of Fire Protection 

Engineering 2nd Edition, P.J. DiNenno, ed., NFPA, Quincy, MA. 15 Fruin, J.J., Pedestrian Planning and Design, Revised Edition, Elevator World, Inc., Mobile, AL, Fruin, 

J.J., ed, 211 p., 1987. 

16 Nelson, H.E. (1990), “FPETOOL User’s Guide,” NISTIR 4439, National Institute of Standards and 

Technology, Gaithersburg, MD. 

17 IES, “Simulex: Evacuation Modeling Software,” Integrated Environmental Solutions, Inc., March, 2001. 18 Safety Code for Elevators and Escalators ASME A17.1 2000, American Society of Mechanical 

Engineers, New York, NY. 

19 Bukowski, R.W., “Protected Elevators for Egress and Access During Fires in Tall Buildings,” Proc of the 

CIB-CTBUH Conf on Tall Buildings, 20-23 October 2003, Kuala Lumpur Mayalasia. 20 Comparison of Worldwide Lift (Elevator) Safety Standards – Firefighters Lifts (Elevators), ISO/TR 

16765:2002(E), ISO, Geneva, Switzerland. 

21 Klote, J.H., Alvord, D.M., Levin, B.M., and Groner, N.E. (1992), “Feasibility and Design Considerations 

of Emergency Evacuation by Elevators,” NISTIR 4870, National Institute of Standards and Technology, 

Gaithersburg, MD. 
Appendix H

Is There a Need to Enclose Elevator Lobbies in Tall 

Buildings?
26 Building Safety Journal August 2005

Is There A Need to 

ENCLOSE ELEVATOR LOBBIES 

IN TALL BUILDINGS?

by Richard W. Bukowski, P.E., FSFPE

Several proposals have been submitted in recent years

to model building code organizations to require

enclosure of elevator lobbies in order to restrict the

movement of smoke to other parts of buildings via hoistways. A significant development in this area occurred

recently when the National Institute of Standards and Technology (NIST)—which was already involved with a 

consortium of industry representatives, codes and standards

developers, and other interested parties in a study of the 

protection of elevators for occupant evacuation and fire

service access1

—was asked by the U.S. General Services

Administration (GSA) to research the conditions under

which enclosed elevator lobbies were called for. This article

will provide an overview of the progress made to date on

this line of research.

Background

Vertical shafts in tall buildings are subject to something called

“stack effect,” which describes an induction of airflow resulting from differences in temperature between the inside and

outside of the shaft. When the outside temperature is colder,

the induced flow is upward (normal stack effect); when the

outside temperature is warmer, the flow is downward (reverse

stack effect). While firestopping is effective in limiting the

upward spread of flames through vertical openings and shafts,

smoke is far harder to stop because even small leakages can

allow it to pass. This has led to the use of smoke management

systems which employ pressure differences to block smoke

flow even through small cracks2

.

There are several examples of fires in which smoke

spread in shafts has been implicated in deaths on upper

floors, with perhaps the most infamous being the November

21, 1980, conflagration at the MGM Grand in Las Vegas.

Although the flames were confined to the casino area on the

first floor of the structure, 61 of the 85 casualties occurred

on upper (above the 20th) floors due to smoke spread up

elevator hoistways and seismic joints between the building

core and wings.3

It is not surprising that such tragedies are frequently cited

as substantiation for proposals to enclose elevator lobbies.

However, the potential for smoke flow in hoistways is a

function not only of leakage of the elevator doors but also

of the strength of the stack flow, fire temperature (buoyancy

flows) and the height of the shaft. Each of these factors was

taken into account in NIST’s analysis of the potential flows

under varying conditions in order to identify those situations where significant shaft flows might be expected.

Shaft Flow Analysis

NIST contracted with John H. Klote, Inc.—which is a well

known for its expertise in the fields of both smoke management and elevators—for the analysis. Klote’s report contains the details of the scenarios examined and the results

obtained for each4 and was summarized in a paper presented

at the 2004 ASME Workshop on Use of Elevators in Fires

and Other Emergencies.5

Scenarios Studied

A number of primary variables were identified for study,

including building size and configuration (five types),

extent of fire (three types), lobby enclosure (two conditions), weather (winter or summer), and two alternate

methods of preventing smoke flow in the shaft. This

resulted in the 27 scenarios shown in Table 1, which were

then evaluated using a combination of numerical models

and NIST’s Consolidated Model of Fire Growth and Smoke

Transport (CFAST)6 and CONTAM multizone airflow and

contamination transport analysis software programs.7
August 2005 Building Safety Journal 27

Building Characteristics

The buildings considered were all office use and were assumed to have typical floor heights of 4.0 meters (13.1 feet) except

for the ground floors, which were assumed to have heights of 6.0 meters (19.7 feet). Total building heights ranged from 6

to 58 floors. The number of elevators and their arrangements were typical for the building’s sizes and configurations—see

Table 2. The buildings were based on several actual GSA office buildings previously studied.8

Table 2. Building Characteristics.

Flow Paths

Buildings are surprisingly leaky, and these leaks are characterized in the smoke management literature.9 Leakages occur

through construction cracks and around doors, especially elevator doors. Values typical of reasonably tight construction were

assumed for this study and are displayed in Table 3. Hoistway vents required by the building codes and increased leakage

due to warpage of some doors by the heat of the fire are included.10

Table 1. Scenarios Examined.

BUILDING NUMBER PASSENGER SERVICE

OF STORIES* ELEVATORS ELEVATOR

A 6 1 bank of 3 elevators None

B 13 1 bank of 6 elevators None

C 16 1 bank of 6 elevators None

D 35 3 banks of 6 elevators: 2

low, medium & high rise

E 58 3 banks of 8 elevators: 2

low, medium & high rise

FIRE FIRE ENCLOSED ALTERNATIVE SCENARIO BUILDING1

TYPE2 FLOOR3 ELEV. LOBBY WEATHER4METHODS5

1 A SP 2 Y W-NW none

2 A FDR 2 Y W-NW none

3 A FDF 2 Y W-NW none

4 A FDF 2 N W-NW none

5 B FDF 2 Y W-NW none

6 B FDF 2 N W-NW none

7 B FDF 2 N W-NW TB

8 B FDF 2 N W-NW JPC

9 C FDF 2 Y W-NW none

10 C FDF 2 N W-NW none

11 C FDF 2 N W-W none

12 C FDF 2 N W-NW TB

13 C FDF 2 N W-NW JPC

14 D FDF 2 Y W-NW none

15 D FDF 2 N W-NW none

16 D FDF 2 N W-NW TB

17 D FDF 2 N W-NW JPC

18 D FDR 2 Y W-NW none

19 D FDR 2 N W-NW none

20 D FDR 2 N W-NW TB

21 D FDR 2 N W-NW JPC

22 D FDF 36 Y S-NW none

23 D FDF 36 N S-NW none

24 E FDF 2 Y W-NW none

25 E FDF 2 N W-NW none

26 E FDF 2 N W-NW TB

27 E FDF 2 N W-NW JPC

(continued)

1. See Table 2.

2. SP is a sprinklered fire, FDR is a fully developed room fire, FDF for fully developed floor fire. 

3. FDR fires are located in a conference room on the floor indicated, FDF fires are located in the open floor plan space on that floor.

4. W-NW for winter with no wind, S-NW for summer with no wind, W-W for winter with wind.

5. TB for temporary barriers over elevator car doors. JPC for judicious positioning of cars within hoistways.

* Does not include mechanical penthouse.
28 Building Safety Journal August 2005

Weather

Because stack effect is driven by the difference between inside and outside temperatures, typical environmental conditions

needed to be taken into account. The following representative conditions were used in the calculations.

• winter outdoor temperature: -16°C (3°F)

• summer outdoor temperature: 35°C (95°F)

• wind speed: 11 meters per second (25 miles per hour)

Interior Temperature

Interior temperatures in buildings are normally maintained in a narrow range around 23°C (73°F), so that was the value used

in the calculations.

Limiting the Spread of Smoke in Shafts 

The spread of smoke in shafts can be limited by sealing leakages and/or by producing pressure differences that result in airflows in the desired direction. The recognition that many leakages are hidden or difficult to seal leads to the use of active

smoke management techniques, particularly for egress stairways, but there are some other techniques that might be 

effective in reducing leakages into elevator hoistways to low levels.

COMPONENT

PATH PATH FLOW AREA4

TYPE1 IDENTIFIER2 COEFFICIENT3 m2/m2 (ft2/ft2)

Exterior wall O W-EXT 0.65 0.00017

Exterior wall below grade5 O W-UG 0.65 0.000085

Interior wall O W-INT 0.65 0.00011

Elevator wall O W-EL 0.65 0.00084

Floor O FLOOR 0.65 0.000052

Roof5 O ROOF 0.65 0.000026

Closed doors m2 ft2

Single door T DR-SI 0.65 0.016 0.17

Double door T DR-DO 0.65 0.027 0.29

Elevator doors6 T DR-EL42 0.65 0.047 0.50

Large elevator doors7 T DR-EL48 0.65 0.049 0.53

Warped single door T DR-SI-W 0.65 0.043 0.46

Warped double door T DR-DO-W 0.65 0.070 0.75

Open doors

Single door T DR-SI-O 0.35 1.95 21

Double door T DR-DO-O 0.35 3.90 42

Shaft equivalent area8

Stairwell O STAIR 0.60 2.3 25

3-car passenger elevator O EL-P3 0.60 230 2500

4-car passenger elevator O EL-P4 0.06 360 3900

2-car service elevator O EL-S2 0.60 160 1700

Open elevator vent9

3-Car passenger elevator O EL-P3V 0.32 0.70 7.5

4-Car passenger elevator O EL-P4V 0.32 1.05 11.3

2-Car service elevator O EL-S2V 0.32 0.52 5.6

Roll down barriers T ROLL 0.65 0.011 0.12

Shafts with cars in place

3-car passenger elevator O EL-P3C 0.65 6.5 70

4-car passenger elevator O EL-P4C 0.65 9.1 98

Table 3. Flow Coefficients and Equivalent Leakage Areas for Building Flow Paths.

Elevator Lobbies in Tall Buildings (continued)

1. O indicates an orifice path for which flow is in one direction, T indicates a two-directional flow path. The two-directional flow is used for doors, and the

leakage is uniformly distributed over the height of the door.

2. The path identifiers are used with CONTAMW for data input.

3. The flow coefficient is defined as m A-1 (2 ρ p)-1/2 where m is the mass flow through the path, ρ is the density of gas flowing in the path, and p is the 

pressure difference across the path.

4. Areas for walls and floors are listed as area of flow path per unit of area of wall or of floor as appropriate.

5. Due to lack of experimental data, the flow areas of the exterior wall below grade and the roof were estimated at half that of the exterior wall and floor,

respectively.

6. This elevator door is 1.07 m (3.5 ft) wide. It is used for all passenger elevators in this study except for that in Building E.

7. This elevator door is 1.22 m (4.0 ft) wide. It is used for the passenger elevators in Building E and the service elevators.

8. Shaft equivalent areas are used to calculate the pressure losses due to friction in shafts. For more information, see chapter 6 of Klote and Milke (2002).

9. Vent area was calculated at 3.5% of the shaft area but not less than 0.28 m2 (3 ft2).

L
August 2005 Building Safety Journal 29

Landing doors for both passenger and freight elevators

are known to be particularly leaky because they open laterally by a mechanism carried on the elevator cars. Gaps, the

provision of safety mechanisms to prevent the doors from

closing on passengers, and the tendency of sliding doors to

jam when subjected to pressure differences all tend to exacerbate the leakage problem. As a result, solutions to reduce

smoke leakage into hoistways generally involve the provision of an enclosed lobby (creating an air lock with an entry

door capable of far better sealing against infiltration) or by

a roll-down barrier that covers the normal elevator door.

Both of these approaches were evaluated.

Suggestions have been made that hoistways themselves

could be blocked during a fire by an extendable or inflatable

barrier, mounted either within them or on the bottoms of the

cars, that would be deployed when needed. This approach

has many limitations (e.g., interference by the elevator

cables unless the car is above the barrier), but it was decided

to examine the potential for positioning a car near the

neutral plane to partially block the hoistway and reduce the

flow in the shaft. If found to be effective, this could be done

for no additional cost beyond programming elevator controllers appropriately. Therefore, the study also evaluated

the “judicious” positioning of elevator cars near the neutral

plane to limit shaft flow.

Another new technology is a type of elevator door seal

that is intended to be tight enough to restrict smoke leakage

into hoistways. These type of seals are currently being

tested in Japan (where they originate) and the U.S. In the

past, however, similar seals were found to be problematic

because they required adjustments to door closing forces

that increased the hazard of passengers becoming struck. It

remains to be seen if the newer seals will perform better.

Methodology

Fires on a lower floor during winter and on an upper floor

in summer were examined to determine the quantity of

smoke that might spread to the upper or lower floors,

respectively, by means of the hoistways (heat is not a significant hazard long distances from a fire source because

temperatures rapidly diminish to near ambient level through

entrainment and heat losses to the surroundings). It was

assumed that all exterior and interior stairway doors were

closed. Windows to the exterior were also assumed to be

closed except for in the case of a fully developed floor fire,

the intense heat of which can break the glass.

The hazards of smoke obscuration and toxic potency were

assessed using engineering criteria frequently employed in

building performance analysis.11 A fire (heat release rate)

curve representative of the scenario being considered was

first chosen—see Figure 1 for the heat release rates selected.

Then the CFAST fire model was used to determine the

burning rate as affected by the geometry and ventilation,

resulting in the production over time of energy, smoke particulates and combustion gasses. Consumption of oxygen

and its effect on burning rate and combustion chemistry was

also computed.

The energy and mass produced moves through the building by buoyancy and building flows, including stack effect.

These were calculated by the model CONTAM, resulting in

estimates of temperature, smoke density and gas concentrations over time in spaces remote from the fire. The exposure

of evacuating occupants would change as they moved from

space to space, but the analysis used the more conservative

approach of evaluating the exposure of stationary occupants

in order to take into account those with disabilities or otherwise unable to escape.

Results

As expected, sprinklered fires were not shown to represent

a significant hazard to occupants because the sprinklers

activated and extinguished the fires before they could

release significant energy or mass. Little or no smoke or

gasses entered the hoistways, and none reached remote

locations in any building regardless of height or other conditions examined. (continued)

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30 Building Safety Journal August 2005

Fully developed room fires (flashovers) released significant energy and mass, and strong fire-induced flows drove

those products to the hoistways. Enclosed lobbies prevented

any substantial portion of that mass or energy from entering

the hoistways, but the absence of a lobby resulted in untenable conditions in terms of reduced visibility and toxicity on

the upper floors of the tallest building, which had the greatest stack effect.

Where the fire spread to the entire floor, enclosed lobbies

continued to provide some protection, allowing sufficient

smoke to exceed visibility limits at remote locations in all of

the buildings but limiting toxicity to less than the limiting

value for the time studied. In addition, times at which visibility limits were exceeded occurred significantly later

when lobbies were present. The increases in time to untenable visibility increased by 50 percent to 200 percent for

lobbies enclosed by normal construction and by 0 percent to

20 percent with the use of roll down barriers due to their

greater leakage characteristics (temporary barriers with

better leakage characteristics would be expected to perform

better). Without lobbies, tenability conditions for both visibility and toxicity were exceeded at locations remote from

the fire in all buildings regardless of height.

The “judicious” positioning of elevator cars had no effect

on smoke flow in the hoistways because the leakage area

around cars is quite large.

Discussion

It may therefore be concluded from the study results that

enclosed elevator lobbies are not necessary in buildings

with operational fire sprinkler systems. From a risk management perspective, this means that the need for enclosed

elevator lobbies depends on the probability that a sprinkler

system will not work (operational reliability) and the consequences (expected losses) of such a failure.

Sprinkler System Reliability

Data on in-service failures of wet pipe sprinkler systems in

U.S. Department of Energy (DOE) facilities show operational reliabilities of 99.2 percent,12 but these systems are

subject to testing and maintenance programs more rigorous

than those typically performed on commercial systems.

Studies of commercial sprinkler systems installed per industry standards indicate an operational reliability of about 95

percent,13 so the decision whether or not to incorporate

enclosed lobbies might be based on a 5-percent probability

of sprinkler system failure unless a maintenance program

comparable to the DOE’s is in place.

Statistics indicate that most sprinkler system failures are

due to impaired water supplies such as closed valves,

blocked pipes, impaired sources, etc., which tend to affect

sections of or the entire system. As such, system reliability

can be increased by active monitoring of water supplies and

controls. The general consensus is that problems with individual sprinkler heads are rare. However, it may well be

asserted that current data do not accurately reflect the

upsurge in the use of quick-response heads, and the fact that

several models of these have been involved in recent recalls

underscores the need to update field reliability data for light

hazard systems commonly used in business and residential

occupancies.

Consequences of Failure

Minimal stack effect was produced in shafts—including

hoistways—in low-rise buildings (less than 7 stories or 75-

feet high), so the spread of smoke and fire gasses to upper

floors may be considered to be of no great concern even

when there are no operational sprinklers. While smoke from

fully developed floor fires exceeded tenability limits in lowrise buildings without elevator lobbies, this occurred long

after such buildings would be expected to be fully evacuated. A risk manager might therefore conclude that enclosed

lobbies are not needed in low-rise buildings, particularly

when sprinklered.

In taller buildings, which experience greater stack effect

and require more time for occupant egress, untenable conditions are reached much sooner if lobbies are not provided

and if sprinkler system failure allows a fire to grow to room

Elevator Lobbies in Tall Buildings (continued)
August 2005 Building Safety Journal 31

flashover or full floor involvement. A risk manager may

therefore decide to provide enclosed elevator lobbies in

high-rise buildings even when sprinklered unless the sprinklers can be shown to have operational reliabilities similar

to that achieved by DOE systems. Elevator lobbies should

be of 2-hour fire-resistance rated construction (1-hour rated

in fully sprinklered buildings) and have direct access to an

egress stair. ◆

Richard W. Bukowski, P.E., FSFPE, is a Senior Engineer

and Coordinator of Standards and Codes for the National

Institute of Standards and Technology Building and Fire

Research Laboratory, chairs several committees and task

groups for the National Fire Protection Association

(NFPA), is Coordinator of the International Council on

Building Standards and Documentation (CIB) Working

Commission 14: Fire, and is active in the work of CIB

TG50: Tall Buildings. He is also the U.S. representative to

ISO TAG8, which advises the International Organization

for Standardization (ISO) Technical Management Board

and provides oversight to all ISO Technical Committees

working in the building and fire areas, and served on the

committee that developed the International Code Council

Performance CodeTM for Buildings and Facilities and on

NFPA’s Standards Council.

Bukowski is a Fellow of the Society of Fire Protection

Engineers and a licensed Professional Engineer in the

States of Illinois and Maryland. His professional awards

include being was named 1997 Automatic Fire Alarm

Association Person of the Year and 2003 Commerce

Department Federal Engineer of the Year by the National

Society of Professional Engineers.

References

1. Bukowski, R.W., “Protected Elevators for Egress and

Access During Fires in Tall Buildings, Strategies for 

Performance in the Aftermath of the World Trade Center.”

Proceedings of the International CIB-CTBUH Conference

on Tall Buildings. CIB Publication No. 290. F. Shafii, R.

Bukowski and R. Klemencic (Eds.). pp 187–192, 2003.

2. NFPA 92, Recommended Practice for Smoke Control

Systems. National Fire Protection Association.

3. Best, R. and D.P. Demers, “Investigation Report on the

MGM Grand Hotel Fire—Las Vegas, Nevada, November

21, 1980,” Fire Journal 76(1), pp 19–37, January 1982.

4. Klote, J.H., “Hazards Due to Smoke Migration through

Elevator Shafts,” NIST GCR04-864-I, Volume 1: Analysis

and Discussion, and NIST GCR04-864-II Volume 2:

Results of Tenability Calculations. National Institute of

Standards and Technology, 2004.

5. Klote, J.H., “Analysis of the Consequences of Smoke

Migration through Elevator Shafts,” Workshop on Use of

Elevators in Fires and Other Emergencies, Conference

Proceedings. Co-sponsors: ASME International, the

National Institute of Standards and Tech-nology, the 

International Code Council, the National Fire Protection

Association, the U.S. Architectural and Transportation

Barriers Compliance Board, and the International Association of Fire Fighters.

6. Peacock, R.D., et al., NIST Technical Note 1299, CFAST,

the Consolidated Model of Fire Growth and Smoke Transport. National Institute of Standards and Technology,

1993.

7. Dols, W.S. and G.N. Walton, NISTIR 6921, CONTAMW

2.0 User Manual. National Institute of Standards and

Technology, 2002.

8. Klote, J.H., et al., NISTIR 4770, Staging Areas for

Persons with Mobility Limitations. National Institute of

Standards and Technology, 1992.

9. Klote, J.H. and J.A. Milke, Principles of Smoke Management. Amercan Society of Heating, Refrigerating and AirConditioning Engineers, 2002.

10. VanGeyn, M, National Fire Door Fire Test Project Technical Report 6285, Positive Pressure Furnace Fire Tests.

Fire Protection Research Foundation, 1994.

11. Purser, D.A., “Toxicity Assessment of Combustion Products,” SFPE Handbook of Fire Protection Engineering.

Third Edition. P.J. DiNenno (Ed.). National Fire Protection Association, 2002.

12. Bukowski, R.W., E.K. Budnick and C.F. Schemel,

“Estimates of the Operational Reliability of Fire Protection Systems,” International Conference on Fire Research

and Engineering, Third Proceedings, pp 87–98. Cosponsors: the Building and Fire Research Laboratory, the

National Institute of Standards and Technology, and the

Society of Fire Protection Engineers.

13. Maybee, W.W., “Sprinkler Performance Update,

1952–1986,” Sprinkler Quarterly, pp 49–51, Spring 1987.
Appendix I

Protected Elevators and the Disabled
SFPE Fire Protection Engineering Page 1 of 10 8/31/2005 

Protected Elevators and the Disabled 

Richard W. Bukowski, P.E., FSFPE 

NIST, Building and Fire Research Laboratory 

Gaithersburg, Maryland 20899 USA 

It was 1989 and I was giving a talk to local federal agencies on the newly-released 

HAZARD I software and its promise for performance-based design for fire safety. After 

the talk several attendees came up to talk to me, including a gentleman in an electric 

wheelchair. He told me that he worked on the 10th floor of a nearby, high-rise office 

building and that when he first came to work there the safety officer did not really know 

what to do with him. He was instructed that in case of a fire evacuation, he was to go to 

the stairway. If there was someone there to open the door (he was quadriplegic and could 

not grip nor turn the knob) he should proceed onto the top landing. Otherwise he should 

wait at the stairway door for assistance. He told me that it was clear to him that they 

wanted to know where to go to collect the body. 

It was just the next year, 1990, when the Americans with Disabilities Act (ADA) was 

passed to provide equal access to public buildings for all Americans. The objective of the 

ADA regulations was to permit people with disabilities access to the places where we 

live, work, and play with little thought of how they would get out in case of emergency. 

Fifteen years later we are still addressing this important issue. 

The purpose of this article is to present the issues that need to be addressed in the 

development of elevators that can be used in fires to safely evacuate occupants, 

particularly those with limited mobility that affects their ability to use stairs. 

Accessibility 

The ADA accessibility requirements are intended to 

result in public buildings that can be accessed and 

used by people with a range of limitations including 

vision, hearing, and mobility. The guidelines provide 

for signs that include Braille markings, strobe lights 

and other visible warnings, and doors with powered 

openers that are wide enough for wheelchairs. 

Smaller changes in elevation require ramps or 

platform lifts that eliminate barriers to wheelchair 

users. 

Building codes contain special provisions for an 

accessible means of egress that either leads out of the 

building (including through a horizontal exit) or to an 

area of refuge, which may be served by an accessible 

elevator. Elevators are the primary means of routine 

ingress and egress for all occupants in most buildings 

and under most conditions, except during fires. 

Elevators are posted with signs warning that they are 

Accessible elevators are required 

by the Building Codes and ADA 

requirements 
SFPE Fire Protection Engineering Page 2 of 10 8/31/2005 

not to be used during a fire. Occupants and firefighters are relegated to stairways that 

may have only the capacity to carry the occupants from a few floors at a time, without the 

counterflow of firefighters trying to move up carrying equipment. And what about those 

people with disabilities (including both disabilities as defined by the ADA and those 

occupants who needed assistance to exit long distances) who now represent 6% to 10% of 

the occupant load? 

Elevator Safety 

While lifts for goods have been in use for thousands 

of years it is only since the development in 1854 of 

the automatic safety brake by Elisha Graves Otis 

that the passenger elevator became a reality. Often 

cited as the safest mode of human transportation, 

millions of people ride elevators daily without 

incident. This laudable safety record has been 

achieved through the pervasive safety culture of the 

elevator industry and the committees who write the 

safety codes that govern the design, installation, 

operation, maintenance, and inspection of passenger 

elevators. In the U.S., this is the American Society 

of Mechanical Engineers (ASME) A17.1 

Committee. 

The issue addressed by Otis’ brake was a failure of 

the lifting rope causing the car to fall. Doors or 

gates on the landing opening and car prevented 

people from falling out or getting their body parts 

caught between the car and shaft wall. Additional 

improvements in safety and reliability over the 

years have led to the admirable safety performance 

of modern elevators. 

A fundamental industry assumption is that 

entrapment in an elevator is a fail-safe condition 

and a special system has been implemented to 

ensure that trapped passengers can be extracted 

quickly and safely. Every elevator is equipped 

with a telephone to summon help, and every elevator maintenance contractor has 

technicians on call 24/7 to respond. Even in major incidents such as the 2003 blackout in 

the Northeast U.S. and Canada, hundreds of entrapment calls were cleared in only a few 

hours. The acceptance of temporary entrapment leads to the common arrangement that, 

if the many safety controls on an elevator sense something is going wrong, the elevator 

controller shuts the system down. In recent times it has been recognized that there are 

two conditions where entrapment is not a safe condition – during an earthquake or during 

a fire. 

Safety brakes located under the car are 

triggered by an overspeed governor in 

the machine room (drawing courtesy 

Mitsubishi) 
SFPE Fire Protection Engineering Page 3 of 10 8/31/2005 

Door Restrictors 

A more recent safety device required on passenger elevators is called a door restrictor. 

These are devices that restrict the ability of a passenger to force open the car door unless 

the floor of the car is within at least 75 mm but not more than 450 mm (3 in to 18 in) 

above or below the level of the landing. Passengers have been known to force open the 

doors and fall down the hoistway if the car became stuck or even to “joyride” on the top 

of the car, especially since the roof hatch began to be locked from the inside. These door 

restrictors have been successful at eliminating many injuries and deaths (according to 

decreases in reports of deaths and injuries from falling down shafts all of which occur in 

elevators not retrofit with door restrictors), but became an issue in the WTC Towers on 

September 11, 2001. There were several cases of occupants entrapped in cars that were 

not close enough to the landing to release the restrictor. The industry is now studying 

ways of releasing restrictors in an emergency that would not lose their safety function in 

other circumstances. 

Elevators and Earthquakes 

The vertical and lateral motions associated with a seismic event can affect the operational 

safety of an elevator. In an earthquake it is possible for the elevator or its counterweight 

(for traction elevators) to be jarred out of their guide rails. The most dangerous result is 

where the car runs into the counterweight. Thus the elevator code requires that all 

elevators located in Seismic Zone 2 or greater are designed with greater clearances, 

retainer brackets where the car and counterweight attach to the rails and with seismic 

switches set to activate at an acceleration of 0.15 g. Activation of the switch causes the 

car to stop, and move in the direction away from the counterweight to the next available 

landing where the doors open and the car is locked out of service until the system is 

manually reset. This can only be done from the machine room by an elevator technician 

after determining that the system can operate safely [ASME 2004]. 

Elevators and Fires 

Beyond the direct impacts on the safe operation of the elevator, there are several 

interactions between the elevator system and the building during a fire. One is the 

hoistway as a vertical shaft spreading smoke through the building. Most landing doors 

open horizontally and are far leakier than other types of doors. The shaft itself is subject 

to what is known as stack effect, which is a vertical airflow resulting from differences in 

indoor to outdoor temperatures and the height of the shaft. This shaft flow draws air into 

or out of the shaft through the landing doors depending on the position of the landing 

relative to the neutral plane and the direction of the shaft flow. [Klote and Milke 1992] 

Stack effect flows are driven by differences in indoor and outdoor temperatures with 

upward flows in winter (outdoors colder than indoors) and downward in summer 

(outdoors warmer than indoors). The greater the difference, the greater the flow; 

therefore stack effect is larger in more extreme climates and for taller shafts. Even 

without a fire, stack effect flows can cause problems in tall buildings, resulting in strong 

flows and noise at landing doors near the top and bottom of the shaft. These flows can 

cause jamming of landing doors and may require seasonal door adjustments by elevator 

technicians. During a fire, stack effect flows can carry smoke and fire gases to remote 
SFPE Fire Protection Engineering Page 4 of 10 8/31/2005 

parts of the building. For example, in the MGM Grand [Fire Journal 1981] and DuPont 

Plaza [Klem 1987] fires which both occurred near the ground floor level, there were 

fatalities on upper floors due only to smoke carried up elevator shafts by stack effect 

flows. 

It is important to note that both examples occurred in unsprinklered (at least in the area of 

the fire) buildings. A recent analytical study by the author [Bukowski 2005] showed that 

stack effect flows sufficient to create safety problems on upper floors would not be likely 

in fully sprinklered buildings (with working sprinkler systems) or in buildings not tall 

enough (less than 75 feet under less than extreme weather conditions) to produce strong 

shaft flows. In some mission critical applications it might be appropriate to provide for 

the small likelihood of a failure of the sprinkler system. [Bukowski 2005] 

Elevators and Water 

Water from fire sprinklers or hose streams can result in safety problems for elevators 

during fires. Water can enter the hoistway and cause electrical shorts in safety controls 

causing them to fail. Water on the drum of the elevator machine can cause the car to slip 

although the safety brake would stop a car from overspeed or falling down the shaft. 

To address this situation, elevators protected by sprinklers in the hoistway or machine 

room are equipped with a shunt breaker to deenergize main power before a sprinkler 

activates. Connected to a heat detector that would activate before the sprinkler, the shunt 

breaker activation removes power and stops the elevator, but can result in entrapment. 

The shunt breaker will not protect the system from water from sprinklers or hose streams 

at landings leaking into the hoistway. 

Firefighters Emergency Operation 

In the mid-1970’s the elevator industry 

developed firefighters emergency operation

to improve the safety of the system during 

fires. Smoke detectors are installed in the 

elevator lobby within 6.4 m (21 ft) of any 

landing door on each floor. The smoke 

detectors protect the elevator system by 

detecting any encroachment of the fire and 

triggering Phase I recall. Here the elevator 

cars are sent immediately to the designated 

landing which is generally the level of exit 

discharge. There the elevators stop, the 

doors open, and the elevators are locked out 

of service. If a fire is detected on the 

designated landing, the cars are sent to 

an alternate floor. 

A fire operation instruction panel is required in every 

elevator fitted for this service (courtesy ASME )

Upon their arrival, firefighters are able to place individual cars back into manual service 

by use of a firefighters key, in what is called Phase II operation. While operating in this 
SFPE Fire Protection Engineering Page 5 of 10 8/31/2005 

mode, a light on the car control panel marked with the symbol of a firefighters hat is 

illuminated. In this mode, the controls in the car operate in a special manner designed to 

protect the firefighter operating the car. For example, the car will move to a selected 

floor but the doors will not open. Depressing the door open button opens the doors but 

only as long as the button is depressed. Thus, if smoke enters the car and the firefighter 

reacts by jumping back, the door will close. 

Additional smoke detectors installed at the top of the hoistway and in the machine room 

monitor the system integrity. If activated, the firefighters hat light in the car begins to 

flash warning the operator that the system may become erratic and to move to a safe 

location. 

It is generally accepted by the experts that as long as the system is operating in normal 

service (before Phase I activates) the elevators are safe to use, even if there is a fire in the 

building. Such a fire would need to be sufficiently remote from the elevator lobby so as 

to not have activated a lobby smoke detector triggering Phase I recall. 

Elevator Assisted Egress 

In the wake of the September 11, 2001 attacks on the World Trade Center Towers, the 

concept of protected elevators for occupant egress and for fire service access from tall 

buildings received new interest. The primary issues are the need for more rapid egress 

from very tall buildings and additional capacity to support simultaneous evacuation of 

occupants who were now reluctant to await a phased evacuation. Since even minimal 

additional egress capacity by stairs has a very large cost penalty in lost leasable space, 

use of the elevators that are already present is a logical approach. But arguably the most 

important issue is to provide for self-evacuation of people with disabilities and those for 

whom evacuation down long stairways presents significant difficulties. 

1993 and 2001 WTC Evacuations 

In the 1993 bombing at the World Trade Center, it was found that many more occupants 

experienced difficulties than just those with traditional disabilities. People with 

temporary disabilities such as broken legs, people with asthma, pregnancy, or obesity all 

reported difficulties in mobility or stamina that limited their own evacuation abilities and 

that of others behind them in the stairways. 

Recently Bukowski and Kuligowski [Bukowski and Kuligowski 2004] benchmarked 

evacuation times for egress systems designed in accordance with modern building codes. 

They found for office occupancies that it requires about 5 minutes to empty a floor and 1⁄2

to 1 minute per floor to egress down stairs without delays for queuing, congestion, or 

resting (total evacuation times would further need to include pre-evacuation times). 

Based on this benchmark, the World Trade towers would have required 1 to 2 hours 

(without congestion delays). Observed evacuation time in the 1993 bombing and total 

evacuation time in 2001 estimated for a full occupant load of 25,000 by state-of-the-art 

egress models that included queuing and congestion was about double the best case times 

or about 4 hours. [Fahy and Proulx, 2002] 
SFPE Fire Protection Engineering Page 6 of 10 8/31/2005 

One crucial observation from 2001 involves the evacuation of 2 World Trade Center 

(South Tower) in the 16 minutes between the aircraft strike on the North Tower and the 

strike on the South Tower. Having seen what happened to the North Tower, many of the 

occupants in the South Tower decided to evacuate. Since their building was undamaged 

many used their normal procedure of elevators. NIST estimated that about 3000 people 

evacuated from above the (eventual) aircraft strike zone using the stairs or elevators 

[Averill 2005]. After the South Tower was hit NIST estimated that only 18 additional 

occupants escaped from above the impact region. 

Protected Elevators 

NIST has been working on the development of protected (also called hardened or Phase 

III) elevators in cooperation with the elevator industry, fire alarm industry, and key codes 

and standards organizations in the hope of developing the needed technology and code 

provisions to put these into practice. This work is making slow but steady progress and 

should be ready for demonstration in a year or two. 

Early work focused on the issues discussed previously including water sensitivity and 

protection of the elevator system from the fire. Enclosed and (real time) monitored 

lobbies would provide a protected space for occupants to await the elevator as well as an 

additional layer of passive protection for the hoistway. Information displays and 

communication to the fire command station would provide reassurance to those waiting, 

and direct access to a stair would provide a second way out for those capable of using it. 

It is expected that people with disabilities would be given priority access to the elevator 

cars. [Bukowski 2003] 

An important benchmark of elevator evacuation performance can be seen in the typical 

design objective for elevator systems. The number, capacity, and speed of elevators are 

typically designed to move 15 % of the total occupant load of the building in 5 minutes. 

This means that a typical system utilizing an efficient evacuation protocol (e.g., ignoring 

hall and car calls and operating in a shuttle mode between a 3-floor fire zone and the 

level of exit discharge) would be capable of evacuating the entire occupant load of 3 

floors of a 20 story building or 6 floors of a 40 story building in 5 minutes. 

Layers of Protection 

In order to protect the elevator system from compromise by the fire and provide a 

protected space in which to wait, protected elevator systems would incorporate enclosed 

lobbies on each floor above the level of exit discharge and would be found in fully 

sprinklered buildings. In a 1993 report done for GSA, Klote et al [Klote 1993] found that 

separate staging areas were not needed in fully sprinklered buildings since the entire 

building remains tenable as long as the sprinkler system is operational and the fire is not 

shielded from the sprinkler. The addition of protected lobbies adds an additional layer of 

protection, not only for the elevator, but also for occupants awaiting the arrival of the 

elevator. This is particularly important for occupants who cannot use the stairs and who 

need to be protected in place until they can egress using the elevators or be assisted by 

others. 
SFPE Fire Protection Engineering Page 7 of 10 8/31/2005 

Hoistway pressurization 

Another function of the lobby is to prevent smoke from exposing people waiting for the 

elevator as well as to prevent smoke from entering the hoistway. While the lobby 

enclosure can be made smoke tight, the door will be opened repeatedly as occupants 

enter, so a pressurization system would be needed. Based on prior NIST work, it is 

important to minimize pressure differences across the landing door that might lead to 

jamming [Klote 1982]. Thus, a system where the hoistway is pressurized and a positive 

pressure of the lobby (with respect to the rest of the floor) is produced by leakage through 

the landing door, will provide the desired result. Pressurization of the order of 12 Pa 

(0.05 inches of water) is a reasonable design value [Klote and Milke 1992]. 

Real-Time Monitoring 

An important layer of protection is the 

ability of the fire service to monitor 

the conditions within the lobbies, 

hoistway and machine room in real 

time to ensure that there are no threats 

to people or systems. These 

monitoring functions will be carried 

out by the fire alarm system and 

displayed in the fire command station 

on a special fire service display. These 

displays comply with National Fire 

Protection Association (NFPA) and 

National Electrical Manufacturers 

Association (NEMA) standards so that 

they are consistent in form and 

operation across all equipment 

manufacturers. All conditions and 

functionality critical to the safe and reliable operation of the system are monitored. 

Conditions in lobbies and status of elevators can be 

displayed in real time in the building fire command 

station 

Information systems 

Crucial to the safety and peace of mind of occupants using the system is the provision of 

real time information on the system status. Displays in the lobbies will show waiting 

occupants that the elevators are in service and how long they will need to wait to be 

served. People who are capable of using the stairs will be free to do so if they feel the 

wait is too long, either taking the stairs to a lower level to reenter and await an elevator, 

or all the way to the street. Should it be necessary to take the elevators out of service, the 

lobby display would indicate that those capable should use the stairs and others could 

communicate directly with the fire command station to request assistance. 

Evacuation mode 

Elevators are the most efficient at moving people in “shuttle mode” where the times 

associated with deceleration, loading, and acceleration are minimized. Thus it has been 

proposed to establish an evacuation mode of operation that will optimize system 

performance. 
SFPE Fire Protection Engineering Page 8 of 10 8/31/2005 

In general, evacuation mode would be triggered on a general alarm in the building. All 

elevators would be captured and returned to the level of exit discharge to unload any 

passengers. An automatic message in the elevators would explain that there is an 

emergency reported in the building and the elevators are being put into service to assist in 

evacuation. Signs on the discharge level would warn people not to enter. One (predesignated) car would be held for fire service access and the rest would go into 

evacuation service; moving to the first priority floor group (fire floor, one above and one 

below). Destination buttons in the car (Car calls) would be disabled and the buttons that 

summon the elevator to a floor (hall calls) would register where occupants are awaiting 

the elevator for egress but would not direct service. 

Once the first priority group of floors is evacuated, the system would serve additional 

floor groups in a logical order until all occupants have been evacuated. If Phase I recall 

is activated at any time in the process, evacuation mode would end, but cars could be put 

into Phase II service if the fire service considers it safe to do so. 

Mobility Impaired Occupants 

The evacuations of the World Trade Center towers 

in 1993 and in 2001 provided some common 

lessons regarding egress of people with impaired 

mobility. First, there are more people who have 

difficulty in moving long distances down stairs in 

very tall buildings than those who usually come to 

mind. People with temporary disabilities (broken 

legs/sprains using canes or crutches, pregnant, or 

those injured in the initiating event), asthmatic or 

other respiratory conditions, obese or other 

conditions that limit stamina, all have been 

observed to require extra time and frequent rest 

stops. In the WTC evacuation 6% of the survivors 

reported having some pre-existing condition that 

limited their mobility. If you add to that, people 

injured by the initiating event or just after 

beginning to evacuate the number could be higher. 

Even women in high heels and men in new dress 

shoes were reported to have caused backups in 

stairs by moving more slowly [Averill 2005]. 

While 6% is not unreasonable for traditional 

disabilities, designing for a disabled population of 

10% would be conservative for many buildings. 

In some buildings such as residences for the elderly, the proportion could be considerably 

higher. A recent paper [Sekizawa 2004] mentions a fire in Japan where 80% of the 

elderly occupants were unable to evacuate down the stairs and used the elevators 

successfully. 

This smokeproof elevator is installed at 

an Italian residential facility for mobility 

impaired people to provide access and 

egress. The glass hoistway enclosure 

permits the fire service to determine if the 

elevator is in use. (courtesy CNR) 
SFPE Fire Protection Engineering Page 9 of 10 8/31/2005 

In the September 11, 2001 evacuation, first responders moving down stairs in WTC 1 

after the collapse of WTC 2 found 40 to 60 mobility impaired occupants on the 12th floor 

where they had been moved. About 20 of these occupants were being assisted down the 

stairs just prior to the collapse of WTC 1. It is unclear how many of these or the 20 to 40 

others who had been staged on the 12th floor perished [Picciotto 2002]. 

Conclusions 

Protected elevators that can provide for unassisted egress of occupants with disabilities 

can result in significant reductions in total evacuation times for tall buildings and more 

efficient flows in stairs by people capable of using them. Considering the optimum flow 

rates down stairs of 30 seconds per floor without congestion or the need to stop and rest, 

elevators designed to move 15% of the occupant load in 5 minutes could evacuate 60 

floors (including wait times) in the same time it takes for occupants to descend 60 floors, 

or 30 minutes. 

By reducing stair flow impediments through the use of elevators for up to half the 

population it should be possible to totally evacuate buildings of any height in the order of 

30 minutes. Those using the elevators would include all people with disabilities and 

those highest in the building, while the stairs would be used by the most physically 

capable from the lower floors. This approach is used by the 88-story Petronas Towers in 

Kuala Lumpur, Malaysia where a total evacuation time in a drill was reported to be 32 

minutes, utilizing a combination of stairs and elevators. [Arliff 2003] 

References

 Arliff, A., Review of Evacuation Procedures for the Petronas Twin Towers, Proc CIBCTBUH Conference on Tall Buildings, Kuala Lumpur Malaysia 2003. 

 ASME, Safety Code for Elevators and Escalators, ASME A17.1-2004 Section 8-

4.10.1.3, ASME New York, NY 2004. 

 Averill, J., et al, Federal Building and Fire Safety Investigation of the World Trade 

Center Disaster: Occupant Behavior, Egress, and Emergency Communications, NCSTAR 

1-7, NIST Gaithersburg, MD 20899 2005. 

 Bukowski, R.W., Is There a Need to Enclose Elevator Lobbies in Tall Buildings, 

Building Safety Journal, Vol III, No. 4, ICC Whittier, CA, August 2005. 

 Bukowski, R.W., Protected Elevators for Egress and Access During Fires in Tall 

Buildings, Proc CIB-CTBUH Conference on Tall Buildings, Kuala Lumpur Malaysia 

2003. 

 Bukowski, R.W. and Kuligowski, E.D., The Basis for Egress Provisions in U.S. 

Building Codes, Proc InterFlam 2004, Interscience Communications, London, 2004. 

 Fire Journal, Fire at the MGM Grand, NFPA Fire Journal, Vol. 75, No. 2, 33-36, March 

1981. 

 Klem, T., 97 Die in Arson Fire at DuPont Plaza Hotel, Fire Journal, Vol. 81, No. 3, 74-

77, 79,+, May/June 1987. 

 Klote, J. H., Elevators as a Means of Fire Escape. American Society of Heating 

Refrigerating and Air Conditioning Engineers Transactions, Vol. 89, No. 2, 1-16, 1983. 

NBSIR 82-2507; 37 p. May 1982. 
SFPE Fire Protection Engineering Page 10 of 10 8/31/2005 

Klote, J.H., Nelson, H.E., Deal, S., and Levin, B.M., Staging Areas for Persons with 

Mobility Limitations, NISTIR 4770, Nat Inst Stand Tech, 18p, Jan 1993. 

 Klote, J.H. and Milke, J.A., Design of Smoke Management Systems, ASHRAE 1992. 

 Fahy, R. and Proulx, G., A Comparison of the 1993 and 2001 Evacuations of the World 

Trade Center, Proc Fire Risk and Hazard Assessment Research Application Symposium, 

Fire Prot. Res. Foundation, Quincy, MA July 24-26, 2002. 

 Picciotto, R., Last Man Down, Berkley Publishing, NY, NY 2002 

 Sekizawa, A., Nakahama, S., Notake, H., Ebihara, M., and Ikehata, Y., Study on 

Feasibility of Evacuation Using Elevators in High-Rise Buildings, Proc ASME 

Workshop on Emergency Use of Elevators, Atlanta GA March 2-4 2004. 
Appendix J

Elevator Controls

N F PA JOURNAL MARCH/APRIL 2006 4 3

By Richard Bukowski, P.E.

Russell Fleming, P.E.

Jeffrey Tubbs, P.E.

Christopher Marrion, P.E.

Jill Dirksen

Chris Duke

Debbie Prince

Lee F. Richardson

Lieutenant Dave Beste, and

Dottie Stanlaske

Elevator

controls

It is important that all parties, from rescue

personnel to building designers understand

the intent of the fire service operation

provisions of ASME A17.1, Safety Code for

Elevators and Escalators.

THE DEVELOPMENT OF THE PASSENGER ELEVATOR is tied directly

to the emergence of tall buildings. While various types of freight lifts

were found in warehouses and factories before the advent of the highrise, these were considered too dangerous to move people. 

In 1854, however, Elisha Graves Otis demonstrated an automatic

safety brake that changed the landscape. Within a few years, his steam

elevators had eliminated one of the major limits to building height. 

Elevator
But, while elevators proved to be one of the

safest forms of transportation, there were

instances where people were killed while using

elevators during building fires. Heat sometimes activated call buttons bringing cars to

the fire floor where smoke prevented the

doors from closing (light beams are in modern

day elevators to detect people in the doorway)

and water in the shaft sometimes shorted out

electrical safety devices or may have caused

failure of braking systems. Thus, the use of

elevators for occupant egress or fire department access was discouraged.

In 1973, the elevator industry developed a

system that recalls elevators and takes them

out of service if smoke is detected in the lobbies, machine room, or hoistway. Mandated

in the American Society of Mechanical Engineers (ASME) A17.1, Safety Code for Elevators

and Escalators,

1 for all automatic passenger elevators, this system involves two distinct

phases of emergency operation. 

In Phase I, the detection of smoke or heat

causes the elevators to be recalled to the ground

floor, unless this is where smoke was detected.

The doors open, and the elevators are locked

out of service. Responding fire fighters may use

the elevators under manual control of a fire

fighter in the car using a special fire fighter key

in what is called Phase-II operation. 

While Phase II operation is used to evacuate

people with mobility impairments, some fire

department standard operating procedures for

high-rise fire fighting rely on stairs for access,

staging, and operations. ASME A17.4, Guide for

Emergency Personnel,

2 contains detailed instructions for fire fighters’ service operation. 

In the 1980s, the United Kingdom developed BS5588 part 53

, a standard for fire

fighter lifts. It describes a fire-fighting shaft

consisting of an elevator, protected lobbies on

4 4 N F PA JOURNAL MARCH/APRIL 2006 WWW.NFPAJOURNAL.ORG

each floor with direct access to one of the

required stairs, and standpipes, all enclosed in

fire resistant construction. According to a survey4 by the International Organization for

Standardization (ISO) committee responsible

for ISO/TC178 elevator standards, this system

is used in a few countries, generally former

British colonies, for buildings greater than 18

meters (60 feet). Recently, BS5588 part 5 has

been adopted as CEN Standard EN 81-73 for

use throughout the European Union.

Also in the 1980s, the Federal Aviation

Administration (FAA) was interested in providing a secondary means of egress from air

traffic control towers. Because a contro l

tower’s footprint is so small, it is not possible

to provide two remote stairs, but any tower of

significant height has an elevator and stairs.

The FAA contacted the National Institute of

Standards and Technology (NIST), and a

cooperative project launched with the elevator

In 1973, the elevator industry

developed a system that

recalls elevators and takes

them out of service if smoke is

detected in the lobbies,

machine room, or hoistway.
WWW.NFPAJOURNAL.ORG N F PA JOURNAL MARCH/APRIL 2006 4 5

industry, coordinated through the National

Elevator Industry Institute, resulted in

changes in the 1997 edition of NFPA 101®, Life

Safety Code®5, that were subsequently incorporated into NFPA 50 0 0®, Building and

Construction Safety Code®. In addition to the technical requirements for the equipment and

components, NFPA criteria also limits the

number of occupants in the tower and requires

periodic drills.

While requirements exist for elevators for

emergency use by fire fighters and people with

mobility impairments, there are currently no

codes or standards for egress elevators for use

by building occupants. There are, however,

egress elevators accepted under performancebased design provisions based on engineering

analysis. An example of where such elevators

can be found is the Stratosphere Tower in Las

Vegas, Nevada.

Atop the 800-foot (250-meter) Stratosphere

Tower is an 11-story building, known as the

Pod. The Pod has an emergency staircase that

is considered impractical for use in emergency

conditions. Thus the four double-deck elevators designed for emergency use. One is

reserved for the fire department, and the others are used under manual control to evacuate

all occupants from the two lower floors of the

Pod, which were designed as areas of refuge.

Occupancy of the tower is limited to the number of people that can be evacuated by the

elevators in one hour.

6

New demands for protected elevators

The attacks on the World Trade Center on

September 11, 2001, showed that access by fire

fighters to incidents on upper floors of tall

buildings was problematic. Fire fighters in

their protective clothing and carrying the normal gear for high-rise firefighting that includes

hose packs and forced entry tools require

about 2 minutes per floor to ascend stairs.

Once they arrive at the fire scene, they are

likely to require rest before they can begin suppression operations. Logistics is also an issue,

especially re-supplying oxygen tanks that have

a practical capacity of 15 minutes to 20 minutes, depending on the level of exertion.

Clearly, using elevators to move people and

equipment to a staging area, which is normally

two floors below the fire floor, is the only reasonable approach. Although many in the fire

service did not trust the safety of elevators

during a fire incident, some departments

be gan to cautiously incorporate elevator

access into their high-rise firefighting procedures after 9/11, requiring inspection of the

hoistway for signs of smoke and sometimes

stationing a fire fighter in the machine room.

In the summer of 2003, NIST approached

the ASME A17 committee with a proposal to

explore the development of protected elevators for fire service access and for occupant

egress in collaboration with the A17 code committee, elevator industry, and fire service.

These groups agreed and organized a workshop to explore issues and barriers. A call for

papers resulted in a range of speakers, most of

whom supported the concept. Bre a k o u t

groups identified many issues and some ideas

on features that should be incorporated into

any such system. 

Based on these results, the ASME A17 committee established two task groups under the

Emergency Operations Committee to develop

recommendations for fire-service access elevators and for occupant egress elevators. 

A key finding from the workshop was that

the incorporation of fire fighters emergency

service operation in the 1980s resulted in systems that could continue to operate safely

during a fire and would safely take the elevators out of service before there was any risk of

entrapment from an effect of the fire. However, many fire departments would manually

initiate recall of the elevators on their arrival to

control access and to ensure that there were no

trapped occupants. While this practice would

not materially affect fire service access, it

would affect the use of the elevators for occupant egress.

The ASME A17 task groups followed a formal hazard analysis using an ISO standard for

risk assessment without the step of assigning

probabilities. While tedious, this process is

thorough and results in a detailed record of the

conditions the committee considered and the

mitigation of all hazards identified. 

Protecting elevators

The ASME A17 task groups largely addressed

the safety issues associated with fire service

access elevators by adding real-time monitoring of critical systems from the fire command

station that the building codes alre a d y

required as the incident command location for

high-rise buildings. This allows the fire service

to monitor the safety and functionality of the

systems and to warn fire fighters by radio if

ELEVATOR CONTROL
the safety of the elevator is in doubt. The task

groups also identified other improvements

that would make it less likely that the fire or

firefighting operations might cause the systems to fail, including better protecting the

power to the system, monitoring the internal

temperature of the controller, and protecting

some critical components in the hoistway

from water damage. Finally, the groups provided arrangements to facilitate self-rescue in

case of entrapment.

Far more complicated are the arrangements

and protocols needed to evacuate occupants

by elevator. Unlike the fire service, elevator

occupants are not trained or equipped to deal

with emergencies. The only thing that can be

assumed is familiarity with the normal use of

the elevators, as these are the primary means

of daily ingress and egress. Thus, while some

degree of proactive management of the evacuation by the fire service is provided, the use of

elevators for evacuation must be as close to

“normal” as possible, with some allowance for

guidance by informational messages.

The task groups’ concept of occupant

egress elevators included protecting the entire

bank of cars to take advantage of the system’s

full handling capacity. This is an elevator

industry term describing the design of the system for normal operation where the number,

size, and speed of the cars, number of floors

served, and occupant load are all considered

to achieve a specific service objective. 

The elevators in an office building are

designed with a handling capacity of 8 percent

to 10 percent (downpeak 5), meaning that 8

percent to 10 percent of the entire population

of the building can be collected from various

floors and transported to the ground floor in

five minutes. Apartment buildings are typically designed for a handling capacity of 4

percent to 5 percent (downpeak 5), and some

high-end offices, such as the new WTC 7

4 6 N F PA JOURNAL MARCH/APRIL 2006 WWW.NFPAJOURNAL.ORG

owned by Silverstein Properties in New York

City, are being designed for 12.5 percent,

meaning shorter waits for an elevator at 5 p.m.

The handling capacity calculation is standardized throughout the elevator industry and is

discussed in design manuals such as the Vertical Transportation Handbook.7

The current ASME A17 requirements for

fire fighter emergency operation are considered effective in maintaining safe operation,

even during a fire. If the elevators are to be

used for occupant egress, it is important to

keep them in service for as long as possible.

This led the task groups to observe that

enclosed and protected lobbies are needed on

every floor, not only to provide a protected

space for occupants to wait, but also to protect

the elevator lobby from smoke or fire exposure that will initiate elevator recall. Previous

work by NIST showed that elevator-landing

doors are particularly susceptible to jamming

with re l a t i vely small pre s s u re differe n c e s

across them. However, a system in which the

hoistway is pressurized and the lobby has a

positive pressure with respect to the rest of the

building by leakage can provide smoke protection for the hoistway and lobby without

causing problems with the landing doors. 

Provision of real-time environmental monitoring of the lobbies and two - w ay

communication with the fire command station

would also be specified. Dynamic signs, which

the fire alarm industry calls textural notification appliances, would be provided in each

lobby to give information to waiting occupants. In most modern systems, the elevator

controller’s dispatch software can provide realtime estimates of the time before an elevator

car arrives at that floor, and this will be specified as part of the system.

Evacuation protocol

To provide the needed efficiencies in quickly

moving occupants, a new operational protocol

is being developed and recommended. Since

elevators are most efficient when the number

of starts and stops is minimized, the elevators

would operate in a shuttle mode in the evacuation protocol. The cars would not respond to

car calls—that is, floor buttons in the car—and

hall calls, or call buttons in the lobby, would

only register that there are occupants waiting

there. First priority would be given to collecting occupants on the fire floor, one floor

above, and two floors below, and taking them

The current ASME A.17 requirements

for fire fighter emergency operation

are considered effective in maintaining safe operation, even during a fire.
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to the main lobby. Note that the initial evacuation zone extends two floors below the fire so

that the lobby normally used by the fire fighters for staging would be unoccupied by the

time they arrive.

Once the fire zone was empty, the elevator

evacuation would proceed from the highest

floors dow nw a rd. People on lower flo o r s

would be told the length of wait for an elevator and they might choose to start down the

exit stair that would be accessible from the

lobby. If any of these occupants needed to

rest, they could enter a lobby and do so, or

wait for an elevator.

By taking advantage of all the handling

capacity of the system, it is unnecessary to

restrict access to the evacuation elevators to

just people with limited mobility. Since the

lower floors would be the last to be served,

there is incentive for most occupants on those

floors to egress by the stairs. By starting with

the upper floors, the occupants who require

the longest egress times by stairs would be

evacuated first, dramatically lowering the total

egress time for even the tallest buildings. 

Many of the features described here are

already being implemented in tall buildings

outside the United States. For example, the

Petronas Towers in Kuala Lumpur reports

that incorporating elevators into the egress

plan has resulted in total evacuation times in

both towers of about 20 minutes. Taipei 101,

which is currently the tallest building in the

world at 101 occupied stories, reports a total

evacuation time for the tower and the very

large podium area at the base of just under

one hour.

Addressing user needs

The fire service must be confident that an elevator is safe and reliable and that they can

escape or be rescued quickly by their colleagues if they become entrapped. The fire

service has the opportunity to train with the

elevator systems and, when the practice

becomes more common, they will have an

opportunity to use them during real fires.

Monitoring critical systems at the fire command station in real time makes them

confident that incident command can relay

warnings by radio if needed and will know

quickly if an entrapment occurs.

Occupant egress elevators provide a different set of challenges. Using them for

emergency egress should be as close to using

them for normal egress as possible, and a

steady stream of information is needed. This

can be addressed primarily by incorporating

dynamic signage, operated from the fire alarm

system, in each elevator lobby to provide a

high level of reliability. Again, monitoring critical systems in real-time and having two-way

communication capabilities would supplement

information transfer and increase reliability.

The occupant egress elevator further

addresses the needs of people with various disabilities by providing a means of egress they

can use with all other building occupants without outside assistance. By protecting all the

elevators, the normal design capacity of the

system would be sufficient for use by everyone, with the backup of the fire service access

elevators to help those who need it after suppression operations have begun. If additional

capacity were needed, the fire service could

press any occupant egress elevators into service under manual control.

Recognizing the potential benefits of protected elevators in federal buildings and

elsewhere, the U.S. General Services Administration (GSA) is providing funding that

supplements NIST’s investment in these activities and has agreed to incorporate such

systems in a future federal building as a

demonstration of the technology. NIST welcomes the opportunity to work with GSA to

advance technologies beneficial to government

workers and to the public.

Fire sprinklers and elevators

Rules relating to sprinkler installation in elevator shafts and machinery rooms have long

been a source of conflict, but there have been

significant efforts to coordinate the requirements of NFPA 13, Installation of Sp r i n k l e r

Systems, with those of ASME A17, Safety Code for

Elevators and Escalators.

The most notable took place following the

February 1991 Symposium on Elevators and

Fire, jointly sponsored by ASME, NFPA, and

the Council of American Building Officials. The

organizations established a code coordination

committee that met in late 1991 and 1992 and

reached several key points of agreement:

Summary of requirements

1. Sprinklers in Elevator Pits: It was agreed that

sprinklers in elevator pits are a good idea

because this is a likely location of fire due to the

accumulation of debris. Although the accumulaELEVATOR CONTROL
4 8 N F PA JOURNAL MARCH/APRIL 2006 WWW.NFPAJOURNAL.ORG

tion of water in the pit is a potential concern,

this concern can take place re ga rdless of

whether sprinkler protection is provided. 

2. Sprinklers in Hoistways: It was agreed

that sprinklers are not necessary at the tops of

hoistways if the hoistway is noncombustible

and the elevator car is constructed in accordance with the flame spread and smoke

development requirements of ASME A17.1.

3. Sprinklers in Machine Rooms: It was

agreed that sprinklers may not be necessary in

an elevator machine room if it is located at the

top of a building and contains nothing other

than elevator equipment. It was further

agreed that concern over water discharge and

p ower-disconnect re q u i rements can be

addressed by requiring means to automatically disconnect the main line power supply to

the affected elevator upon or prior to the

application of water.

These points of agreement we re largely

adopted into the 1994 edition of NFPA 13

through a major rewrite of Section 4.5.5. The

NFPA 13 requirements have changed very little

since that time. Now contained in Section 8.14.5

of the 2002 edition of NFPA 13, the rules make

specific accommodations for elevators.

Pit sprinklers: Sidewall sprinklers are to be

placed within 2 feet (61 centimeters) of the

floor of an elevator pit, without regard to the

normal distances required below a ceiling. The

NFPA 13 Annex suggests placing the sidewall

sprinklers near the side of the pit below the

elevator doors and taking care to avoid interference with the elevator toe guard. The pit

sprinklers can be omitted for enclosed, noncombustible shafts that do not contain

combustible hydraulic fluids. Since sprinklers

at the base of the shaft are not expected to discharge onto operating components of the

elevator, they can be connected directly to the

building sprinkler system with no special valving or delay mechanism.

Hoistway sprinklers: Upright or pendent

sprinklers are required at the tops of elevator

hoistways, except noncombustible hoistways
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for passenger elevators with car enclosure

materials meeting ASME A17.1. 

Machine room sprinklers: The standard

has no special rules for elevator machine

rooms, except to require that machine room,

sprinklers and sprinklers at the tops of hoistw ays be of ordinary or intermediate

temperature rating. In other words, high temp e r a t u re rated sprinklers that would be

delayed in operation are not permitted. Sprinkler protection of elevator machine rooms is

expected as part of a complete sprinkler system since these spaces are not specifically

excluded from the need for sprinklers. 

An Annex section in NFPA 13 discusses the

ASME A17.1 requirement that power to the

elevators be shut down upon or before the

application of water in elevator machine

rooms or hoistways, and suggests this can be

accomplished by a sufficiently sensitive detection system or by using devices that effect

power shutdown immediately upon sprinkler

activation, such as a waterflow switch with no

time delay.

The NFPA Committee on Automatic Sprinklers is now completing work on the next, 2007,

edition of NFPA 13. One of the proposals

accepted in this cycle allows the option of sidewall sprinklers at the top of hoistways rather

than upright or pendent sprinklers. A proposal

that would have required the hoistway sprinklers to be part of a preaction system was

rejected on the basis that there are other ways to

meet the ASME A17.1 requirements. Another

proposal would have eliminated sprinklers from

the elevator machine room under certain conditions of smoke detection, signage prohibiting

storage, and control of combustible contents, as

now permitted in the Commonwealth of Massachusetts. The Technical Committee rejected

this proposal on the basis that “buildings are to

be fully sprinklered which includes these types

of spaces. Storage can occur in these types of

spaces regardless of signage.” The Committee is

aware that reliance on housekeeping practices

has historically been an inadequate substitute

for complete sprinkler protection.

In the view of the fire sprinkler community,

the current rules re p resent a re a s o n a b l e

a p p roach to elevator protection. Unfortunately, continued lack of consistency in the

application and enforcement of these rules can

create problems that go beyond the lack of

p rotection. Disagreements among multiple

authorities having jurisdiction for an elevator

installation have led in some instances to lastminute changes in protection, with

consequences of improper valving, inadequate

protection against freezing, or other problems. 

At the least, it is necessary that elevator protection issues be discussed at the project planning

stage. Ideally, those discussions will lead to

recognition that sprinkler protection in accordance with NFPA 13 is reasonable and proper.

Elevator smoke control

Deadly fires, such as the 1980 MGM Grand

Hotel and Casino fire8 and the 1988 First

Interstate Building fire ,9 h ave shown that

unprotected elevators can provide a significant

path for vertical smoke movement from fires

through building. 

Several factors, including the lack of sprinkler protection on the fire floor, elevator doors

that did not provide an effective smoke barrier,

as well as the combined effects of the natural

buoyancy of hot smoke and the stack effect,

resulted in smoke spread through the elevator

hoistways to upper levels. A properly designed

smoke management system could have helped

to mitigate smoke movement through the elevator shafts in these high-rise buildings. 

Designers have several alternatives when

designing smoke management systems for elevator shafts10, including pressurize the elevator

hoistway; pressurize the elevator lobby; and

exhausting the fire floor, which creates a positive pressure in the elevator hoistway relative

to the fire floor.

Passive systems

These methods can be used individually or in

combination.

Pressurize Ho i s t wa y : Some jurisdictions

require hoistway pressurization when elevator

lobbies are not provided. In general, dedicated

supply fans are used to pressurize hoistways to

a minimum pressure 0.05 inches (0.13 centimeters) of water column. Since the elevator

machine room in cable elevators is open to the

h o i s t w ay through the cable sleeves, these

rooms can be pressurized along with the shaft. 

Elevator doors are typically not tight-fitting

and tend to be a major source of leakage in the

shaft, as do vents. Doors and vents, as well as

other sources of leakage, must be accounted

for in the design. 

In addition, the piston effect may need to be

considered if elevators are expected to be used

by responders or others during as fire event. 

ELEVATOR CONTROL
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Pressurize Elevator Lobby: If an elevator lobby is

provided, this lobby can be pressurized along

with the elevator shaft. A second design goal

for these types of system is that the opening

f o rce for the elevator lobby doors cannot

exceed 30 pounds (13.6 kilograms) at the latch

side when it is operating and the pressure

should not interfere with the opening or closing

of the elevator doors. This approach typically

allows smaller fans, since the leakage air is

lower, but a duct system is necessary to distribute air to the various floors. 

Exhaust Fire Floor: Exhausting the fire floor

has a similar effect as pressurizing the hoistway

or lobby; however, these systems tend to be

larger, more costly and more complicated than

elevator pressurization systems. The goal of

this approach is to limit smoke to the fire floor.

Passive Systems: Smoke tight elevator hoistways and/or lobbies can be an effective means

of limiting smoke movement. If protected lobbies are not provided, doors on hold-open

devices or deployable smoke barriers can be

installed across the elevator doors to maintain

an effective smoke barrier. Given the effect i veness of quick-response sprinklers, the

requirement for smoke-tight separations is a

constant topic of debate. 

Design considerations

When designing smoke management systems

for elevators, as well as other areas, it is helpful to understand the stack effect, a

phenomenon that occurs when there are temperature differences between the air outside

the elevator shaft and the air in the rest of the

building. Where the air outside the shaft is

cooler than the air inside it, buoyancy causes

the hot interior air to flow toward the top of

an elevator shaft, while air from the lower

areas of the building or outside the building

enters the shaft towards the bottom to replace

the hot air. This causes a general upward flow

that can help push smoke into the shaft.

When the temperature difference is reversed,

the opposite flow results.

Other design considerations include the piston effects, wind effects, and normal HVAC

effects that need to be taken into consideration.

As elevators travel up within the shaft, air from

within the top of the shaft is pressurized and air

in the bottom of the shaft is de-pressurized.

Pressures are reversed when elevators are moving down. Wind velocity may also influence the

design, as the wind will increase pressure on the

side being impacted by the wind and decrease

pressure on the downstream side of the building. Normal HVAC is typically shutdow n

during emergency operation. Klote11 describes

methods for accounting for the piston effect and

wind velocity.

Consideration should be also be given to

providing automatic sprinklers when designing these systems, as the 0.05 inches of water

column assumes that a large fire would not

occur within the space. Additionally, emergency power is necessary for required life

safety systems. 

Although the design of smoke management

systems presents challenges, smoke management techniques can increase the level of

elevator safety in high-rise buildings. With the

recent discussions about the use of elevators

for evacuation, it is perhaps even more critical

to consider smoke management solutions for

elevators now than ever before. 

Elevator sump pumps

Elevator sump pits are intended to keep water

away from the equipment at the bottom of an

elevator shaft if the hoistway fire suppression

system is activated. Just allow the water to

drain into the elevator sump pit, and the

equipment stays dry and functional. It’s as

simple as that. Or is it? 

Anyone designing an elevator sump pump

system must consider not only removing discharged sprinkler water, but also preventing

any oil that has leaked from the elevator’s

hydraulic lift from entering the sewer system.

If the hydraulic system works properly, it generally releases only a small amount of oil. If

the system fails, however, a sizable volume

could be lost. This oil, combined with the volume of water discharged by one sprinkler,

provides a design challenge for the engineer.

In an effort to keep oil from leaking into their

sewer systems, some states are trying require

the design and installation of large sum pits

below elevator shaft floors from which water

may be pumped out and disposed of later.

Unfortunately, a blanket requirement mandating that a sump pit contain a pump is not

necessarily the right way to design the system. 

Section 2.2.2.5 of the 2000 edition of ASME

A17.1 requires all elevator pits with Firefighters’ Emergency Operations (FEO) to have a

drain or sump pump. ASME A17.1 also

requires a connection to the emergency power

supply and protection of circuits to ensure that
WWW.NFPAJOURNAL.ORG N F PA JOURNAL MARCH/APRIL 2006 5 1

accidental grounding or short-circuiting does

not occur after an emergency has begun.

Instead of a sump pump, an oil separator or

some other device can be used to remove oil

from the elevator shaft, thus preventing discharge into the sanitary sewer. However, an

oversized oil separator is a maintenance issue,

and an undersized oil separator will not

remove oil effectively.

Replacing the oil separator with a system

called an “oil minder” could help resolve the

issue. The oil minder concept relies on the fact

that oil floats on water. As water is pumped

from the bottom of the pit and the water level

falls, the oil minder’s sensing device detects

the oil and shuts off the pump, thus allowing

the water out and keeping the oil in.

This controversy has been a long time in

the making, but a blanket requirement to provide an elevator sump pump creates more

design issues than it solves.

Pros and cons of elevator door restrictors

When entering an elevator, most passengers

do not realize they have agreed to be securely

locked in that elevator cab until the car

reaches its destination. Should the elevator

lose power before reaching its destination, all

methods of self-evacuation are mechanically

prohibited. This applies equally to emergency

personnel and the public.

Door restrictors, which ASME A17. 1

requires on passenger elevators, are mechanical devices designed to prevent a passenger

from opening the elevator car or hoistway

doors more than 4 inches (10.2 centimeters)

when the elevator car is outside the “unlocking zone.” ASME defines the unlocking zone

as “a zone extending from the landing floor

level to a point not less than 75 millimeters (3

inches) or more than 450 millimeters (18

inches) above and below the landing.”

The requirement for door restrictors was

implemented to pre vent passengers fro m

falling into an open hoistway underneath the

elevator platform while trying to evacuate

from an elevator that is stuck between floors.

Is this a real concern? Unfortunately, it is. 

Picture yourself in an elevator that has

stopped 5 feet (1.5 meters) above the landing.

If you could open the elevator car door, you

would have access to the hoistway door interlock, which is typically easy to open from this

position. Once you opened the standard hoistway door, you would discover that you now

had access to an opening 2 feet (0.6 meters)

high from which you could try to exit the elevator. What you wouldn’t be able to see is the

unprotected space underneath the platform

and platform guard. If you were to lower yourself backward from the elevator, your feet

would tend to push into the hoistway. If you

were to jump forward, you would risk falling

backward into the hoistway.

So why not lock passengers in the elevator?

Imagine being trapped inside an elevator that

ELEVATOR CONTROL
5 2 N F PA JOURNAL MARCH/APRIL 2006 WWW.NFPAJOURNAL.ORG

lost power only 19 inches (0.5 centimeters)

above a landing in the World Trade Center on

September 11, 2001. Or imagaine being an

emergency responder who found himself

trapped and unable to override the door

restrictor. This is not exactly farfetched.

In the attacks on the World Trade Center in

1993 and 2001, many people found themselves

trapped inside elevators. In 1993, there were no

door restrictors on the elevators. By September

11, 2001, however, about half of the elevators

had been retrofitted with these devices. On that

day, the few successful escapes that are known

to have taken place were from those elevators

that had not yet been equipped with the door

restrictor devices.

On May 18, 2004, Alan Reiss, Deputy

Director of Aviation at The Port Authority of

New York and New Jersey testified before the

9/11 Commission, saying “Another item that

should be looked at is the elevator code

requirement that door restrictors must lock

the elevator doors closed when the elevator is

not level with a landing. This is a requirement

of the current codes, and such devices were

being installed as elevators were modernized

at the World Trade Center. These devices are

meant to improve safety and prevent accidental falls into the shaft, but they have the

potential consequence of trapping individuals

in an elevator when it is stuck between floors,

preventing escapes such as took place in both

1993 and 2001.”

Recently, Northwest Territories in Canada

modified the CSA B44-04, Elevator Safety

Code, to allow extended platform guards as an

alternative to door restrictors in some cases.

Platform guards are sheet metal extensions

mounted directly from the car sill and supported to restrict hoistway access below the car

platform. The code modification to Requirement 2.15.9.5 states that “A platform guard

may be used as an alternative to the requirement set out in 2.12.5.1 if the platform

guard...is installed so that the hoistway opening space below the platform guard is limited
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to not more than 250 milimeters (9.8 inches)

between the floor and the bottom of the platform guard, regardless of the location of the

elevator car when it is stopped.”

While this alternative certainly prevents

falling into the hoistway and allows for selfevacuation if necessary, the pit depth on many

existing elevators is insufficient to accommodate this extended guard length. In addition,

the platform guard does not prevent injuries

during the unassisted evacuation of an elevator that has stopped significantly above or

below the landing, other than the falling scenario described above. 

So if power is lost while traveling in an elev a t o r, how likely is it that you will be

prevented from getting out of the elevator? In

a building with the typical 10-foot (3-meter)

floor-to-floor height and a maximum unlocking zone of 18 inches (45.7 centimeters) above

and below the floor, the elevator car doors

will be mechanically restricted during 70 percent of the hoistway travel. The probability

increases to 95 percent where the minimum

unlocking zone of 3 inches (7.6 centimeters)

above and below the floor is employed. 

In any case, there is a significant potential of

being locked in the elevator should there be a

loss of power. This is a fact of which most passengers, including the public and emergency

responders, are probably unaware.

Emergency operation overview

ASME A17.1, Safety Code for Elevators and Escalators, includes special provisions for elevator

operation during fire emergencies. These are

identified as Phase I Emergency Recall Operation and Phase II Emergency In-Car Operation. 

Phase I Emergency Recall Operation is

used to take elevators out of normal service.

This prevents building occupants from going

to the fire floor and also makes the elevators

available for use by firefighters. Recall operation can be activated manually by firefighters

f rom the key-operated “FIRE RECA L L”

switch located at the designated level. Manual

activation causes the elevator(s) to return nonstop to the designated level. 

Recall operation can also be activated automatically by the fire alarm system in response

to the actuation of specific fire alarm initiating

devices. These initiating devices are those

re q u i red at each elevator lobby, elevator

machine room, and elevator hoistway when

sprinklers are installed in those hoistways.

The use of smoke detectors is required unless

environmental conditions require the use of

another type of automatic initiating device

such as a heat detector. Automatic activation

of recall operation causes the elevator to

return nonstop to either the “designated level”

or the “alternate level” as determined by the

building configuration and the location of the

first of these initiating devices to actuate. The

designated level is typically the level where

firefighters would normally arrive. The alternate level is used when the first initiating

device to actuate is located at the designated

level, either in the lobby or in the machine

room if it is located at the designated level.

Note that only these specific fire alarm initiating devices can activate recall operation. Fire

alarm signals from devices in other building

locations do not result in elevator recall. 

Each elevator car is equipped with a special

visual signal (fire hat) that will illuminate when

Phase I Emergency Recall Operation is activated manually or automatically. This visual

signal remains activated until elevator operation is restored to automatic operation.

Once Phase I Emergency Recall Operation

has been activated and elevator cars have

returned to the appropriate level, Phase II

Emergency In-Car Operation can be activated. Phase II operation is activated

manually by firefighters from the key-operated

“FIRE OPERATION” switch located in each

elevator car. Once activated fire fighters have

control of the elevator.

There is a potential that operation of the elevator could be adversely affected during a fire

event. To help warn firefighters of this potential,

the special visual signal (fire hat) used to indicate that activation of Phase I Emergency Recall

Operation is caused to illuminate intermittently

(flashing instead of steady illumination). The

trigger for this intermittent illumination is when

Phase I Emergency Recall Operation is activated automatically by a fire alarm initiating

device located in elevator machine room or

hoistway, since a fire in these locations could

impact the operation of the elevator. It should

be noted that when the visual signal is flashing,

Phase II Emergency In-Car Operation is still

permitted and fire fighters are allowed to continue using the elevator at there own discretion

based on their knowledge of the fire conditions.

ASME A17.1 also includes special provisions for automatic elevator shutdown when

elevator equipment is located where the appliELEVATOR CONTROL
5 4 N F PA JOURNAL MARCH/APRIL 2006 WWW.NFPAJOURNAL.ORG

cation of water from automatic fire sprinklers

could cause unsafe elevator operation. The

use of heat detectors located in proximity to

the sprinkler heads is one means used to

achieve elevator shutdown. Heat detector

operation causes the main line power to the

elevator to be automatically disconnected.

This is typically referred to as “shunt trip”

due to the name of the mechanism used to

operate the main line power circuit breaker.

When elevator shutdown occurs the elevator

will stop in place due to the failsafe operation

of the elevator braking mechanism. 

Because of the potential of entrapment associated with shunt trip operation, re v i s i o n s

processed for the 2006 edition of ASME A17.1

will require the heat detectors used for shunt

trip to initiate Phase I Emergency Recall Operation and delay the removal of power and the

release of water to allow the completion of

recall. Note that if the elevators are already

operating on Phase II Emergency In-Car Operation, the recall operation will not occur, but

s h u t d own and water release will still be

delayed. If the elevator is on Phase II operation, the delay will allow the car to go to the

next selected floor. Once the car has stopped at

the floor all registered calls are canceled and

shunt trip will activate. As a warning to fire

fighters of the impending elevator shutdown,

the heat detectors used for this operation will

also cause the special visual signal (fire hat) to

illuminate intermittently. Note that in the case

of impending elevator shutdown, once the elevator car has stopped at a landing, it will

remain at the landing and car calls will not regi s t e r. While the new shunt trip prov i s i o n s

should greatly minimize the risk of entrapment,

it should be recognized that complete elimination of this risk may not be possible.

Elevators and the fire service

Although elevators normally operate flawlessly, they can fail. Their safe operation

should not be taken for granted.

In many jurisdictions, building owners test

Fi refighters’ Emergency Operation (FEO )

monthly in accordance with Section 8.6.10.1

of the 2004 edition of ASME A17.1. And

authorities having jurisdiction over elevator

licensing requirements should also test FEO

regularly. In addition, those jurisdictions that

have adopted NFPA 1, Uniform Fire CodeTM,

should also be testing and assuring at each elevator has an FEO. Since fire fighters cannot

be certain when FEO was last tested or the

quality of the inspection, however, they should

confirm that the elevator is operating properly

before using it during a fire.

An elevator’s FEO consists of a Phase I and

a Phase II.

Phase I is activated by the Phase I key

switch or by a fire alarm initiating device

(FAID). The FAIDs that initiate Phase I recall

are located at each floor the elevator serves,

typically in the elevator lobby; in the elevator

machine room; and in the elevator hoistway,

when required. When Phase I is activated, the

elevator ceases normal operation, illuminates

the fire fighter helmet pictograph, and returns

the elevator non-stop to the designated level

or, if the FAID initiating Phase I is on the designated level, to an alternate landing. This

keeps the public from taking an elevator to the

fire floor and renders the car call buttons, corridor call buttons, and automatic door

reopening devices inoperative.

Once recalled, the elevator will not operate

until it is reset or the Phase II switch located in

the elevator is placed in the “on” position. 

Upon arrival at a fire, fire fighters should

confirm that all elevators have recalled to the

designated or alternate recall floor. This can

normally be done from the fire control room.

If the elevators have not been recalled, they

should be recalled manually using the Phase I

key switch in the fire control room. If an elevator does not manually recall, fire fighters

must search for it to confirm that no one is

trapped inside or above the fire floor.

When a fire occurs at the elevator’s designated recall landing, the elevators may

automatically recall to an alternate floor. Once

at the alternate floor, the elevator can still be

recalled manually to the designated landing by

activating the Phase I key switch in the elevator lobby or, when applicable, by activating

both the Phase I key switch in the elevator

lobby and the key switch in the fire control

room. The Phase I key switch in the elevator

lobby should only be activated when fire fighters know that the designated level is safe. 

Before using the elevator, fire crews should

check the hoistway for fire, water, or smoke

and make sure the helmet pictograph is not

flashing. In newer elevators, the flashing pictograph indicates that the elevator may

malfunction and possibly trap the fire fighters

in the elevator. After checking the hoistway

and pictograph, the Phase II key switch must
WWW.NFPAJOURNAL.ORG N F PA JOURNAL MARCH/APRIL 2006 5 5

be placed in the “on” position. 

Before traveling to an upper floor, fire fighters must test the “door open” and “door

close” buttons to confirm that they operate

properly. Both buttons require constant press u re in Phase II operation and must be

depressed until the door is completely closed

or opened. If the button is released before the

doors are fully closed or open, they will automatically reverse direction. 

Once the doors have been tested, a floor

can be registered. While traveling to the

selected floor, fire fighters should depress the

“call cancel” button to ensure that all car calls

cancel and the elevator stops at or before the

next available landing. Before leaving the elevator, fire fighters should test the “hold”

position of the Phase II key switch to confirm

it is operating properly.

ASME A17.1 requires all equipment necessary for the operation of Phase II to be located

in the main car-operating panel behind a

locked cover, labeled “Firefighters’ Operation,” that can be opened with the fire service

key. ASME A17.1 also requires a “run/stop”

switch behind the cover that will cancel all

registered calls and cut power to the elevator

when placed in the “stop” position.

Training

To prevent injuries and deaths, every fire

department should develop, implement, and

strictly enforce of standard operating procedures that specifically address elevator use

during fires. Every fire fighter and fire inspector should be trained to operate FEO ,

including Phase I and Phase II, emergency

power activation, and fire fighter self-rescue. 

Fire fighters, fire inspectors, and building

owners must become familiar with the codes

specific to elevator FEO. They must be diligent about testing and inspecting its operation

and take time to research and implement an

elevator-training program. Not only will this

increase the reliability of the elevators, but it

might save the life of a fire fighter.

Emergency operation on an elevator

In the event of a fire, the Firefighters’ Emergency Operation (FEO) on an elevator may

prove invaluable in controlling the fire and

safely evacuating the building. 

Since 1973, ASME A17.1 Safety Code for Eleva t o rs and Es c a l a t o rs,

1 2 , 1 3 has re q u i red that

elevators travelling 25 feet (7.2 meters) or

more be equipped with a feature that, when

initiated, will return the elevator to the main

floor or another designated floor of the building. This feature is commonly referred to as

Phase I Emergency Recall Operation and can

be started with a key-switch or by a fire alarm

initiating device.

Beginning in 1981, ASME A17.1 further

required all automatic elevators with Phase I

Emergency Recall Operation to be equipped

with a feature that allows fire fighters or other

authorized personnel to operate the elevator

during an emergency from within the car. This

feature is commonly referred to as Phase II

Emergency In-Car Operation.

One of the most reliable methods of

ensuring that elevator equipment will function

correctly is to verify that it has been properly

maintained and inspected. ASME A17. 1

requires that the Phase I Recall of all elevators

with FEO be tested monthly using the lobby

key switch and that the Phase II Emergency

Operation be tested a minimum of a one-floor

run. Deficiencies found during the monthly

testing procedure must be corrected.

A record of the test results, usually in the

form of a test log located in the elevator

machine room, must be made available to elevator personnel and the authority hav i n g

jurisdiction. A sample monthly fire service test

log may be downloaded without charge at

www.naesai.org. 

Many elevator inspection agencies train fire

service personnel how to use the Phase I and

Phase II Emergency Recall Operation. If such

training is not available, however, fire fighters

can follow some basic instructions to ensure

that the Phase I and Phase II features are operating properly:

To recall the elevators, fire fighters should

insert the key into the designated level keyELEVATOR CONTROL

One of the most re l i a b l e

methods of ensuring that

elevator equipment w i l l

function correctly is to verify

that it has been pro p e r l y

maintained and inspected
5 6 N F PA JOURNAL MARCH/APRIL 2006 WWW.NFPAJOURNAL.ORG

operated switch, turn the switch to the “on”

position, and remove the key. All elevators

should return to the designated level and park

with the doors open. Then the fire fighters

should enter the elevator and push a car button to ensure that the elevator will not leave

the floor.

Once this has been verified, the emergency

responders can initiate Phase II by inserting

the key in the key-switch, turning the switch

to the “on” position, and verifying that the

key can be removed when the switch is in that

position. The responder can then press the

desired floor button. If more than one floor

button is pressed, the elevator will travel to

the first available floor and all other floor calls

will be cancelled.

To cancel the floor selection, the responder

can press the “Call Cancel” button. The elevator will go to the next available floor, and

the doors will stay closed until the next step

has been initiated.

Once the car has arrived at the floor, the fire

fighter should press and hold the “door open”

button to open the car door. If the button is

released before the doors fully open, the doors

will close. This allows the doors to close immediately if there is a fire or smoke at that floor.

To hold the car at the floor once the doors

have opened, fire fighters can turn the key in the

car to the “hold” position and remove the key.

This will ensure that the car will stay at the landing until Phase II is initiated again or the in-car

switch has been turned to the “off” position.

To close the elevator door, fire fighters can

press and hold the “door close” button. If the

button is released before the doors are fully

closed, the doors will reopen.

Finally, to return the car to the recall floorturn the Phase II key to the “off” position.

The car doors will close automatically, and

the elevator will return to the recall floor.

Endnotes

1. Safety Code for Elevators and Escalators,

ASME A17. 1 - 2000, American Society of

Mechanical Engineers, New York, 2000.

2. Guide for Emergency Personnel, ASME A17.4-

1999, ibid

3. Fire Precautions in the Design, Construction,

and Use of Buildings, BS 5588 Part 5 1991, Code

of Practice for Firefighting Lifts and Stairs, British

Standards Institution, London.

4. Comparison of Worldwide Lift (elevator)

Safety Standards – Fire fighters Lifts (elevaPostScript Picture

Logo flame only

tors), ISO/TR 16765:2002(E), International

O r ganization for Standardization, Geneva,

Switzerland, 2002.

5. NFPA 101®, Life Safety Code®, 2000, National

Fire Protection Association, Quincy, MA.

6. Quiter, J. R. Application of Performance

Based Concepts at the Stratosphere Tower, Las

Vegas, Nevada. Rolf Jensen and Associates,

Inc., Deerfield, IL. Fire Risk and Hazard Assessment Symposium. Re s e a rch and Pr a c t i c e :

Bridging the Gap. Proceedings. National Fire

Protection Research Foundation. June 26-28,

1996, San Francisco, CA, 118-126 pp, 1996.

7. Vertical Transportation Handbo o k ,

George R. Strakosch, Editor, John Wiley &

Sons, Inc., New York, New York, 1999.

8. Best, R. and Demers, D., Investigation

Report on the MGM Grand Hotel Fire, Las

Vegas, Nevada. Revised Report, Jan 1982.

NFPA, Quincy, MA, 1982. 

9. Isner, M. and Klem. T., Fire Investigation

Report: World Trade Center Explosion and

Fire, New York, New York, February 26.

NFPA, Quincy, MA, 1993.

10. NFPA, Recommended Practice for Smoke-Cont rol Sys t e m s, (NFPA 92A), National Fi re

Protection Association, Quincy, MA, 2006. 

11. Klote, J., Principles of Smoke Management (NFPA 92B), American Society of

Heating, Refrigeration, and Air-Conditioning

Engineers, Atlanta, GA, 2002. 

12. ASME A17.1-2004 Safety Code for Elevators and Escalators: Section 2.27—Emergency

Operation and Signaling Devices

13. ASME A17.2-2004 Guide for Inspection of

Elevators, Escalators, and Moving Walks.

About the authors

RICHARD W. BUKOWSKI P.E., FSFPE is Standards

and Codes Coordinator for the Building and Fire

Research Laboratory of the National Institute of Standards and Technology and Senior Engineer in the

Integrated Performance Assessment Group. Mr.

Bukowski is very active within the U.S. and international

standards communities. He is a member of the Standards Council of the National Fire Protection

Association, which is the body that administers the

NFPA's standards development process and issues all

NFPA documents. Mr. Bukowski is Coordinator of the

International Council on Building Standards and Documentation (CIB), Working Commission 14: Fire, and is

active in the work of CIB TG37: Performance-based

Building Regulatory Systems and CIB TG50: Tall Build-
WWW.NFPAJOURNAL.ORG N F PA JOURNAL MARCH/APRIL 2006 5 7

ings. He was appointed by ANSI as U.S representative

to ISO TAG8, which advises the ISO Technical Management Board and provides oversight to all ISO Technical

Committees working in the building and fire areas. He is

a member of the NFPA, member of the Research Section, Building Fire Safety Systems Section, and

Education Section, a Fellow of the Society of Fire Protection Engineers, and is a licensed Professional

Engineer in the states of Illinois and Maryland.

RUSSELL P. FLEMING, P.E. is the executive vice-president for the National Fire Sprinkler Association and a

member of several NFPA technical committees including the NFPA 13 technical committee. He is also a

regular columnist for the NFPA Journal® and a former

member of the NFPA Board of Directors.

JEFFREY TUBBS, P.E. is an Associate Principal and

staff group leader of their Westborough, MA office. Jeff

has a broad range of experience with unique projects;

he has focused upon providing innovative, pragmatic

solutions in the context of both prescriptive and performance codes throughout the U.S. and internationally.

Jeff holds positions on various fire and life safety committees, including secretary of ASHRAE TC5.6: Control

of Fire and Smoke, and member of the NFPA smoke

Management committee (Responsible for NFPA 92A,

92B and 204) and the Assembly Occupancy Committee, and an alternate member on ICC’s Code

Technology Committee. Jeff led Arup’s efforts to assist

the NIST’s National Construction Safety Team investigation of the February 20, 2002 fire at the West Warwick

Station Nightclub with egress issues.

CHRISTOPHER MARRION, P.E. is an Associate Principal with Arup in their New York City office, where he

leads the N.Y. Arup Fire group. Chris has worked for

various fire engineering consulting firms in the United

States, United Kingdom, Hong Kong, and Europe for

the last 15 years. He has been involved with various

committees in the fire industry, including SFPE/NIST—

National R&D Roadmap for Fire Safety Design And

Retrofit of Structures Workshop—Steering Committee;

New York City Department of Buildings—New NYC Bldg

Code Committees for Egress and Fire Protection Systems; SFPE Performance-Based Design

Committee—Steering Committee; SFPE Design Basis

Fires Committee—Chair; ICC/SFPE Enforcer’s Guide to

Performance Based Design Review; and NFPA 72,

Appendix B—Engineering Guide for Automatic Fire

Detection—Chair. Chris was also a member of the

FEMA/ASCE Building Performance Assessment Team

for the World Trade Center assessment. 

CHRIS DUKE is the owner CNY Elevator Consultants in

Syracuse, New York. He is a member of the A17.1

Repair, Renovation, and Replacement Committee and

the A17.1 Existing Installations Committee.

DEBBIE PRINCE is a Code Specialist employed with

Motion Control Engineering, Inc. since March 1987;

she’s a member of A17 Electrical and Emergency Operations committees.

JILL DIRKSEN is the Managing and Technical Director

for the American Society of Plumbing Engineers. Prior

to her employment with the association, she worked at

Albert Kahn Associates in Detroit, Michigan. She has

held many board positions on local ASPE chapter level

and serves as Co-Chairman on the ASPE standard committee for Hot Water Temperature and Control.

LEE F. RICHARDSON is a senior electrical engineer at

NFPA where he is responsible for several standards,

which include NFPA 72®, National Fire Alarm Code®. He

is also the co-editor of the National Fire Alarm Handbook and a member of the ASME A17.1 Emergency

Operations Committee. He is also a frequent contributor

to the NFPA Journal.

DAVE BESTE is a Lieutenant at the Bellevue, Washington, Fire Department and a former Elevator Constructor.

He is a member of the ASME A17.1 Emergency Operations Committee, an affiliate member of the

International Association of Fire Chief’s (IAFC) Fire and

Life Safety Section, and has developed and instructs

Elevator Safety and Rescue for Fire Fighters.

DOTTIE STANLASKE is the Executive Director for

NAESA International (National Association of Elevator

Safety Authorities). In her role of Executive Director, Ms.

Stanlaske represents NAESA at various national and international codes and standards, and industry association

meetings,including the ASME A17 Elevator and Escalator

Safety Code Committees, and the International Standards

Organization, ISO Technical Committee 178. She is a veteran of the elevator industry having held positions of

increasing responsibility in labor, supervision and management for Beckwith and Otis Elevator companies. She is

also a former elevator inspector for various states including Massachusetts and Washington.

ELEVATOR CONTROL
Appendix K

Emergency Egress Strategies for Buildings
InterFlam 2007 Page 1 of 11 final3/14/2007 

Emergency Egress Strategies for Buildings 

Richard W. Bukowski, P.E., FSFPE 

NIST Building and Fire Research Laboratory 

Gaithersburg, Maryland 20899 USA 

INTRODUCTION 

The primary strategy for the safety of building occupants in emergencies 

(especially fires) is by facilitating their relocation to a safe place. In other than a few 

institutional occupancies (health care and detentional) this generally involves the use of 

stairs as part of a protected means of egress (MOE) for vertical evacuation. For tall 

buildings with large populations, providing sufficient stair capacity for simultaneous 

egress has been considered impractical by code making organizations, so the strategy of 

phased evacuation has been employed. To this point in time, little attention has been paid 

to the special needs of people with disabilities and other (permanent or temporary) 

physical limitations in moving on stairs. 

In the aftermath of September 11, 2001 new attention is being paid to many issues, 

especially emergency egress from tall buildings. A number of experts have called for a 

fundamental rethinking of egress strategies including all of the possible components that 

might be employed. In September 2006 a workshop was organized in Atlanta by CIB 

W14:Fire and TG50:Tall Buildings, with one of the discussion topics devoted to this 

issue. This paper is intended to continue that discussion. 

PERFORMANCE METRICS FOR EGRESS 

In performance design, the usual performance metric for egress systems is that of 

timed egress analysis. Here a range of calculation methods from simple hand 

calculations to sophisticated computer simulations that may include behavioral rules of 

human interaction are used to estimate the Required Safe Egress Time (or RSET). Fire 

models or calculational methods estimate the time available before escaping occupants 

are exposed to untenable conditions, Available Safe Egress Time (ASET) and as long as 

RSET is less than ASET, safety is assumed to be achieved. 

A problem is that the design parameter for means of egress in regulation is that of 

capacity. MOE components are rated by the number of people (total) per unit width. 

Thus there is no direct connection between regulatory design requirements and the 

critical performance metric of egress time. A detailed discussion of the basis for egress 

systems design in regulation can be found in Bukowski and Kuligowski1

. 

COMPONENTS OF A MEANS OF EGRESS 

A MOE consists of an exit access (normally a common use corridor leading to the 

exit), the exit itself (normally a stair), and an exit discharge (normally a door to the 

outside or into a protected corridor leading to the outside). Egress stairs may incorporate 
InterFlam 2007 Page 2 of 11 final3/14/2007 

areas of rescue assistance which are part of enlarged landings providing space for people 

(especially with disabilities) to move out of the flow to rest or await assistance. Egress 

stairs may also incorporate transfer corridors that are used to shift the vertical alignment 

of the stair horizontally, to go around equipment or to maintain minimum required stair 

separation at floors where the building floor area changes. 

This separation into a horizontal travel component on the originating floor, a vertical 

component to travel from the originating floor to the level of exit discharge (or other safe 

location), and a horizontal component to travel to the building perimeter would be 

common to any egress system. Further, the horizontal components are unlikely to be of a 

length that an occupant would require more than a few minutes to traverse, so any 

improvements to them would be unlikely to provide any significant impact on overall 

performance of the MOE, although their reliability might be improved. 

STAIRS 

Stairs are the primary means of vertical travel during fire emergencies and are 

generally effective and reliable, but with several significant shortcomings. Most building 

regulations require at least two independent stairs so that a single event cannot block 

access to both. This independence comes from the location of the stairs remote from 

each other. In some locations scissor stairs (two, intertwined stairs in a common shaft) 

are popular since they minimize the building space required. The disadvantage is that 

they are not remote and can both be easily compromised by openings in the separating 

partition. However, when counted as a single stair they provide additional stair capacity 

in a better configuration than a single, wider stair since there is better access to handrails 

as people descend. 

Another shortcoming of stairs in high rise buildings is that standard firefighting 

procedures involve the designation of one of the stairs as the attack stair, in which the fire 

hose is extended to permit its advance onto the fire floor. Once the hose is extended in 

the stair and charged with water it is nearly impossible for occupants to pass from above. 

Further, once the door to the fire floor is opened to advance the hose, smoke may enter 

the stair and contaminate the floors above. Thus it may be necessary to delay firefighting 

until all occupants clear the stair above the fire floor. 

This was observed in the fire in the 52-story Boston Prudential Center on January 2, 

19862. The fire began on the 14th floor while the floor was undergoing a tenant fitout 

with an estimated 1500 occupants in the building. The 14th floor door to stairway B 

failed early in the fire, permitting smoke and fire to make this stair untenable above the 

12th floor. This left only stair A for both occupant egress and fire attack. The fire 

department could not begin to attack the fire until evacuation was complete – about one 

hour. The fire severity was somewhat limited by the fact that the fire floor was 

unfinished and the fuel consisted primarily of stored construction materials. If the fire 

floor door to stair A had also failed, any remaining occupants above the fire would have 

been trapped. 
InterFlam 2007 Page 3 of 11 final3/14/2007 

A conservative estimate of the time needed for most occupants to descend undamaged 

and smoke-free egress stairs is about one floor per minutea. But a growing proportion of 

the population has difficulty in traveling on stairs and a small number of people cannot 

use any stairs without assistance. In general, the number of people who have difficulty 

with stairs increases with building height. These people include those with obvious 

mobility impairments (wheelchair, walker, and crutch users) but increasingly include 

people with respiratory or cardiac conditions, obesity, and those with temporary 

conditions ranging from pregnancy to sprains. 

Today there are buildings under construction and planned where stairs are impractical for 

anyone in the upper reaches of a building 250 to 350 floors in height. For stairs used as a 

means of egress in fires, the record has been very good but not without incident. The 

most frequent problem is contamination of a stair by smoke due to a door not closed or to 

(usually pre-existing) breaches in the stair enclosure. Stair enclosures compromised by 

the initiating event (as was the case at the World Trade Center in both the 1993 and 2001 

attacks) are rare, but stair enclosures are only required by regulation to exhibit fire 

resistance, with no requirements for structural integrity nor impact resistance. Such 

requirements are only now being considered in response to NIST’s WTC 

recommendations3

. For example, New York City has adopted a building code 

requirement4 for egress stair enclosures to comply with level 2 performance for impact 

resistance under ASTM C 16295. 

As mentioned above, any stairs represent significant challenges for some people with 

disabilities. With some conditions, a person’s wheelchair provides critical life support 

and the person may not survive for long if separated from it. Such chairs are usually 

quite heavy and difficult for even several people to carry down stairs. Evacuation chairs 

that can be used to convey many wheelchair users or others with mobility limitations 

down stairs cannot accommodate these life support devices. These evacuation chairs or 

even just the physical support of another can allow some people with disabilities to 

traverse some stairs, but this requires people willing to assist, is fatiguing if the distance 

traversed is long, and can slow the flow of people in the stair. All these shortcomings 

need to be considered when determining RSET. 

The most detailed studies of flow on stairs were performed by Templar in 19756

 and 

influenced the regulatory requirements still in place today. Although Templar found that 

the current 1100 mm (44 in) minimum stair was “adequate,” a 1400 mm (56 in) stair was 

“preferable.” Recently Pauls7

 has challenged the applicability of these to modern society 

due to the increased trend to obesity and lower stamina. Larger people need more stair 

width to maintain the same flow, move more slowly, and are capable of traversing fewer 

flights of stairs before resting. Pauls’ hypothesis is supported by recent studies of drills8

and fire evacuations9 showing travel speeds down stairs decreasing to a quarter of what 

was observed in Templar’s work. Since the costs to the owner in lost rent over the life of 

 

a

 Reported flow rates down stairs are often in the range of (20 to 30) seconds per floor but can slow as 

building height increases. Rates of 50 seconds per floor were reported in the 2001 World Trade Center 

evacuation. Ambiguity of cues, debris in the stairs, or the presence of impaired occupants can slow flows 

even further. Thus a rule of thumb estimate of one minute per floor is reasonable. 
InterFlam 2007 Page 4 of 11 final3/14/2007 

the building for space used by wider stairs can be very high, even significant construction 

costs of alternate approaches to these problems may be cost effective. 

Recently, proposals have been submitted to both US model building code organizations 

to increase the minimum width of required egress stairs from 1100 mm (44 in) to 1400 

mm (56 in) where the stair serves a cumulative occupant load of more than 2000 

people10. The US General Services Administration estimated that the cost of 

construction of this wider stair is increased by about 21 %, and that the cost in lost rental 

of the space occupied by the wider stair is $250 000 to $500 000 per year for a 50 story (2 

stairway) office building, depending on geographic location11. 

CORE ARRANGEMENT 

Most tall buildings are designed with a core area which contains the elevators, 

stairs, and shafts in which the utilities run vertically through the building. The core 

usually serves as the building’s spine and often plays a significant role in the structural 

system. Because the core is most often infrastructure and common use space it is less 

likely to generate revenue for the owner. The designers spend a great effort to “optimize” 

the core design, meaning to make it as small as possible, maximizing the revenue 

producing space on each floor. 

The exit access is generally arranged just outside and surrounding the core, with the 

stairway doors facing outward and cross corridors providing access to elevator lobbies. 

This exposes the exit access to the exterior of the building, protected only by any 

partitions that may provide for separation of spaces. In its new 7 World Trade Center12, 

the architects (SOM) moved the exit access to the center of the core such that the 

(reinforced concrete) core protects the access corridor and creates a refuge area on each 

floor. While this makes the core larger the protected space can shelter the floor 

occupants from external, natural and man-made hazards with direct access to the stairs 

and elevators. The cost-benefit of such arrangements needs to be examined. 

An aspect of egress system design associated with the arrangement of the core is 

remoteness. Buildings are required to have at least two, independent exits, separated by a 

minimum distance; usually not less than one third of the diagonal dimension of the space 

served. Remoteness is intended to ensure that no single incident can block access to both 

stairs. Some regulations permit the separation distance to be measured along a walking 

path between exits, which can allow exits to be adjacent but separated by a perpendicular 

wall of at least half the required dimension in length. If the initiating event compromises 

this wall, the remoteness is defeated. 

OCCUPANT EGRESS ELEVATORS 

Elevators are the normal means of vertical transport in any building taller than a 

few stories. However during fires, the safety of elevators can be affected by the fire itself 

and by water from sprinklers and fire hoses, so the policy worldwide is not to use 
InterFlam 2007 Page 5 of 11 final3/14/2007 

elevators during fires. Elevators are also taken out of service during earthquakes when 

the lateral acceleration exceeds a level that might compromise further safe operation. 

In the 1980’s the elevator industry developed Firefighters Emergency Operation (FEO) 

that is now required in building regulations worldwide. In FEO, detection of smoke in 

the elevator lobby on any floor or in the machine room results in the elevators being 

immediately recalled to the designated landing (generally the level of exit discharge) and 

taken out of service. The responding fire brigade can use a special key to re-activate 

individual cars to be driven manually by a firefighter. In this mode, hall calls are 

ignored and the in-car controls operate somewhat differently to provide enhanced safety. 

Most regulations permit the fire brigade to use elevators being driven by a firefighter to 

be used to assist people with disabilities in evacuation. 

While there are currently no regulations that generally permit occupant egress elevators 

there are a growing number of systems being approved worldwide under performancebased or alternate solutions provisions. Much of this recent acceptance is associated with 

an intensive effort in the US by NIST, the American Society of Mechanical Engineers 

(ASME) and the elevator industry to develop requirements for occupant egress elevators, 

as documented in a number of publications13, , 14 15. 

The prospect of using the elevators for occupant egress in fires is being enthusiastically 

embraced by building owners, designers, and regulators for several reasons. First, it 

permits the location of assembly occupancies (bars, restaurants, and observation decks) 

on upper floors of tall buildings without the building-code-mandated penalty of larger 

stairs running the full height of the building to accommodate the occupant load. This is 

premium space based on the views available from the top. An example is 30 St. Mary 

Axe in London, which incorporates a bar and restaurant on the top floor and protected 

elevators running between the assembly space and street level. Second, egress elevators 

directly address the needs of people with disabilities for self-evacuation. Developers of 

high-rise condominiums for the elderly see egress elevators as a significant marketing 

advantage. An example is Petronas Properties in Kuala Lumpur and Marriott Corp. in the 

US, both of whom are developing high rise condominium properties marketed to older 

residents. Third, integrating egress elevators into the evacuation procedures of very tall 

buildings has a very significant impact on total egress times. An example is Taipei 101 

where the total evacuation time was reduced from 2 hours to 57 minutes when elevators 

were incorporated into the evacuation plan16. 

FIRE SERVICE ACCESS ELEVATORS 

While fire service access elevators are not a part of the means of egress they do 

have a significant impact on occupant egress in tall buildings. For any building of 

sufficient height that egress has not completed before the fire service begins to move into 

position to begin operations, there is a conflict between occupants leaving and firefighters 

entering resulting from counterflow in the stairs. NIST studies of the WTC evacuation

and of drills in federal buildings indicate that counterflow has little effect on occupant 

evacuation but significant impact on fire service access, delaying the start of operations 
InterFlam 2007 Page 6 of 11 final3/14/2007 

and separating firefighting teams. Transferring fire service access to protected elevators 

eliminates counterflow along with numerous additional advantages to operational 

efficiency17. 

It should be noted that the use of fire service access elevators does not eliminate the issue 

of the fire department taking over an attack stairway which is then blocked for occupant 

use from above by the charged hose. This would still occur because the fire attack would 

still be made from the stair – however the impact is greatly lessened if the occupants are 

using elevators for egress or if there are additional stairs. 

ELEVATOR EGRESS STRATEGIES 

When incorporating elevators into fire evacuation it is important to exploit their 

strengths while protecting their weaknesses. The typical design metric for elevators in a 

modern high rise commercial building is to provide sufficient car capacity and speed to 

be capable of moving 10 % of the total population of the building in 5 minutes during 

peak times at the start and end of the work day. Thus, any high rise building is able to 

move its entire population by elevators in one hour or less with the elevators provided for 

normal use. 

Elevators are most efficient when operating in shuttle mode (avoiding time needed for 

accelerating and decelerating smoothly). Further, it makes sense to use the elevators to 

move those with the longest distance to go, first. Occupants of lower floors (without 

disabilities) have a choice to use the stairs. Another consideration is that it is unlikely 

that any large building will initiate a complete evacuation on an automatic alarm due to 

the potential for significant business disruption without cause. But there is recent 

experience with occupants of large buildings initiating a full scale evacuation on their 

own if they suspect something is wrong in their building. This and other issues are being 

studied in a survey of high rise building occupants attitudes regarding building 

evacuation18. 

Thus, an elevator evacuation protocol is likely to begin with an initial alarm summoning 

the fire department and taking the designated fire service elevator out of service to await 

fire department arrival at the designated landing. The remaining elevators will go into 

evacuation mode where they collect occupants of the fire zone (fire floor and two floors 

above and below) to shuttle them to the level of exit discharge. The elevators would then 

wait at the designated level for a decision by the incident commander for partial or 

complete evacuation or for a return to normal service. Waiting at the designated level 

prevents arriving people from taking the elevators to upper floors during the fire. 

A decision for total evacuation would initiate a second phase of the evacuation protocol 

where the elevators would collect occupants from the highest floors first, shuttling them 

to the level of exit discharge and returning for another load, working their way down 

from the top. Hall calls would register people awaiting pickup but would not alter the 

sequence. People with disabilities would not be given any priority since all occupants are 

accommodated equally in this system. 
InterFlam 2007 Page 7 of 11 final3/14/2007 

Enclosed lobbies on every floor would provide a protected space in which to wait and 

serve to protect the hoistway from smoke/fire (delaying the initiation of Phase I recall) 

and from water intrusion from sprinklers or hose streams. Real time signs in every lobby 

would report system status in real time including how long before cars would arrive to 

evacuate that floor. The signs at the level of exit discharge would warn not to enter as the 

elevators are in evacuation mode. Conditions in the lobbies and machine room would be 

monitored in real time from the incident command. Once staging is completed, the fire 

service elevator can be used to pick up the injured or stragglers. All of this can be 

accomplished with commercially available systems. 

REFUGE FLOORS 

In several Asian countries (China, Singapore) tall buildings must be provided with 

refuge floors every 20 to 25 floors. These are usually mechanical floors (no normally 

occupied space) with at least 50 % of the floor area configured as an area of refuge (2-hr 

separations to equipment spaces, no fuel load, space to hold all occupants of the floors 

between refuge floors at 0.3 m2 or 3 ft2per person). They are required to be open on two 

opposite sides so that smoke will not accumulate. Refuge floors provide a protected 

space for occupants to rest or to await assistance, or to cross between stairways19. 

Requirements for refuge floors are relatively new and are currently found in only a few 

buildings. No real evacuations have occurred but there is some experience from drills 

that indicates there may be a problem when people reach a refuge floor and decide to wait 

there rather than continuing the evacuation20. Occupants accumulate on the refuge floor 

such that additional arriving occupants cannot enter. This may be an artifact of a drill 

where the occupants know they are not in danger and that they will be returning to their 

floor after the drill. Also, a study using cfd models showed the open sides could permit 

smoke to enter from an external fire plume originating on a lower floor21. Recent 

revisions require drencher systems on the open sides. 

The World Financial Center currently under construction in Shanghai incorporates refuge 

floors and also utilizes two observation elevators running on the outside of the super 

columns on diagonal corners of the building. These elevators were originally designed to 

provide express service only to the observation deck on the top floor. These observation 

elevators were modified to stop at each of the refuge floors to be used for occupant egress 

in fires. Thus the furthest an occupant would need to travel in the stairs is 25 floors (13 

floors if procedures were to suggest using the closest refuge floor even if it was above 

your position). Occupants not capable of using the stairs to reach a refuge floor would be 

picked up by a firefighter driving an interior elevator under FEO. 

ACTIVE EVACUATION MANAGEMENT 

Increasingly, experts are saying that occupant evacuation proceeding during fire 

department operations should be actively managed, since those operations can result in 

risks to occupants due to changing conditions. This was seen in the Cook County office 
InterFlam 2007 Page 8 of 11 final3/14/2007 

building fire22 and others where suppression operations make the attack stairway 

untenable above the fire floor. Such active management involves monitoring in real time 

to identify conditions that require a modification to the evacuation, and a means to 

communicate instructions. 

Monitoring would likely involve the installation of video cameras in the stairways (one 

proposal submitted to the ICC in the US is for cameras every five floors). Some concerns 

have been raised about the workload of monitoring all these cameras. With modern 

security cameras and software it is unnecessary for a person to monitor the images. The 

software monitors the image and, as long as there are people moving down the stairs the 

image is in background. Should there be no people or no movement for a preset time the 

image is brought forward for the operator. This would allow rapid identification of 

blockages without undue distraction. These cameras can also identify smoke in the stair 

which would require redirection of occupants through the voice communication systems 

already present under current codes. 

COMMUNICATION SYSTEMS FOR EGRESS MANAGEMENT 

Since the early 20th Century fire alarm systems have been provided in buildings to 

notify occupants of the need to evacuate. Once the alarm was sounded there was no 

further need for communication since the action was simply to leave the building as 

quickly as possible. This changed in the mid-1980’s when phased evacuation was 

introduced for tall buildings where the egress system could not support simultaneous 

evacuation. It was felt that where occupants were asked to wait for their turn to evacuate, 

it is necessary to provide a means of making pre-recorded and live, voice messages until 

the evacuation was complete. This communication was carried out from a fire command 

center specifically arranged for the fire department to conduct incident command. 

New York City adopted Local Law 5-1973 which required voice communication systems 

for new, high rise (defined as exceeding 100 feet or 30.5 m in height) office buildings and 

extended this requirement to new mercantile and all high rise hotel occupancies through 

Local Law 16-1984. In the U.S., the National Fire Protection Association’s Technical 

Committee on Protective Signaling Systems developed NFPA 72F (High Rise Voice 

Communication Systems, which was published in 1988 and then incorporated as a 

chapter in the consolidated National Fire Alarm Code, NFPA 72 (1993 and subsequent). 

Total evacuation of tall buildings has been a rare event, but as society becomes more risk 

averse we may find that it occurs more frequently. Also, fire is not the only condition 

that might trigger a total evacuation. Severe weather, chemical spills, earthquakes, major 

water leaks, workplace violence, and large-scale power outages are only some of the 

conditions that have led to building evacuations. In some cases the emergency action is 

to shelter within the building, which may involve some relocation. The complexity of 

getting occupants to take the desired action makes an even stronger case for 

communication systems and proactive evacuation management. 
InterFlam 2007 Page 9 of 11 final3/14/2007 

Human factors research clearly shows that people will generally make the right decisions 

when provided with the (clear and unambiguous) information upon which to base those 

decisions23. Events such as the 1993 and 2001 World Trade Center evacuations as well 

as evacuations and drills carried out in other tall buildings show the range of things that 

can go wrong when evacuating large number of people. These all demonstrate the need 

to actively manage evacuations, including monitoring the process to identify problems, 

and communications systems to give directions that resolve these problems. 

Today, emergency communication systems are common, even in smaller buildings. 

These initially provide to specific areas (individual floors or fire zones, stairs, and 

elevators) or to the entire building, pre-recorded or digitally generated voice instructions 

initially, and the ability for the incident commander to issue live instructions during the 

incident. Current discussions include the provision of cameras in refuge areas and stairs 

to provide the incident commander the ability to monitor the evacuation process and to 

quickly identify problems. To reduce monitoring workload these would be arranged to 

only display their image if the system detected no people or people not moving in the 

stairs, or if a call were placed from the location to the command center. 

Dynamic signs are being discussed to provide textural information in real time. These 

could display the time before elevators arrive at a given floor as part of an elevator 

evacuation system, or to give directions at key points in the egress system on which 

direction to go. Such dynamic signs have been installed in the new WTC 7 building on 

the transfer floor, within the egress stairs to instruct occupants on which street exits to 

use. These signs can display any messages entered from either the fire command or 

security center of the building. 

Another experimental information system developed by the US General Services 

Administration is a text pager that is issued to any hearing impaired occupant and 

available to hearing impaired visitors at the security desk. This system can display 

messages and instructions in real time during any incident and vibrates to get the user’s 

attention. The only problems noted in technology studies is getting people to carry them 

and recovering units issued to visitors. 

PERFORMANCE GOALS FOR EGRESS SYSTEMS 

In its recommendations for changes to codes, standards, and practices resulting 

from the WTC collapse investigation, NIST recommends that buildings be designed for 

“timely, complete evacuation.” The point is not that total, simultaneous evacuation will 

become the norm or will even be common; but it is reasonable to expect that every 

building will need to be completely evacuated a small number of times over its lifetime. 

In the recommendations, timely is not defined. Recent experience with the use of 

elevators for occupant egress in very tall buildings indicates that it is possible to evacuate 

the entire population of any building of any height within one hour, without any changes 

to the number, size, or speed of the elevators that would be present if they were not used 

for evacuation. Thus, the goal of being able to evacuate a building in one hour or less is 

achievable as an RSET. 
InterFlam 2007 Page 10 of 11 final3/14/2007 

In modeling of occupant egress it is recommended that a safety factor of 2 by applied 

when dealing with the uncertainties of human behavior24. In keeping with this 

conservative approach it is reasonable to double the time available and to require a 

minimum of 2 h of ASET (available safe egress time) and this is a common requirement 

today for the fire resistance of the primary structural frame in sprinklered high rise 

buildings. The result should represent a reasonable and conservative performance goal 

for complete evacuation (including people with disabilities) within one hour. In addition 

this permits people with disabilities to self-evacuate with every one else and without the 

need for assistance or special devices. 

CONCLUSIONS 

From this discussion it appears obvious that protected elevators will become a 

primary means of vertical travel in tall buildings. Assuming regulatory agreement with 

the performance goal of total evacuation in one hour or less, occupant egress elevators 

would be required in buildings taller than about 50 stories and fire service access 

elevators in buildings taller than (6 to 9) stories. At the estimated one floor per minute 

rate, buildings of up to 50 stories can be evacuated in one hour or less using stairs alone. 

Most fire departments report a preference to use elevators to access fires above the sixth 

floor. Discussion and consensus is needed on the role of stairs, refuge floors, 

communication systems, and procedures for egress, relocation, or protection in place in 

the range of incidents that may be encountered in any building. In some cases, formal 

threat assessment may be needed to identify scenarios that need to be considered. 

Where protected elevators are provided for occupant egress much of the occupant load 

would be carried by the elevators. Thus there may be less need for wider stairs, and the 

avoided costs of wider stairs should be more than adequate to cover the additional costs 

for protecting the elevators and adding monitoring. Owners then would be free to place 

assembly occupancies high in the buildings without the need for increasing stair capacity. 

People with disabilities would be afforded the ability to self-evacuate with all other 

occupants without the need for special arrangements or equipment. In an event where 

the incident commander decides to require simultaneous evacuation of a building, the 

entire population should be capable of clearing the building in an hour or less. An hour 

should be an achievable RSET even for very tall buildings and it should be well within 

the practical ability of safety designs to provide a protected environment (ASET) of two 

hours in which to carry out an evacuation including a conservative factor of safety of 2 

for variation in human behavior and capability. 

REFERENCES 

 

1

 Bukowski, R.W. and Kuligowski, E.D., The Basis for Egress Provisions in U.S. Building Codes, 

InterFlam 2004, Edinburgh, UK, July 2004. 

2

 Klem, T. and Kyte, G., Fire at the Prudential Building, Fire Command, 53, No. 3, 14-19, March 1986. 3

 NCSTAR 1 Final Report on the Collapse of the World Trade Center Towers, Chapter 9 

Recommendations, Nat Inst Stand Tech, Gaithersburg, MD 20899 2005. 

4

 Local Law 26-2004, Ammendments to the Building Code of New York City, New York City Department 

of Buildings, 2004. 
InterFlam 2007 Page 11 of 11 final3/14/2007 

 5

 Standard Classification for Abuse-Resistant Nondecorated Interior Gypsum Panel Products and FiberReinforced Cement Panels, ASTM C 1629/C 1629M-05, ASTM International, West Conshohocken, PA. 

6

 Templar, J., The Staircase, Studies of Hazards, Falls, and Safer Design, MIT Press, Atlanta, GA 1992. 7

 Pauls, J., Selected Human Factors Aspects of Egress System Design, presentation at CIB TG50 and W14 

Joint Symposium on Tall Buildings and Fire, September 2006, proceedings available at 

http://www.cibworld.nl/ 

8

 Averill, J. and Peacock, R., SFPE PED Conference proceedings (in press) 9

 Averill, J., Mileti, D., Peacock, R., Kuligowski, E., Groner, N., Proulx,G., Reneke, P., and Nelson, H., 

Occupant Behavior, Egress, and Emergency Communications, NCSTAR 1-7, NIST, Gaithersburg, MD 

2005, available at http://wtc.nist.gov/ 

10 Life Safety Code, NFPA 101-2006, Table 7.2.2.2.1.2 (B), Nat Fire Prot Assn, Quincy, MA 02269 

11 David Frable, GSA, private communication. 

12 Details of the design of 7 WTC can be viewed on the Silverstein Properties website 

http://silversteinproperties.com/ 

13 Bukowski, R.W., Protected Elevators for Egress and Access During Fires in Tall Buildings, Strategies for 

Performance in the Aftermath of the World Trade Center. CIB-CTBUH Conference on Tall Buildings. 

Proceedings. Task Group on Tall Buildings: CIB TG50. CIB Publication No. 290. October 20-23, 2003, 

Kuala Lumpur, Malaysia, Shafii, F.; Bukowski, R.; Klemencic, R., Editors, 187-192 pp, 2003. 14 Bukowski, R. et al, Elevator Controls, NFPA Journal, Nat Fire Protect Assoc., Quincy, MA 100, No 2, 

March/April 2006 

15 Bukowski, R., Protected Elevators and the Disabled, Fire Protection Engineering, SFPE, Bethesda, MD, 

Issue 28, Fall, 2005. 

16 Hsiung, K., Wen, W., Chien, S., and Shih, B., A Research of the Elevator Evacuation Performance for 

Taipei 101 Financial Center, Proc 6th International Conference on Performance-based Codes and Fire 

Safety Design Methods, 14-16 June 2006, SFPE Bethesda, MD 2006. 

17 Kuligowski, E.D. and Bukowski, R.W., Design of Occupant Egress Systems for Tall Buildings, Use of 

Elevators in Fires and Other Emergencies Workshop Proceedings. Co-Sponsored by American Society of 

Mechanical Engineers (ASME International); National Institute of Standards and Technology (NIST); 

International Code Council (ICC); National Fire Protection Association (NFPA); U.S. Access Board and 

International Association of Fire Fighters (IAFF). March 2-4, 2004, Atlanta, GA, 1-12 pp, 2004, 2004. 

18 Fire Protection Research Foundation Project on High Rise Occupants and Evacuation, Fire Protection 

Research Foundation, Quincy, MA 02269. 

19 Code of Practice for the Provision of Means of Escape in Case of Fire, Part II, Section 21 Refuge Floors, 

Hong Kong Building Authority, 1996. 

20 Meacham, B., Refuge Floors in Tall Buildings: The Asian Experience, presentation at CIB TG50 and 

W14 Joint Symposium on Tall Buildings and Fire, September 2006, proceedings available at 

http://www.cibworld.nl/ 

21 Yuen, K., Lo, S., and Yeoh, G., Numerical Simulation of Wind-Smoke Effect on Designated Refuge 

Floor in High Rise Buildings, Proc InterFlam “99, Volume 2. June 29-July 1, 1999, Edinburgh, Scotland, 

Interscience Communications Ltd., London, England, 1273-1279 pp, 1999 

22 Proulx, G. and eid, I., Occupant Behavior and Evacuation during the Chicago Cook County 

Administration Building Fire, Journal of Fire Protection Engineering, SFPE Bethesda, MD, 16, No 4, 2006. 23 Proulx, G. and Koroluk, W., Fires Mean People Need Fast, Accurate Information, NRCC-41088, CABA 

Home and Building Automation Quarterly, 17-19, Summer 1997. 

24 Nelson, H.E. and Morwer, F. W., Emergency Movement, SFPE Handbook of Fire Protection 

Engineering, 3rd ed., SFPE Bethesda, MD, 2002. 
Appendix L

Emergency Egress from Buildings, Part 1: History and 

Current Regulations for Egress Systems Design
Emergency Egress from Buildings 

Part 1: History and Current Regulations for Egress Systems Design 

Richard W. Bukowski, P.E., FSFPE 

NIST Building and Fire Research Laboratory 

Gaithersburg, Maryland 20899 USA 

INTRODUCTION 

For most of history buildings were short enough that stairs provided for access were 

sufficient for rapid egress in the event of fire. Even in single stair (mostly residential) 

buildings, experience showed that this stair was sufficient for fire egress as long as the 

fire did not expose or block access to the stair. Fire resistant apartment doors shielded 

the stair from most fires and exterior fire escapes provided a second egress path 

beginning early in the 20th Century. 

The 1854 invention of the elevator safety brake enabling the passenger elevator is 

credited with facilitating increases in building height and the first so-called skyscraper in 

Chicago in 1885. These buildings utilized steel frames protected by masonry or tile and 

were dubbed “fireproof construction” providing a (possibly false) sense of security. By 

1914 authorities had begun to question these arrangements as evidenced by a move to 

change the term “fireproof” to “fire-resistive,” and description of egress provisions in 

regulations as “exceedingly deficient.”1

Model building regulations in the US started with the National Building Code published 

by the National Board of Fire Underwriters (NBFU) following the Great Fire of Boston 

(1872). Property loss claims from this fire resulted in more than 70 insurance companies 

being driven into bankruptcy, causing insurance interests to form the NBFU and to 

develop building fire safety rules aimed at reducing property losses in fires. These rules 

became the first model building code, called the National Building Code (NBC), and first 

published in 1905. The NBFU was able to tie compliance with their rules to their 

Municipal Grading Schedule on which insurance rates are based. Cities needed favorable 

rates to attract investment, so they were motivated to adopt regulations consistent with 

the National Building Code2. The first (1905) edition of the NBC required exit stairs to 

have a minimum width of 20 in (510 mm)*. 

The purpose of this paper is to document current regulatory requirements for means of 

egress in fires, their origins and scientific basis, and the approaches used in other 

countries. Then the paper will present an argument for why these approaches and 

requirements should be re-evaluated to reflect changes both in buildings and in their 

occupants. Finally the paper will make some suggestions for reasonable revisions to 

 

*

 This paper will cite primary dimensions in the units found in the code cited. Thus U.S. codes will show 

English units first and non-U.S. will show metric first. Unit conversions are approximate because the paper 

cites the equivalent values found in the building regulations of various countries which are normally round 

numbers. 
design practice along with a more holistic philosophy that takes better account of human 

behavior and is based on a more appropriate performance metric. 

ORIGINS OF THE 44 INCH EXIT STAIR IN THE US 

In the 1913 National Fire Protection Association (NFPA) Proceedings3, the Committee 

on Fireproof (later, Fire-Resistive) Construction reported a number of recommendations, 

including one for minimum 44-in exit stairs (unobstructed width except that handrails 

would be permitted to intrude not more than 3 1⁄2 in on each side). That same year NFPA 

formed their Committee on Safety to Life. That committee’s first activity was to conduct 

a comprehensive review of fire safety issues and regulatory approaches found in building 

codes and local regulations in several, geographically diverse cities. At the NFPA’s 1914 

meeting they reported that, 

“... existing laws are exceedingly deficient in this very important matter of egress. A 

number of states report frankly that they have no real legislation upon the subject, 

many City Ordinances are of the most indefinite character, and in some the 

matter is simply left to the discretion of the fire department or other officials.” 

In the 1914 NFPA Proceedings, section on egress, the Safety to Life Committee cites the 

1913 NFPA Annual Meeting report of the Committee on Fire-Resistive Construction in 

which they said was presented, 

“... a splendid set of specifications for the construction of a standard building. Egress 

received detailed attention; -- specifications for smoke-proof towers, for stairs, 

for horizontal exits, and for the capacity of vertical and horizontal exits were 

included.” 

The committee also cites the 1913 laws of the New York State Department of Labor 

which, “... as regards fundamentals appear to agree entirely with the requirements of 

our Committee ...” Extracting from the referenced New York statute, they cite, 

“a. For buildings erected in the future, a minimum of 22 inches of stair width 

shall be required for not to exceed 14 persons on any one floor. 

 b. On buildings already erected this figure is reduced to 18 inches as a minimum. 

c. A 44-inch stair in new buildings permits 28 persons to be housed on each floor 

above the first one. 

d. In arriving at this decision the idea has been that all of the persons on all floors 

shall be able to remain in the stair tower without any movement, a person 

requiring about 22 inches in width, and one person to stand on every other stair.” 

They further characterize the New York laws’ stair geometry (7 3⁄4 in riser height by 10 in 

tread) as “good”, and that they recommend a minimum 44 inch wide stair for new 

buildings as this width is 

“reported sufficient to prevent three persons from forming an arch and blocking traffic.” 

EXIT CAPACITY 

The above explains why the US designs exits for “capacity” and why the capacity is 

based on the population of a single floor. The exit is sized to “store” people, motionless 
within the protected exit enclosure, such that the population of one floor will fit within 

one flight of the stair, with each person in a space 22 inches wide and standing on every 

other step. 

This philosophy was recognized in the 1935 National Bureau of Standards (NBS now 

NIST) publication, Design and Construction of Building Exits 4 . Developed by the 

Department of Commerce Building Code Committee, this report included survey data on 

exit sizes and configurations drawn from eight cities chosen, “... with a view to covering 

places varying in size and sufficiently distributed to give a fair cross section of building 

construction.” The survey included population counts on typical floors and compiled 

data on movement of people in buildings (railway terminals and schools). Studies of the 

flow of occupants of government buildings during fire drills were conducted and the data 

presented as discharge rates for stairs (as a function of width and stair geometry), ramps, 

and doorways. 

The data were used to suggest possible approaches to calculating minimum width of exits 

necessary to provide for occupant safety. These included (note that the descriptive text is 

paraphrased from the 1935 report): 

1. Capacity Method, which is based on the concept of storing occupants on the stairs 

within a protected stair enclosure, and allowing for the subsequent safe and 

orderly evacuation of the building. It recognized that travel down a long series of 

stairs in high buildings is exhausting even to normal persons. Objections of 

building owners over the loss of rentable space are noted as well as the comment 

by some authorities that people may not stand still in stairways, even in high 

buildings. 

2. Flow Method, which is based on the concept that people will move down the 

stairs at a typical flow, assumed to be 45 persons per 22 in unit of width per 

minute and 60 persons per minute through doorways. It is stated that this method 

is usually coupled with an assumed time in which it is safe to exit the building and 

that this method calls for considerably less stairway width than the capacity 

method. However they felt that it would be limited to a few occupancies and to 

buildings of low to moderate height since continuous movement down stairways 

in high buildings cannot be expected without serious effects on some occupants. 

3. Combined Method suggests the flow method for lower buildings shifting to the 

capacity method for taller buildings also accounting for type of construction and 

use. Once again they point out that tall buildings would require a disproportionate 

amount of space devoted to stairways as compared with useable floor area. 

4. Probability Method considers only the population of the six, most densely 

populated floors since it is improbable that simultaneous evacuation of all floors 

of a large building is needed. This is the first time that phased evacuation (as 

currently practiced in tall buildings) is suggested. 

5. Floor Area Method relates area to units of exit width needed as a function of 

construction type and use. Like the probability method, simultaneous evacuation 

of all floors is not considered but the number of floors considered varies with 

occupancy. 
In the end, the 1935 report suggests that the needs of the vast majority of buildings can be 

met with the provision of two, two-unit-width (44 in) stairs. The capacity method 

(occupants waiting within the exit enclosure) is appropriate for low buildings with a 

gradual shift to the flow method for taller buildings where people will be less comfortable 

waiting in the stair. For tall buildings the floor area method has some application as these 

are of fire resistive construction and only those near the floor of origin are initially at risk 

but six floors is not sufficient for larger buildings. They suggest half of the floors should 

be considered. 

EARLY THOUGHTS ON ELEVATORS AS A MEANS OF EGRESS 

Both the 1914 NFPA ProceedingsError! Bookmark not defined. and the 1935 NBS report discuss 

the possible use of elevators for egress from tall buildings. In 1914 the Committee on 

Safety to Life expressed the opinion that, “... elevator shafts properly enclosed and with 

openings adequately protected have decided value from an escape standpoint, and are 

absolutely necessary in high buildings.” They cited as “... loss of life possibilities in 

many modern so-called fireproof buildings ...” the common practice of unenclosed stair 

and elevator shafts that might permit a fire in lower stories that, “... spread with 

unexpected speed could result in a loss of life which would stagger the civilized world.” 

The Committee called for enclosing elevator shafts, improving the fire resisting powers 

of elevator doors, ensuring the integrity of the electric current applied to elevators, and 

“drilling” elevator operators in emergency procedures, including that persons in the upper 

stories shall first be taken to the ground. 

The 1935 NBS report discusses a credit for elevators against required aggregate exit 

width. They discount automatic elevators as unsuitable as their “...capacity and rate of 

speed is not great.” And “... they are not subject to a single will as in the case of an 

elevator operator, but to demands from many tenants.” While there was a suggestion in 

the formulae of the flow method that five elevators might be equal to a single unit of exit 

stair width for some construction types and use, in the end they concluded that the 

uncertainties were such that no direct credit be given for elevators but to recognize their 

availability in high buildings. 

EARLY REGULATORY APPROACHES IN THE US 

The 1914 report of the Committee on Safety to Life included detailed recommendations 

for the design and arrangement of egress stairs and fire escapes with the intent that this 

material would be incorporated by others into building regulations. No code or standard 

was produced by the Committee until the 1927 publication of the first edition of the 

NFPA Building Exits Code (NFPA 101-T)5

 which later became the Life Safety Code. 

The 1927 edition of NFPA 101-T defined stairs as Class A, B, or C. Class A stairs were 

the main stair of a newly-constructed Assembly occupancy, and were 44 in (1100 mm) 

wide (handrails could intrude not more than 3 1⁄2 in (89 mm) on each side) with a rise of 

not more than 7 in (178 mm) and a tread of not less than 10 1⁄2 in (267 mm). Class B 

stairs were for new construction of all stairs not required to be Class A, and for existing 
construction where Class A stairs would be required if new. Class B stairs were the same 

width as Class A but the rise was permitted to be not more than 7 3⁄4 in (197 mm) with a 

tread of not less than 9 1⁄2 in (241 mm). Class C stairs covered existing stairs in existing 

buildings and were at least 36 in (0.9 m) wide (not less than 32 in, 0.81 m between 

handrails, but stairs less than 44 in (1100 mm) wide only required a handrail on one side). 

Occupant load on a floor dictates required capacity (total width of stairs in number of 22 

in units) required in a minimum of two stairs located “as remote as practical.” 

The 1935 NBS report included recommended code language in an appendix that did not 

follow any of the five methods for calculating minimum exit widths discussed previously. 

They explained that tentative requirements were drawn up and compared against the 

results of the field studies. Eventually a consensus of the Committee was reached and 

was presented in the recommended code language. 

The suggested code requirements largely followed the capacity method for at least two 

stairs of two (22 in, 550 mm) units of exit width each, with the floor area method used 

(by means of occupancy load factors consistent with those found in current regulations) 

to determine aggregate width. No suggestions of maximum egress time (including no 

references to fire resistance times associated with construction types, building height, and 

use) that might facilitate the use of the flow method, and no mention of partial evacuation 

of tall buildings as discussed in the probability and floor area methods was made. These 

recommendations were consistent with those in the 1927 edition of NFPA 101-T, but this 

is not surprising since the Committee on Safety to Life was represented on the NBS 

Committee. The requirements suggested in the NBS report and NFPA 101 were adopted 

in the model codes and building regulations throughout the US until the mid-1980’s when 

the 22 in (550 mm) unit of exit width was abandoned for assessing exit capacity in units 

of people per inch, but retaining the 44 in (1100 mm) minimum width. This method 

provides similar results for aggregate exit width but provides more capacity credit for 

fractions of the 22 in unit. 

SCIENTIFIC STUDIES OF FLOW RATE 

The 1935 NBS report included field surveys of discharge rates down exit stairs and 

through doors for various government buildings during drills and for subway and rail 

terminals at rush hours. The data collected were discussed by the Committee and a 

consensus reached that there was a clear correlation between width and flow. The 

committee agreed that, “... rates of 45 persons per 22-inch unit per minute for travel 

down stairways, and 60 persons per 22-inch unit per minute through doorways, which 

had been in use on the basis of earlier observations, were sufficiently confirmed to 

warrant their retention in connection with the requirements under development.” 

Almost from the start there were issues raised with the assumed flow rate on stairs of 45 

persons per minute per (22 in) unit of exit width. Togawa6 in Japan conducted research 

in the 1940’s and 50’s, that showed for densities above 1 person per square meter (10 

square feet) that flow rates decreased significantly. His data suggested a flow rate of 26 

persons per minute per (22 in) unit of exit width. 
Pauls has published extensively on this topic and continues to be the scientific conscience 

of stair design in the US codes. Pauls7 and Fruin8 both discussed the concept of effective 

width of a stair, which is generally 0.3 m (1 ft) narrower than the actual width due to the 

natural tendency of people to keep a distance from walls and handrails. Fruin further 

spoke of the personal space (buffer) around people that increases their effective space 

requirement. Pauls found that for people walking on stairs their body sways from side to 

side and they desire sufficient space so that they do not make contact with the person 

beside them. Pauls work confirmed that of Togawa finding that flow rate in stairs at 

typical densities is about 27 persons per minute per (22 in) unit of exit width. Extensive 

studies in Russia also confirmed the effects of density on flow rates including the values 

suggested by Pauls and Togawa, as reported in a 1969 book by Predtechenskii and 

Milinskii9

. 

From the data collected by NIST in the investigation of the World Trade Center (WTC) 

collapse on September 11, 2001, the flow rate in the stairways can be estimated10. For 

WTC 1, there were approximately 7900 survivors who exited the building over the 102 

minutes between the aircraft strike and the collapse. The building had three stairs, two at 

44 in (1100 mm) and one at 56 in (1400 mm). Assuming the occupants used the stairs 

equally, there were 2630 people in each 2-unit wide stair who exited in 102 minutes, or 

13 people per minute per unit of exit width. The NIST study found that the egress flow 

decreased by about 80 % in the last 20 minutes before collapse. If one assumes the 2630 

people exited in 82 minutes, the flow rate would be 16 people per minute per unit of exit 

width. These estimates support the argument that current flow rates may be significantly 

less than the rate suggested by Pauls and Togawa in the 1970’s and one third the rate 

proposed in 1914Error! Bookmark not defined.. 

SCIENTIFIC STUDIES OF EXIT WIDTH 

Clearly, the current 44 in (1100 mm) minimum exit stair width is intended to support two, 

22 in queues of occupants either standing still (capacity method) or moving down the 

stair (or a single queue of occupants moving down and being passed by firefighters 

moving up, known as counterflow). The 22 in dimension for the width of a person was 

offered in 1914 as originating with soldiers standing in a lineError! Bookmark not defined.. 

Challenges to the adequacy of the 22 in dimension include the need to provide for body 

sway as people move down the stair (Pauls), and the need to allow for some personal 

space (Fruin, Predtechenskii and Milinskii). Recently, the adequacy of the basic 22 inch 

dimension is being questioned in light of the increasing size and weight of the typical 

person, especially in the US. The 22 inch dimension refers to the width of a person at the 

shoulders, which is assumed to be the widest part. Predtechenskii and Milinskii suggest 

that 4 in (100 mm) be added to each side to allow for a personal buffer except that for 

low obstructions (like handrails) the additional space is not needed since one’s shoulders 

are at a higher level and will extend over the obstruction. 
From anthropometric data for 

modern Americans, the width at 

the hip is approaching the width at 

the shoulder, and it seems that this 

exception may no longer be valid. 

Thus, with the shoulder width of 

the 97.5th percentile adult male 

reaching 20 in (510 mm) 11 and 

allowing the 4 in on each side for 

handrail and personal space, the 

new unit of exit width should be 

28 in (700 mm) and the minimum 

stair width 56 in (1400 mm), see 

Fig 1. 

Arguably the most comprehensive 

studies of movement on stairs were 

conducted by Templer, beginning with 

his doctoral research 12 and including 

work at NBS13 in the 1980’s. Templer 

observed the movement of many 

individuals up and down stairs of varying width and tread geometry, tabulating variables 

ranging from quantitative (speed, number of stumbles) to qualitative (perceived comfort). 

From this work Templer concluded that the minimum width of an egress stair should be 

56 in (1400 mm). 

Figure 1 Anthropometric data for adults 

Reprinted with permission from NFPA 101® the Life Safety 

Code®, copyright © 2006 National Fire Protection Association

SCIENTIFIC STUDIES OF TREAD GEOMETRY 

One of the earliest studies of stair geometry was conducted by an architect in France 

named Francois Blondel14. Blondel was primarily interested in comfort rather than safety 

and observed that the main stairs of classic cathedrals were comfortable to use and 

accommodated large numbers of people attending services. He made measurements and 

found that the ratio of stair height to tread depth was a constant, and he related this 

dimension to the length of the human gait. His formula was 2R+G=24 in, where R is the 

rise and G is the going (or run). Templer adjusted Blondel’s formula for the use of the 

old (pre French Revolution) inch and a modern gait more like 28 in (71 cm) and arrived 

at a modern (metric) formula, 2R+G=710. The so-called 7/11 stair geometry commonly 

required in US codes meets the relation 2R+G=635. 

Templer15 summarizes a number of research studies of stair geometry and safety. Many 

such studies were conducted by observing people moving up or down stairs in buildings. 

Observations in subway or train stations at rush hours provided data for higher population 

densities. A few studies were conducted in laboratory settings on specially constructed 

stair sections where the geometries and stair angle could be varied systematically. 

Templer himself conducted several of these studies, including some at NBS. 
Most of the studies reviewed concluded that the measure of Total Energy Cost per Meter 

Rise is a useful metric for the evaluation of stair design for normal use and comfort; 

however stair safety is more closely related to the likelihood of missteps which is a 

function of how the stair relates to the human gait. In both cases the effect is different for 

ascent and descent, with descent being more hazardous. 

When ascending a stair a person walks on the ball of the foot with less of the foot placed 

on the step. Shorter treads (goings) and higher risers produce fewer missteps. When 

descending a stair the heel and most of the foot needs to be placed on the tread. Too 

much of the front of the foot extending over the nosing results in rotation of the foot and 

a fall, or a distorted gait while trying to place more foot on the tread. Tread depths of at 

least 11 in (280 mm) are recommended to accommodate the 95th percentile foot, but 

considering only gait and accident history treads (goings) of at least 9 in (230 mm) are 

required. Riser heights of 6.3 in to 7.2 in (160 mm to 183 mm) had the fewest missteps. 

Other dimensions apply to curved stairs16. 

Other factors relevant to stair safety include lighting, slip resistance, single steps (most 

codes prohibit flights of fewer than three steps), handrails, and inability to detect the edge 

of the tread due to lack of contrast. 

REVIEW OF INTERNATIONAL CODE REQUIREMENTS FOR EGRESS 

STAIRS 

The building regulations summarized below are from countries that are widely disbursed 

and culturally different, and should be representative of any range of methods used to 

treat egress. Where the original code documents are published in languages other than 

English, the codes used were official translations published in English, so they can be 

presumed accurate. 

Characteristics of egress stair design include the factors previously discussed as well as 

the minimum number of egress stairs provided, maximum travel distance to a stair, width 

of doors and passageways, interior finish, lighting and marking, headroom, and handrails. 

All of the codes examined address all of these characteristics and all are reasonably 

consistent in requirements. For example, all require handrails on both sides of an egress 

stair and a center handrail when stair width exceeds 1800 mm (71 in). It is interesting to 

note that, while all the codes require a minimum of two egress stairs from every floor, 

many of the codes address specific conditions in which a single stairway is permitted, and 

some are quite liberal in this regard. Design occupant loads are generally consistent 

among most building regulations in the world. 

United States 

In the United States model building regulations are developed by private sector, nonprofit organizations and are adopted by State and local governments with modifications 

that reflect local needs and practices. Two such model codes exist but the requirements 

of both are reasonably consistent, especially with respect to egress system design. A 
detailed review of current US building code requirements for egress system design is 

provided by Bukowski and Kuligowski17. 

In the US codes, the minimum width for an egress stair is 1100 mm (44 in) except that a 

space served by no more than 50 people can have a 900 mm (36 in) stair. The capacity of 

a stair (number of people served per floor) is 0.3 in per person unsprinklered and 0.2 in 

per person sprinklered. Thus, for the 1100 mm (44 in) stair the capacity is 147 

unsprinklered and 220 sprinklered. As an example, the design occupant load for offices 

specified in US building regulations is 10 m2 per person (100 ft2 per person). 

 

Australia 

In Australia the legal responsibility for regulation of buildings rests with the States and 

Territories. Since 1996 a national model building code, the Building Code of Australia 

(BCA) has been developed under a mutual agreement (and funding) by the Australian 

Building Codes Board, and is adopted with local modifications by the States and 

Territories. The local modifications are published as individual annexes in the BCA 

document. 

The BCA 200618 is a performance-based code that includes prescriptive requirements 

drawn from the predecessor code as deemed-to-satisfy requirements within the published 

code document. While it is common to use performance analysis to address such issues 

as travel distances, remoteness requirements, or fire resistance requirements for shaft 

enclosures, stair geometries and minimum widths generally comply with the prescriptive 

rules. 

The minimum clear width (between handrails) of a required exit stair serving a storey or 

mezzanine accommodating up to 100 people is 1000 mm (39 in). Stairs serving a storey 

that accommodates more than 100 but not more than 200 must have an aggregate width 

of at least 1000 mm (39 in) plus 250 mm (10 in) for each 25 people (or fraction thereof) 

in excess of 100, and stories accommodating more than 200 must have an aggregate 

width of 2000 mm (78 in) plus 500 mm (20 in) for every 75 people (or fraction thereof) 

in excess of 200 unless the stair or ramp is steeper than 1 in 12, when the additional 500 

mm (20 in) is for every 60 people in excess of 200. Design occupant loads are similar to 

the US codes. For example, for offices the design load is 10 m2 per person which is 

identical to the US 100 ft2 per person. 

Stair geometry is specified as a range for both the riser (rise) and going (tread), along 

with a range of the ratio of twice the riser plus the going (Blondel’s formula). The values 

specified are a riser between 115 mm and 190 mm (4.5 in and 7.5 in), a going between 

250 mm and 355 mm (10 in and 14 in) and the ratio (2R+G) between 510 and 700. 

United Kingdom 

The UK building regulations apply to England and Wales but not in Scotland or Ireland. 

In 1985 UK adopted a performance-based code and converted its prescriptive rules to 
Approved Documents which represent deemed-to-satisfy rules. Approved Document B19

deals with Fire Safety. 

Section 5 deals with Design for Vertical Escape for buildings other than Dwellings, with 

minimum stair widths for simultaneous evacuation on Table 7 and for phased evacuation 

in Table 8. Table 7 lists the maximum capacity (number of persons served) as a function 

of stair width and number of floors. Stair widths range from 1000 mm (39 in) to 1800 

mm (71 in) with the provision that stairs wider than 1800 mm must be divided by a 

handrail. Thus the minimum permitted width is 1000 mm (39 in). For a stair of 1100 

mm equivalent to the US minimum 44 in stair, 260 people can be accommodated on two 

floors, increasing by 40 people for each additional floor. For phased evacuation 120 

people per floor can be accommodated by a 1100 mm (44 in) stair with an additional 10 

people for each 100 mm (4 in) in width. Design occupant loads in Approved Document 

B are somewhat more conservative than in other codes, for example offices are 6 m2 (60 

ft2

) per person. 

Some insights into the development of the table appear in the supporting text in 

Approved Document B. Provision 4.25 presents an alternative to using Table 7 for stairs 

1100 mm (44 in) or wider to determine number of persons served (P) for simultaneous 

evacuation by applying the formula P=200w+50(w-0.3)(n-1). Note 5 to this formula 

explains that 200w represents the number of persons estimated to have left the stair after 

2.5 min of evacuation and the second term represents the number accommodated on the 

stair at that time. This implies that they are assuming a flow of 45 persons per minute per 

510 mm (22 in) of width and a storage capacity of 50 people per (meter minus 0.3, which 

may represent Fruin’s boundary space) in each story of stairway. This appears to follow 

the 1935 NBS recommendation for a combination of the flow method and the capacity 

method with the assumption that the first 2.5 min of evacuation time is safe. 

It is also interesting to note that Approved Document B suggests that buildings in excess 

of 30 m (100 ft) in height be designed for phased evacuation. This has somewhat 

different stair capacity requirements but also suggests that the capacity should be 

provided by the stairs remaining after any one is discounted as being used by the fire 

service for fire attack. Appropriate arrangements are to be worked out for specific 

building conditions in consultation with the fire brigade. This is in addition to a 

requirement that buildings in excess of 30 m (100 ft) in height be equipped with a 

firefighting shaft including a protected elevator dedicated to emergency response service. 

Spain 

Spain has a national building regulation developed by the Ministry of Housing and issued 

by Royal Decree. Like Australia, Spain recently adopted a performance-based building 

regulation that includes deemed-to-satisfy requirements within the code that are based on 

the traditional rules. Because Spain is a Member State of the European Union (EU) they 

fall under the Construction Products Directive of the EU which requires coordination of 

construction regulations so that the regulations do not become a barrier to free trade 

within the Union. 
The Spanish regulations20 (Section SI 3, table 4.2) assign evacuation capacity (number of 

occupants who may use the stair) of protected stairs as a function of stair width and 

number of floors to be traveled. For unprotected stairs they assign different values for 

travel upward and downward as a function of width. Stair widths ranging from 1000 mm 

(39 in) to 2400 mm (95 in) are covered, implying a minimum width of 1 m (39 in). A 

1100 mm (44 in) wide stair corresponding to the US minimum, can accommodate 248 

people on two floors, increasing by 36 people for each additional floor. 

Occupant loads in the Spanish code are consistent with other countries; e.g., offices are 

10 m2 (100 ft2) per person. Stair geometry is regulated in the code section on protection 

from falling (Section SU) where stair treads must be at least 280 mm (11 in) and risers 

130 mm (5 in) and no more than 185 mm (7 in), with the tread to riser ratio of 4:1 for the 

entire length of the stair. 

Hong Kong 

The Hong Kong building regulations are prescriptive and derive from the British rules. 

Following the return of Hong Kong to Chinese sovereignty their designation as a Special 

Administrative Region (SAR) permitted them to continue using prior regulations. There 

is a separate document for Means of Escape in Case of Fire 21 (MOE). Table 5 

(unsprinklered building) and Table 6 (sprinklered building) are similar to the Spanish 

table, providing a discharge value (number of occupants who may use the stair) as a 

function of width and number of stories. Widths range from 1050 mm (41 in) to 1900 

mm (75 in) in 150 mm (6 in) increments, and values for widths exceeding 1900 mm are 

permitted by linear extrapolation (without limit). A 1100 mm (44 in) wide stair 

corresponding to the US minimum, can accommodate 242 (unsprinklered) or 452 

(sprinklered) people on two floors, increasing by 32 people for each additional floor. 

Occupant loads in the Hong Kong code are only slightly greater than other countries; e.g., 

offices are 9 m2 (90 ft2) per person. Stair geometry requirements specify treads at least 

225 mm (9 in) and risers not more than 175 mm (7 in). 

The Hong Kong MOE includes a unique requirement for refuge floors in buildings 

exceeding 25 stories in height. Every 25 stories an unoccupied floor (normally a 

mechanical floor) must arrange at least 50 % of its area as an area of refuge (2 h fire 

separation) for occupants to rest or to cross between stairways. They are required to be 

open on at least two sides (with water curtains) above a safe railing height to provide 

natural smoke control. They must be served by a fireman’s lift to facilitate rescue 

assistance. These requirements have also been adopted in other areas of China and in 

some other Asian countries. 

Peoples Republic of China 

Regulations for building fire safety in China are contained in the Code for Design of 

Building Fire Protection22 (GBJ 16-87) and published as a National Standard that is 

locally enforced. Section 5.3 deals with Safety Evacuation of Civil Buildings. 
The total width of stairs is specified per 100 people for buildings of specific height (in 

stories) and construction class (1 through 4) along with a minimum width of any stair of 

1100 mm(44 in). While the definitions of the Chinese construction classes do not align 

completely with those specified in US codes, an approximate correlation is presented 

below. 

Class 1 or 2 buildings (similar to US Type IA and IIIA) require a minimum aggregate 

width of 650 mm (26 in) per 100 people for 1 and 2 story buildings, 750 mm (30 in) per 

100 people for 3 story and 1000 mm (39 in) per 100 people for 4 story or higher . Class 3 

buildings (similar to US Type IIIB) require a minimum aggregate width of 750 mm (30 

in) per 100 people for 1 or 2 story, 1000 mm (39 in) for 2 story and 1250 mm (49 in) for 

4 story or higher. Class 4 buildings (similar to US Type IV heavy timber) require 1000 

mm (39 in) per 100 people for 1 and 2 story buildings. Class 4 buildings are not permitted 

taller than 2 stories. 

Japan 

Japan regulates building safety through a national law that is promulgated by the national 

government, through the Ministry of Land, Infrastructure, and Transport (MLIT). The 

Building Standard Law of Japan23 (BSL) is utilized nationally without local amendment 

and is enforced by local officials who are empowered to determine compliance or lack 

thereof, but not empowered to issue variances or determination of equivalencies. These 

can only be determined by the MLIT. Unlike most building regulations the BSL 

combines building and zoning regulations. 

Beginning in 2000 the Building Standard Law was revised to a performance-based 

structure with the prescriptive rules moved into the Building Standard Law Enforcement 

Order to facilitate updating and interpretation. 

Chapter II, Article 23 deals with stairs which may be through stairs or escape stairs. This 

article establishes a minimum stair width of 1200 mm (47 in) with stair treads of 240 mm 

(9.5 in) or more and a rise of 200 mm (8 in) or less. 

Chapter V of the BSL Enforcement Order deals with Evacuation Facilities. Article 120 

addresses through stairs provided for access and egress, and article 121 requires that at 

least two through stairs be provided. Article 122 requires that certain through stairs be 

designated as escape stairs and be constructed in accordance with article 123. None of 

these articles address stair width or geometry. Article 124 requires that the aggregate 

width of escape stairs in stores (mercantile) be not less than 600 mm (24 in) per 100 m2

(1000 ft2) of floor area of the largest floor served by the stair. 

It does not appear that the Japanese code incorporates the concept of occupant load but 

rather specifies required stair capacity in terms of the floor area served, which is the 

equivalent of applying a uniform occupant load to all use categories in the group. The 

Japanese code typically groups assembly type uses, educational, mercantile, and 

residential uses when specifying minimum widths of stairs, doors, and corridors. 
Part 2: New Thinking on Egress from Buildings 

BUILDINGS ARE TALLER 

At the start of the 20th Century the 

tallest building in the world (Park Row 

Building in Manhattan) stood just 391 

feet (119 m). By 1913 the record 

height had doubled with the completion 

of the Woolworth Building at 792 feet 

(241 m). Record heights crossed the 

thousand foot mark in 1930 with the 

Chrysler Building (1046 feet, 319 m)) 

and went to 1250 feet (381 m) with 

completion of the Empire State 

Building the following year (1931). 

The World Trade Center (1368 ft, 417 

m in 1971), Sears Tower (1450 ft, 442 

m in 1974) and Petronas Towers (1486 

ft, 448 m in 1998) ended the century 

with the tallest building record just 

short of 1500 feet (457 m). 

The early 21st Century has seen a rapid 

surge skyward, first in Asia and then in 

the Middle East. The height record (as 

of this writing) is Taipei 101 at 1671 ft 

(510 m), but several taller buildings are 

under construction. The Burj Dubai 

Tower is estimated to top out at no less 

than 2624 ft (800 m) and there is said 

to be a building planned for elsewhere 

in the Middle East at 3280 ft (1000 m). 

Prior to the World Trade Center 

Towers, nearly all the tall buildings 

were tapered (or stepped) for a number 

of reasons, ranging from reducing 

structural loads to not casting shadows on 

neighboring buildings (see Fig 2). This meant 

that the occupant load decreased on the higher floors, decreasing the cumulative load on 

the stairs, unless there was an assembly use at the top such as an observation deck or 

restaurant. Today, most of the taller buildings are uniform with height with no such 

decrease in the number of occupants served by the stairs. 

Figure 2 - Timeline of World's Tallest Buildings 

Source: Skyscraper Museum (used with permission) 
In tapered buildings the number or width of the egress stairs can be increased for the 

lower floors to accommodate the increased occupant load. However, for tall buildings of 

uniform cross section the cumulative occupant load can lead to congestion, and the 

number of stairs needed to accommodate simultaneous egress would require so much 

space that the building would not be economical. Here, emergency plans rely on phased 

evacuation; but this should theoretically include fire endurance for any building elements 

that might impact egress at least as long as the required egress times. 

Up to and including the Empire State Building these tall buildings were typically Type 

1A (4 hr) construction. Thus a reasonable limit on egress times would be 2 h (the 4 h fire 

resistance time with a safety factor of 2). From a flow and egress time perspective, using 

a conservative 1 min per floor descent rate would limit heights of Type 1A buildings to 

100 floors. A rate of 50 floors per hour is used to allow for notification, pre-movement, 

and horizontal travel times as well as some rest stops in the stairs. 

Beginning with the World Trade Center Towers it became common to permit Type 1B 

construction (3 hr). With an occupant load of 390 per floor (110 floors) and three egress 

stairs (6 1⁄2 units of total exit width) total (simultaneous) evacuation times were estimated 

at about four hours (including congestion, queuing, and transfer corridors), which is 

consistent with the egress times observed in the 1993 bombing. Applying the criterion of 

a total egress time of half the fire resistance time, one would want the building to 

withstand a fire for 8 h or until complete burnout of all combustibles, whichever occurs 

first. 

PEOPLE ARE BIGGER AND LESS FIT 

Morbid Obesity Rate (BMI>30)

0

5

10

15

20

25

30

35

1980 1985 1990 1995 2000

Year

Percent

Japan

Norway

France

Sweden

Finland

Spain

Canada

United Kingdom

Australia

United States

In the early 20th Century the 22 

in (1.1 m) unit of exit width 

was sufficient for the 95th

percentile US adult male. In 

the 21st Century this is no 

longer the case. The American 

male is larger with a 95th

percentile shoulder width of 20 

in (510 mm), which requires a 

28 in unit if exit width and a 56 

in (1.4 m) stair (applying 

Templer’s 4 in on each side to 

account for body sway and 

personal space). Templer did 

not allow the 4 in to a handrail 

since people were narrower at the waist and hip than at the shoulder, but this is no longer 

true. 

Figure 3 - Obesity rates by country 

Data: International Obesity Task Force, EU Briefing paper, 2005 

The physical condition of the average occupant is such that the exertion of descending 

many flights of stairs is no longer possible without frequent rest stops and a slower pace. 
High percentile (95th) average weights have increased substantially in recent years (Fig 3), 

and the number of people reporting that they need assistance due to physical conditions 

has also increased. 

The WTC Investigation found 6 % of occupants reporting the need for assistance in 

traveling down stairs. These increases can be attributed to the widespread adoption of 

modern accessibility regulations that have made it easier for people with mobility 

limitations to be more active in society, and to the recognition that there are many 

conditions not generally considered to be disabilities that can limit the ability of people to 

move down many flights of stairs. 

NEW TECHNOLOGIES 

A number of new technologies are available to address limitations of the past. One of the 

most promising is the ability to design and operate elevators safely and reliably during 

fires. Here the ability to provide reliable power, sophisticated operational protocols, and 

real time monitoring of critical functions, permit the use of protected elevators as a 

primary means of egress in fires. Further, fire departments have recognized the need for 

protected elevators to provide logistical support to operations in tall buildings. 

Modern fire alarm systems combine reliability, flexibility, and advanced functionality 

that permits real time monitoring and tactical support for incident management not 

previously possible. With the advent of the industry 

standard24 fire service interface in the U.S., it is 

possible for the incident command to actively 

manage the evacuation process for improved safety 

and efficiency. For example, it is possible to 

monitor conditions in the stairways in real time and 

to advise occupants to change stairs to avoid 

congestion, especially where crossover corridors or 

refuge floors are provided. Inexpensive cameras 

and digital image processing software make it 

possible to present images for action to fire service 

personnel only when issues arise, permitting a few 

personnel to monitor many locations. 

Advances in photoluminescent materials now 

permit issues of lighting levels and contrast within 

stairs to be addressed without the need for complex 

emergency power systems(Fig 4). When fully 

charged by continuous ambient light these materials 

provide more light for longer periods and can be 

applied to highlight stair nosing and handrails and 

as path lighting in transfer hallways. 

Figure 4 - Photoliminescent materials can be 

used to illuminate stairways 

Source: NRC Canada (used with permission) 
REFUGE FLOORS 

The incorporation of refuge floors in tall 

buildings in Asia also represents a new 

approach worthy of review. As 

discussed earlier, these are arranged 

every 20 to 25 floors (generally on 

mechanical floors) to provide a protected 

area for occupants to rest temporarily on 

their journey down the stairs and to 

cross over from one stair to another. 

Refuge floors are also intended as 

protected space in which people with 

disabilities can await rescue by the fire 

department (fire service elevators are 

generally arranged to be able to stop at 

the refuge floors). Figure 5 - Refuge floor in a Hong Kong high-rise during a 

fire drill Source: Arup (used with permission) 

Since these requirements are fairly new there have been no emergency evacuations of 

buildings so equipped, but there have been evacuation drills that have shed some light on 

performance (Fig 5). One issue identified in drills is that many occupants decide to wait 

on the refuge floor for the “all clear” which fills the available space, preventing 

additional people to enter the floor from the stair. Without wardens or fire service 

personnel stationed on the floor to keep people moving, the purpose is defeated. It is not 

clear in a real emergency if this will be a problem since occupants may be motivated to 

get completely out of the building. 

PERFORMANCE METRICS FOR EGRESS SYSTEMS 

In the U.S., Australia and Japan, the design of egress systems are based on the population 

of the largest, single floor. In U.K., Spain, and China the number of floors served by the 

stair impacts the total number of people served by a stair of a given width. Yet in any 

performance analysis of an egress system in these or other countries, regulators require a 

timed egress analysis to estimate Required Safe Egress Time (RSET) which is compared 

against Available Safe Egress Time (ASET). ASET is generally determined by fire 

modeling to estimate conditions in the egress path that might lead to injury or death. 

Clearly the appropriate performance metric is time, yet there is no regulatory 

performance objective nor design criterion for egress systems in terms of time in any of 

the codes examined. As early as 1914 the Safety to Life Committee recognized that 

designing egress stairs on the basis of flow (of occupants down the stair) required some 

“assumed time in which it is safe to exit the building” which is the ASET mentioned 

above. 

For compliance with the life safety objective of any building regulation, it is reasonable 

to determine ASET as the time to reach potentially incapacitating or lethal conditions 
anywhere within the means of egress. Considering the fact that the means of egress is 

designed to protect people within it from exposure to fire or smoke, it is also reasonable 

to assume that a limiting ASET would be the time to fire-induced partial structural 

collapse. If burnout occurs before collapse, there is no theoretical limit to the ASET 

though a reasonable value may be prescribed instead. Currently, the fire resistance time 

of structural components and assemblies rated by a standard fire exposure in units of time 

has not been shown to correlate with the time to structural failure of the component, 

assembly, or system as a whole for an arbitrary real fire. Clearly, some factor of safety 

that is appropriate for the level of uncertainty is needed in order to approximate ASET by 

the fire resistance rating in cases where local collapse is estimated to occur before 

burnout. 

Based on these arguments an appropriate performance objective for egress systems 

design may be that the time needed for total evacuation of the building be less than the 

required fire resistance time for the primary structural frame (i.e., the columns and other 

structural members including girders, beams, trusses, and spandrels having direct 

connections to the columns and bracing members designed to carry gravity loads). 

Where the fire resistance time is determined by test against a standard fire curve (i.e., 

ASTM E119 or ISO 834) a safety factor could be applied that is large enough to account 

for the variability of egress performance and the uncertainty in the fire resistance time 

representing the time to failure of at least one element of the primary structural frame. 

Where the fire resistance time is determined by engineering analysis following the 

Natural Fires or other similar method which accounts for the actual design level fire event, 

some lower safety factor could be applied 

since the predicted time to structural failure 

would be expected to be less uncertain 

although the egress variability would be the 

same. For the sake of this discussion factors 

of safety of 2.0 and 1.5, respectively will be 

used; however, the actual values represent 

policy decisions that need to be established 

through the model code development and 

regulatory adoption processes. 

Since high-rise buildings in any of the codes 

examined for this paper are required to 

have a primary structural frame of not less 

than 3-h fire resistance as determined by 

standard test, the total evacuation time would be required to be no more than 1 1⁄2 h, 

reflecting the safety factor of 2.0 discussed above. Recent analyses have shown that 

evacuation times of 1 h may be achievable with stairs in buildings up to about 50 stories 

and with a combination of protected elevators and stairs for most buildings of any height, 

without increasing the number or size of the stairs or elevators above current practice; 

this objective is clearly practicable25. 

Figure 6 – Interior of skybridge connecting the 

Petronas Towers at mid-height Source: Bukowski 

(used with permission) 
These same arguments can be applied to the issue of a performance objective for fire 

department access. Since U.S. codes require provision of 30 min of local water supply in 

high rise buildings, it is reasonable to say that it should be possible for the fire 

department to be able to put water on a fire at any height within 30 min. The 30 min 

local water supply requirement includes both sprinkler and standpipe flows, and in that 

initial 30 min there would be no standpipe flow, so this results in a safety factor. Using 

protected elevators fire departments can meet the 30 min objective for buildings of any 

height. Using fire department response time and a conservative estimate of 2 min per 

floor for ascent with equipment it is straightforward to determine the height threshold for 

fire service access elevators. 

RETHINKING EGRESS SYSTEMS DESIGN 

Some will argue that, other than some specific extreme events like the World Trade 

Center attacks, there have been no reported failures to evacuate even the tallest buildings. 

Therefore there is no reason to change what has been done for more than 100 years. 

There are several things wrong with this argument. 

First, there have been some failures in tall building evacuations. A real evacuation of 

both Petronas Towers for a bomb scare in 2001 resulted in an evacuation time of several 

hours when the skybridge (Fig 6) jammed with occupants crossing to the opposite tower 

in accordance with the original evacuation plan. By incorporating elevator egress for 

floors above the skybridge the total time for total (simultaneous) evacuation of both 

towers was observed in a drill to be 20 min26 . For Taipei 101 an evacuation drill 

conducted prior to opening showed a total 

evacuation time of about 2 1⁄2 h. The fire brigade 

reported being uncomfortable with this time. 

Incorporating protected elevators for egress from 

the upper floors reduced that time to just under one 

hour27. 

As discussed previously, buildings have become 

much taller and heights continue to increase beyond 

the ability of anyone from the upper stories to 

egress down stairs. Also, these buildings are much 

less tapered with height compared to early 

skyscrapers, with larger occupant loads in the upper 

floors. People today are larger and less fit, and 

accessibility regulations have resulted in a growing 

fraction of occupants with mobility limitations 

requiring egress assistance. Increasingly, there are 

people in buildings who cannot be moved down 

stairs under any circumstances (Fig 7). Following the collapse of the WTC buildings, 

occupants of tall buildings are reluctant to delay egress and are not comfortable with long 

egress times. 

Figure 7 –Typical powered wheelchair with 

attached ventilator is used by people with 

severe disabilities such as Christopher 

Reeve. He could only survive away from his 

chair for a few minutes, and he and the 

chair weighed 300 kg (660 lb) (photo used 

with permission) 
STRAWMAN EGRESS SYSTEM PERFORMANCE METRICS 

Based on the prior review and discussion the following suggestions are provided to 

facilitate the needed rethinking of the philosophy and details of egress system design for 

buildings. Thresholds and performance levels are public policy decisions that need to be 

made in conformance with the methods in place for making regulatory decisions in an 

individual country. These usually require public consultation and a legislative or 

administrative process. The suggestions provided in the following sections include 

provisions that would be formatted as code requirements (in bold) followed by 

explanatory material. 

Performance Objectives 

Buildings shall be designed and arranged such that the responding fire brigade can 

access a fire on any floor and begin suppression operations within 30 minutes of the 

transmission of the original alarm, 95 % of the time. 

It is expected that this objective will require the provision of a fire service access elevator 

in buildings with occupied floors more than 30 m (100 ft) above the level of fire 

department access. The 95 % criterion is intended to recognize that conditions may exist 

that prevent the objective from being met on occasion, but that most expected conditions 

should be considered. The 30 min limit is based on the U.S. requirement for local water 

supply for automatic suppression systems. 

Buildings shall be designed and arranged such that 98 % of the expected occupants 

are able to evacuate the building without outside assistance in a time not exceeding 

half of the required fire resistance time of the primary structural frame. 

In the U.S. model building codes buildings taller than 4 stories are required to be Type I 

construction with either 3-h (Type IA) or 2-h (Type IB) fire resistance as determined in 

ASTM E119 for elements comprising the primary structural frame. Thus the maximum 

total egress time (applying a safety factor of 2.0) would be either 1.5 h or 1h, respectively. 

The 98 % reflects an expectation that there may be some occupants who will require the 

assistance of the fire brigade for egress, but that even most occupants with disabilities can 

either self-evacuate or require only assistance from other occupants. It is expected that 

this requirement would result in occupant egress elevators in Type IA buildings taller 

than 80 stories and Type IB buildings taller than 50 stories. 

Protected Fire Service Access Elevators 

Where required, at least one elevator serving every floor shall be designated for use 

by the fire service in emergencies. This elevator shall be powered by normal and 

emergency power, with both power and control wiring protected by fire resistant 

construction at least equal to the fire resistance requirement applicable to the 

primary structural frame. Any alarm transmission to the fire brigade shall result in 

the designated fire service elevator being taken out of normal service and recalled to 
the designated level. The designated fire service elevator shall open on every floor 

into a protected lobby with direct access to a building stair containing a standpipe 

and any other required equipment for fire department use. The elevator equipment 

shall be protected from compromise by water from sprinklers or firefighting. 

Reliable communication with fire service personnel using the elevator and 

monitoring of critical functions in the fire command center shall be provided. 

Fire service access is not normally considered part of the egress system design except to 

the extent operations within the building can have an impact on the evacuating occupants. 

The only code found where this is explicitly discussed is in UK Approved Document B 

which suggests that in tall buildings one stair may need to be discounted because it will 

be blocked by operations on the fire floor and one or two floors below. It should also be 

recognized that this “attack stair” may be compromised on any floor(s) above the fire due 

to smoke leakage into the stair from the fire floor when the hose is advanced onto the 

floor, since the standpipe is located within the stair. Only where a vestibule is provided 

(in the U.S. called a smokeproof tower or fire tower) would the stair itself be kept mostly 

smoke free. However, the evacuation assistance provided by the fire service, especially 

by the fire service elevator, will have a significant impact on the success of the 

evacuation. 

Protected Occupant Egress Elevators 

Where required, all elevators except any designated fire service elevator(s) shall be 

designed and arranged to permit their safe use for occupant evacuation. These 

occupant elevators shall be powered by normal and emergency power, with both 

power and control wiring protected by fire resistant construction at least equal to 

the fire resistance requirement applicable to the primary structural frame. 

Occupant egress elevators shall operate in a hoistway protected from the adverse 

effects of water and opening into a protected lobby on each floor that serves as an 

area of refuge while awaiting the elevator. The lobby shall be sized to accommodate 

75 % of the occupant load of the floor at 0.5 m2 (5 ft2) per person. Elevator lobbies 

shall have direct access to an egress stair and be provided with two-way 

communications to the fire command center and approved means to provide real 

time information to waiting occupants. 

On a fire alarm the elevators shall begin evacuating occupants of the fire floor and 

two floors above and below the fire floor, taking them to the level of exit discharge 

before returning for another load until all 5 floors are evacuated. On a decision for 

a full building evacuation by the official in charge the elevators shall evacuate all 

remaining occupants from the highest floors and proceeding downwards, shuttling 

occupants to the level of exit discharge before returning for another load. 

Information systems on all floors except the level of exit discharge shall 

communicate to occupants the status of the system and the estimated wait time. 

Information systems on the level of exit discharge shall indicate that the elevators 

are out of service and people should not enter. 
Occupant egress elevators are by far the fastest means of evacuating a tall building. In 

normal service the number, size, and speed of passenger elevators in most buildings are 

designed to be able to move approximately 10 % of the total population of the building 

from random floors to the level of exit discharge in 5 min. This means that any building 

of any height can be totally evacuated by elevator in one hour or less without increasing 

the number, size, or speed of the elevators normally provided. Modern elevators utilize 

computerized controllers capable of sophisticated operational protocols, and the addition 

of real time monitoring and information systems can add the necessary reliability and 

guidance to users to permit their use for egress during fires. In addition, occupants use 

the building elevators every day for normal ingress and egress. The use of the elevators 

for egress in fires is not appreciably different as long as the people are provided with 

sufficient information to make decisions. 

Considerable effort by NIST, the elevator industry, the American Society of Mechanical 

Engineers (ASME), and the building code organizations is being put into the 

development of standards and code requirements for protected elevators both for fire 

service access and for occupant egress. The language suggested above for both purposes 

is consistent with that effort but the activity needs to play out to arrive at a consensus on 

requirements for the elevator equipment. Similarly, proposals are being considered by 

the model building code organizations for the building code related parts of the systems. 

Again, the performance objectives above are consistent with those proposals but the 

process should play out to arrive at a consensus of the involved parties. 

Stair Width 

Where stairs are the primary means of vertical egress in fires and other emergencies 

such stairs shall be a minimum width of 1400 mm (56 in). Where protected 

elevators are provided as the primary means of vertical egress in fires and other 

emergencies stairs shall be a minimum width of 1100 mm (44 in). 

Wider stairs are needed to accommodate the increased body size of occupants but this 

additional width is not needed where most occupants would be expected to egress by 

elevator. Further, any building provided with occupant egress elevators would also have 

fire service access elevators, eliminating the issue of counterflow except for the fire floor 

and one or two floors below in the attack stair. 

Stair Capacity 

Where stairs are the primary means of vertical egress in fires and other emergencies 

sufficient stair capacity shall be provided to accommodate the maximum number of 

building occupants on all floors except any with direct access to the outside, within 

the stairways. Where protected elevators are provided as the primary means of 

vertical egress in fires and other emergencies sufficient stair capacity shall be 

provided to accommodate at least half the maximum number of building occupants 

on all floors except any with direct access to the outside, within the stairways. Any 

floor containing an assembly space that results in a higher occupant load when 
provided with an area of refuge sized to accommodate 100 % of the occupant load 

of that floor with direct access to a stair and an occupant egress elevator, shall be 

permitted to neglect the additional occupant load for the purpose of determining 

stair capacity. 

While the philosophy of “storing” stationary occupants in stairs is not intended, the stairs 

remain a more protected space within the building. Some occupants may choose to use 

stairs (particularly on the lower floors) and the ability to find refuge in stairs is an 

important redundancy. Where occupant egress elevators are provided it is expected that 

most occupants will use them, but some minimum capacity for refuge is needed. 

Likewise, the provision of assembly occupancies (restaurants, bars, conference facilities, 

observation decks, ...) that result in local concentrations of additional people traditionally 

required additional stair capacity that continued through the building to the level of exit 

discharge. With occupant egress elevators most of these people will egress by elevator 

and it is only necessary to accommodate them temporarily while they await the elevators. 

The capacity of an egress stair is defined as the number of occupants who can 

descend the stair in a time equal to one half the fire resistance time of the primary 

structural frame, at a flow rate of 47 occupants per minute per meter of stair width 

(26 occupants per minute per unit of exit width). (The design flow rate is a policy 

decision among (81, 47, or 30) occupants per minute per meter with 47 being used in 

this example). 

The number of occupants that could be served by a stair should be based on the flow or 

discharge rate (Flow Method as defined in the 1935 NBS report) over 1h (Type IB) or 1 

1⁄2 h (Type IA). Table 1 below shows discharge rates per hour, per (22 in) unit and per 

meter, and for a 1100 (44 in) and 1400 (56 in) stair, based on assumed flows of 45 

occ/min/unit (which has no specific scientific basis but is used in the UK Approved 

Document B), 26 occ/min/unit (based on the work of Togawa and Pauls), and 16 

occ/min/unit (based on estimates from the NIST WTC report). If one used a flow rate of 

26 occ/min/unit, a single 1100 mm (44 in) stair could serve 2160 people (4320 for two 

stairs) and a 1400 mm (56 in) stair could serve 2750 people (5500 for two stairs). This 

would be the total number of occupants served by the stair(s) on all floors except those 

with direct egress to the outside (who would not use the stairs). This would also be 

limited to 50 or 80 stories since it would take longer than (1 or 1 1⁄2) hours to descend 

from greater heights. 

Table 1 – Total Number of Occupants Served by an Egress Stair Based on Flow 

Flow 

occ/min/unit 

Flow 

occ/min/meter 

Dis Rate 

occ/h/unit* 

Dis Rate 

Occ/h/meter*

Dis Rate 

Occ/h/1.1 m* 

Dis Rate 

Occ/h/1.4 m* 

45 81 2700 4860 5350 5830 

26 47 1560 2820 3100 3380 

16 30 960 1800 1980 2160 

* Multiply by 1.5 for Type IA Construction where ASET is 1 1⁄2 h 
In a system designed by the flow method it is important to ensure that the flow through 

doors is equal to or greater than the stair flow so that flow restrictions and congestion is 

avoided. This raises an interesting issue. There seems to be consensus that flow through 

doors is about 60 occupants per minute per door regardless of width. If a design stair 

flow rate of 26 occupants per minute per unit is selected, the stair flow in a 2-unit (44 in, 

1100 mm) stair is 52 per minute which can be accommodated by a single door. In a 2 1⁄2

unit (56 in, 1400 mm) stair the flow is 65 per minute which will theoretically result in an 

accumulation of 5 people per minute at the upstream side of a single door. It needs to be 

determined if 56 in stairs need double doors to prevent congestion, as this can be a 

significant cost issue in design. 

Stair Geometry 

Current requirements in the building codes reviewed are consistent with the research 

recommendations. 

Refuge Floors 

Horizontal transfer corridors designed as means of egress components shall be 

provided every 25 floors (generally on mechanical floors) to link all egress stairs and 

to provide the ability to safely move between stairs. 

The initial experience with refuge floors indicates that the provision of a means to 

transfer stairways has merit but the provision of a large space to “rest” encourages delays 

in evacuation that may be counterproductive to safety. The protected lobby with direct 

access to a stair provided as part of the occupant egress elevator system can provide for 

rest stops if needed, but most occupants would use the elevators and not need to rest. 

Thus, it is recommended to not provide refuge floors but to consider a protected 

horizontal transfer corridor linking all stairways on the mechanical floors. The 25 floor 

increment is based on the Asian requirement for refuge floors but could be flexible where 

only stairway crossovers are provided. 

Evacuation Management 

Video cameras shall be installed every 5 floors in every egress stairway and in every 

egress elevator lobby with the images displayed in the fire command center. Image 

analysis software shall be employed to minimize the fire department burden for 

monitoring these images. 

The potential for changing conditions impacting the safety and efficiency of the 

evacuation suggests that full building evacuations need to be actively managed. The 

addition of cameras in the stairs and egress elevator lobbies which can be monitored in 

the fire command can facilitate such management. Using available software developed 

for the security industry the monitoring burden in fire command can be minimized. 

Images from cameras in stairs would be kept in background except when no movement is 

detected for some time interval, indicating no people or no movement of people. Images 
from lobby cameras would be kept in background except when movement is detected, 

indicating there are people in the lobby needing pickup. If that floor has not yet been 

evacuated this information can be registered with the elevator controller. If the floor has 

already been evacuated the presence of stragglers would be noted to the fire department. 

Placement every 5 floors is considered reasonable for the purpose. More frequent is 

probably not necessary for active management of egress but less frequent might permit 

unobserved blockages. 

CONCLUDING REMARKS 

The increasing height of buildings coupled with changing demographics and public 

concerns about the safety of tall buildings have led to a call for a fundamental rethinking 

of egress systems. This paper provides a review of the approaches currently found in 

building regulations internationally, and attempts to identify the origins of these 

specifications including the extent to which they may be based on scientific data or 

consensus opinion. The case for moving to a performance metric of time is presented and 

a set of criteria for evaluating egress systems against safe egress time is suggested. 

Performance criteria based on practical objectives are suggested but these and suggested 

regulatory thresholds need to be vetted through the existing consensus process of model 

code development and regulatory adoption followed in the adopting jurisdiction. The 

result should be a design approach that addresses the needs of occupants and buildings of 

all heights with criteria based on sound engineering principles. 

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