A1110D T^SflS?

NBS

PUBLICATIONS

NBSIR 82-2507

Elevators As A Means of Fire

Escape

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

May 1982

Sponsored by:

Office of Construction Research

eterans Administration

fashington, DC 20420

1932

c. 2

aTiunal hiiKHAi 09 STANDARUS

LIBRARY

NBSIR 82-2507 jut 7 1982

ELEVATORS AS A MEANS OF FIRE

ESCAPE

John H. Klote

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

May 1982

Sponsored by:

Office of Construction Research

Veterans Administration

Washington, DC 20420

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
• 'XH'-I* . MnOi-t, ‘i **- a. > m

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TABLE OF CONTENTS

Page

LIST OF FIGURES iv

LIST OF TABLES iv

Abstract 1

1 . INTRODUCTION 1

2. PROBLEMS WITH ELEVATORS 2

3. CONCEPTUAL SOLUTION 4

3.1 Elevator Controls 4

3.2 Electric Power 4

3.3 Fire and Smoke Protection 5

4. FIELD TESTS 5

4.1 Building 1 6

4.2 Building 2 7 4.2.1 Wing C 8

4. 2. 1.1 All Smoke Control Systems Operating . 8

4. 2. 1.2 Stairwell Pressurization and Elevator

Shaft Pressurization Operating .... 9

4. 2. 1.3 Elevator Shaft Pressurization

Operating 10

4.2.2 Wings B and D * . . 10

4. 2. 2.1 Pressurized Stairwells 12

4.3 Building 3 12

4.4 Building 4 14

5. DISCUSSION AND CONCLUSIONS 16

6. FUTURE DIRECTION 17

7 . ACKNOWLEDGEMENTS 17

8 . REFERENCES 18

iii
LIST OF FIGURES

Page

Figure 1. Floor Plans for Building 1 20

Figure 2. Floor Plan for First Floor for Building 2 21

Figure 3. Typical Floor Plan above the First Floor for

Building 2 22

Figure 4. First Floor Plan for Building 3 23

Figure 5. Typical Floor Plan above the First Floor for

Building 3 24

Figure 6. Typical Floor Plan for Building 4 25

LIST OF TABLES

Page

Table 1. Pressure Across Elevator Doors of Building 1 . . . . 26

Table 2. Pressures in Wing C of Building 2 with all Smoke

Control Systems Operating .... 27

Table 3. Pressures in Wing C of Building 2 with the Corridor

Pressurization System Not Operating ... 28

Table 4. Pressures in Wing C of Building 2 with only the

Elevator Shaft Pressurization . . 29

Table 5. Pressures in Wings B and D of Building 2 30

Table 6. Pressures in Building 3 31

Table 7. Pressures in Building 4 32
ELEVATORS AS A MEANS OF FIRE ESCAPE

John H. Klote

Abstract

This paper is the initial report of an ongoing project at NBS to investigate the use

of elevators as a means of fire escape for the

handicapped. The use of stairwells for fire

evacuation poses a problem for people who

cannot use stairs because of physical disabilities. This paper discusses some of the

major problems associated with the use of

elevators as a means of fire exit and proposes

a conceptual solution to those problems. A

report is made on field tests of four buildings

with elevator protection systems. These protection systems and their interactions with other

systems are examined.

Key Words: Building fires; elevators (lifts);

egress; evacuation; handicapped; pressurization;

smoke control; stairwells.

1 . INTRODUCTION

In most elevator lobbies in the United States there are signs

which have statements similar to the following:

- WARNING - ELEVATOR SHALL NOT BE

USED IN THE EVENT OF FIRE

USE MARKED EXIT STAIRWAYS

1
Unfortunately some people cannot use stairs because of physical

disabilities. Because of this problem, the Veterans Administration

(VA) is sponsoring a project at National Bureau of Standards (NBS)

,

Center for Fire Research (CFR) to investigate the feasibility of using

elevators as a means of fire exit for the physically handicapped. This

project consists of a field investigation stage and an analysis stage.

The field tests are intended to provide information concerning the

performance of systems intended for elevator protection. During the

analysis stage the most promising protection systems will be analyzed

in detail. The ultimate goal of this project is to provide information

which can be used by building designers.

This paper contains a brief discussion of the problem, presentation

of a conceptual solution, and a report of field tests on four buildings

which have smoke control systems intended to protect elevators during

fire situations. Some of the buildings tested had other types of smoke

control systems in addition to systems for elevator protection. These

systems are also discussed in terms of their interaction with the

elevator protection system.

2. PROBLEMS WITH ELEVATORS

The National Fire Protection Association (NFPA) 101, Life Safety

Code 1976 [1]^ lists the following problems involved with the use of

elevators as fire exits.

1. "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 or smoke, or panic may develop.

Numbers in brackets refer to the literature references listed at the

end of this paper.

2
2 . Automatic elevators respond to the pressing of buttons in such a way that it would be quite possible for an elevator in use for

descent from floors above a fire to stop automatically at the

floor involved in the fire and the doors to open automatically

exposing occupants to fire and smoke.

3. 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.

4. 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 ."

It is common practice for elevators serving more than three floors

2 to automatically descend to the ground floor in the event of a fire . Fire fighters have keys with which they can manually control elevators

and use them during building evacuation and fire fighting. However,

smoke infiltration into elevator shafts frequently threatens life and

hinders elevator use by fire fighters.

It is also current practice to top vent elevator shafts serving

3

more than three floors . The intent of such venting is to allow the

elevator shaft to act as a smoke shaft carrying smoke from the fire

floor out of the building. However, because of leakage around elevator

doors this feature may significantly contribute to smoke movement into

floors beyond the fire floor by way of the elevator shaft itself.

The operation of elevators under fire conditions is mandated by section

211.3 of ANSI A17.1 [2].

The requirement for vents in elevator shafts is listed in section 100.4

of ANSI A17.1 [2]

.

3
In Section 3 a conceptual method is presented to overcome the

above problems and allow fire evacuation by means of elevators.

3 . CONCEPTUAL SOLUTION

In order to overcome the problems discussed in the proceeding

section, an elevator system used as a fire exit needs to have the

following attributes:

1. Elevator control must assure safe and efficient evacuation.

2. Reliable electric power must be supplied.

3. Elevator lobbies and the elevator shaft must be protected against

fire and smoke.

3.1 Elevator Controls

The elevator can be controlled so that it will descend to the

ground in the event of a fire alarm. Fire department personnel or other authorized personnel can then use the elevators for evacuation.

With the elevators controlled by authority figures, the likelihood that

a large number of people would crowd into the elevator and make it

impossible to close the doors will probably be reduced.

3.2 Electric Power

Considerable experience exists in assuring the supply of electrical

power for critical functions in hospitals, communication facilities,

computer facilities, and the like. The most common methods employed

are emergency batteries, emergency generators, and multiple power

feeds. While it is beyond the scope of this paper to examine methods

of assuring power reliability, it appears that state-of-the-art solutions

are available for elevator systems.

4
3.3 Fire and Smoke Protection

Considerable information is available concerning the fire resistance

of walls, partitions, floors, doors, etc. The ability to design and

build elevator lobbies and elevator shafts that can withstand severe

building fires has existed for years. However, smoke protection is a more difficult problem.

Smoke movement can be controlled by the use of air flow and

pressure differences. However, smoke control is a new field and no consensus has been reached as to what constitute reasonable air flows

and pressure differences for elevator protection and further no accepted

methods exist of achieving these air flows and pressure differences in

the case of elevator protection. The development of this information

is critical to the main goal of this project, i.e., to determine the

feasibility of using elevators as a means of fire exit for the handicapped.

In implementing elevator shaft pressurization, the jamming of

elevator doors in the open position can be a potential problem. The

forces used to close the doors of automatic elevators are limited so as

to prevent injury to any person who might be in the way of the doors.

A differential pressure across the doors would add to the friction

forces that the door closer must overcome. A sufficiently large

differential pressure could cause an elevator to jam in the open

position. During this initial series of field tests, the successful

operation of elevator doors was observed for a range of differential

pressures to provide some information regarding this concern.

4. FIELD TESTS

Field tests were performed in four buildings with pressurized

elevator shafts. These tests form an initial screening of some existing

systems, and the systems tested should not be considered model designs

for smoke control. However, some useful insight into elevator shaft

5
pressurization can be gained from these tests. None of these elevators

were intended for general evacuation but were intended for use by the

fire department for rescue and fire fighting. Accordingly, none of

these elevators were provided with a pressurized lobby.

In all of these tests the difference between the indoor and outdoor

temperatures was very small. Also, during these tests the wind velocities

were relatively calm and accordingly no wind data was taken. In general

the pressure fluctuations due to the wind did not exceed 1.2 Pa (0.005

in H^O) and so only average values of pressure difference are listed in

the tables. There was one exception among the field tests where the

fluctuation exceeded this level; this is specifically addressed in the

discussion

.

In all but one of the elevator shaft pressurization systems tested,

the pressurization was by a propeller fan. This type of fan is usually

intended to move a large quantity of air against a very low pressure

4 head . However, when a propeller fan operates at higher pressure heads

the flow rate drops dramatically. For this reason, the actual flow

rates of the fans in these tests were probably much lower than the

rated capacities of the fans.

4.1 Building 1

The building 1 is a four story office building located in Ohio.

The building shown in figure 1, has a four story elevator with two cabs

which open onto an atrium. The elevator shaft was pressurized by a roof mounted propeller fan rated at 2000 5,/s (4300 cfm) at 31 Pa (1/8

in H

? 0) static pressure.

General information concerning propeller fans and other fan types is

provided by ASHRAE [3].

6
With all the elevator doors closed the pressurization system

maintained differential pressures across the elevator shaft in the

range of 3.0 to 5.0 Pa (0.012 to 0.02 in H^O) as listed in table 1. In

this paper, the phrase differential pressure across the elevator shaft means the pressure difference between the elevator shaft and the elevator

lobby where a higher elevator shaft pressure is considered positive.

While the pressurization system was operating, the elevator doors

opened and closed normally. In addition, because the elevators are programmed to go to the ground floor during a fire alarm, the pressurization system was also tested with the elevator cabs at ground level and

an elevator door open at ground level. Under this arrangement, no pressure differential could be measured across the elevator door (however, movement of cigarette smoke indicated that there was some air

flow out of the shaft)

.

4.2 Building 2

The building 2 also located in Ohio is a motel consisting of four

wings as shown in figures 2 and 3. The main lobby and front desk are located in wing A which is one story high. Wings B, C, and D contain

the guest rooms. Wing C is four stories, and wings B and D are both

seven stories.

Wings B, C, and D have pressurized stairwells, pressurized corridors,

and pressurized elevator shafts. The concept behind pressurized stairwells is that pressurization can prevent smoke infiltration into the

stairwell and thus the stairwell will be a smoke free means of fire

exit (considerable information regarding pressurized stairwells is

available in the literature; for example [4-9]). The concept of cor- ridor pressurization is to prevent smoke infiltration to the corridor,

again providing a smoke free means of fire exit. To date no research

has been done on pressurized corridors.

7
These smoke control systems are intended to be activated only in

the wing in which smoke is detected or in which sprinkler flow is

detected. Automatic closing doors separate wing C from the other wings

when the smoke control systems in wing C are activated. For this

reason wing C was studied separately.

4.2.1 Wing C

All of the smoke control fans for wing C were roof mounted propeller

fans. The corridor fan supplied air into a duct which supplied the

corridors on each floor. This fan was rated at 1900 £/s (4000 cfm)

.

The stairwell fans were both located on top of the stair shaft and

dumped air directly into the shaft. These fans were rated at 1900 £/s

(4000 cfm) each. The elevator fan, rated at 2300 £/s (4800 cfm),

supplies air to the top of the elevator shaft. The elevator shaft in

wing C contained one cab but the shaft was sized so that another cab

could be added.

4. 2. 1.1 All Smoke Control Systems Operating

With all three of the smoke control systems operating in wing C

the pressure differential across the elevator and stairwell 1 are

listed in table 2. The elevator pressurization system maintained

differential pressures in the range of 16 to 12 Pa (0.065 to 0.050 in

H^O) across the elevator shaft when all elevator doors were closed.

Throughout the tests the elevator doors opened and closed properly.

The pressures across stairwell 2 were checked and determined to be in

the same range as those across stairwell 1.

The elevator pressures were much higher for the test in this

building than for the test in the building 1 (see table 1) . Both

systems are four stories and the pressurization fans were rated in the same range at 2000 £/s (4300 cfm) for building 1 and 2300 £/s (4800

cfm) for wing C. The major difference was that the building 1 shaft

8
had eight elevator doors and the wing C shaft only had four doors.

This would suggest that the higher pressures across the elevator shaft

in wing C were due to the lower leakage area of this shaft.

As in the case of the building 1, tests were run with the elevator

cab at the ground level (floor 1) and with the elevator door open. In

this situation there was a pressure difference of 1.7 Pa (0.007 in H^O) across the elevator shaft at the second level. This is considerably

better than the similar situation in the building 1 where no pressure

difference could be measured.

The effect on the pressurized elevator shaft of opening a door to

the pressurized stairwell was evaluated. As might be expected, opening

a stairwell door on a particular floor reduced the level of elevator

shaft pressurization on that floor. When the fourth floor stairwell

door was opened the pressure difference across the fourth floor elevator

shaft dropped from 16 to 7.5 Pa (0.065 to 0.030 in H^O) . When the same

thing was done on the first floor the pressure difference across the

elevator shaft dropped from 16 to 12 Pa (0.065 to 0.050 in 1^0)

.

Therefore, the elevator shaft pressurization system successfully maintained positive pressurization with a stairwell door open and the

elevator door closed. Other tests were made which determined that an open elevator door had no measurable effect on the stairwell pressurization system.

4. 2. 1.2 Stairwell Pressurization and Elevator Shaft

Pressurization Operating

A test was performed with only the stairwell pressurization systems

and the elevator shaft pressurization system operating, in order to

determine the effect of shutting off the corridor pressurization system.

The pressures for this test with all elevator doors closed are listed

in table 3. It is apparent by comparing this data with that for the

corridor system operating (table 2), that in general the corridor

pressurization system had little effect on the performance of the

9
elevator shaft pressurization system. The exception to this was at the

first floor where without corridor pressurization the elevator shaft

pressure decreased from 16 Pa to 10 Pa (0.065 to 0.040 in 1^0) . Due to

the unknown nature of the flow paths throughout the building, it is

difficult to determine the cause for this pressure drop on the first

floor. It may have been due to an increase in the wind velocity or to

a change in the building flow network. One possible change in the flow

network could occur when the maid service opened the door to a guest

room which had an open window. The decrease could also simply reflect

a new steady state flow condition for the building.

4. 2. 1.3 Elevator Shaft Pressurization Operating

A test was made with only the elevator shaft pressurization

operating to further evaluate the interaction between the different

smoke control systems. The pressures for this test with all elevator

doors closed are listed in table 4. By comparing these data with the

tests when all the smoke control systems were on (table 2) and when the

stairwell system was on (table 3) , it is apparent that in general the

operation of the other smoke control systems had minor effect on the

performance of the elevator shaft pressurization system. An exception

to this is at the fourth floor where the pressure dropped by 2 or 3 Pa

(0.007 or 0.012 in 1^0) depending on with which test it is compared.

It can also be noted that the pressure across the elevator shaft at the

first floor was approximately the same with all three systems on or with only the elevator shaft system on. Again, these exceptions may be

due to changes in the wind, changes in the building flow network, or simply reflect a new steady state flow condition.

4.2.2 Wings B and D

Wings B and D are both seven stories and are connected to each

other at each floor by corridors without barriers to air or smoke

movement. Automatic closing doors separated wing B from wings A and C.

For these reasons wings B and D were tested together as one unit. The

10
elevator shaft pressurization system was tested with the stairwells and

corridor systems on. The pressures, listed in table 5, were measured

with the stairwell doors and elevator doors closed. It can be observed

that the differential pressures across the elevator shafts varied

considerably from floor to floor. For the elevator shaft in wing B the

pressures ranged from 2.0 to 10. Pa (0.008 to 0.040 in H^O) . The range

over which the elevator shaft in wing D varied was somewhat less, from

5.0 to 11. Pa (0.020 to 0.045 in H^O)

.

In order to determine if these pressure differences changed with

time, a number of the measurements were repeated. The new measurements

agreed well with the data in table 5 except for floor 6 of the elevator

in wing B. This had been the point of lowest pressure across the

elevator at 2.0 Pa (0.008 in ^0) in the initial measurements. It was

remeasured in the range from 2.5 to -2.5 Pa (0.01 to -0.01 in H^O)

.

The negative pressure indicated the elevator shaft was at a lower

pressure than the corridor. Such fluctuations between positive and

negative pressure have been observed in previous field tests of pressurized

stairwells [3] and were attributed to wind effects. However, the wind

effects would not cause the elevator shaft pressures to vary from floor

to floor to the extent discussed above.

It was thought that these variations in elevator shaft pressures

might be due to a large air connection from the building to the outside

at one or more floors. Wings B and D were checked for such connections.

It was observed that a number of the guest room windows were open, but

the doors from rooms to the corridor were closed. Therefore, no direct

flow path from the corridors to the outside could be found. It can

also be observed from figures 2 and 3 that these wings B and D are connected to wing A at the first floor and connected to wing C at

floors 1 through 4. These connections and the open guest room windows

resulted in a complicated flow network which obviously differed con- siderably from floor to floor. These differences could result in

variations in the pressures across the elevator shafts from floor to

floor

.

11
4. 2. 2.1 Pressurized Stairwells

It can be observed from table 5 that the differential pressure

across the stairwell doors was uniform over the height of the stairwells.

It can also be observed that the level of pressurization was considerably higher for stairwell 5 than for the other three. This happened

even though each of the stairwells was supplied by propeller fans rated

at 3800 Z/s (8000 cfm) . The cracks around the doors of stairwell 5

were small and the doors were not undercut. The doors to stairwells 3

and 4 were undercut approximately 16 mm (5/8 in) . Based on previous

studies, this increased leakage area can account for the lower pressures

in stairwells 3 and 4. While the doors to stairwell 6 were as tightfitting as those to stairwell 5, the exterior door to stairwell 6 had

no latch and was held open by air pressure. When this exterior door was closed the leakage was similar to that in stairwell 5, and the

pressure across stairwell 6 was measured to be 85 Pa (0.34 in 1^0) at

the first floor door from the stairwell to the corridor.

4.3 Building 3

The building 3 is a 20 story apartment building used for student

housing in Detroit, Michigan. Floor plans for the building are shown

in figures 4 and 5. There is one elevator shaft with two cabs. The

elevator is pressurized from the top by a propeller fan rated to supply

8000 Z/s (17000 cfm) at 62 Pa (1/4 in 1^0) static pressure. Continuous

corridor pressurization is obtained by a system which supplies conditioned air into the corridor on each floor. This conditioned air is

supplied by a roof mounted air handling unit with a supply fan rated at

14000 Z/s (30000 cfm) at 560 Pa (2-1/4 in H^O) static pressure. The

building plans indicated that the stairwells were also pressurized by

propeller fans; however, these fans were installed backwards, which

would result in exhausting rather than pressurizing the stairwells^.

Maintenance personnel at building 3 stated that arrangements were

underway to correct this problem.

12
For this reason, these fans were not operated during these tests;

however, the corridor pressurization system was operating throughout

the tests.

Table 6 lists the pressures across the elevator with the elevator

shaft unpressurized and pressurized. With the elevator shaft unpressurized, the upper floors of the shaft had positive pressures and the

lower floors had negative pressures. This indicates that air was

flowing into the shaft at the bottom and out of the shaft at the top.

This flow is referred to as stack effect and frequently occurs when the

building temperature is greater than the outside temperature. However,

during this test the building temperature was 2°C (3.6°F) below the

outside temperature. Obviously, other driving forces must have existed.

As might be expected, when the elevator pressurization system was

on, the level of pressurization increased with building height (table

6) . The elevator shaft pressurization system failed to maintain positive

pressurization at the basement and first floor. Therefore, in the

event of a fire on one of these levels the smoke would infiltrate the

shaft, and the smoke would then be distributed by the elevator shaft

throughout the building.

At a number of times during these tests a direct air connection

existed from the building to the outside for a short period of time.

On the first floor this resulted from opening the ground floor door.

On the other floors it occurred as a result of having an open door to an apartment which also had an open balcony door to the outside.

Specific data for such occurrences are listed as notes to table 6. As

expected, in all cases the pressure across the elevator shaft increased

at the floor with the direct air connection to the outside.

13
4.4 Building 4

The building 4 is a 12 story apartment building for the aged in

Detroit, Michigan. Figure 6 is a typical floor plan for this building.

The building has one elevator shaft with two cabs. Unlike any of the

other test buildings discussed in this paper, building 4 has automatic

closing doors which separate the elevator lobby from other building

spaces. The building was equipped with pressurization systems for the

stairwells and elevator shaft and with unique smoke control capabilities

for the corridors.

Both stairwells and elevator shafts have their own specially

dedicated pressurization fans located at ground level. These three

fans were centrifugal type rated at 440 2,/s (930 cfm) at a static

pressure of 370 Pa (1.5 in 1^0) . From experience, it was apparent that

these fan capacities were too low, and therefore they would have almost

no pressurizing effect for the stairwells or the elevator shaft.

The corridor smoke control consisted of a corridor supply system

and two corridor exhaust systems. Conditioned air was continuously

supplied to the corridors from a roof mounted air handling unit. The

supply fan was a centrifugal type rated at 12,300 2/s (26,100 cfm) at

311 Pa (1.25 in H^O) of static pressure. The supply air was distributed

through a vertical duct which dumped air into a plenum over the elevator

lobby. Air from the plenum was supplied directly to the corridors on either side of the elevator lobby. Upon inspection of the building it was found that air from the plenum on each floor was leaking through

cracks around door frames, lights and electric switches into the

elevator lobby.

The two corridor exhaust systems were designed so that they could

exhaust air on the fire floor from either side of the elevator lobby.

Each corridor exhaust system had a roof mounted exhaust fan rated at

2000 2/s (4300 cfm) at 93 Pa (3/8 in 1^0) of static pressure. Each

exhaust fan was connected to a vertical exhaust duct (see figure 6)

14
connected to the corridor at each floor. Behind the exhaust grilles on each floor was a normally closed damper. In the event of a fire alarm

the procedure for activation of the smoke control systems entail the

following events:

1. The stairwell pressurization systems are activated.

2. The elevator pressurization system is activated.

3. The roof mount corridor exhaust fans are activated.

4. The normally closed dampers of the corridor exhaust system are opened only on the floor from which the fire alarm originated.

Events 3 and 4 above result in practically all of the capacity of

exhaust fans being concentrated on the floor were the fire alarm

originated. The concept behind use of these exhaust systems was to

exhaust smoke from the fire floor and to create a level of pressurization

on non-fire floors to prevent vertical smoke movement within the building. A problem with exhausting air from the fire floor corridor is

that the exhaust might pull smoke from an apartment into the corridor

and thereby cause evacuation problems on the fire floor. An analysis

of the benefits and shortcomings of corridor exhaust systems is beyond

the scope of this paper.

As stated earlier, the elevator lobbies in this building were

separated from the rest of the building by automatic closing doors (see

figure 6) . The elevators were not intended for building evacuation,

but were intended for rescue and fire fighting by the fire department.

The smoke control systems were tested to determine the extent to which

they provided a pressurized elevator lobby on the fire floor. A pull

box on the fifth floor was pulled to activate the smoke control systems .

There is a problem with activating such a smoke control system from a pull box in that the box could be pulled on other than the fire floor.

15
Differential pressures were measured at a number of locations on the

4th, 5th, and 6th floors. These pressure measurements are listed in

table 7 . The elevator lobby was positively pressurized with respect to

the corridor at a level of 6.2 Pa (0.025 in 1^0) on the fifth floor

where the corridor system was exhausting air. On the fourth where

there was no corridor exhaust, only slight elevator lobby pressurization

of 0.75 Pa (0.003 in l^O) existed. It can be observed from the data in

table 7 that the elevator pressurization system could not maintain

positive pressure across any of the elevator doors measured. The

pressurization system for stairwell 1 performed slightly better with a positive pressure of 6.2 Pa (0.025 in H^O) across the stairwell at the

fifth floor. This pressure was higher than for the other floors and was due to the corridor exhaust on the fifth floor.

5. DISCUSSION AND CONCLUSIONS

1. The potential problem of elevator door jamming open was not observed

in any of these tests. However, none of these pressurization

levels exceeded 16 Pa (0.065 in ^0)

.

2. Elevator shaft pressurization decreased when an elevator door was

opened. In the building 1 elevator, when a ground floor door was

open the pressure dropped so low that it could not be measured.

In wing C of the building 2 when a ground floor elevator door was

open, the elevator pressure dropped from 12 Pa (0.050 in ^0) to

1.7 Pa (0.007 in H^O) . This decreased pressure reduces the level

of smoke protection of the pressurized elevator shaft.

3. The pressure differences produced across elevator shafts B and D

of the building 2 varied considerably from floor to floor.

Apparently these variations were due to variations in the building

flow network. Because these pressure variations could result in

the failure of a pressurized elevator system, further study of

this problem is needed.

16
4 . The pressurized elevator shaft of building 3 was 21 stories tall

and the system failed to maintain positive pressurization at the

basement and first floor. Pressurization air to this system was

supplied by a roof mounted propeller fan which dumped air into the

top of the elevator shaft. The failure of the system at the lower

floors indicates that there is a limit to how tall an elevator

shaft can be successfully pressurized with only a single injection

point of supply air. Possibly the concept of multiple injection

which is used for pressurized stairwells might be appropriate for

elevator shafts. Further study of this problem is needed.

5.

The tests on building 4 demonstrated that exhausting the corridor

of the fire floor can help maintain a positive pressurization of

the elevator lobby and of the stairwell. However, since corridor

exhaust can also pull smoke from adjacent spaces into the corridor,

the benefits of corridor exhaust need further study.

6

.

FUTURE DIRECTION

Additional field tests are planned for buildings which have

pressurized elevator lobbies. A computer analysis will be performed to

investigate the effects of various parameters on the performance of

elevator smoke control systems. The computer analysis will utilize a computer program [10] specifically written at NBS for analysis of

pressurized stairwells and of pressurized elevator shafts. Ultimately

the information gained will be published in a form suitable for use by

building system designers.

7

.

ACKNOWLEDGEMENTS

Thanks are due to the Beachwood Ohio Fire Department and the

Detroit Michigan Building and Safety Department for their cooperation.

In particular, appreciation is extended to Chief Leonard Billings of

17
Beachwood, Samuel Schugar of Detroit, and Robert Taylor of Republic

Steel Corp. for their aid in locating suitable test buildings and their

help during testing. Special appreciation is expressed to William

Schmidt of the Veterans Administration and to his son, William Schmidt,

Jr., for their considerable help during testing.

8 . REFERENCES

[1] Code for Safety to Life from Fire in Buildings and Structures,

NFPA 101-1976, National Fire Protection Association, Inc., Quincy,

HA, 1976, pp. 222.

[2] American National Standard for Elevators, Dumbwaiters, Escalators

and Moving Walks, ANSI A17.1, American Society of Mechanical

Engineers, New York, 1978.

[3] ASHRAE Handbook and Product Directory - 1979 Equipment, American

Society of Heating, Refrigerating, and Air Conditioning Engineers,

New York, NY, 1979.

[A] Klote, J. H. , Stairwell Pressurization, ASHRAE Transactions 1980,

Vol. 86, Part 1, American Society of Heating, Refrigerating and

Air Conditioning Engineers, New York, NY, 1980.

[5] DeCicco, P. R. , Cresci, R. J., Correale, W. H. , Report of Fire

Tests, Analysis, and Evaluation of Stair Pressurization and Exhaust

in High-Rise Office Buildings, performed for the City of New York

by the Polytechnic Institute of Brooklyn, Baywood Publishing Co.,

New York, NY, Sept. 1972.

[6] Fung, F. C. W., Evaluation of a Pressurized Stairwell Smoke Control

System for a 12 Story Apartment Building, Nat. Bur. Stand. (U.S.),

NBSIR 73-277, June 1973.

18
[7] Hedsten, G. C., Building and Stair Pressurization System, ASHRAE

Journal, Vol. 20, No. 7, July 1978, p. 32-35.

[8] denOuden, L. , The Effect of Opening and Closing of Doors on the

Pressure Levels in a Building in which the Stairwell is Pressurized,

CIB Symposium on the Control of Smoke Movement in Building Fires,

Vol. II, Watford United Kingdom, Nov. 1975, p. 42-49.

[9] Dias, C., Stairwell Pressurization in a High Rise Building, ASHRAE

Journal, Vol. 20, No. 7, July 1978, p. 24-26.

[10]

Klote, J. H. , A Computer Program for Analysis of Pressurized

Stairwells and Pressurized Elevator Shafts, Nat. Bur. Stand.

(U.S.), NBSIR 80-2157, January 1981.

19
bOC

H

3

bO

•H

20

Note:

For

symbols

see

Figure 3
Note: For symbols see Figure 3

SW4

COURTYARD

OUTSIDE POOL

WING C

GAME

ROOM

COAT

ROOM

\W INSIDE

T SHOP

T RESTAURANT

MAIN LOBBY C

U

, HilM

E

POOL

AD':

U

SW1

FRONT DESK

WING A

Figure 2. Floor Plan for First Floor for Building 2 21
SW6

WING C

4 STORIES

Elevators

Closed door

Open stairs

Figure 3. Typical Floor Plan above the First Floor for Building 2 22
CO

03

03

00

23

Figure

4.

First

Floor

Plan

for

Building

3
24

Figure

5.

Typical

Floor

Plan

above

the

First

Floor

for

Building

3
25

Figure

6.

Typical

Floor

Plan

for

Building

4
Table 1. Pressure Across Elevator Doors of Building 1

Differential Pressure

Floor (Pa) (in H

2 0)

3 3.0 0.012

2 3.8 0.015

1 3.8 0.015

Ground 5.0 0.020

Indoor temperature - 24°C (75°F)

Outdoor temperature - 26°C (78°F)

26
Table 2. Pressures in Wing C of Building 2 with all

Smoke Control Systems Operating

Elevator Stairwell 1 Floor (Pa) (in H

2 0) (Pa) (in H

2 0)

4 16

a 0.065a

67 0.27

3 16 0.065 72 0.29

2 12 0.050 62 0.25

1 16

b 0.065

b

67 0.27

Indoor temperature - 25°C (77°F)

Outdoor temperature - 23°C (74°F)

aWhen the fourth floor stairwell door was opened the pressure difference

across the elevator shaft dropped to 7.5 Pa (0.030 in H^O)

.

bWhen the first floor stairwell door was opened the pressure difference

across the elevator shaft dropped to 12 Pa (0.050 in H^O)

.

27
Table 3. Pressures in Wing C of Building 2 with

the Corridor Pressurization System Not Operating

Floor

Elevator

(Pa) (in H

2 0) (Pa)

Stairwell 1 (in H

2 0)

4 15 0.060 67 0.27

3 16 0.065 65 0.26

2 14 0.055 72 0.29

1 10 0.040 67 0.27

Indoor temperature - 25°C (77°F)

Outdoor temperature - 23°C (74 °F)

28
Table 4. Pressures in Wing C of Building 2 with

only the Elevator Shaft Pressurization

Elevator Stairwell 1 Floor (Pa) (in H

2 0) (Pa) (in H

2 0)

4 13 0.053 -1.2 -0.005

3 15 0.060 0 0

2 15 0.060 0.25 0.001

1 16 0.065 0 0

Indoor temperature - 25°C (77°F)

Outdoor temperature - 23°C (74°F)

Negative pressures represent air flow from building into the shaft.

29
Table

5.

Pressures

in

Wings B

and D

of

Building 2

no o m in

CN o o nOm t—1 X rH rH i o i o i rH • • • • cu c o o o o

fc •H u

•H

03 /“N

4-J 03 ln

m i vO i <r i C/3 X CNJ CN rH rH

S—*'

LT) o

Csl o on o rH >1 rH X CO CNJ i CNJ t CO CO 03

rH • • • • • a; c o O o o o 3

•H 4)

h CuO

03

4-J 03 LO CNJ i i m r^ -a

C/3

X NO h- rH

'W' 4) 03

CO <t o CU CN m m s

rH

X i—i

rH rH rH i—1 • • i • i • 1 '3

<U c o o o o 3 £ •H 3 U '—' •H 0=

03 /~N CJ

4-1 03 i CN i CN 1 4-1 CO X CO CO <fr 3i—1 O

/'“N 3

CO o

CN LO CN CO <r 3

rH

X rH rH rH rH rH 2 rH • • i • i • • 03

CU

a o O o o o £ •H vD H '—/ •H i—!

03 /^-N i—1

4-» 03

O i CN i m

m 3

CO

X co CO CO CO CO v— ? Pn Pi pit o H a in 3

/«—

v

i£5 4-1

O

O o oc CO 00

m CO r^- v—

3 u CNJ <r CNJ 1—1

CO cn <r <r sx

O 00

X o o o o o o o o n-r

4-J

C • • • • • • U o O

03 *H e o o o o o o o © <r > ^ •H <r CM Pi

<D 'w' CM

O

rH

Q l O

w /-N, o o LO CN

m l *3

03 • • • • • rH rH 4) X o •n -a- 00 ON rH rH a) Pi Pi V-/ rH Pt 3 O 3 4-1 •H

4-J 3 Pt

/^N aj pl 3 o O 00 oo in CO m o Pi 4) 4-1

5-i CNJ CNJ o CM CN CO co 4) a. O 00 X O o o o o o o B* s 3

4->

C • • • • • • • I 4)

03 «H

C o o o o o o o 4) 4-1 Pt 3 > s •H 4-» O Pi

a) V*/ Pi

O 3 \—1 PQ Pi O i—1 3

pa

N

O o IPT 3

03 o o o CN CN

O -a 3 X • • • • • • o T3 u *3 Pi '— LO CNJ 1-" nO 00 00 rH 3 3 3 Cu H o 3

Pi o Pi O 3 iH O vO m co CN rH O' 3 i—1 Pi 3

30
Table 6. Pressures in Building 3

Elevator Elevator

Floor Unpressurized Pressurized

(Pa) (in H

2 0) (Pa) (in H2 0)

21 2.5 0.010 8.7 0.035

20 2.5

a o.oioa 7.5 0.030

19 0.75 0.003 6.2

b 0.025b

18 1.2

a 0.005a 5.5 0.022

17 0.75 0.003 4.0 0.016

16 0.75 0.003 3.2 0.013

15 0.75 0.003 3.0 0.012

14 +0 +0 2.7 0.011

12 +0 +0 2.5 0.010

11 0 0 2.0 0.008

10 1.2 0.005 5.0 0.020

9 0 0 3.0 0.012

8 1.2 0.005 5.0 0.020

7 0 0 1.5 0.006

6 0 0 2.2 0.009

5 -0 -0 1.2 0.005

4 +0 +0 1.2 0.005

3 -0.75 -0.003 3.7 0.015

2 -0 -0 1.2 0.005

1 -8.7° -0.035C -4.0d -0.016 d

B -6.2 -0.025 -2.0 -0.008

Indoor temperature - 25°C (77 °F)

Outdoor temperature - 27°C (81°F)

Negative pressures indicate air flow from the building into the shaft.

aPressure was 8.7 to 10 Pa (0.035 to 0.040 in H^O) when a direct air

connection to the outside existed.

Pressure was 22 Pa (0.09 in 1^0) when a direct air connection to

the outside existed.

QPressure was 2.5 Pa (0.010 in H^O) when a ground floor door was open.

^Pressure was 15 Pa (0.060 in H^O) when a ground floor door was open.

31
Table 7. Pressures in Building 4

4th Floor 5th Floor3 6th Floor

Location (Pa) (in H

2 0) (Pa) (in H

2 0) (Pa) (in H2 0)

Elevator lobby door 1

(lobby pressurized) 0.75 0.003 6.2 0.025

Elevator door with both

lobby doors closed -2.5 -0.010 -0.75 -0.003 0 0

Stairwell 1 door 0 0 6.2 0.025 1.2 0.005

Indoor temperature - 23°C (73°F)

Outdoor temperature - 24°C (75 °F)

Fire alarm sent from fifth floor so that corridors are exhausted on this

floor only.

32
NBS°’l 14A rev . Z.8C) U.S. DEPT. OF COMM.

1 BIBLIOGRAPHIC DATA

1. PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. Publ i cation Date

SHEET (See instructions) NBSIR 82-2507 May 1982

4. TITLE AND SUBTITLE

ELEVATORS AS A MEANS OF FIRE ESCAPE

5. AUTHOR(S)

John H. Klote

6. PERFORMING ORGANIZATION (If joint or other than NBS. see in struction s)

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

Office of Construction Research

Veterans Administration

Washington, D.C. 20420

10. SUPPLEMENTARY NOTES

J Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. I f document includes a significant

bibliography or literature survey, mention it here)

This paper is the initial report of an ongoing project at NBS to investigate

the use of elevators as a means of fire escape for the handicapped. The use of

stairwells for fire evacuation poses a problem for people who cannot use stairs

because of physical disabilities. This paper discusses some of the major problems

associated with the use of elevators as a means of fire exit and proposes a conceptual solution to those problems. A report is made on field tests of four

buildings with elevator protection systems. These protection systems and their

interactions with other systems are examined.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Building fires; elevators (lifts); egress; evacuation; handicapped; pressurization;

smoke control; stairwells.

13. AVAILABILITY

^CX| Unlimited

| | For Official Distribution. Do Not Release to NTIS

| Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. - 20402.

|XXj Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

37

15. Price

$ 7.50

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