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U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

June 1983

Prepared for:Administration

Construction 08H

DC 20420

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NBSIR 83-2715

SMOKE CONTROL FOR ELEVATORS

John H. Klote

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

June 1 983

Prepared for: Veterans Administration

Office of Construction 08H

Washington, DC 20420

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

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

TABLE OF CONTENTS

Page

LIST OF FIGURES iv

LIST OF TABLES v

Abstract 1

1 . INTRODUCTION 2

2. PROBLEMS WITH ELEVATORS 3

3. CONCEPTUAL SOLUTION 5

3.1 Elevator Controls 5 3.2 Electric Power 5 3.3 Fire and Smoke Protection 6

4. FIELD TESTS 7

4.1 Building 1 8

4.2 Building 2 9

4.2.1 Wing C 10

4. 2. 1.1 All Smoke Control Systems Operating 10

4. 2. 1.2 Stairwell Pressurization and

Elevator 12

4. 2. 1.3 Elevator Shaft Pressurization

Operating 12

4.2.2 Wings B and D 13

4. 2. 2.1 Pressurized Stairwells 14

4.3 Building 3 15

4.4 Building 4 17

4.5 Building 5 19

4.6 Building 6 21

5. ELEVATOR LOBBIES 22.

5.1 Pressure Differences 23

5.2 Open Doors 26

6. HORIZONTAL PRESSURE PROFILES 26

7. VERTICAL PRESSURE PROFILES 29

8. CONCLUSIONS 31

9. FUTURE DIRECTION 32

10. ACKNOWLEDGMENTS 33

11. REFERENCES 33

iii
LIST OF FIGURES

Page

Figure 1 . Floor plans for building 1 44

Figure 2. Floor plan for first floor for building 2 45

Figure 3. Typical floor plan above the first floor for

building 2 46

Figure 4. First floor plan for building 3 47

Figure 5. Typical floor plan above the first floor for

building 3 48

Figure 6. Typical floor plan for building 4 49

Figure 7. Floor plan for ground level of building 5 50

Figure 8. Typical floor plan for floors 3 through 19 of

building 5 51

Figure 9. Typical floor plan for floors 20 through 36 of

building 5 52

Figure 10. Elevation of building 6 53

Figure 11. Relationship between flow areas and pressure

differences for an elevator lobby pressurized

indirectly through the elevator shaft 54

Figure 12. Pressure difference from the shaft to the outside

during winter conditions (TQ < T

g

) 55

IV
LIST OF TABLES

Page

Table 1. Pressure across elevator doors of building 1 35

Table 2. Pressures in wing C of building 2 with all smoke

control systems operating 36

Table 3. Pressures in wing C of building 2 with the corridor

pressurization system not operating 37

Table 4. Pressures in wing C of building 2 with only the

elevator shaft pressurization 38

Table 5. Pressures in wings B and D of building 2 39

Table 6. Pressures in building 3 40

Table 7 . Pressures in building 4 41

Table 8. Pressure differences from building 5 42

Table 9. Pressure differences from building 6 43

v
.
SMOKE CONTROL FOR ELEVATORS

John H. Klote

National Bureau of Standards

Washington, D.C. 20234

This paper is the second report of an ongoing project at the

National Bureau of Standards (NBS) to investigate the use of smoke

control in an attempt to allow 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 six buildings with elevator

protection systems. A simple relationship is developed for the

pressure differences across the elevator shaft and across the

elevator lobby for one type of elevator pressurization system.

Vertical pressure profiles of such systems are also discussed.

Key words: Building fires; elevators (lifts); egress; evacuation;

handicapped; pressurization; smoke control; stairwells.

1
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

Unfortunately some people cannot use stairs because of physical

disabilities. Because of this problem, the Veterans Administration (VA) is

sponsoring a project at the 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. The ultimate goal of this

project is to provide information which can be used by building designers.

This paper is the second report on this project. The first report [1]*

contained 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. The

information from the first report is presented herein as a convenience to the

reader. In addition, this paper contains a report of field tests on two

additional buildings. A simple relationship is developed for the pressure

differences across an elevator shaft and the elevator lobby, and vertical

pressure profiles are also discussed. Some of the buildings tested had other

^Numbers in brackets refer to the literature references listed at the end of

this paper.

2
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) , Life Safety Code

(NFPA 101-1976) [2] 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.

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.

3
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 to

O 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 provide top vents in elevator shafts

o serving 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 to floors beyond the

fire floor by way of the elevator shaft itself.

2

3

The operation of elevators under fire conditions is mandated by section 211.3

of ANSI A17.1 [3] .

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

ANSI A17 .1 [3]

.

4
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

floor in the event of a fire alarm. Fire department 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

5
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.

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. Even though smoke protection is a more difficult

problem, smoke movement across a barrier can be prevented by the use of

pressure differences as discussed in section 5.1.

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 pressure difference across

the doors would add to the friction forces that the door closer must overcome.

A sufficiently large pressure difference could cause an elevator to jam in the

open position. In the early stages of this project it was felt that this door

jamming problem might be so significant that it might prohibit the use of

elevators as a means of fire exit. However, successful operation of elevator

doors without jamming in the field tests has shown that this problem is not

the concern it was originally envisioned to be.

6
4. FIELD TESTS

Field tests were performed in six buildings with pressurized elevator

shafts. These tests form a screening of some existing systems. The reader is

cautioned that the systems tested should not be considered model designs for

smoke control. However, some useful insight into elevator shaft pressurization can be gained from these tests. The primary purpose of all of the

pressurized elevator systems was for use by the fire department for rescue and

fire fighting. Only two buildings (buildings 4 and 5) had elevator lobbies

separated by barriers from other building spaces.

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 did not exceed 1.2 Pa (0.005 in ^0) , 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 many 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 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.

^General information concerning propeller fans and other fan types is provided

by ASHRAE [4].

7
4.1 Building 1

The first test building 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 Jl/s (4300 cfm) at 31 Pa (1/8 in 1^0) static

pressure

.

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 t^O) as listed in table 1. 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).

This drop in pressurization can be explained by comparing the flow areas

of closed elevator doors with that of open elevator doors. Even though flow

areas were not measured for this building, in a report by Tamura and Shaw [5]

measurements of this type were reported for seven buildings. They found the

o flow area around closed elevator doors to be in the range of 0.051 to 0.065 m

^In this report, 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.

8
(0.55 to 0.70 ft^) and that of an open elevator door with cab in place at 0.56

(6.0 ft^). If the leakage paths for the elevator shaft tested in building

1 are in the same range, then opening an elevator door amounts to approximately doubling the total flow area from the elevator shaft to the building.

This accounts for the significant decrease of shaft pressure.

4 .2 Building 2

The second building (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 and

corridors is that pressurization can prevent smoke infiltration, thus maintaining the stairwell or corridor as a smoke free means of fire exit.

Considerable information regarding pressurized stairwells is available in the

literature in [6-11]. To date no literature is available on pressurized

corridors

.

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

.

9
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 i/s (4000 cfm) . The stairwell fans

were located on top of each of the stair shafts and dumped air directly into

the shaft. These fans were each rated at 1900 i/s (4000 cfm). The elevator

fan, rated at 2300 i/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 across stairwell 1 are listed in

table 2. The elevator pressurization system maintained differential pressures

in the range of 12 to 16 Pa (0.050 to 0.065 in 1^0) 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 building 1 (see table 1). Both systems are four stories

and the pressurization fans were rated in the same range; 2000 i/s (4300 cfm)

for building 1 and 2300 i/s (4800 cfm) for wing C of building 2. The major

difference was that the building 1 shaft had eight elevator doors and the wing

C shaft only had four doors. This would suggest that the higher pressures

10
across the elevator shaft in wing C were due to the lower leakage area of this

shaft

.

As in the case of 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 1^0) across the elevator

shaft at the second level. A pressure drop was expected after the experience

with an open elevator door in building 1. The decreased pressure difference

in both cases reduces the level of smoke protection of the pressurized

elevator shaft.

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 door dropped from

16 to 7.5 Pa (0.065 to 0.030 in 1^0) . 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 l^O) . These results demonstrate that the elevator

shaft pressurization system was capable of maintaining positive pressurization

with a stairwell door open and the elevator door closed. Other tests demonstrated that an open elevator door had no measurable effect on the stairwell

pressurization system.

11
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 the corridor pressurization system generally had little effect

on the performance of the 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

H

2 O) . 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 a door was opened 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 just the stairwell system was on (table 3), it is

apparent that the operation of the other smoke control systems generally had a

12
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 t^O) 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 they may 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 elevator shaft pressurization

system was tested with the stairwell 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

2 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 t^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

13
H

2 O) in the initial measurements. It was remeasured in the range from 2.5 to

-2.5 Pa (0.01 to -0.01 in 1^0) . 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 [6] 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 also can 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

considerably from floor to floor. These differences could result in variations in the pressures across the elevator shafts from floor to floor.

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 l/s (8000 cfm) . The cracks

14
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

tight-fitting 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 Ih^O) at the first floor door from the

stairwell to the corridor.

4.3 Building 3

The third building 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 £/s (17,000

cfm) at 62 Pa (1/4 in t^O) 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 14,000 l/s (30,000 cfm) at 560 Pa (2-

1/4 in H

2 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

stairwells0

. For this reason, the stairwell fans were not operated during

these tests; however, the corridor pressurization system was operating.

£Maintenance personnel at building 3 stated that arrangements were underway to

correct this problem.

15
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.

16
4.4 Building 4

The fourth building 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 Si/s (930 cfm) at a static pressure of 370 Pa (1.5 in

H

2 O) . 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 l/s (26,100 cfm) at 311 Pa (1.25 in t^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.

17
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 l/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) 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 mounted 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 the

exhaust fans being concentrated on the floor where 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.

18
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^. Differential pressures were measured at

a number of locations on the fourth, fifth, and sixth 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 l^O)

on the fifth floor where the corridor system was exhausting air. On the

fourth floor where there was no corridor exhaust, only a slight elevator lobby

pressurization of 0.75 Pa (0.003 in PU^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 1^0) 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.

4.5 Building 5

The fifth building is a 38 story office building located in Seattle,

Washington. The floor plan at ground level is shown in figure 7. Located

under the ground level is a mall and below that is a parking level. There is

^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.

19
an escalator between the mall and the ground level. Figure 8 is a typical

floor plan of floors 3 through 19 which are served by the low rise elevators.

Figure 9 is a typical floor plan of floors 20 through 36 which are served by

the high rise elevators. The freight elevator served all floors.

A concept called the "life safety core" was used in the design of this

building. A two hour fire rated partition encloses the elevators and the

stairwells. This core is sprinklered and pressurized through the elevator

shafts and stairwells. Automatic closing doors are located between the

elevator lobby and the building (see figures 8 and 9).

Air is supplied to the elevator shafts by a 60,400 i/s (128,000 cfm)

vaneaxial fan located on the ground floor. This fan also supplies air to the

bottom half of the two stairwells. The top half of the stairwells were

supplied by a 3,780 i/s (8,000 cfm) vaneaxial fan located in the mechanical

penthouse on the 37th floor. Even though the elevator shafts have only one

injection point each at ground level, the stairwells had a ducted supply

system with injection points every five floors. Unfortunately there was no

way to tell exactly how the air from the ground floor fan was distributed

between the stairwells and the elevator shafts. In order to facilitate

pressurization, the elevator shafts are not vented to the outside.

The pressurization system maintained pressure differences from the

elevator shaft to the elevator lobby in the range of 22 to 45 Pa (0.09 to 0.18

in H

2 O) as listed in table 8. The level of stairwell pressure was somewhat

lower. This was done without any problems of elevator doors jamming open.

The elevator doors in this building were sealed on the sides with a wipe type

20
gasket in order to reduce the leakage areas around the doors. This was a

surprise because it was believed that such sealing was not feasible with

commercially available elevator doors.

The air flowing from the elevator shaft to the lobby resulted in a lobby

pressurization relative to the building of 12 to 40 Pa (0.05 to 0.16 in l^O)

as listed in table 8. It should be noted, that there was a non-powered

exhaust duct connected to each elevator lobby to relieve some of the pressurization air when the lobby doors were closed. The inlet to this exhaust was

fitted with a automatic modulating damper which was intended to maintain a

pressure difference of 12 Pa (0.05 in H^O) across a closed lobby door. On

some floors, it appeared that this damper was not operating properly.

However, it is apparent that this system is capable of maintaining pressurization of the elevator lobby with respect to the other building spaces as stated

above

.

The above tests were conducted with the elevator doors, stairwell doors

and lobby doors closed. It is believed that if lobby doors were open on some

floors, the pressure difference across closed lobby doors on other floors

would drop. Unfortunately, the testing time in the building was limited and

this could not be verified.

4.6 Building 6

The sixth building is a 22 story apartment building also located in

Seattle, Washington. The only public corridors in this building were located

on the terrace and ground levels, and the 3rd, 7th, 11th, 15th and 19th floors

21
as shown in figure 10. The main entrances to each of the apartments was

located on one of these floors. The apartments were multistory with their own

internal stairs.

The elevator shaft housed two cabs and was pressurized by a 8,500 l/s

(18,000 cfm) centrifugal fan which supplied air to the bottom of the shaft.

Both stairwells were bottom injection systems supplied by one 4,700 1 /

s

(10,000 cfm) centrifugal fan each, and each stairwell had a barometric relief

damper to the outside at the top of the shaft.

With the elevator pressurization system and both stairwell pressurization

systems operating, the pressure from the elevator shaft to the corridor was in

the range of 45 to 72 Pa (0.18 to 0.29 in t^O) as listed in table 9. Even

with these high pressure differences, there were no problems with elevator

doors jamming open. These elevator doors differed from all the doors in the

other buildings tested in that these doors were single leaf sliding doors and

the others were double leaf sliding doors.

5. ELEVATOR LOBBIES

All of the elevator pressurization systems which have been reported on

here were primarily intended for use by the fire service for fire fighting and

to aid in rescue. The life safety core concept in building 5 was also

intended for fire evacuation of the handicapped. This building has an

elevator lobby which is indirectly pressurized through the elevator shaft.

This or some other method of pressurizing the elevator lobby is essential to

prevent smoke infiltration of the lobby while handicapped persons await evacuation.

22
5.1 Pressure Differences

When the lobby doors are closed, an overpressure of the elevator lobby

with respect to the building will prevent smoke infiltration from the building

spaces into the lobby. It is appropriate to consider both minimum and maximum

allowable pressure differences. The maximum pressure difference should be a

value which does not result in excessive door opening forces. Clearly, a

person's physical condition is a major factor in determining a reasonable door

opening force for that person. Section 5-2. 1.1. 4. 3 of the National Fire

Protection Association (NFPA) Life Safety Code [12] states that the force

required to open any door in a means of egress shall not exceed 222 N (50

lb) . However, many smoke control designers feel that a lower value should be

used, especially in occupancies which involve the elderly, children, or the

handicapped. NFPA is currently evaluating proposals to reduce its maximum

door opening force from 222 N (50 lb) to 133 N (30 lb)

.

For the sake of discussion, if the maximum door opening force is

considered to be 133 N (30 lb), and the force to overcome the door closer is

27 N (6 lb), a hinged door 0.91 x 2.13 m (36 x 84 in) would have a maximum

allowable pressure difference of 100 Pa (0.40 in ^0) .

The criterion for selecting a minimum allowable pressure difference

across the elevator lobby is that no smoke leakage shall occur during building

evacuation. In this case the smoke control system must produce sufficient

pressure differences so that it is not overcome by the forces of wind or

buoyancy of hot smoke.

23
The pressure diMerence between a fire compartment and its surroundings

can be expressed as

where

AP = pressure difference, Pa (in H^O)

Tq = absolute temperature of the surroundings, °K (°R)

T

F

= absolute temperature of the fire compartment, °K (°R)

h = height above the neutral plane between fire compartment and

surroundings , m (ft)

K„ = coefficient, 3460 (7.64) o

The neutral plane is the plane of equal hydrostatic pressure between the

fire compartment and its surroundings. For a fire with a fire compartment

temperature of 800°C (1470°F), the pressure difference 1.52 m (5.0 ft) above

the neutral plane is 13 Pa (0.052 in 1^0) . Fang [13] has studied pressures

caused by room fires during a series of full-scale fire tests. During these

tests, the maximum pressure difference reached was 16 Pa (0.064 in 1^0) across

the burn room wall at the ceiling. If the elevator lobby walls are subject to

smoke of lower temperature, a lower pressure difference due to buoyancy will

result. For a smoke temperature of 400°C (750°F), the pressure difference

24
caused by smoke 1.52 m (5.0 ft) above the neutral plane would be 10 Pa (0 .04

in H

2 O). Water spray from sprinklers cools smoke from a building fire and

reduces the pressure differences due to buoyancy. Thus the pressure difference that could result from buoyancy is highly dependent upon the fire intensity and its proximity to the elevator lobby. However, it is apparent that

pressurization of the elevator lobby to a level of 20 to 25 Pa (0.08 to 0.10

in H

2 O) would be sufficient to counter most any buoyancy pressure difference.

The pressure differences due to wind can become very large in the event

of a broken window in a fire compartment. A wind of 22 m/s (50 mph) can

result in a pressure difference in the order of 200 Pa (0.80 in l^O)

.

Obviously if a system were designed such that it would not be overcome by such

a wind pressure, then the door opening forces would be unacceptably high

during times of low wind velocity.

One potential solution to the wind problem is to vent the fire floor on

all four sides to relieve such pressures. For a building which is much longer

than it is wide, it may be appropriate to vent the fire floor only on the two

longer sides. A second possible approach is reliance upon fire sprinklers.

Even though little research has been done on the subject, it is obvious that

the operation of fire sprinklers reduces the chances of a window breaking in a

fire compartment. A third approach is the use of a vestibule between the

elevator lobby and the building in an attempt to provide additional protection

against the forces of the wind. Further research is needed with respect to

wind and methods to minimize wind effects on pressurized elevator systems.

25
5 .2 Open Doors

It is accepted that when a door in a boundary of a smoke control system

is open, smoke may flow through the open door into the space which is intended

to be protected. However, the door of an elevator lobby intended for evacuation of the handicapped is a very special case. Due to the basic instinct for

self preservation, people inside the elevator lobby will not do nothing while

smoke flows into the lobby through an open doorway. Obviously, the lobby

occupants will see to it that lobby doors are only open for the short periods

of time needed for other people to take refuge inside the lobby. Thus smoke

infiltration of the elevator lobby will be kept to a minimum provided that

positive lobby pressurization is maintained. Small quantities of smoke that

do infiltrate when a door is momentarily opened will be purged by the lobby

pressurization air. This approach eliminates the need to consider a design

air flow through open elevator lobby doorways to prevent smoke infiltration of

the lobby.

6. HORIZONTAL PRESSURE PROFILES

Consider an elevator protection system where the elevator lobby is

pressurized indirectly by air leakage from the elevator shaft. The flow from

the elevator shaft to the lobby can be expressed as

qel a

el <2)

where

26
Qel

= volumetric air flow rate from the elevator shaft to the lobby,

m^/s (cfm)

A£e

= flow area between the elevator shaft and the lobby, m^ (ft^)

AP

£L = pressure difference between the elevator shaft and the lobby, Pa

(in l^O)

Kg = constant, 0.839 (2610)

The flow from the lobby to the building can be expressed as

\b a

lb

K

f

/Ahl (3 >

where

:

O Qle = volumetric air flow rate from the lobby to the building, m /s

(cfm)

O O = flow area between lobby and buildings, m (ft )

AP = pressure difference between the lobby and the building, Pa (in Ld

h

2 o)

With a system where no air is supplied or exhausted directly to or from

the elevator lobby, and neglecting any small changes in air density, the flow

from the elevator shaft to the lobby equals the flow from the lobby to the

building.

27
Qel Qlb (A)

The pressure difference from the elevator shaft to the building equals

the sum of the pressure differences from the shaft to the lobby and from the

lobby to the building.

AP = AP

EB EL + AP

LB

(5)

Substituting eq . (2) and (3) into eq . (4), rearranging and cancelling Kg

yields

AP

AP

EL

LB

( 6 )

Dividing eq . (5) by AP and substituting eq . (6) and rearranging yields

LB

AP

AP

LB

EB

1 +

1 (7)

It can be observed from these two equations that their pressure differences are functions of the areas Agg and Agg. Equation (7) is illustrated

graphically in figure 11. For a lobby leakage area half that of the elevator

shaft leakage, the pressure difference, AP , from the lobby to the building

is 80% of the total pressure difference, AP , from the elevator to the

LB

building. Obviously, arbitrary design values of AP and AP cannot be

LB LB

selected without regard to leakage areas, Agg and Agg.

28
7. VERTICAL PRESSURE PROFILES

When the pressure in an elevator shaft and outside can be considered

hydrostatic, the pressure difference from the shaft to the outside can be

expressed as

AP

EO ( 8 )

where

AP^q = pressure difference from the elevator shaft to the outside at

height y above the elevator shaft bottom, Pa (in 1^0)

AP^^, = pressure difference from the elevator shaft to the outside at the

EOb

elevator shaft bottom, Pa (in 1^0)

Tq = absolute temperature of outside air, °K (°R)

Tg = absolute temperature of air inside the elevator shaft, °K (°R)

Kg = coefficient, 3460 (7.64)

y

= height above the elevator shaft bottom, in (ft)

Equation (8) is valid when the wind velocity and the pressure loss in the

shaft due to friction are negligible. This relation gives the pressure

difference from the shaft to the outside as illustrated in figure 12 for

29
winter conditions (i.e., T

Q

< T

g ). For tall buildings when the outside

temperature is cold, the pressure difference, AP , is much greater at the top EO

of the shaft than it is at the bottom. During summer conditions (i.e., T

g <

T ) , the opposite case is true.

In the case of a pressurized elevator shaft, the pressure difference,

AP , between the elevator shaft and the lobby and the pressure difference,

EL

AP , between the lobby and the building are of particular interest. These

pressure differences are dependent on the building flow network, including

particular values of flow areas, and are also dependent on whatever other

smoke control systems there are in the building. Because AP varies considerably according to eq. (8), it can be expected that AP and AP will also

vary considerably with height. This means that at any one time the system

will be producing a range of pressure differences. It is our concern that

these all be within the range of allowable minimum and maximum pressure

differences as discussed in section 5.1. This concern is obviously more acute

for tall buildings, especially ones located where extreme outside temperatures

can exist in either summer or winter.

For a few simple cases, straightforward equations for these pressure

differences can be developed. However, for most realistic cases (i.e.,

buildings with zone smoke control systems or with vertical leakage through

floor and shafts), straightforward solutions for AP and AP are not readily

EL LB

apparent. To the extent that the building flow paths are known, such cases

can be analyzed with the aid of a digital computer and a computer program such

as the NBS program for analysis of smoke control systems [14].

30
8. CONCLUSIONS

1. The potential problem of elevator doors jamming open was not

observed in any of the field tests, even for pressure differences as

high as 72 Pa (0.29 in l^O) which occurred in building 6. Therefore, the door jamming problem is not the major concern that it was

envisioned to be in the early stages of this project.

2. For a pressurized elevator shaft, the increase in total flow area

resulting from opening an elevator door can significantly reduce

shaft pressurization levels below those when all elevator doors are

closed. Field tests on building 1 and the elevator shaft in wing C

of building 2 illustrate this. Obviously, such a decrease in

pressurization can reduce the level of smoke protection of the

system

.

3. Sealing elevator doors on the sides to reduce the leakage area is

feasible as was observed at building 5.

4. Elevator lobbies which are separated from other spaces on the floor

by closed doors can be pressurized indirectly by supplying pressurization air into the elevator shaft as was done in building 5.

Obviously, considerations (see section 3) beyond smoke control must

be addressed in order to use elevators for building evacuation. In

addition, a system with air supplied through the elevator shaft may

have the drawback of loss of lobby pressurization when lobby doors

on other floors are open.

31
5. Consideration of a design air flow through open elevator lobby

doorways to prevent smoke infiltration of the lobby is not

necessary. This is because lobby occupants, acting out of self

preservation, will keep lobby doors closed to prevent smoke infiltration (see section 5.2).

6. For systems that are supplied pressurization air through the

elevator shaft only, arbitrary design values of the pressure differences across the elevator shaft and across closed lobby doors cannot

be selected. These pressure differences are related to each other

as a function of leakage areas (see section 6).

7. Insufficient information exists at this time to design elevator

pressurization systems to withstand the forces of wind (see section

5.1).

9. FUTURE DIRECTION

All of the testing done so far in this project has consisted of pressure

measurements in existing buildings with systems intended to protect elevators.

Even though these tests are valuable, they do not provide a basis for prediction of how such systems will react to real fires. For this reason, tests to

evaluate the performance of simulated elevator protection systems during fire

conditions are needed. During such a test series the effects on these systems

of parameters such as open doors and windows should be evaluated.

32
10. ACKNOWLEDGMENTS

Thanks are due to the Beachwood Ohio Fire Department, the Seattle Fire

Department, and the Detroit Michigan Building and Safety Department for their

cooperation. In particular, appreciation is extended to Chief Leonard

Billings of Beachwood, James J. Tracy III of Seattle, Samuel Schugar of

Detroit, and Robert Taylor of Republic Steel Corp. for their aid in locating

suitable test buildings and for their help during testing. Special appreciation is expressed to William A. Schmidt of the Veterans Administration and to

his son and daughter, William A. Schmidt, Jr. and Karen J. Schmidt, for their

considerable help during testing.

11. REFERENCES

[1] Klote, J. H., Elevators as a Means of Fire Escape, Nat. Bur. Stand.

(U.S.), NBSIR 82-2507, May 1982.

[2] Code for Safety to Life from Fire in Buildings and Structures, NFPA 101—

1976, National Fire Protection Association, Inc., Quincy, MA, 1976, pp.

222 .

[3] American National Standard for Elevators, Dumbwaiters, Escalators and

Moving Walks, ANSI A17.1, American Society of Mechanical Engineers, New

York, 1978.

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

of Heating, Refrigerating, and Air Conditioning Engineers, New York, NY,

1979.

[5] Tamura, G. T. and Shaw, C. Y. , Air Leakage Data for the Design of

Elevator and Stair Shaft Pressurization Systems, ASHRAE Transactions

1976, Vol. 82, Part 2, pp. 179-190, 1976.

[6] 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.

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

Analysis, and Evaluation of Stair Pressurization and Exhaust in HighRise Office Buildings, performed for the City of New York by the Polytechnic Institute of Brooklyn, Baywood Publishing Co., New York, NY,

Sept. 1972.

33
[8] Klote, J. H. , Smoke Control by Stairwell Pressurization, Engineering

Applications ot Fire Technology Workshop, Society of Fire Protection

Engineers, Boston, MA, to be published.

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

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

[10] 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, pp. 42-49.

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

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

[12] Code for Safety to Life from Fire in Buildings and Structures, NFPA 101—

1981, Quincy, MA , National Fire Protection Association, 1981.

[13] Fang, J. B., Static Pressures Produced by Room Fires, Nat. Bur. Stand.

(U.S.), NBSIR 80-1984, Feb. 1980.

[14] Klote, J. H., A Computer Program for Analysis of Smoke Control Systems,

Nat. Bur. Stand. (U.S.), NBSIR 82-2512, June 1982.

34
Table 1 . Pressure Across Elevator Doors of Building 1 (all elevator doors closed)

Floor

Differential

(Pa)

Pressure

(in H

2 O)

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)

35
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 (7 7°F)

Outdoor temperature - 23°C (74°F)

When the fourth floor stairwell door was opened the pressure difference

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

2 0)

.

bWhen the first floor stairwell was opened the pressure difference

across the elevator shaft dropped to 12 Pa (0.050 in h’ 2 0)

.

36
Table 3. Pressures in Wing C of Building 2 with the

Corridor Pressurization System Not Operating

Elevator Stairwell 1 Floor (Pa) (in H

2 0) (Pa) (in H2 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 ( 7 4 °F

37
Table 4. Pressures in Wing C of Building 2 with

Only the Elevator Shaft Pressurization

Floor (Pa)

Elevator

(in H

2 O) (Pa)

Stairwell 1 (in H

2 O)

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 (7 7°F)

Outdoor temperature - 23°C (74°F)

Negative pressures represent air flow from building into the shaft.

38
Table

5.

Pressures

in

Wings B

and D

of

Building 2

/-“N cO O

m

m

vO CN o o cO

m

3d r-H r-H o o 1—

• • 1 • l • 1 i—l c o o o o

QJ *H

Sc

wPi •H

CO /—

+j to

m

m . VO 1 <r

co eu CN CN 1 r-H 1 r-H 1

—so o r^. o *“H 10

3d CO CN CN CO CO • • 1 • 1 • §1- o O 1 o 1 o o

Pi •H

CO

Q

m CN 1 r>- 1 m

OT * r'- 1 i£> 1

/—

o m in ^ 3d r-H r-H *—

r-H • • 1 • 1 • i 3 e o o 1 O 1 o i Sw

C'. r-'- 1 CN 1 CN

OT £

CO co 1 <r 1 <fr 1 o m CN CO <fr 3d i r-H r-H r-H r-H • • 1 • | • • 3 c o o o O o O

-H

g ~H

•H o 1 CN

m

m

CO ^ CO CO 1 CO 1 CO co o

CN o o 00 CO 00

m CO

)-i 3d -<r CN r-H CO CO O 00 o o o o O o o 4-> C C • • • • • • • CO *rH 'H o o o o o o o > 3 w /—

fa

01 fa o

<H

Q o m

fa o o m CN

m o o ncO • • • • • • • fa o m 00 o> r-H r-H >—

r-H r-H

U

C-> o o -N- <r CN

CN o 1 CN o 00 00 in CO m o l Pi 33 CN o CN CN CO CO <u O 00 O o o o o o o CD Pi

4->

C 3 • • • • • • • u 3

CO -H -H o o o o o o o 3 4J > 32 4-1 CO

0) co Pi fa PQ M 3 w ^ o o o CN CN r^. o <D a

CO • • • • • • • a. E

fa LO CN •vO

X

X o E <u

r-H 0) 4-1 4J

Pi Pi O

*H o o oo

lO

m CO CN r-H o

-a

ro

4-1 rH c 3

fa

w o

39

Ground

floor

exterior

door

of

stairwell 6

had

no

latch

and

was

held

open

by

air

pressure.
Table 6. Pressures in Building 3

Floor

(Pa)

Elevator

Unpressurized

(in H

2 0) (Pa)

Elevator

Pressurized

(in H

2 0)

21 2.5 0.010 8.7 0.035

20 2.5 a 0.010a 7.5 0.030

19 0.75 0.003 6.2 b 0.025 b

18 1 .2 a 0.005 3 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 O

• 100 -0.035 c -4 ,0d -0.016d

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

2 0) when a direct air

connection to the outside existed.

^Pressure was 22 Pa (0.09 in H

2 0) when a direct air connection to the

outside existed.

cPressure was 2.5 Pa (0.010 in H

2 0) when a ground floor door was open.

^Pressure was 15 Pa (0.060 in H

2 0) when a ground floor door was open.

40
Table 7 . Pressures in Building 4

4th Floor 5th Floor3 6th Floor

Location (Pa) (in H

2 O) (Pa) (in H

2 0) (Pa) (in H

2 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)

aFire alarm sent from fifth floor so that corridors are exhausted on this floor only.

41
Table 8. Pressure Differences from Building 5

Elevator to Stairwell 2 Lobby to

lobby to lobby rental space

Floor (Pa) (in H

2 0) (Pa) (in H

2 0) (Pa) (in H

2 0)

36 22 0.09 12 0.05 40 0.16

30 27 0.11 5 0.02 30 0.12

21 25 0.10 12 0.05 27 0.11

20 45 0.18 25 0.10 12 0.05

10 25 0.10 12 0.05 25 0.10

3 30 0.12 12 0.05 12 0.05

main lobby 27 0.11 — — — —

Average building temperature 25°C (77°F)

Outside temperature 17°C (63°F) at start of test and 21°C (70°F) at end of

test

42
Table 9. Pressure Differences from Building 6

North South

Elevator to Corridor to Stairwell Stai rwel

Corridor Apartment to Corridor to Corridor

Floor (Pa) (in H

2 0) (Pa) (in H

2 0) (Pa) (in H

2 0) (Pa) (in H

2 o;

19 72 0.29 30 0 ,.12 72 0.29 75 0,.30

11 45 0.18 10 0 ,.04 105 0.42 100 0,.40

main lobby 55 0.22 a 35 0 ,14 a

77 0.31 a 122 0 .49 b

Average building temperature 25°C (77°F)

Outside temperature 19°C (66°F)

aPressure differences taken with ground floor exterior lobby door open.

^Pressure between south stairwell and outside.

43
44

Note:

For

symbols

see

Figure 3
SW6

Figure 2 - Floor Plan for First Floor

for Building 2

45
SW6

GR GR

WING D

7 STORIES

SW4 1

GR

SW2

SW5

^WING B

/7 STORIES

GR SW3f

GR AD

GR

Symbols:

A Atrium

AD Automatic Closing Door

AS Apartment Space

C Cafeteria E Entry

GR Guest Rooms

MS Mechanical Shaft

S Open Stairs SW Stairwell

OS Office Space

T Toilet U Utility Space

V Vestibule

Baa Elevators

1

1

Closed Door

GR

GR

SW1

WING C

4 STORIES

Figure 3 - Typical Floor Plan above the

First Floor for Building 2

46
CO

47

Figure

4

-

First

Floor

Plan

for

Building
4 8

<D 43

jj ro CO OJ 00 03 .1 > c O -H

43 h3i—1 •H u_ e 3

ctf PQ 03 i—1 09 PU J-I 00 o

Vj HH CO o o o H

rH

O

Pn

O E rH >% rH pH 00 nju 4-> •H CO o PH U

Li- rH H Ph 09

4-» 1 o lO

<DIH3

00

'rH pH
EXHAUST

DUCTS

O

IMuoo

i—

pH 00 iH C

CO *H O T3

•H i—

CL 'H ^ 3 H 09 I vO

01

J-l 3

00

49
Note:

For

Symbols

See

Figure 3

CDoHB

LU

f4H

CDo

CD CD

0£ oMBS

50

Figure 7-

Floor

Plan

for

Ground

Level

of

Building 5
Figure 8 - Typical Floor Plan for Floors

3 through 19 of Building 5

51

Note:

For

Symbols

See

Figure 3
Figure 9 - Typical Floor Plan for Floors

20 through 36 of Building 5

52

Note:

For

Symbols

See

Figure 3
Figure 10 - Elevation of Building 6

53
AP.

d/AP

1.0

Figure 11 - Relationship between flow

areas and pressure differences

for an elevator lobby

pressurized indirectly through

the elevator shaft.

54
Height,

y

Figure 12 - Pressure difference from the

shaft to the outside during

winter conditions (T_ < T )

o s 55
NBS-114A (REV. 2-80

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO. NBSIR - 83-2715

2. Performing Organ. Report NoJ 3. Publication Date

June 1983

4. TITLE AND SUBTITLE

Smoke Control for Elevators

5. AUTHOR(S)

John H. Klote

6. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions) 7. Contract/Grant No. NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

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

Veterans Administration

Office of Construction 08H

Washington, DC 20420

10. SUPPLEMENTARY NOTES

| | 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. If document includes a significant

bibliography or literature survey, mention it here) This paper is a second report on 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 evaculation 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 six

buildings with elevator protection systems.

A simple relationship is developed for the pressure differences across the elevatoi

shaft and across the elevator lobby for one type of elevator pressurization

system. Vertical pressure profiles of such systems are also discussed.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Building fires; egress; elevators (lifts); evaculation; handicapped;

pressurization; smoke control; stairwells.

13. AVAILABILITY

[_Xj Unlimited

| | For Official Distribution. Do Not Release to NTIS

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

[X] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

60

15. Price

USCOMM-DC 6043-P80