NAT'L INST. OF STAND & TECH

A 11 10 la bTOMflT

NBSIR 75-701

Evaluation of Smokeproof Stair

Towers and Smoke Detector

Performance

Francis C. W. Fung and Richard H. Zile

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

September 1975

Final

Prepared for Office of Policy Development and Research

Department of Housing and Urban Development

Washington, D.C. 20410

QC

100

.U56

75-701

1975

NBSIR 75-701

EVALUATION OF SMOKEPROOF STAIR

TOWERS AND SMOKE DETECTOR

PERFORMANCE

Francis C. W. Fung and Richard H. Zile

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

September 1975

Final

Prepared for Office of Policy Development and Research

Department of Housing and Urban Development

Washington, D.C. 20410

U.S. DEPARTMENT OF COMMERCE, Rogers C.B. Morton, Secretary

James A. Baker, III, Under Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

FOREWORD

Smoke as a critical factor in the safety of persons in a fire situation in a high-rise building has received considerable attention in recent years [1,2] 1. In case of fire in such

a structure, the initial buoyancy forces due to heat may be

augmented by a stack effect resulting from weather conditions

to cause air and smoke to travel more rapidly upwards in stairways and elevator and utility shafts. This vertical movement

of smoke not only speeds smoke infiltration into the upper

levels of a building, but can also leave travel paths clogged

with smoke, thus hindering or preventing evacuation and obstructing the efforts of firefighters.

Recent research abroad and in the United States has indicated the feasibility of smoke control by means of ventilation

make-up, air input, and pressurization or venting of the stairwells. From a brief survey of the current status of smoke

control in high-rise buildings it appears that the basic principles and guidelines for these techniques are being studied

widely [3-12]. For a more detailed literature discussion,

refer to Hobson and Stewart's article [13]; and for general

guidelines on high-rise smoke control, see the work by

Galbreath, McGuire and Tamura [14]

Current smoke control activities at the National Bureau

of Standards (NBS) are aimed at evaluating the techniques

quantitatively. With this in mind two approaches have been

taken: first, to conduct high-rise smoke simulation experiments that can quantitatively measure the smoke movement under

controlled and uncontrolled conditions; and second, to model

the smoke simulation experiments analytically: to establish

a smoke movement prediction program which will form the basis

for optimizing smoke control design standards.

Numbers in brackets refer to the literature references

listed in section 8.

iii
SI Conversion Units

In view of the present accepted practice in this country

for building technology, common U. S. units of measurement

have been used throughout this paper. In recognition of the

position of the United States as a signatory to the General

Conference on Weights and Measures, which gave official

status to the metric SI system of units in 1960, assistance

is given to the reader interested in making use of the coherent system of SI units by giving conversion factors

applicable to U. S. units used in this paper.

1 in = 0.0254 m (exactly)

1 ft = 0.3048 m (exactly)

1 ft/min (fpm) = 5.08 x 10~ 3 m/s

1 ft 3 /min (cfm) = 4.719 x 10~ 4

m

3 /s

1 in H o 0 = 248.84 pascal (pa)

iv
CONTENTS

Page

FOREWORD iii

SI CONVERSION UNITS iv

LIST OF TABLES . . vi

1. INTRODUCTION 1

2. TEST BUILDING 2

3. TEST METHOD AND INSTRUMENTATION - SMOKEPROOF STAIR TOWERS 4

4. TEST METHOD AND INSTRUMENTATION - SMOKE DETECTORS 5

5. RESULTS 6

5.1. Tests of Smokeproof Stair Towers .... 6

5.2. Laboratory Test of Smoke Detectors ... 7

5.3. Field Tests of Smoke Detectors .... 7

6. DISCUSSION OF RESULTS 7

7. CONCLUSIONS & RECOMMENDATIONS 9

8. REFERENCES 10

APPENDIX A.. 17

APPENDIX B . . . . 17

v
LIST OF TABLES

Page

Table 1. Smoke Movement Test 1 12

Table 2. Smoke Movement Test 2 (Study of

Door Openings) 13

Table 3. Smoke Detector Laboratory Tests 14

Table 4. Smoke Detector Field Tests 15

Table 5. Visual Observations of Smoke Detector

Field Tests 16

vi
EVALUATION OF SMOKEPROOF STAIR TOWERS

AND SMOKE DETECTOR PERFORMANCE

Francis C. W. Fung and Richard H. Zile

A study was made by the National Bureau of

Standards to evaluate the effectiveness of a smokeproof stairwell tower installed in a highrise apartment building. Tests were also made of

photoelectric-type corridor smoke detectors.

A quantitative experimental technique of smoke

simulation and smoke movement measurement was

used. Factors diminishing the effectiveness of

the stair towers, preventing smoke infiltration

and limiting the response of the detectors, are

noted

Key words: High-rise buildings; photoelectric

smoke detector; smoke control; smoke movement

simulation; smokeproof tower.

1. INTRODUCTION

Smokeproof towers and an accessory corridor smoke

detection system provided in a high-rise apartment building

were the subjects of study by the National Bureau of Standards (NBS)

The building had been constructed under the Operation

BREAKTHROUGH program of the Department of Housing and Urban

Development (HUD) . The "Guide Criteria for the Evolution of

Operation BREAKTHROUGH Housing Systems" [15], prepared by

the National Bureau of Standards, contains the recommendation

that in apartment buildings over six stories in height, one

exit stairway should be in a smoke-proof enclosure (definition

in appendix A)

The housing system producer (HSP) had the option of

using any suitable design method to satisfy the recommended

requirement. Three satisfactory methods are described in

the previously cited publication of the National Research

Council of Canada, "Exploratory Paper on Control of Smoke

Movement in High Buildings" [14]

Early in the BREAKTHOUGH program, the HSP requested a waiver of the Volume I MFHR (Multi-Family High Rise) Guide

Criteria Sections L.4.2.1 and L.4.2.2 for one of the buildings

at the Jersey City Operation BREAKTHROUGH Prototype Site.

1
These criteria recommend that corridor length dead ends not

exceed 20 feet (40 feet with automatic smoke detection in

corridors) and that a minimum of two exits be provided

spaced at least one-half corridor length apart. The HSP, in

order to meet certain constraints of this particular industrialized system, requested permission to place the required

remotely- located stairways in the center core of the building. HUD granted these waivers on the basis that the NBS

recommendations for certain compensating fire-safety provisions

be incorporated into the design over and above the related

recommendations in the Guide Criteria. The purpose of this

field investigation was to evaluate elements of the alternate

design to insure their life safety adequacy:

1. Smoke detectors provided in the corridors, spaced

approximately 30 feet on center. These smoke

detectors were to be connected to the building fire

alarm system according to the recommendations of

the Guide Criteria.

2. Both stairwells to be made smokeproof instead of

one as called for in the Guide Criteria (Volume I,

L.4.2.9)

3. A Class B, one-hour smoke barrier door to be installed

to divide each floor corridor into two smokeproof

areas. For structural reasons, the barrier was

placed to one side of the center of the corridor

length, as seen in figure 1. The door was to be

self-closing and held open with an electro-magnetic

device, which released upon actuation of the building

fire alarm system. , The other recommended safety provisions applicable to the

building are listed in appendix B.

2. TEST BUILDING

The tests were conducted in an 18-story precast concrete

apartment building; a typical floor plan is shown in figure

1. As already stated, and seen on the floor plan, the two

required exit stairways were placed together in the center

core of the building.

The design used by the HSP to render the stairways

smokeproof was by provision of vestibules between the corridors

and stairways. For smoke relief, the vestibules were vented

to an adjoining shaft that ran the full height of the building

and was open to the outside on alternate floors. The required

smoke detectors were of the photoelectric type.

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3. TEST METHOD AND

INSTRUMENTATION-SMOKEPROOF STAIR TOWERS

The experimental program to study the effectiveness of

the smokeproof towers in the building was conducted in comparatively mild winter weather. Smoke was simulated by a net

airflow out of a designated "burn-room" (third floor apartment

3E, fig. 1). The air was mixed with a predetermined precentage of sulfur hexafluoride (SFg) tracer gas2 and heated to a

temperature approximately 10 °F above the corridor temperature.

The range of reference concentrations of the SFg tracer gas-*

in the air from the burn-room was of the order of 200 parts

per billion (ppb) , which was the maximum reference concentration for each experiment. Two smoke movement simulations

were tested, as presented in tables 1 and 2.

The test procedures in the two trials were similar. However, as there was some indication in the first test that

the effectiveness of the smokeproof towers could be defeated

by the passage of persons through the isolating vestibules,

the second test was conducted with people instructed to

deliberately pass from the 16th and 17th floors into the

stairwells during the period of simulated smoke release.

Prior to the beginning of each experiment the burn-room

air was preheated to a temperature of approximately 80 °F by

setting the thermostat of the forced air heating furnace

in that apartment. A window box- type fan as. shown in figure

1 was used to draw the preheated air from the burn-room and

blow it into the corridor. A cardboard mask was installed

in the hall doorway, in the same vertical plane as the fan,

to allow air from the burn-room only to be channeled through

the fan. The measured airflow through the fan was approximately 900 cfm with an average pressure of approximately 0.04

inch H2O across the fan.

At the beginning of a test a standard lecture-size

bottle of SFg gas, located inside the burn- room in front of

the fan, was turned on to continuously deliver a predetermined

amount of SFg to the burn-room air supply. The infiltration

was then traced by sampling at different locations as tabulated

in tables 1 and 2.

SFg was chosen as a tracer gas because of its electron capture

property for detection, as well as being odorless, colorless,

harmless and stable.

OSHA concentration limits of SFg is 1000 ppm as set forth in

the Federal Register, Volume 36, No. 157, August 13, 1971.

4
Flow rates of the simulated smoke were determined from

velocity measurements made with a thermo-anemomenter having

a low range of 100-500 feet per minute (fpm) , and a high

range from 500 to 1,200 fpm. Average velocities were obtained

by making a traverse of nine points as for square or rectangular ducts.

The continuous release of SFg gas into the burn-room

was metered by a ball-type flow meter with a range of 0.05

to 0.5 ftVhr. In each test a slight turn of the needle

valve unseated the ball to a position registering approximately

0.01 ft 3 /hr. This range of metering of SFg diluted with the

approximately 900 cfm airflow from the burn-room usually

leads to a burn-room SFg concentration of the order of 185

ppb. This concentration of SFg was found to be acceptable

for experimental purposes since the gas analyzer sensitivity

is readable at 1 ppb. This means that the relative concentration in relation to the burn-room can be measured to

one part in one hundred. Additional accuracy of the normalized measurements could be obtained by raising the burn-room

SFg concentration. However, an increase by an order of magnitude of burn-room SFg concentration would lead to a doubling of the purge time between experiments, since the disappearance of the released SFg in the building is exponential.

In the present series of experiments a purge time of 3 hours

was required between experiments to clear the building of

residual SFg.

The air and SF6 specimens taken at the several sampling

locations were analyzed by a portable gas chromatograph having

an electron capture .cell fitted with a 300 mc radiation

source. The response of the instrument to SFg is exponential

and the usable range is between 1 and 1,000 ppb. If dilution

of samples is necessary, the usual syringe technique can be

used.

Static pressures were measured by a Magnehelic pressure

gauge of 0.01 to 0.5 inch H2O range.

4. TEST METHOD AND

INSTRUMENTATION-SMOKE DETECTORS

Prior to field testing, the smoke detectors provided in

the building corridors were laboratory evaluated for sensitivity at different airflow velocities to provide data for

correlating the field performance with laboratory sensitivity

values. The tests were run at 15, 50 and 150 fpm airflow.

5
Five detectors taken from the third floor corridor were

tested in the NBS smoke test chamber, using pieces of punk

as the smoke source. A description of the test procedure is

included in a paper by Bukowski and Bright [16]

Two field tests of smoke detectors were conducted in

the third floor corridor. As shown in figure 1, optical

photometers Nos. 1 and 2, were installed at ceiling level

near detectors 1 and 2, respectively. A third photometer

was located in the corridor at a 3-ft height under detector

No. 2, and near the exit to the stairwell.

The tests were run with 3-minute smoke candles as smoke

sources. In the first test, the candle was placed on the

corridor floor in front of apartments 3B and 3C , at a point

approximately 10 ft horizontally from detector No. 1. For

the second test, the candle was located in the kitchen of

apartment 3C. Due to the inclusion of self-closing apartment

doors, as required by the Guide Criteria, the corridor door

of the apartment was forcibly held open.

Light attenuation at the photometers was indicated on

continuous strip-chart recorders that were actuated at the

moment of initiation of smoke from lighting a candle. The

photometers had a 1-1/2-ft light path. Attenuation of

light due to smoke was translated to voltage attenuation

through a photocell and amplifier. Voltage readings were

converted to optical densities.

5. RESULTS

5.1. Tests of Smokeproof Stair Towers

The results of the two smoke movement tests are presented

in tables 1 and 2 . The measured SFg concentrations in terms

of ppb and percent of burn-room concentration are tabulated

for given times and locations. Other test variables and

temperature variations are listed in the tables.

A comparison of the corridor and stairwell SFg concentrations for corresponding times in test 1 indicates that

the stairwell functioned well as a smokeproof stair tower

except for a high level concentration of tracer gas at the

18th floor. In the second test, where doors on 16th and

17th floors were opened for exiting to the stairwell during

the test, the accumulation of SFg in the exitway became

progressively worse to the point that the upper half of the

stairwell was heavily contaminated.

6
5.2. Laboratory Tests of Smoke Detectors

Results of the tests of smoke detectors made in the NBS

laboratory are summarized in table 3. For each detector the

smoke level at which it alarmed is tabulated for the three

tested airflow velocities.

When tested at an airflow of 150 fpm, each of the five

detectors met the recommendation for Operation BREAKTHROUGH

acceptability that activation occur at a smoke concentration

not greater than 0.01 optical density per foot. However, at

15 fpm airflow, none of the detectors met the recommendation

and three of the five failed to respond at 50 fpm.

Results of the tests of the installed smoke detectors

made in the third floor corridor of the building are presented in table 4. The smoke concentration at different

times for each test is tabulated in terms of percent obscuration per foot (ob/ft) and optical density per foot (od/ft)

In both tests, the smoke barrier doors were released upon

actuation of the alarm by a detector.

Table 5 lists the visual observations for the two smoke

detector tests. From these observations and the data in

table 4, the apparent sensitivity of the detector was 0.87

od/ft (86.4% ob/ft) for detector field test 1, and 0.15

od/ft (28.9% ob/ft) for detector field test 2. With the

airflow velocity in both tests less than 10 fpm, none of the

detectors was capable of meeting the sensitivity recommendations for Operation BREAKTHROUGH.

The results of the tests with smokeproof stair towers

indicated that the smoke moved generally upward, principally

through the elevator shafts. For the inside to outside

temperature difference of 26 °F, the upward movement appeared

to be rather fast as indicated by the 16th floor corridor

SFg concentration of 27.5% at 5 minutes and 68.1 percent at

15 minutes.

The high level of SF6 found in the 18th floor stairwell

was a cause of concern, as the smokeproof stairwell is not

connected to the corridor by design. One explanation was

that due to the proximity of the corridor vestibule door and

the stairwell door (see fig. 1) it was possible to defeat

5.3. Field Tests of Smoke Detectors

6. DISCUSSION OF RESULTS

7
the exterior venting feature if both doors were open simultaneously. It was noted that when a person exits from the

corridor to the stairwell, the self-closing mechanism of

both doors delays the closing, and allows both door openings

to coincide for a period of time.

To check the possible effect of door opening overlap

was the reason for the second smokeproof stair tower test.

As noted in the results, there was a large concentration of

SFg in the stairwell, probably aggravated by the lack of a

means of venting at the top of the stair shaft.

The poor sensitivity at low air velocities of the photoelectric type detectors installed in the building can be

attributed to a smoke entry problem. Thus, with these devices

the efficiency of smoke detection in the corridors of the

building will be largely a function of the velocity of the

smoke-laden air.

In the two field tests of smoke detectors, where air

velocities were less than 10 fpm, actuation of the alarm by

a detector occurred in approximately the same time. As the

smoke concentration in the corridor in the first test developed

much more rapidly than in the second, the detector sensitivity

in the first test was much lower than in the second. This

difference in sensitivity is believed to be due to the transient delay of smoke particles in entering the detector sensor

chamber as smoke concentration continues to grow outside the

smoke detector. In this way an apparent lower sensitivity

value for the case of sudden heavy smoke evolution as compared

to the case of more gradual smoke evolution could be expected..

In both field tests of smoke detectors, the alarm was , actuated by the response of the first detector, which was the

nearest to the smoke source. In the first test, photometer

3, farthest from the smoke source . registered 0.15 od/ft one

minute after alarm, and reached a maximum of 0.23 od/ft at

10 minutes. The same photometer, in the second test showed

a maximum of 0.1 od/ft after alarm for the duration of the

test; photometer 2 did not register greater than 0.1 od/ft

at one minute after alarm. The od/ft of 0.1 has been considered the upper limit of smoke concentration for human

tenability, but this value is now considered by some to be

too high, with a value on the order of 0.06 od/ft being

suggested.

8
7. CONCLUSIONS AND RECOMMENDATIONS

The following are the conclusions and recommendations

resulting from this study:

1. The vertical movement of smoke through elevator

shafts in a high-rise apartment building, with no

smoke control measures, in the case of a simulated

fire is very rapid. Using 2 percent burn-room concentration as a safety limit, the results indicate

that the portion of the building above the neutral

plane, approximately the midheight, is rendered uninhabitable after a duration of five minutes.

2. Smokeproof corridor doors actuated by smoke detectors

can be effective if the pressure difference across

the door due to the ventilation system is in the

favorable direction, i.e., lower pressure on the

fire side.

3. A smokeproof tower with an exterior venting vestibule

of the type used in the building investigated may

not be smoke free if there is a problem of door

opening overlap in the vestibule. Possible remedies

for this type of smoke accumulation in the tower is

by top-venting which was incorporated in the test

building subsequent to the final tests, or a detector actuated exhaust fan at top of the tower.

Another method would be to speed-up the operation

of the door closers so that the doors remain open

, for the least possible period of time. However,

with a number of people passing through at one time,

as in an emergency, it is probable that there will

be overlap in the opening of the vestibule entry

and exit doors, thus defeating the venting system.

In this case, it may be necessary to give consideration to the use of pressurized vestibules to prevent the entrance of smoke.

4. As the sensitivity of the photoelectric type smoke

detectors installed in the test building appears

to depend strongly on airflow velocity, consideration

should be given to changes in the aerodynamic entry

design of the detectors to allow operation at the

low air velocities normally encountered in building

corridors, the use of another type of detector.
8. REFERENCES

1. HutCheon, N. B. and Shorter, G. W. , Smoke Problems in

High-Rise Buildings, ASHRAE Journal, 9 (1968).

2. Galbreath, M. , Fire in High Building, National Research

Council of Canada, Fire Study No. 21 (1968).

3. McGuire, J. H .

, Control of Smoke in Building Fires, Fire

Technology, Vol. 3, No. 3 (Aug. 1967).

4. McGuire, J. H., Control of Smoke in Building Fires, Fire

Technology, Vol. 3, No. 4 (Nov. 1967)

5. Tamura, G. T., and Wilson, A. G. , Building Pressures

Caused by Chimney Action and Mechanical Ventilation,

ASHRAE Transactions, Vol. 73, Part II (1967).

6. Tamura, G. T. and Wilson, A. G. , Pressure Differences

Caused by Chimney Effect in Three High Buildings,

ASHRAE Transactions, Vol. 73, Part II (1967)

7. Barrelt, R. E. and Locklin, D. W. , Computer Analysis

of Stack Effect in High-Rise Buildings, presented at

ASHRAE 1968 Annual Meeting at Lake Placid, New York,

(Aug. 1968).

8. Butcher, E. G., Fardell, P. J. and Clarke, J., Pressurization as a Means of Controlling the Movement of

Smoke and Toxic Gases on Escape Routes, Joint Fire

Research Organization Symposium No. 4, Movement of Smoke

on Escape Route in Buildings, Paper 5, Watford, England,

(1969).

9. Butcher, E. G. and Hall, M. , Smoke Tests in New Law

Courts Building, Joint Fire Research Organization

Research Note No. 889, Borehamwood, England (1971).

10. Mechanically Ventilated Smoke Proof Enclosure, Los

Angeles Fire Department, City of Los Angeles BFP and

PA Requirement No. 56 (1970)

11. Butcher, E. G. , Cottle, T. H. and Bailey, T. A., Smoke

Tests in the Pressurized Stairs and Lobbies of a 26-

Story Office Building, CP 4/74, Building Research

Establishment, Fire Research Station, Borehamwood, England.

12. Fung, Francis 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)

10
13. Hobson, P. J. and Stewart, L. J., Pressurization of

Escape Routes in Buildings, Heating and Ventilating

Research Association, Bracknell Berkshire, England.

14. Galbreath, M. , McGuire, J, H. and Tamura, G. T.

,

Exploratory Paper on Control of Smoke Movement in HighRise Buildings, NRC No. 11413, National Research Council

of Canada, Ottawa, (1970)

15. Guide Criteria for the Evaluation of Operation BREAKTHROUGH Housing Systems, Department of Housing and Urban

Development (HUD), Vol. 1, Multifamily High-Rise.

16. Bukowski, R. W. and Bright, R. G., Some Problems Noted

in the Use of Taguchi Semiconductor Gas Sensors as

Residential Fire/Smoke Detectors, Nat. Bur. Stand. (U.S.)

NBSIR 74-591 (Dec. 1974).

11
Table 1. Smoke Movement Test 1

Percent

of

Time Concentration Burn Room

Location (min) (ppb) Concentration

4th floor corridor 5 0 0

4tn rioor stair ej U u 4th floor corridor 20 2.3 1.2

^cn rxoor stair 9ni\j u U

4th floor corridor 50 5.8 3.0

4th floor stair 50 0 0

5th floor corridor 6 0 0

jtn noor stair QO u u 5th floor corridor 30 0 0

5th floor corridor 54 7.8 4.1

6th floor stair 44 0 0

9th floor stair 47 " 0 0

16th floor corridor 5 53.2 27.5

1.6th floor stair 5 0 0

16th floor corridor 15 131.8 68.1

16th floor stair 17 * 1,5. 0.8

18th floor corridor 30 137.9 71.2

18th floor stair 32 126.3 65.2

Burn Room Location: Apt. 3E in front of elevator

Burn. Room Concentration: 193.65 ppb

Burn Room Over Pressure: 0.04" H2 0

Burn Room Out Flow: 824 cfm

Temperature, Outside: 54 °F

Inside: 70 °F

Burn Room: 82 °F

12
Table 2. Smoke Movement Test 2

(Study of Door Openings)

Percent

of

Time Concentration Burn Room

Location (min) (ppb) Concentration

4 th floor corridor 5 0 0

4th floor stair 5 0 0

4th floor stair 35 1.0 0.5

4th floor corridor 40 1.6 0.8

10th floor corridor 5 3.25 1. 7 10th floor stair 5 0

• 0

10 th floor corridor 15 10.5 5.5

10th floor stair 15 0 0

10 th floor corridor 25 33.7 17.8

10th floor stair 25 4.1 2.2

14th floor corridor 35 58.1 30.6

14th floor stair 35 33.1 17.4

14 th floor corridor 43 58.1 30.6

14th floor stair 43 47.2 24.9

18th floor corridor 47 87.9 46.3

18th floor stair 47 94.6 49.8

18th floor corridor 55 120.3 63.4

18th floor stair 55 120.3 63.4

Burn Room Location: Apt. 3E in front of elevator

Burn Room Concentration: 189.8 ppb

Burn Room Over Pressure: 0.03" H2O

Burn Room Out Flow: 870 cfm

Temperatures, Outside: 58 °F

Inside: 74 °F

Burn Room: 82 °F

13
Table 3. Smoke Detector Laboratory Tests

Alarm Points at Different Air Velocities

Detector

No.

15 f pm 50 f pm 150 f pm

od/ft*

** ob/ft od/ft ob/ft ob/ft ob/ft

1 1.061 13.09% 0.0068 1.55% 0.0044 1.0%

2 0.056 12.10% 0.0029 0.67% 0.0019 0.44%

3 0.107 21.77% 0.048 10.42% 0.0050 1.15%

4 0.106 21.72% 0.014 3.08% 0.0064 1.46%

5 0.058 12.50% 0.011 2.61% 0.0028 0.65%

od - optical density

ob - obscuration

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•I—) TJ

CU TJ CU

1—1 CO CU 42

fO 43 CJ o CJ tO CO CO O

•H ft

O

u > 4-4 U O4-4 O. D- o CX cO

(-1 tO o 4-1 4-J TJ d 4-> d

•H cu

d o u o u u U 4-4 o E 4-4

4-1 o u CU O tO cu ^, O d rH M o

4-4 •H tO 2 B

4J CO E to

J-l o CO cu CO

CU c O to 4-J 4-J a M-4 rH 3 >, 43

4-4 TJ

d > 60

d

u cu •H tO *H o cu •H (0 E CU rH

•H o. tO o 43

4J rH

m 4-1 cd >% CU CJ rH 4-J CO •U rH CO CU •H 43 CO u-t CU 4-1 o CO fO M O 4J

CO

d !-i

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43 CU 3 O

d 4-J

d

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CO •H

u o

4-J rH CU CU 4J •H CU d tO E tO 14-1 CO

CU CJ

O r4 o •H o E 3 d c M 4-1 S3 r/) rH rH

CU O. a O

•K* rH CN oo 15
Table 5. Visual Observations of Smoke

Detector Field Tests

Test 1 - High Smoke Level Time

Time

min: sec Observations

0:0 Smoke candle lit, located in front of Apartments 3B and 3C at

floor level, distance to detector 1 about 10 ft.

1:00 Heavy smoke immediately in area adjacent to smoke candle.

2:00 Movement of smoke front towards first detector at low velocity,

very little diffusion observed at this point.

Velocity of smoke front less than 10 fpm.

3:00 Heavy smoke surrounding detector 1.

3:45 Alarm went off at detector No. 1.

5:00 Gradual movement of smoke, also diffusion of smoke front. Smoke

contained by closed smoke barrier door.

10:00 Maximum smoke level reached at photometer 3.

0:0 Smoke candle lit inside Apartment 3C kitchen.

1:00 No visible smoke out of Apartment 3C door yet.

2:00 Light smoke slowly approaching first detector at velocity less

than 10 fpm.

2:50 Light smoke approaching second detector.

3:30 Alarm went off at detector No. 1.

7:00 Smoke diffused and filled coridor, however, contained

to one side of closed smoke barrier door. Smoke

intensity is at a maximum at this point.

10:00 Smoke intensity leveling off due to leakage through

apartment and stairwell. Observer on other side of

corridor protected by smoke barrier door still not

affected by smoke.

15:00 Termination of test, smoke barrier door effectively protects

observer on other side of door. Only light smoke infiltrated.

Test 2 - Low Smoke Level Test

16
APPENDIX A

Definition of "smokeproof stair enclosure," Criterion

L.4 f 2.9, Vol. I , Operation BREAKTHROUGH Guide Criteria.

"A stair enclosure so designed that the movement

of products of combustion, produced by a fire

occurring in any part of the building, into the

smokeproof stair enclosure, should be limited by

the use of an appropriate design method to ensure

that with the minimum winter exterior dry bulb

temperature (based on the ASHRAE design tables

for 97-1/2 percent probability for the geographical

location of the building) , the atmosphere in the

stair enclosure should not, during a period of

two hours, develop a contaminated atmosphere

emanating from the fire area that is more than one

(1) percent of the volume of the smokeproof stair

enclosure.

APPENDIX B

Other safety provisions incorporated in lieu of exit

stairway separation:

1. Single-station-type smoke detectors should be

installed in the two end apartments , one apartment

at each end of the building; having travel distances

greater than 50 feet within the apartment. Because

of the apartment length, two smoke detectors in

each apartment would be necessary.

2. The building areas on either side of the smoke

barrier doors should have separate heating,

ventilation and air conditioning services.

3. Apartment doors should be Class B, one-hour fireresistance doors with 250 °F-30-minute temperature

limits. Door frames should also be "labeled".

Doors should be tight- fitting with no more than

1/8-inch clearance at the top and sides and 3/4-

inch at the bottom. The doors should be equipped

with self-closing devices.

4. The wall between the stairwells should be 1-1/2-

hour in fire resistance and carried through to the

corridor wall between the elevator shafts.

USCOMM-NBS-DC

t 17
U-S. DEPT. OF COMM. 1 DTtfi! t^ATIrtM AD DL*13ADT

BIBLIOGRAPHIC DATA NBS IR 75-701

A Oov t Accession

No.

3. Recipient's Accession No.

j T'fT'I 17 l\in CI IQTITI Ci 4, illLb AINU ol) r> 1 1 1 LU

evaluation or brooKeproor btair lowers

and Smoke Detector Performance

3. Publication Date September 1975

6« Performing Organization Code

7. AUTHOR(S)

Francis C. W. Fung and Richard H. Zile

8. Performing Organ. Report No. IR 75-701

9, PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4928283

__

11. Contract/Grant No.

1 2* Sponsor ing Org an izat 1 on Name and Comple te Address (S tt&ot, C»i fy, S tste } ZIP)

Office of Policy Development and Research

Department of Housing and Urban Development

Washington, D..C. 20410

13. Type of Report & Period

Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-\yord or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) .

i

'

• A study was made by the National Bureau of Standards to

evaluate the effectiveness of a smokeproof stairwell tower

installed in a high-rise apartment building. Tests were

also made of photoelectric-type corridor smoke- detectors

.

A quantitative experimental technique of smoke simulation

and smoke movement measurement was used. Factors diminishing the effectiveness of the stair towers, preventing smoke

infiltration and limiting the response of the detectors

>

are noted.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) , High-rise buildings; photoelectric smoke detector;

smoke control; smoke movement simulation; smokeproof tower.

18. AVAILABILITY [1? Unlimited

["~~! For Official Distribution. Do Not Release to NTIS

1

1 Order From Sup. of Doc, U.S. Government Printing Office

" Washington. D.C. 20402. SD Cat. No. C13

1 Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

21. NO. OF PAGES

23

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

22. Price

$ 3-25

USCOMM.DC 29042-P74