NBSIR 76-1126

u

/ B /

a

Filed Investigation of

Residential Smoke Detectors

Richard W. Bukowski

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

November 1976

Final Report

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
Bukowski, R. W., Field investigation of

residential smoke detectors. Southern

Bldg. pp. 28-31 (Apr 11-May 1977).

o
NBSIR 76-1126

FIELD INVESTIGATION OF

RESIDENTIAL SMOKE DETECTORS

Richard W. Bukowski

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

November 1976

Final Report

U S. DEPARTMENT OF COMMERCE. Elliot L. Richardson. Secretary

Edward O. Vetter. Under Secretary

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

NATIONAL BUREAU OF STANDARDS. Ernest Ambler. Acting Director

CONTENTS

Page

/ LIST OF FIGURES iv

LIST OF TABLES vi

FOREWORD vii

Abstract 1

1. INTRODUCTION 1

2. EXPERIMENTAL PROCEDURE 2

2.1. Description of Test Buildings 2

2.2. Research 2

2.3. Detectors 3

3. RESULTS 4

4. DISCUSSION OF RESULTS 9

5. CONCLUSIONS 11

APPENDIX A. ESCAPE CRITERIA 38

A1 . Critical Smoke Level 38

A2 . Critical Carbon Monoxide Concentrations. ... 41

A3. Critical Temperature 43

REFERENCES 44
LIST OF FIGURES

Page

Figure 1. Room Identification: Basement Floor

Plan — J.R. Whitehouse Residence 13

Figure 2. Room Identification: 1st Floor Plan —

J.R. Whitehouse Residence 14

Figure 3. Room Identification: 2nd Floor Plan —

J.R. Whitehouse Residence 15

Figure 4. Room Identification: Floor Plan —

Lakeshore Residence 16

Figure 5. Detector Locations: 1st Floor Plan —

J.R. Whitehouse Residence 17

Figure 6. Detector Locations: 2nd Floor Plan —

J.R. Whitehouse Residence 18

Figure 7. Detector Locations: Floor Plan —

Lakeshore Residence 19

Figure 8. Fixed Light Beam Locations (Smoke):

1st Floor Plan —- J.R. Whitehouse Residence 20

Figure 9. Fixed Light Beam Locations (Smoke): 2nd

Floor Plan — J.R. Whitehouse Residence. . 21

Figure 10. Location of Light Beams for Smoke

Measurements (Except for Ignition Room)

:

Floor Plan — Lakeshore Residence 22

Figure 11. Fixed Temperature Measurements: 1st

Floor Plan — J.R. Whitehouse Residence. . 23

Figure 12. Fixed Temperature Measurements: 2nd

Floor Plan — J.R. Whitehouse Residence. . 24

Figure 13. Fixed Temperature Measurements and Gas

Sampling Locations: Floor Plan —

Lakeshore Residence 25

Figure 14. Gas Sampling Locations: Basement Floor

Plan — J.R. Whitehouse Residence 26

Figure 15. Gas Sampling Locations: 1st Floor Plan — J.R. Whitehouse Residence 27

IV
LIST OF FIGURES (cont'd)

Page

/ Figure 16. Gas Sampling Locations: 2nd Floor Plan — J.R. Whitehouse Residence 28

Figure 17. Fire Locations and Portable Ignition

Room Instrumentation: Floor Plan —

Lakeshore Residence 29

Figure 18. Fire Locations and Portable Ignition Room

Instrumentation: 1st Floor Plan —

J.R. Whitehouse Residence ........ 30

Figure 19. Fire Locations and Portable Ignition

Room Instrumentation: Basement Floor

Plan — J.R. Whitehouse Residence. .... 31

Figure 20. Theoretical Ability to Sense 1st Floor

Fires: Detectors on 1st and 2nd Floor.

(J.R. Whitehouse Residence). . 32

Figure 21. Ability of Detector "E" to Sense Fires

(J.B. Whitehouse Residence). . 33

Figure 22. Ability of Detector "E" on 2nd Story to

Sense Fires on 1st Story.

(J.B. Whitehouse Residence) 34

Figure 23. Ability of Detector "E" to Sense 1st

Story Fires. (Lakeshore Residence). ... 35

Figure 24. Ability of " Rate-of-Rise" Detector in

Room of Ignition to Sense Fires.

(Winter Experiments) ........... 36

Figure 25. Ability of "No-Lag" 135 °F Heat Detector

in Room of Ignition to Sense Fires .... 37

v
LIST OF TABLES

Page

Table 1. Detector Identification 5

Table 2. Test No. Jr-16. . 7

Table 3. Test No. Jr-18 8

Table A1 . Frequently-Cited Critical Smoke Levels. ... 40

Table A2 . Allowable Carbon Monoxide Levels from

Various Sources 42

vi
FOREWORD

This paper is excerpted from the report "Detector

Sensitivity and Siting Requirements for Dwellings," R. W.

Bukowski , et al., Report No. NBS-GCR-75- 51 available from

National Technical Information Services, Springfield, Va

.

22151, order number PB 247483 ($10.00 per copy).

Only the key points relating to detector response,

effectiveness, location, and sensitivity have been included

herein. The full report contains all of the raw data, observations, and data analysis for these tests.

FIELD INVESTIGATION OF RESIDENTIAL SMOKE DETECTORS

Richard W. Bukowski 1

Abstract

A test program was undertaken to evaluate the

effect of sensitivity and placement of residential

smoke detectors on their response to fires in homes.

The tests were conducted in two homes scheduled for

demolition and used actual furnishings in typical

configurations. In addition to the detector

response times, the homes were highly instrumented

with data on smoke, temperature, and gas concentration measured for all tests.

The tests showed that smoke detectors can be

highly effective in providing adequate warning of a

fire before conditions in the home become dangerous.

Key words: Detector sensitivity; detector siting;

escape time; fire tests; heat detectors; residential

fires; smoke detectors.

1. INTRODUCTION

At the present time, standards for fire detector location in dwellings, as well as standards for fire detector

sensitivity, are based mostly on laboratory data and engineering judgement without the benefit of extensive full-scale

data to provide guidance. For example, as new methods of

fire detection have developed, laboratory evaluations have

been modified in attempts to provide realistic exposure

environments; however, this has led to a multiplicity of

evaluation techniques. These are only loosely interrelated,

making comparative judgements difficult between detectors

simulated by different characteristics of fire. As more and

more jurisdictions make dwelling fire detection mandatory,

it becomes increasingly important to develop experimental

data to back up and improve existing standards.

The primary purpose of this study was to investigate

detector siting and sensitivity as they relate to escape potential in residential fire situations. Although a number

of actual detectors were used in the investigation, it was

Mr. Bukowski is presently a Research Engineer in the Program

for Fire Detection and Control Systems in the Center for

Fire Research at the National Bureau of Standards.

1
not the intent of this project to judge the merits of the

individual detectors used. The detectors were selected to

provide a cross section of the several detection principles

now available and to represent the current level of technology available in residential type detectors.

2 . EXPERIMENTAL PROCEDURE

2.1. Description of Test Buildings

Two test buildings were used for the program. These

homes, made available by the U.S. Department of the Interior

(National Park Service) , were scheduled for demolition as

part of a land clearance program associated with the establishment and expansion of the Indiana Dunes National

Lakeshore

.

The primary test site (referred to as the J.R. Whitehouse

residence) was a two-story brick structure with basement.

(For room layouts see figures 1 through 3) . Interior walls

on the first and second stories were plaster on wood lath.

The floors were wood. The basement walls were wood paneled.

The building had a gas forced-air heating system, to which a central air conditioning unit was fitted for the summer test

conditions. Registers were located in every room with returns

in all first floor rooms except the bathroom. There were no

returns on the second floor.

The second test site (referred to as the Lakeshore residence) was selected primarily because it employed a hot-water

baseboard heating system (fig. 4). This building was a single

story brick residence with basement. All walls were wood

paneled. The first story had wood floors.

The buildings selected represent major variations in

geometry. Since the prime vehicles for moving smoke throughout a residence are the fire itself and the HVAC system, the

heating systems in these two buildings should be representative of most types of heating systems, with the possible

exception of radiant heat and individual space heaters.

2.2. Research

It was the plan of the research program to conduct a series of experiments in the primary test site over several

seasons, so that the full range of outdoor conditions which

significantly affect indoor conditions, e.g. heating, cooling,

etc., would be encountered. The secondary test site was

utilized only during the winter season since this would pro2
vide the maximum "stack effect" and since central air conditioning of a dwelling with hot water baseboard heat is not

readily achieved.

t Detector location (figs. 5-7) were selected in accordance with the four levels of protection defined in the 1974

edition of NFPA/74. Two detectors of each type with two

different sensitivities were installed at each required

detector location. At one of the detector locations the

effect of wall versus ceiling mounting was investigated by

installing some detectors on the ceiling and some on the

wall for several experiments and then reversing the mounting.

Instrumentation for the experiments included light

beams (figs. 8-10) for measuring smoke obscuration on the

ceiling in the room in which the fire was being burned, on

the ceiling at each detector location, and at the 5-ft (1.5-m)

level along the primary escape path and in representative

bedrooms. For this report the primary escape path refers to

the normal route used by the occupants in exiting the building from the bedrooms.

Individual thermocouples and vertical thermocouple

arrays (figs. 11-13) were installed in the burn-room and the

primary escape path and several representative locations

throughout the dwelling. Equipment to monitor carbon monoxide

carbon dioxide, and oxygen levels was installed in the burnroom, escape path and representative bedrooms (figs. 13-16).

Both smoldering and flaming ignition fires were initiated in various rooms of the dwellings using upholstered

furniture and mattresses typifying the respective rooms

(figs. 17-19). The rooms selected were those which showed

the highest percentage of fatal residential fire starts in

NFPA records [1]^.

2.3. Detectors

The detectors selected for use in these experiments

were typical ionization, photoelectric, dual gate (combination ionization and resistance bridge) and rate-of-rise of

heat detectors. One high sensitivity (1 percent per foot

obscuration nominal) and one low sensitivity (2 percent per

foot obscuration nominal) detector was used at each detector

location. This was done to provide data on the response of

various types of detectors to realistic fire conditions, as

2 Numbers in brackets refer to the references listed at the

end of this paper.

3
well as to determine the differences in response time and

escape time potential for two different levels of sensitivity

of the same detector and type. The detectors selected were

considered to be representative of the best detectors of

their individual type at the time of selection. All detectors were connected to a 25 clock elapsed time indicator

panel which indicated detection time to the nearest second

after fire ignition.

The sensitivity of each detector employed in the test

series was initially determined by Underwriters' Laboratories

(UL) in accordance with the sensitivity test requirements of

their applicable standards. The sensitivity of every detector was checked using the same methods after each series of

experiments to insure that the detectors had not shifted in

sensitivity

.

The actual sensitivities of the detectors used are

given in table 1. Some units vary from the nominal 1 and 2

percent values requested due to variations in the different

manufacturer's calibration techniques.

3. RESULTS

In total, 40 experiments were conducted in this program.

Twenty-seven experiments at the primary test site, and 13 at

the secondary site. Of these experiments, 60% were smoldering

ignitions, 32.5% flaming ignitions and 7.5% other miscellaneous tests. This ratio of smoldering to flaming ignitions

was selected to correlate approximately with NFPA data on

residential fires [1].

The ignition source for all smoldering ignitions was a 500-watt charcoal igniter with approximately 20 inches

(0.508 m) of exposed cal-rod. The charcoal igniter was

placed in contact with the item to be burned and energized

from 120 Volts AC at time zero. The igniter was held in

firm contact with the material for 120 seconds before removal.

This generally resulted in a self-sustaining smoldering of

the item. The U-shaped original charred area generally

filled in completely within the first five minutes forming a circular charred area which grew radially outward at varying

rates depending on the surface material. In most cases

transition to flaming occurred not sooner than one hour

after ignition and, in some cases, transition to flaming

never occurred prior to test termination.

Flaming ignitions were achieved by positioning a small

metal waste basket filled with loosely crumpled paper adjacent to the piece being ignited. A piece of folded newspaper

was draped over the arm of a chair or a sheet placed on a

4
Table 1. Detector Identification

Manufacturer

Code Type

Preset Sensitivity

(%/ft)

Theoretical Measured

Clock

Number

A Photo 1 1.19 1

B Dual Gate 2 3.89 2

F ION 2 2.81 3

E Photo 1 0.96 4

B ION 2 2.02 5

E Photo 2 1.98 6

F ION 1 1.61 7

A Photo 2 1.4 9

E Photo 2 1.81 10

A Photo 1 1.27 11

F ION 1 1.34 12

F ION 2 3.04 13

B Dual Gate 2 2.19 14

ROR ROR 15F/min 15F/min 15

H ION 1 1.91 16

H ION 2 2.04 17

H ION 1 1.81 18

H ION 2 2.04 19

ROR ROR 15F/min 15F/min 20

ROR ROR 15F/min 15F/min 22

A Photo 2 2.09 24

E Photo 1 0.96 25

5
mattress so that it hung down over the wastebasket. The contents of the wastebasket were ignited with a match at time

zero

.

The results for a typical flaming ignition experiment

are shown in table 2. This was a flaming ignition of a chair

in the living room of the primary test site. The test was

conducted during the winter with the heating system on.

The important points to note in this table are the order

in which the detectors responded by type and the escape time

(or time between detector alarm and untenable conditions in

the primary escape path) provided by each. Note that the

ionization detectors responded first followed by the photoelectrics. The minimum escape time provided by the slowest

detector in this test was 344 seconds (5.73 minutes). The

maximum escape time provided by the first responding detector

was 904 seconds (15 minutes) . These results are typical of

the flaming ignitions conducted during the winter.

Table 3 shows the results of a typical smoldering ignition from the same series. This was again conducted during

the winter in the primary test site but with the heating

system off. In the case of the smoldering fires the photoelectric detectors are generally grouped first and the ionization detectors coming in later; however the ionization

detector from manufacturer F responded within the photoelectric grouping. This general faster response of the photoelectric detectors was typical of the smoldering ignition

tests conducted. In this case note that the minimum escape

time provided by any smoke detector was 143 seconds (2.38

minutes) from the dual gate detector on the second floor.

This detector generally responded poorly to smoldering fires

primarily due to its sensitivity of 3.89%/ft (0.086 OD/m)

,

nearly the maximum sensitivity allowed by U.L. for detectors.

Discounting this sample as being non-representative of normal

production due to its poor sensitivity setting the minimum

escape time then becomes 322 seconds (5.36 minutes). It is

also interesting to note that the escape time provided by the

first detector responding was approximately 1974 seconds

(33 minutes) . In comparing the escape times provided by all

detectors at a particular location it appears that the variations are more a function of sensitivity and detector design

than detection mode

.

All data taken is recorded in the source report, including curves showing the time histories of all of the various

measured quantities throughout the buildings. These include

temperature, light obscuration, and concentrations of carbon

dioxide and carbon monoxide in the fire room, bedrooms, and

6
Table 2. Test No. Jr-16

Escape

Clock No. Type Sensitivity Alarm Time

(%/ft) (s) (s)

First Floor Detectors (Ceiling)

12 I 1.34 158 904

19 I 2.04 339 723

13 I 3.04 357 705

18 I 1.81 372 690

14 DG 2.19 384 678

11 P 1.27 389 673

10 P 1.81 438 624

25 P 0.96 443 619

9 P 1.40 540 522

15 ROR 15F/min NO —

Second Floor Detectors (Wall)

7 I 1.61 229 833

5 I 2.02 382 680

16 I 1.91 439 623

24 P 2.09 526 536

6 P 1.98 718 344

20 ROR 15F/min NO —

Second Floor Detectors (Ceiling)

17 I 2.04 319 743

3 I 2.81 362 700

2 DG 3.89 488 574

4 P 0.96 556 506

1 P 1.19 658 404

Heat Detector in Fire Room

22 ROR 15F/min 1502 -440

TC FT 1 5 OF 1370 -308

TC FT 150F 1510 -448

Test No . : Jr-16

Data

Fire Type: F (Chair) Season: Winter

Tenability Limits Exceeded: 1060 s AC/Heat: On

Flame at: 0s Test Terminated at: 1546 s

Fire Location: Living Room

7
Table 3. Test No. Jr-18

i Clock No. Type Sensitivity

(%/ft)

Alarm

(s)

Escape

Time

(s)

First Floor Detectors (Ceiling)

25 P 0.96 1296 1974

10 P 1 . 81 1468 1802

12 I 1.34 1475 1795

11 P 1.27 1666 1604

9 P 1.40 1907 1363

14 DG 2.19 1918 1352

13 I 3.04 1965 1305

18 I 1.81 2076 1194

19 I 2.04 2222 1048

15 ROR 15F/min NO —

Second Floor Detectors (Wall)

4 P 0.96 1722 1548

17 I 2.04 2157 1113

1 P 1.19 2659 611

3 I 2.81 2703 567

2 DG 3.89 3127 143

Second Floor Detectors (Ceiling)

7 I 1.61 1910 1360

24 P 2.09 2001 1269

6 P 1.98 2504 766

5 I 2.02 2863 407

16 I 1.91 2948 322

20 ROR 15F/min NO —

Heat Detector in Fire Room

22 ROR 15F/min NO

TC FT 135F NO* —

TC FT 150F NO* —

ling Temp Never Exceeded 90°F

Data

Test No.: JR-18 Fire Type: S (Mattress) Season: Winter

Tenability Limits Exceeded: 3270 s AC/Heat: Off

Flame at: None s Test Terminated at: 3720 s Fire Location: 1st Floor Bedroom

8
positions along the escape route. It is our hope that much

more information can be derived from this data than we have

had the opportunity to discuss here.

4. DISCUSSION OF RESULTS

In general, all smoke detectors responded well to all

fires. The photoelectric type detectors seem to respond

better to the smoldering type fires and the ionization detectors seem to respond better to the flaming fires. Both types

however, provided adequate escape time for all fires.

There appeared to be no significant difference observed

in the response of detectors mounted on the ceiling or on the

wall. Response time and escape time potential was somewhat

better for the higher sensitivity units as would be expected.

After a literature search, tenability limits were selected

above which the normal escape path would be considered unpassable. These limits were 0.07 OD/ft (0.02 OD/m) at the

150 °F or 400 ppm CO anywhere in the path. (For a discussion

of the selection of limits of tenability see Appendix A of

this paper.) From these limits the time of untenability was

determined for each test and performance curves were developed

for both theoretical and actual detectors . The theoretical

detector results are based on light beam measurements taken

at detector locations and assume the detector can sense the

condition with no time lag. Actual detector response was

ahead of the theoretical times for some fires, probably due

to individual detector characteristics.

The performance curves (figs. 20-25) indicate the frequency of success (ordinate) that a given detector and location would provide for any required escape time (abscissa)

.

The success frequency for a given escape time is the percentage

of the total number of experiments conducted in which that

escape time or greater was obtained. Required escape time

may vary considerably depending on size and configuration of

the structure, and the age and physical condition of occupants.

Times in the range of 120 to 300 seconds seem reasonable.

The curves are separated into response by 1% or 2% detectors

to smoldering or flaming fires-^ in one test building. Some

curves show the differing effects of winter and summer conditions where important.

The theoretical smoke detector performance is shown in

figure 20 for two escape criteria, 0.03 and 0.07 OD/ft (0.009

and 0.02 OD/m). The choice of these escape criteria has a

3 For example S, 2% refers to 2% detectors and smoldering ignitions and F; 1% refers to 1% detectors and flaming ignitions.

9
small effect on the theoretical results. The curves show

that both the theoretical and actual detectors provide inadequate protection (mostly negative escape times) when fires

and detectors are on different floors.

In the primary test site, the escape times obtained

from detectors installed on the second floor responding to

first floor fires seem somewhat marginal (as shown in fig. 22).

According to NFPA/74 level four requirements for installing

the detectors, there would be no detector on the first floor

if there were no first floor bedrooms. The results of the

experiments seem to indicate that this situation would result

in marginal performance under many first floor fire conditions.

It should be noted that poor performance of 2nd floor

detectors with 1st floor fires was accentuated in the summer,

particularly for smoldering ignitions. This is shown by comparing figures 21 and 22. Since all summer experiments were

conducted with the HVAC system operating, summer experiments

with no forced circulation may emphasize the effect further.

These conditions are being studied in phase 2 of this project,

currently under way.

The lakeshore test building with a 30-ft (9.15-m) central

hallway had a bedroom configuration which would require a smoke detector near one end of the hallway. An additional

detector located at the other end of the hallway significantly

increased escape time potential. This is shown in figure 23

where A and B are detector locations at either end of the hall.

The response of the heat detectors employed was considerably different from the response of the smoke detectors.

Rate-of-rise thermal detectors with a 50-ft (15.24 m) space

rating were installed on each detector board. In addition,

in experiments 13 through 40 a similar rate-of-rise detector

was included in the room of fire origin for each experiment.

The results of the experiments indicate that these heat detectors, including the one in the room of fire origin, failed

to respond to a majority of the fires. When they did respond

they were considerably slower than the smoke detectors and

provided little or no escape time prior to occurrence of

dangerous conditions in the primary escape path.

Thermocouple readings at the ceiling in the room of fire

origin were used to evaluate the escape potential provided

by a 135 °F (57 °C) fixed- temperature heat detector assuming

no thermal lag. These results indicate that no thermal lag

fixed-temperature heat detectors in every room would have

little life saving potential in the residential fire situations

simulated here. The curves for the heat detectors are given

in figures 24 and 25.

10
5. CONCLUSIONS

The following conclusions were drawn from these experiments :

/ 1. A residential smoke detector with small lag time, of

either the ionization or photoelectric type, would provide

more than adequate life saving potential under most residential fire conditions, when properly installed. Even in the

case of rapidly building flaming ignition fires the detectors

would provide adequate warning before dangerous conditions

were reached in the primary escape path.

2. While detectors set at nominal 2 percent-per-foot

obscuration generally provided adequate warning, those

detectors whose sensitivities were near 1 percent-per-foot

(actual) provided a significant increase in escape time for

smoldering fires. The effect was much smaller for flaming

fires

.

3. In these tests, fixed temperature 135 °F (57 °C)

or rate-of-rise heat detectors in the room of fire origin

provided little life saving potential. These detectors

failed to respond to a majority of the fires and when they

did respond they were considerably slower than smoke detectors

located remote from the fire.

4. During forced air heating there appears to be very

little difference in smoke levels obtained in the bedroom with

the bedroom doors open or closed. Under central air conditioning, however, somewhat reduced smoke levels were obtained in

the bedrooms with the doors closed.

Experiments conducted with fires in closed bedrooms

resulted in lethal conditions in the bedroom before response

of detectors outside the bedroom. Thus, the person in the

room of fire origin would not be warned in time unless the

detectors were in the bedroom or the door was open. Since

there was no increased hazard to the occupants from fires

originating outside the bedroom when the bedroom doors were

open and the open doors would greatly increase the chances

of saving the occupant when the fire starts in the bedroom,

it may be best to sleep with bedroom doors open when detectors

are present in the home.

5. Response time of detectors on the second floor for

first floor fires were considered inadequate. Thus, it would

appear that NFPA/74 should be revised to require at least one

detector on each level of a residence, especially when centrally air-conditioned.

11
6. Installation of one smoke detector at each end of

a long central hall would significantly increase the escape

time potential in comparison with one detector at one end

of the hall.

7. Under expected residential fire conditions it

appears that there is no difference in life saving potential

between ionization and photoelectric detectors. Although

some response difference is noticed depending on the type of

combustion, (flaming or smoldering) the differences are

minimal when compared on an escape time and life saving

potential basis.

8. Smoke conditions produced by the fires indicate

that there should be no significant difference in detection

times for ceiling mounting or wall mounting within 12 inches

(30 cm) of the ceiling. However, individual detectors with

highly directional properties may function quite differently

in these two positions.

12
Figure 1. Room Identification: Basement Floor

Plan — J.R. Whitehouse Residence

13
Living Room

(L) Bedroom

(B)

J

Approx. Scale

1/8" = l’-O

Figure 2. Room Identification: 1st Floor Plan —

J.R. Whitehouse Residence

14
Figure 3. Room Identification: 2nd Floor Plan —

J.R. Whitehouse Residence

15
Upper Level

Lower Level

Approx Scale:

1 / 16 " = 1

1 -0

Figure 4. Room Identification: Floor Plan —

Lakeshore Residence

16
KEY

wwwwv Ceiling Mounted

W////A Wall Mounted, 9 In. Below Ceiling

Figure 5. Detector Locations: 1st Floor Plan —

J.R. Whitehouse Residence

1 17
KEY

:m/mm Ceiling Mounted

ESS5253 Wall Mounted, 9 In Below Ceiling

Figure 6. Detector Locations: 2nd Floor Plan —

J.R. Whitehouse Residence

Scale

l’-O

18
Upper Level

Approx Scale:

1/16" = l'-O

KEY

mm Ceiling Mounted

Wall Mounted,

9 In. Below Ceiling

Figure 7. Detector Locations: Floor Plan —

Lakeshore Residence

19
KEY

Ceiling Mounted

Wall Mounted, 5 ft High

Figure 8. Fixed Light Beam Locations (Smoke):

1st Floor Plan — J.R. Whitehouse

Residence

20
KEY

Ceiling Mounted

Wall Mounted, 5 ft High

Figure 9. Fixed Light Beam Locations (Smoke):

2nd Floor Plan — J.R. Whitehouse

Residence

21
Approx Scale:

1/16" = l'-O

KEY

iling Mounted

uES Wall Mounted at 5 ft

Note - Top Bsmt Stairs: only

tests 34-40, Bsmt Ceiling

only tests 28-36

Figure 10. Location of Light Beams for

(Except for Ignition Room)

:

Lakeshore Residence

22

Smoke Measurements

Floor Plan —
KEY

X Thermocouple Profile

-f- Thermocouples 5 ft High

£ Thermocouple 4 in Above Hot Air Register

^ Ceiling Thermocouple (13 ft High)

Figure 11. Fixed Temperature Measurements:

1st Floor Plan — J.R. Whitehouse

Residence

23
KEY

X Thermocouple Profile

+ Thermocouples 5 ft High

Figure 12. Fixed Temperature Measurements:

2nd Floor Plan — J.R. Whitehouse

Residence

Scale

l'-O

24
Upper Level

Approx Scale:

1/16" = l'-O

KEY

Thermocouples 5 ft high

X Thermocouple Profile

O Gas Sampling Location

^ Thermocouple 4 in. Above

Baseboard Heater

Figure 13. Fixed Temperature Measurements and

Gas Sampling Locations: Floor Plan —

Lakeshore Residence

25
KEY

® Summer Experiments

© Winter Experiments

I i 2

Approx

.

1 / 8

” =

\

Figure 14. Gas Sampling Locations: Basement

Floor Plan — J.R. Whitehouse

Residence

1

I

I J

Scale

l'-O

26
KEY

® Summer Experiments

© Winter Experiments

Figure 15. Gas Sampling Locations: 1st Floor

Plan — J.R. Whitehouse Residence

27
KEY

(D Summer Experiments

© Winter Experiments

Figure 16. Gas Sampling Locations: 2nd Floor

Plan — J.R. Whitehouse Residence

28
ITT T

Approx Scale:

1/16" = I'-O

KEY

1 Ceiling Light Beam (Smoke)

X Thermocouple Profile

O Gas Sampling Location

Fire Location

Figure 17. Fire Locations and Portable Ignition

Room Instrumentation: Floor Plan —

Lakeshore Residence
KEY

Ceiling Light Seam (Smoke)

Light Beam (and Temp. Profile)

at Wall, 8 ft High

X Thermocouple Profile

Fire Location

Figure 18. Fire Locations and Portable Ignition

Room Instrumentation: 1st Floor Plan — J.R. Whitehouse Residence

30
KEY

Ceiling Light Beam (Smoke)

Thermocouple Profile

Fire Location

Figure 19. Fire Locations and Portable Ignition

Room Instrumentation: Basement Floor

Plan — J.R. Whitehouse Residence

J

Scale

l'-O

31
Lead

Time,

minutes

Lead

Time,

minutes

32

Figure

20.

Theoretical

Ability

to

Sense

1st

Floor

Fires:

Detectors

on

1st

and

2nd

Floor.

(J.R.

Whitehouse

Residence)
Lead

Time,

minutes

Lead

Time,

minutes

71U

<3

in cn

T3COorJ

cnv£

f-t HT3

4)

Ti t: ca 22

CL

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i-> 73

71

—* - C

C 71 tN 4)

71 -H 0

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33

Figure

21.

Ability

of

Detector

"E"

to

Sense

Fires

(J.B.

Whitehouse

Residence)
G0 o

*4 ‘Aouanbajj ssaaang

W

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tu

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(NW

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x:

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r—I G H O

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(N

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34
Lead

Time,

minutes

Lead

Time,

minutes cn

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4-1

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44

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35
4 H

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cn

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01

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36
Lead

Time,

minutes

Lead

Time,

minutes

% ssaaons

35

Figure

23.

Ability

of

Detector

"E"

to

Sense

1st

Story

Fires.

(Lakeshore

Residence)
Lead

Time,

minutes

Lead

Time,

minutes

<n

V

T3 <J c C O 0) u

-3

v

—

(0 C/1 a

a» 3 2 H 2

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w

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uo

4-> u

(D

4-> 0 Qu D XW 0 U W CD •H 4J

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PS 0 = D

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>1

w

4-J

C

-H 0

«-l CO •H

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<N0

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S3cn

36
o

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CM 0

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<31

U

<u

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X

u

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IX

37
APPENDIX A. ESCAPE CRITERIA

In order to judge adequacy of the warning provided by

various detectors used in this study, measurements were made

of temperatures, carbon monoxide concentrations, and light

obscuration at 5 ft above the floor in bedrooms and along

routes of escape to ground level doors. Critical values

adopted as the limits beyond which escape would not be possible were optical density of 0.07 per ft, temperature of

150 °F, or a time-averaged concentration of CO of 0.04 percent

over a one-hour period. The basis for these choices are given

in the following paragraphs. In all of the present experiments, the limiting value of light obscuration was reached

first, and thus the escape times cited are based on this criterion of untenability

.

Al . Critical Smoke Level

Presently, there does not appear to be any completely

satisfactory way to specify the tenability limits in terms

of optical properties of smoke. The situation would be complicated enough if only light transmission through smoke were

important, but the effects of respiratory and eye irritation

on behavior and visual accuity are also involved.

Table 1 shows some frequently-cited values of critical

smoke level from the literature. Obviously, a wide range of

smoke densities is represented there. Among references [2-

5] , at least a rough consensus can be found for a critical

optical density of 0.07 per ft over a viewing distance of

about 15 ft, when only light obscuration is involved.

References [6] and [7] cite critical smoke densities

which are said to take account of eye irritation. The optical

density of 0.002 per ft derived from reference [6] is probably unreasonably low because it represents the onset of apprehension rather than the limit of endurance of the observers.

The optical density of 0.07 per ft derived from reference [7]

is said to be based on the results of the Los Angeles School

Burns No. 2 [8]. Nowhere in those results is a critical

value of 20 percent light transmission over a 10 ft path

length to be found. As a matter of fact, reference [8] mentions only that 80 percent obscuration is the critical value

for tenability, but identifies neither the location nor the

length of the light path. From the information given in

reference [8] and its predecessor study [9], it is possible

to surmise that the light beam subject to 80 percent obscuration might have been as short as 11 ft or as long as 60 ft.

It appears most probable that the light beam involved a double traverse of a corridor 10-15 ft wide, or a path length

38
of 20-30 ft. The critical optical density for that case would

be 0.023 to 0.035 per ft. On this basis, it appears more

reasonable to assign a critical optical density of about 0.03

per ft to the results of the Los Angeles School Burns.

Rasbash [10] reassessed his earlier work and later work by

Jin [11-13] and concluded that his original correlation [2]

represents a useful worst condition which includes in an

approximate way the effects of eye irritation. From a study

of behavior of people in fires by Wood [14] , he also judged

that a minimum visibility for escape from fire is about 30

ft, and that this corresponds to an optical density of 0.08

per meter or 0.025 per ft. Thus, the best estimates now

possible suggest limits of 0.03 to 0.07 per ft for the

critical optical density.

For the dwelling fire situation, escape routes are not

usually long and are familiar to occupants. Thus, it appears

reasonable to adopt a critical smoke level of 0.07 per ft

along escape routes.

39
Table Al . Frequently-Cited Critical Smoke Levels

Source

Minimum

Light

Transmission

(%)

Viewing

Distance

(ft)

Optical

Density

(per ft)

Criteria Applied

Rasbash [2] 10 10 0.10 (Empirical correlation*

10.5 15 0.06 5 of visibility of illu12.6 20 0.045 minated objects)

Kingman, et

al. [15]

5 2 0.65 Visibility of sign held

4 ft away and illuminated

by hand-held lamp in

smoke-filled room

Shern [6] 80 0.002 Apprehension in observers

without OBA in smokefilled room

Shern [6] 60 0.0044 Judgement of observers

with OBA in smoke-filled

room

Gross, et

al. [4]

16 10 0.079 Assumed value

Los Angeles

Fire Dept.

[7]

20 10 0.070 Visibility and eye irritation of observers in

smoke-filled corridor

Bono and

Breed [4]

10 11.3 0.088 Visibility of illuminated

exit signs photographed

from outside smoke-filled

room Malhotra [5] 11 14.8 0.064 Visibility of illuminated

signs observed from outside smoke-filled room

* Correlation: V 1.40/D . 767

where

:

d is optical density per meter

V is distance of vision in meters

40
A2 . Critical Carbon Monoxide Concentrations

The toxicology of carbon monoxide is probably better

understood and more fully reported ' than that of other constituents of fire gases; nevertheless there are areas of considerable disagreement concerning its effects. This is true

particularly for long-term exposure to low concentrations of

carbon monoxide. Table 1 shows the physiological effects of

carbon monoxide as reported by various sources. A reasonable

one-hour limit of 0.04 percent may be inferred from these

data

.

Since all of the data in table 1 are for situations

wherein carbon monoxide concentration dbfes not vary with

time, it is reasonable to expect that the minimum concentration allowable in a fire situtation will be greater than

0.04 percent. This is because the carbon monoxide concentration will be near zero at the start of the fire, and will

increase with time as fire gases permeate the space. If the

carbon monoxide concentration increases linearly with time,

the maximum concentration attained will be twice the average

concentration

.

The treatment due to Minchin [16] suggests that the

average carbon monoxide concentration, rather than the maximum, is the appropriate indicator of physiological response.

Thus, it appears that a logical one-hour limit for a fire

situation in which carbon monoxide increases linearly with

time would be one having a maximum average carbon monoxide

concentration of 0.04 percent.

The data indicate that carbon monoxide concentration

does in fact increase almost linearly with time during the

time periods of interest, and a time-average concentration

of 0.04 percent has been chosen as the critical level. In

only 2 of the 40 experiments did cabron monoxide concentrations approach this level before the optical density reached

0.07 per ft. Nevertheless, the occurrence of the critical

optical density preceded the occurrence of critical carbon

monoxide levels in all of the experiments.

41
Table A2. Allowable Carbon Monoxide

Levels from Various Sources

Carbon Monoxide Physiological

Reference (%) Exposure Effect

Bowes and

Field [17] 0.1 1 hr Unstated

Pryor, et al. 0.04 4 hr Lethal

[18] 0.04 2 hr Collapse

0.04 1 hr Headache

0.03 3 hr Collapse

0.03 1.5 hr Headache

0.02 4-5 hr Collapse

0.02 2-3 hr Headache

Yuill [19] 1.5 5 s Lethal

0.3 5 min Lethal

0.15 30 min Lethal

0.045 2 hr Lethal

Gross, et al. 0.005 8 hr None

[20] (Based 1.0 2-5 min Lethal

on refs. [21 9 22 and 23]

)

Autian [24] 0.01 8 hr None

Minchin [16] 0.1 4 5 min Collapse

0.05 9 0 min Collapse
A3. Critical Temperature

The maximum temperatures to which humans may be exposed

are not well defined, and thus are subject to considerable

controversy. Yuill's [19] data showing a four-hour limit of

130 ° F indicates that the appropriate temperature limit for

escape from a dwelling must be somewhat higher. The value

of 150 °F was adopted as the criteria of untenability in

reference [9]

,

and this appears to be the minimum which could

be considered applicable to the present experiments. This

temperature was never exceeded at the five-foot level along

an escape route before untenable smoke occurred. Hence, adoption of any limiting temperature above 150 °F would lead to

identical conclusions in this study.

43
REFERENCES

[1] A Study of Fatal Residential Fires, NFPA Report FR72-1,

National Fire Protection Association, Boston, Mass.

[2] Rasbash, D. J. , Smoke and Toxic Products Products at

Fires, Trans, J. Plastics Inst., p. 55 (Jan. 1967).

[3] Gross, D. , Loftus, J. J. and Robertson, A. F. , A

Method for Measuring Smoke from Burning Materials,

ASTM STP422 (1967)

.

[4] Bono, J. A. and Breed, B. K., Study of Smoke Ratings

Developed in Standard Fire Tests in Relation to Visual

Observations, Underwriters' Laboratories Bulletin of

Research No. 56 (1965) .

[5] Malhotra, H. L. , Movement of Smoke on Escape Routes,

Part 1 — Instrumentation and Effect of Smoke on

Visibility, Joint Fire Research Organization, Fire

Research Note 651 (Jan. 1967) .

[6] Shern, J. H. , Smoke Contribution Factor in the Fire

Hazard Classification of Building Materials, ASTM STP422

(1967)

.

[7] Anonymous, Fire Detection Systems in Dwellings, Quarterly

of NFPA, Vol . 65, No. 3, p. 201 (Jan. 1963).

[8] Anonymous, Operation School Burning No. 2, National

Fire Protection Association, Boston, Mass. (1961).

[9] Anonymous, Operation School Burning, National Fire

Protection Association, Boston, Mass. (1959).

[10] Rasbash, D. J., Sensitivity Criteria for Detectors

Used to Protect Life, 75h International Seminar on

Problems of Automatic Fire Detection, I.E.N.T., Aachen,

Germany, held March 5 and 6, 1975.

[11] Jin, T. , Visibility through Fire Smoke I, Fire Research

Institute, Japan (July 1969).

[12] Jin, T. , Visibility through Fire Smoke II, Report of

Fire Research Institute of Japan, 33 (1971).

[13] Jin, T. , Visibility through Fire Smoke III, Bull, of

Japanese Assoc. Fire Science and Eng., 22 (1972).

[14] Wood, P. G. , The Behavior of People in Fires, JFRO

,

Borehamwood, England, Fire Research Note No. 953.

44
[15] Kingman, F. E. T., Coleman, F. H. and Rasbash, D. J.,

The Products of Combustion in Burning Buildings, Brit.

J. Appl . Chem. , Vol. 3, p. 463-8 (1953).

[16] Minchin, L. T. , Mild Carbon Monoxide Poisoning as an

Industrial Hazard, Ind. Chem., Vol. 30, p. 381 (1954).

[17] Bowes, P. C. and Field, P., The Assessment of Smoke

Production by Building Materials in Fires — 2. Test

Method Based on Smoke Accumulation in a Compartment,

Joint Fire Research Organization, Fire Research Note

749 (March 1969) .

[18] Pryor, A. J. , Johnson, D. E. and Jackson, N. N.,

Hazards of Smoke and Toxic Gases Produced in Urban

Fires, SWRI Report No. 03-2402, OCD Work Unit 2537B,

Contract DAHC 20-70-0212 (Sept. 1969).

[19] Yuill, C. H. , The Life Hazard of Bedding and Upholstery

Fires, J. Fire and Flamm. , Vol. 1, p. 312 (Oct. 1970).

[20] Gross, D., Loftus, J. J. , Lee, T. G. and Gray, V. E.,

Smoke and Gases Produced by Burning Aircraft Interior

Materials, NBS Building Science Series 18 (Feb. 1969).

[21] Henderson, Y. and Haggard, H. W. , Noxious Gases,

Rheinhold, New York (1943).

[22] Elkins, H. B., The Chemistry of Industrial Toxicology,

(John Wiley and Sons, New York, 1959).

[23] American Conference on Government Industrial Hygienists,

Document of Threshold Values, Cincinnati, Ohio (1966

Edition)

.

[24] Autian, J. , Toxicologic Aspects of Flammability and

Combustion of Polymeric Materials, J. Fire and Flamm.

,

Vol. 1 , p. 239 (July 1970) .

[25] Heskestad, G., Escape Potentials from Apartments

Protected by Fire Detectors in High-Rise Buildings,

FMRC Serial Number 21017. Department of HUD, Contract

Number H-2034R (June 1974)

.

45
NBS-1 1 4A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 76-1126

2. Gov’t Accession

No.

3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

FIELD INVESTIGATION OF RESIDENTIAL SMOKE DETECTORS

5. Publication Date November 1976

6. Performing Organization Code

7. A UTHOR(S)

Richard W. Bukowski

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4928677

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street , City, State, ZIP)

Same as No. 9

13. Type of Report & Period Covered

Final Report

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant in formation. If document includes a significant

bibliography or I iterature survey, mention it here.) A test program was undertaken to evaluate the effect of

sensitivity and placement of residential smoke detectors on

their response to fires in homes. The tests were conducted in

two homes scheduled for demolition and used actual furnishings

in typical configurations. In addition to the detector response

times, the homes were highly instrumented with data on smoke,

temperature, and gas concentration measured for all tests.

The tests showed that smoke detectors can be highly effective

in providing adequate warning of a fire before conditions in the

home become dangerous.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize^onty the first letter of the first key word unless a proper name; separated by semicolons) Detector sensity; detector siting ; escape time;

fire tests; heat detectors; residential fires; smoke detectors.

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