NBS

PUBLICATIONS

A 11 IDE 7 4 fl 4 5

NBSIR 88-3696

Suppression of Wood Crib Fires

With Sprinkler Sprays: Test

Results

William D. Walton

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Gaithersburg, MD 20899

January 1988

QC

100

U 5 6

88-3696

1988

d in part by:

I Services Administration

igton, DC

n n

NBSIR 88-3696

Research Information Center

National bureau of Standards

Gaithersburg, Maryland 20899

SUPPRESSION OF WOOD CRIB FIRES

WITH SPRINKLER SPRAYS: TEST

RESULTS

William D. Walton

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Gaithersburg, MD 20899

January 1988

Supported in part by:

General Services Administration

Washington, DC

U.S. DEPARTMENT OF COMMERCE, C. William Verity, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
'
TABLE OF CONTENTS

page

LIST OF TABLES iv

LIST OF FIGURES v

ABSTRACT 1

1. INTRODUCTION 2

2. SELECTION OF FUEL PACKAGES 4

3. HEAT RELEASE RATE MEASUREMENT 6

4. METHOD OF WATER APPLICATION 6

5. CARDBOARD BOX TESTS 8

6. WOOD CRIB TESTS . 10

7. COMPARISON WITH OTHER EXPERIMENTS 13

8. SUMMARY AND CONCLUSIONS 16

9. ACKNOWLEDGEMENTS 17

10. REFERENCES ............ 17

ill
LIST OF TABLES

Table 1. Crib Test Summary

page

20

iv
LIST OF FIGURES

page

Figure 1. Sprinkler Density (20 gpm total flow) 21

Figure 2. Cardboard Box Configurations 22

Figure 3. Cardboard Box Heat Release Rate, Free Burn 23

Figure 4 . Sprinkler Densities for Horizontal Cardboard Box Tests .... 24

Figure 5 . Horizontal Cardboard Box Heat Release Rate 25

Figure 6. Crib Configurations 26

Figure 7. Single and Double Crib Heat Release Rate 27

Figure 8. Single Crib Heat Release Rate 28

Figure 9. Double Crib Heat Release Rate 29

Figure 10. Single Crib Heat Release Rate*, Spray Density Above 0.1

gpm/ft2 ......... 30

v
H

'
Suppression of Wood Crib Fires with Sprinkler Sprays: Test Results

William D. Walton

ABSTRACT

A series of fire tests was conducted to examine the effect of sprinkler sprays

on the burning rate of materials. Tests were conducted on an array of empty

cardboard boxes and two sizes of wooden cribs representing light hazard fuel

packages. Free burn tests and tests with selected sprinkler sprays applied

during the steady burning period were conducted. Free burn heat release rates

are compared to heat release rates with sprinkler sprays operating.

Key Words: burning rate; compartment fires; crib fires; fire growth; fire

tests; heat release rate; oxygen consumption; sprinklers.

1
1 . INTRODUCTION

The General Services Administration has expressed a need for developing

sprinkler design criteria for use in government office spaces which ensure

adequate, cost effective fire protection. The Center for Fire Research at the

National Bureau of Standards under the sponsorship of the General Services

Administration, has completed the first phases of a multi-phase research

project addressing the use of quick response sprinkler technology in office

occupancies. The major areas of the first phases of this project were to 1)

examine the potential applicability of quick response technology to office

occupancies, 2) characterize office fuel packages, and 3) measure the effect

of sprinkler spray density on suppression. The work to date has demonstrated

some of the potential benefits of using quick response sprinkler technology

and provided part of the basis for developing design criteria based on the

fuel packages and the amount of water required to extinguish these packages.

The extension of quick response sprinkler technology to office occupancies has

been addressed in a series of full scale demonstration testsfl] 1. These tests

showed that quick response sprinklers operating within their design limits

controlled a specific set of office fires as long as the water was flowing.

These tests indicated that the conditions in the compartment remained sub1 Numbers in brackets indicate literature references at the end of the

paper

.

2
lethal. In addition, the tests provided heat release rate data for some

typical office fuel packages.

The above tests did not address the minimum application rate of water to

achieve control or extinguishment. Instead all sprinklers were operated in

accordance with their Underwriters Laboratories listing. In order to examine

design criteria for sprinklers in office space, it is desirable to have an

•understanding of effect of water application rate on fire control and

extinguishment

.

Therefore, a series of tests have been conducted which examine the effect of

varying water application rates on the burning rate of fires of a size

expected in office occupancies at the time of sprinkler actuation.

3
2. SELECTION OF FUEL PACKAGES

From previous tests, it was found that quick response sprinklers in office

environments operated when fire sizes were the order of 400 kilowatts [1].

Therefore, it was decided to focus on fires with a heat release rate of

approximately 400 kilowatts. Previous work on residential quick response

sprinklers has concentrated on upholstered furniture. An informal survey of

offices indicated that a significant portion of the fuel loading was

cellulosic material being principally paper and some wood. As a result, it

was decided to concentrate on cellulosic materials for these tests.

So the criteria for selecting a fuel package were that it be cellulosic

material representative of office fuel packages with a heat release rate of at

least 400 kilowatts in a free burn environment. In addition, the fuel package

had to be reproducible and relatively inexpensive. A final criterion was that

water could be applied at a time of known heat release rate. The tests were

designed to focus on the effect of water spray on burning rate and not on

sprinkler activation time. From a practical standpoint this required a low or

zero natural fire growth rate at the time of water application.

A pilot test series was conducted to examine several candidate fuel packages.

The first were simulated desks constructed of both particle board or plywood.

These tests indicted that these combustible simulated desks with no paper

material on them would not burn consistently and with sufficient heat release

rate in the free burn environment to be used in this study.

4
The second fuel package examined was empty cardboard boxes. Tests were

conducted using stacks of boxes with ignition on either the vertical or

horizontal faces. These tests indicated that the growth rate of the fire was

too rapid to apply water repeatedly at the time a predetermined heat release

rate occurred. In addition, there was substantial variation in the sprinkler

spray density over the area of the boxes, which would make the results

difficult to characterize.

The final fuel package examined was wood cribs. Cribs have long been used to

evaluate sprinkler performance and are the principle fuel in the Underwriters

Laboratory test for listing standard sprinklers [ 2 ] . Cribs are also part of

the fuel package used for listing residential sprinklers [ 3 ] . The Underwriters

Laboratories tests are designed as pass -fail tests and do not directly provide

information on burning and water application rates. Cribs can be constructed

to provide a wide variety of burning rates and once fully ignited burn at an

almost constant rate for a period of time. For the purposes of this study

water could be applied during this steady burning period of known heat release

rate

.

The burning fuels in many real fires will be partially shielded from direct

sprinkler spray impingement. The lower layers of a crib are partially

shielded from direct impingement from overhead sprays. Cribs therefore can be

considered to be representative of shielding found in office fuel packages.

Because of the many advantages indicated, wood cribs were the primary fuel

package used in this test series.

5
3. HEAT RELEASE RATE MEASUREMENT

The heat release rate of the burning fuel packages was determined using oxygen

consumption calorimetry. A discussion of the principles of oxygen consumption

calorimetry can be found in reference [4] and its use in determining the heat

release rate of large furniture items in reference [5]. To summarize the

method of oxygen consumption calorimetry, all of the gaseous combustion

products from the burning item are designed to flow through a duct where the

mass flow rate and the oxygen concentration are measured as a function of

time. From these measurements the rate at which oxygen is consumed by the

fire can be determined. For most common fuels the rate of heat release is

proportional to the rate of oxygen consumption regardless of the fuel burned.

In these tests, the collection and processing has been computerized with

measurements taken and reported every 10 seconds

.

4. METHOD OF WATER APPLICATION

The water spray used in the suppression tests was applied from commercially

available sprinkler heads. The spray from the heads was therefore

representative of sprinkler sprays found in practice. The heat sensing

elements were removed from the heads and water application was remotely

controlled by the test operator. The sprinkler head deflector was located

95.75 inches (2.43 m) above the floor and the sprinkler was offset radially

from the fuel package. The offset distance varied according to the test

conditions. No ceiling was installed for these tests.

6
The amount of sprinkler water spray which reaches the floor is commonly known

as the sprinkler density with units of gallons per minute per square foot

(millimeters per minute) . Sprinkler density is usually measured by collecting

the spray in pans over a period of time and measuring the water accumulated in

each pan with no fire present. For the tests reported on here, 14 inch (0.36

m) square pans placed adjacent to one another were used with a collection time

of 10 minutes. It has been shown density varies widely as a function

sprinkler type, height above the floor, operating pressure and obstruction to

the spray [6]. In addition, for a given set of conditions, the density varies

significantly over the wetted floor area. Figure 1 shows an example of

sprinkler density over half of a sprinkler spray pattern. Beyler measured a

number of these spray patterns which can be found in reference [7].

In order to generate a number of different densities for the suppression tests

a combination of techniques were used. These included varying the pressure

and thus the flow, using different sprinklers, varying the orifice size and

using two sprinklers simultaneously. In all cases spray patterns within the

normal use range were maintained.

Early testing indicated that the local density over the area of the 14 inch

(0.36 m) square pans was vary sensitive to minor variations in the flow

conditions. As a result, densities were measured before and after each of the

suppression tests. Uniform densities were impossible to achieve over large

areas such as those used in the cardboard box tests. It was possible however

to achieve relatively uniform densities over the area of the test cribs.

7
5. CARDBOARD BOX TESTS

Two free burn tests were conducted on cardboard boxes. Although not directly

used in the subsequent analysis of minimum water flow rates for fire control

performed with cribs, the cardboard box tests provide data of interest. The

first test was on a vertical array of boxes and the second on a horizontal

array of boxes. In addition, two sprinkler spray tests were conducted on

horizontal arrays of boxes. The boxes used in each test were 18 inches

(0.46 m) on each side with a weight of approximately 0.55 lb (1 kg). The

boxes were empty and sealed with filament tape. A total of 32 boxes were used

in each test and the configurations for the vertical and horizontal arrays are

shown in Figure 2. The ignition source for the vertical box array was 100 ml

of heptane in 3.75 inch (95 mm) diameter by 1.25 inch (32 mm) high pan. The

ignition source for the horizontal box array was a 6 inch (152 mm) by 1/2 inch

(13 mm) diameter braided cotton wick soaked in heptane.

The heat release rates for the cardboard box free burn tests are shown in

Figure 3 . This figure shows the growth rate for the vertical array is more

rapid than for horizontal array. In addition, the peak heat release rate for

the vertical array was nearly 3 . 6 MW while the peak for the horizontal array

was approximately 1.6 MW. These tests indicated that it would be very

difficult to apply water repeatedly to the vertical box fires at the same

point during the growth stage of the fire. This is due in part to the fact

that the data collection for heat release rate lags the actual fire

development by approximately 30 seconds.

8
Two sprinkler spray tests were conducted with the horizontal box array.

Average sprinkler densities of 0.043 and 0.065 gpm/ft2 (1.75 and 2.65 mm/min)

were used. The sprinkler densities over the area of the array are shown in

Figure 4 and the heat release rates are shown in Figure 5. While these tests

were able to measure the effect of sprinkler sprays on the heat release rate,

as with the vertical boxes, it was difficult to apply water repeatedly at the

same point during the growth stage of the fire.

When a fuel package as large as the horizontal box array is used there is

typically a variation in sprinkler density over the fuel area. As shown in

Figure 4, for an average density of 0,043 gpm/ft2 (1.75 mm/min) over the fuel

package the local density ranged from 0.025 to 0.056 gpm/ft2

(1.02 to 2.28 mm/min) while for an average of 0.065 gpm/ft2 (2.65 mm/min) the

range was 0.040 to 0.090 gpm/ft2 (1.63 to 3.67 mm/min). These local densities

are measured over a 14 inch (0.36 m) square area and the actual local

variation in density is likely greater. Although it was thought that the

effect of density variations may average out over the area of the fuel, test

observations showed that areas with very low density continued to burn while

areas with higher density were extinguished. The water from the areas with

higher density could not effectively reach the burning areas, indicating the

density variations are not averaged out in these tests.

9
6. WOOD CRIE TESTS

Wooden cribs of two sizes were used in the test series. Both sizes were

constructed of fir sticks 1.5 inches (38 mm) high by 1.5 inches (38 mm) wide

and 2 ft (0.61 m) long. The sticks were fastened together with 8d common

nails at both ends. The overall crib sizes were 2 ft (0.61 m) wide by 2 ft

(0.61 m) deep with 6 sticks per layer. Two different heights were used, 1 ft

(0.30 m) high with 8 layers of sticks and 2 ft (0.61 m) high with 16 layers.

The 2 ft (0.61 m) high crib was effectively two of the 1 ft (0.30 m) cribs

stacked one on top of the other. The 1 ft (0.30 m) high crib will be referred

to as a single height crib and the 2 ft (0.61 m) high crib as a double height

crib. The configuration of the cribs is shown in Figure 6. The cribs were

placed on 4 in. (102 mm) high concrete blocks, one center on each side such

that only the outermost sticks rested on the blocks. A 18 by 24 in.

(0.46 by 0.61 m) metal pan with 600 ml of heptane was centered under the crib

as an ignition source. The burning time of the heptane was approximately 120

seconds

Table 1 gives a summary of crib test information. It shows the average

sprinkler spray densities used in the crib tests. The averages were developed

from water collection in four pans forming a square 28 inches (0.71 m) on a

side. This area is slightly larger than the cribs which are 24 inches (0.61

m) on a side. Also shown in Table 1 are the highest and lowest densities from

the 4 pans

10
Table 1 gives the time during which water was applied in each test. Although

it difficult to establish exactly when extinguishment occurred, this time is

representative of the time at which all flaming and most of the smoldering had

ceased. This time, when multiplied by the average density, gives the total

water used per unit area which is an approximation of the water required for

extinguishment. Table 1 also shows the crib weight and the distance from the

sprinkler centerline to the leading edge of the crib. The crib weights

include the weight of the nails used in constructing the crib. There appears

to be a slight trend in the relationship between density and water used,

indicating that higher densities require less water. This may be due in part

to the difficulty in establishing an exact time for extinguishment and the

variability in crib weights. More likely this results from less deep burning

or charring in the cribs which were quickly extinguished.

To simplify the presentation of the results, the heat release rates have been

adjusted so that the period of steady crib burning appears to begin at time

zero. The time from ignition to spray application was normally 330 seconds,

although this was extended in a few tests to allow for complete crib

involvement. In those cases the heat release curves have been adjusted to

show a uniform time of spray application.

Figure 7 shows the free burn heat release rate for the single and double cribs

along with a single and double crib sprinkler test each with a density of

0.119 gpm/ft2 (4.85 mm/min) . This figure shows the heat release rate at the

time of spray application ranged from 0.42 to 0.50 MW for the double cribs and

from 0.20 to 0.27 MW for the single cribs. The heat release rates for both

11
sprinkler tests show the rapid drop in heat release rate as the crib surfaces

directly exposed to the spray are extinguished. The initial reduction in heat

release rate is followed by a period of more gradual reduction as water drips

down through the crib. Test observations show that water does not reach the

floor under the crib until approximately the time of extinguishment. The

initial reduction in heat release rate is almost the same for the single and

double cribs but it takes a much longer time for water to reach the lower

layers of the double crib.

Figure 8 shows the heat release rates for the complete series of single crib

tests and Figure 9 the heat release rates for the double crib tests. Figure 8

shows a spray density of 0.02 gpm/ft2 (0.82 mm/min) has almost no affect on

the overall burning of the crib and there is a gradual reduction in

extinguishment time as the density is increased from 0.039 gpm/ft2

(1.59 mm/min) to approximately 0.1 gpm/ft2 (4.07 mm/min). The test with a

density of 0.061 gpm/ft2 (2.49 mm/min) appears to fall out of place with

respect to the other tests. This and the crossovers of the tests with

densities over the range of 0.039 to 0.084 gpm/ft2 (1.59 to 3.42 mm/min) are

probably a result of the limits of test precision and small differences in the

cribs and sprays. Densities from 0.1 to 0.2 gpm/ft2 (4.07 to 8.15 mm/min)

extinguished the single cribs so rapidly that differences are difficult to

measure. Figure 10 shows only the tests with densities above 0.1 gpm/ft2

(4.07 mm/min) on an expanded scale. From these tests it appears that a twofold increase in density at the higher rates has almost no affect on the

extinguishment of the fire.

12
The heat release rates shown in Figure 9 for the double cribs follow the same

general trends as those for the single cribs. Although the number of tests is

limited, it appears that a density of 0.2 gpm/ft2 (8.15 mm/min) or greater

would be required for rapid crib extinguishment.

7. COMPARISON WITH OTHER EXPERIMENTS

The data produced in these tests may be compared to results produced by other

researchers in the fire suppression field. Each of the cribs used in these

tests are open in the sense of the correlations for burning rate developed by

Block[8]. That is, the burning rate of the crib is controlled by the internal

surface area and not restricted by the porosity of the crib structure. The

area of the exposed surfaces of a crib with a square cross section is given by

[9].

Ae = 2nb 2

[ (2i/b+l)N-n(N-l) ] (1)

where: b is the stick thickness (m)

n is the number of sticks per layer (-)

N is the number of layers (-)

i is length of a stick (m)

From Block's study, the heat release rate of a burning open structure crib is

Q = AE ECb'° 5 (2)

where: E is the heat released from combustion of a unit mass of

pyrolysis products (kJ-kg' 1

)

C is an empirical constant for the mass of pyrolysis product

produced per unit surface area and unit time (kg • m" 1 • 5

• s" 1

)

13
Values of C for various materials are available from work by Block [8] and

Quintiere and McCaffrey [10], and range from 0.88x10' 3 kg • m” 1 • 5

• s" 1 to

1.33xl0” 3 kg • m” 1 • 5

• s” 1

.

The value of C for the Fir wood used in this study can be calculated from

equations 1 and 2 using the measured heat release rate and known crib

geometry. For the two cribs used in these tests.

Single Crib

b = 0.0381 m

n = 6

N = 8

Z = 0 . 61 m

A£ = 3.87 m

2

Q = 240 kW

Double Crib

0.0381 m

6

16

0.61 m

7.63 m

2

460 kW

Using a value of E = 18600 kJ-kg” 1 [8,10] the values of C calculated from

equation 2 are found to be 0.65x10” 3 and 0.64x10” 3 kg • m" 1 5

• s” 1 for the single

and double cribs respectively.

In experiments by Tamanini [9], crib fires were extinguished by water sprayed

predominately from the four sides of the crib. Based on his work, a critical

water application rate to prevent complete loss of open crib structure during

the burning was 0.0015 kg-m” 2 -s _1

. To limit the mass loss during extinction

to the order of 10 percent, he found that the water application rate must be

increased to the range of 0.005 to 0.010 kg-m” 2 -s -1.

14
For the crib fires in this study, rapid extinction of the single and double

cribs were achieved with water spray densities from the sprinkler of

0.1 gpm/ft2 and 0.2 gpm/ft2

( 6. 78x10' 5 and 1.36x10" 4 m/s). As an

approximation, the rate of water application to the burning cribs may be

calculated by multiplying the floor area occupied by each crib (0.372 m

2

) by

the product of spray density and water density, yielding water mass flow rates

to the cribs of 0.025 kg/s and 0.050 kg/s corresponding to the 0.1 and 0.2

gpm/ft2 spray densities. Dividing the rate of water application by the

corresponding crib exposed surface area yields nearly equal values for both

cribs tested for the area specific water application rate for rapid extinction

of 0.0065 kg -m' 2 -s' 1

. This value is within the range of values found in

previous testing by Tamanini

.

As with Tamanini 's work, the natural scatter of experimental results in spray

extinguishment research at best allows estimates of fire control and

extinction only within a factor of two. Although the spray geometry and crib

scale were different in this study than pervious work by Tamanini, the results

support continued use of crib surface area specific water application rates

from 0.005 to 0.01 kg-m' 2 -s _1 for rapid extinction of wood crib fires.

15
8. SUMMARY AMD CONCLUSIONS

These tests have provided some preliminary information concerning water

application rates for controlling or extinguishing a selected group of light

hazard fuel packages. In addition they have pointed out a number of

difficulties in measuring the rate of water application required to control or

extinguish fires.

The limited number of cardboard box tests did not provide sufficient

information to generalize extinguishment of these fires. They did point out

the difficulties in conducting suppression experiments on large fuel packages

and also provided information on the heat release rate of these fuels.

The wood crib tests provided information on the rate of reduction in burning

as a function of water applied and a limit above which the application of

additional water made little difference. This critical limit was

approximately 0.1 gpm/ft2 (4.07 mm/min) for the single crib with an average

heat release rate of 0.24 MW and 0.2 gpm/ft2 (8.15 mm/min) for the double crib

with an average heat release rate of 0.46 MW. For the wood cribs tested, a

doubling of the crib size and the corresponding heat release rate resulted in

a doubling of the water application rate to achieve rapid extinguishment.

While this result may not necessarily apply to all fuel packages, it does

indicate the importance of rapid sprinkler response in reducing the water

requirement for rapid fire control. Calculations indicated that for wood

cribs, the critical spray application rate could be predicted within a factor

of two.

16
The variability of the measured sprinkler sprays points out the difficulty in

establishing criteria using critical water application rates.. Local sprinkler

densities have been shown to vary widely over the spray pattern and typically

differ by a factor of two or more from the average values used for design

purposes. The crib tests have shown that this variation could have a major

impact on the time to extinguish or control the fire. As a result, the

ability of water wetting of adjacent fuel to control fire spread should be

examined when developing sprinkler density criteria. Fire development in

wetted fuels has not been examined in this study.

9 . ACKNOWLEDGEMENTS

Appreciation is extended to J. Breese, P. Martin, R. McLane , G. Roadarmel, J.

Shields, J. Steel, M. Womble, R. Zile and particularly D. Madrzykowski of the

Center for Fire Research for assistance in conducting these tests and to D.

Evans for assistance in the analysis. In addition, appreciated is extended to

D. Bathurst and W. Blazek of GSA for their support of this project.

10. REFERENCES

[1] Walton, W.D. and Budnick, E.K., Quick Response Sprinklers in Office

Configurations: Fire Test Results. Nat. Bur. Stand. (U.S.) NBSIR 88-3695; 1988

J anuary

.

17
[2] Standard for the Installation of Sprinkler Systems In One- and Two-Family

Dwellings and Mobile Homes 13D. Quincy, MA: Nat. Fire Prot. Assn.; 1984.

[3] Standard on Automatic Fire Detectors 72E. Quincy, MA: Nat. Fire Prot.

Assn . ; 1984

[4] Parker, W.J., Calculations of the Heat Release Rate by Oxygen Consumption

for Various Applications. Nat. Bur. Stand. (U . S .

NBSIR 81-2427-1; 1982 March.

41 p

[5] Babrauskas , V. Lawson, J.R., Walton, W.D. and Twilley, W.H. Upholstered

Furniture Heat Release Rates Measured with a Furniture Calorimeter. Nat. Bur.

Stand. (U.S.) NBSIR 82-2604; 1982 December. 73 p.

[6] Beyler, C.L., The Effects of Selected Variables on the Distribution of

Water from Automatic Sprinklers, Volume 1: Analysis. Univ. of Maryland, Dept

of Fire Prot. Engr . ; 1977.

[7] Beyler, C.L., The Effects of Selected Variables on the Distribution of

Water from Automatic Sprinklers, Volume 2: Distribution Test Maps. Isodensity

and overlay Comparison Maps. Univ. of Maryland, Dept of Fire Prot. Engr.;

1977.

[8] Block, J.A., A Theoretical and Experimental Study of Nonpropagating FreeBurning Fires. Thirteenth Symposium (International) on Combustion; 1970

August 23-29; Salt Lake City, UT . The Combustion Institute; 1971. 971-978.

18
[9] Tamanini , F. , The Application of Water Sprays to the Extinguishment of

Crib Fires. Combustion Science and Technology. 14: 17-23; 1974.

[10] Quintiere, J.Q. and McCaffrey, B.J., The Burning of Wood and Plastic

Cribs in an Enclosure: Volume 1. Nat. Bur. Stand. (U.S.) NBSIR 80-2054; 1980

November

.

19
Table

1.

Crib

Test

Summary

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CM in O' i—I CM CO

tP> CO <X r—i rP rP o o o o o o

m o co vo co oo

cm mo o cm en o

<0 O' rP tP iP CM O O O O O O

C

P

GX O <f I—I on CM MO

a> cm m O' i—i t—i m

OO O' O O* '—l iP rP p

<P o o o o o o

(0

T 1 U3 bO X

p -p

•p p

00 CJ>

a) rP CO X X

G -p O P Q O

20

*Time

over

which

water

was

applied

during

the

test.
Sprinkler

,.9 -,0T o o o o tH tH o o o o o o o o o o o o o o o o o o o o o o o o tH rH tH o o o o o o o o o o o o o o o o o o o o o

CM I—1

<r CM CM CM tH o o o o o o o o o o o o o o o o o o o o

CO

m CD CO CO CM rH o o o o o o o o o o o o o o o o o o o

CD CD CO CD

m CM CM rH o o tH o o o o o o o o o o o o o o o o o CO tH m m m CM o

tH rH tH tH o o o o o o O o o o o o o o

CO CD CNJ CO o CD CO tH o o O t—(

tH tH o o o o o O o o o o o o o

P-v r—1

CO

m CM CD CO CM o o rH tH tH tH o o o o o o o o o o o o o

'3' CO CO CD

m CD

m CM tH

H CNJ tH tH tH o o o o o o o o o o o o o o pv CD <T CM pv CM o tH CNJ tH tH tH tH o o o o o o o o o o o o

CD in CO CO o p^m tH o O rH tH tH t—1 o o o o o O o o o o o o o m <D CNJ o o CD m CM o o O tH tH tH o o o o o O O o o o o o o

CO CO CD CO CD CD CO tH o o o O o o o o o o o o o o o o o o o o Pv CO CD CD CM o o rH o o o o o o o o o o o o o o o o o

CO cn pvm -T CO tH o o H o o o o o o o o o o o o o o o o o

CO CD -3- CD CO CM tH o o tH o o o o o o o o o o o o o o o o o

CM <r CO CO CM tH o o o o o o o o o o o o o o o o o o o o o

tH CO CNJ rH o o o o o o o o o o o o o o o o o o o o o o o o «H CM o o o o o o o O o o o o o o o o o o o o o o o o

CN34J

4-1

CM4-> 4-1

CU

GO2&c04-) M0) -P

fO0) J-i 00c(1) T3

<U

5-1 (0 ea T3 00 rHo G ^

•H

G

^N -H 4-)

21

Figure

1.

Sprinkler

Density

(20

gpm

total

flow)
22

Figure

2.

Cardboard

Box

Configurations
(MW) a^ey aseai ay }eaH

c

3

cQ

23

T

ime

(s)

Figure

3.

Cardboard

Box

Heat

Release

Rate,

Free
0.042 0.041 0.037 0.041

0.047 0.042 0.049 0.046

0.052 0.053 0.052 0.045

0.052 0.047 0.056 0.037

0.042 0.027 0.025 0.026

-* 4

' - 8

"

Average = 0.043 gpm/ft2

Note: Density in gpm/ft2

0.040 0.046 0.044 0.049

0.070 0.082 0.081 0.077

0.070 0.087 0.090 0.079

0.059 0.076 0.080 0.065

0.050 0.046 0.057 0.050

4 ' - 8

" *-

Average = 0.065 gpm/ft2

Figure 4. Sprinkler Densities for Horizontal Cardboard Box Tests

24
25

Figure

5.

Horizontal

Cardboard

Box

Heat

Release

Rate
CD

DCO

LU

_!CDIDOQ

CDDCO

LU

_Joz

c/5

26

Figure

6.

Crib

Configurations
27

Figure

7.

Single

and

Double

Crib

Heat

Release

Rate
.30

o

XT CD LD cu cn CD m o

cu C\J cu o o o o

o o o o o o o o o o

(MW) 3}ey aseat ay ^Gay

cn

cus

•M

h~

28

Figure

8.

Single

Crib

Heat

Release

Rate
r

7—

r

o or CO ru CD o O' CO Ol CD O

CD in or or CO CO cu 0—1 vi O O

o o o o o o o o o O O

(MW) a^eu aseaiau }eaH

O

O

in

o

LD

co

o

o

cu

o

in

o

o

o

cn

o

ln

r^

o

o

CD

o

in

or

o

o

m

o

m

o

cn

CDE

-I—

I

h29

Figure

9.

Double

Crib

Heat

Release

Rate
o

o r^ CO Lf) OJ cn CO n o

m oj OJ cu 1 1 1 o o o o

o o o o o o o o o o o

(MW) a^ey aseatay }eaH

CSJ

30

Figure

10.

Single

Crib

Heat

Release

Rate,

Spray

Density

Above

0.1

gpm/ft
NBS»1 14A irev. 2 «ac) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR-88/ 3696

2. Performing Organ. Report No. 3. Publication Date

January 1988

4. TITLE AND SUBTITLE

Suppression of Wood Crib Fires with Sprinkler Sprays: Test Results

5. AUTHOR(S)

William D. Walton

S. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions)

NATIONAL BUREAU OF STANDARDS

U.S. DEPARTMENT OF COMMERCE

GAITHERSBURG, MD 20899

7. Contract/Grant No.

S. Type of Report & Period Covered

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

U.S. General Services Administration

Washington, DC 20405

10. SUPPLEMENTARY NOTES

2 Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most si gn ificant information. If document includes a significant

bi bliography or literature survey, mention it here)

A series of fire tests was conducted to examine the effect of sprinkler sprays

on the burning rate of materials. Tests were conducted on an array of empty

cardboard boxes and two sizes of wooden cribs representing light hazard fuel

packages. Free burn tests and tests with selected sprinkler sprays applied during

the steady burning period were conducted. Free burn heat release rates are compared

to heat release rates with sprinkler sprays operating.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) burning rate; compartment fires; crib fires; fire growth; fire tests; heat release

rate; oxygen consumption; sprinklers

13. AVAILABILITY

|X 1 Unlimited

| | For Official Distribution. Do Not Release to NT1S

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

20402.

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

14. NO. OF

PRINTED PAGES

36

15. Price

$11.95

USCOMM-DC 8043-P80
-

.

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