Fire Effects and Fire Control in

Nitrocellulose Photographic-Film Storage

United States Department of Commerce

National Bureau of Standards

Building Materials and Structures Report 145
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UNITED STATES DEPARTMENT OF COMMERCE • Sinclair Weeks, Secretary NATIONAL BUREAU OF STANDARDS . A. V. Astin Director

Fire Effects and Fire Control in

Nitrocellulose Photographic-Film Storage

J. V. Ryan, J. W. Cummings, and A. C. Hutton

Building Materials and Structures Report 145

Issued April 2, 1956

For sale by the Superintendent of Documents, U. S. Government Printing Otfice Washington 25, D. C. - Price 20 cents

Foreword

Although the manufacture of nitrocellulose film in the United States was

discontinued during 1950, large quantities of this type of film containing important information of a historical or record nature were accumulated for many

years and must be preserved. The highly flammable character of this film

complicates the problems of preservation.

Several investigations have been carried out by various organizations to determine the pressures that were developed in vented chambers during the

burnout of loads of nitrocellulose film. However, little if any work has been

done to establish the most effective methods of reducing the hazard of such

fires. Because the problems of nitrocellulose-film storage were common to many organizations, an Inter-Agency Advisory Committee for Nitrate Film

Vault Tests was formed to sponsor a large-scale investigation to provide

information for recommendations for safe storage. The committee was composed of representatives from several interested Government and private

organizations, such as the National Archives, Department of Defense, Motion

Picture Association of America, and the National Automatic Sprinkler and

Fire Control Association. This report presents the results of that investigation and the conclusions based thereon. A. V. Astin, Director.

in
Contents

Page

Foreword hi

1. Introduction 1 1.1. Background 1 2. Experimental facilities and procedure... 2

2.1. Chambers for preliminary program of 1940-1941 at the National

Bureau of Standards 2

a. Steel chamber 2

b. Vault 2

2.2. Beltsville vault 2

a. Film racks and containers 3

b. Load and ignition 5

c. Sprinklers 6

d. Detectors 6

e. Instrumentation ..1 7

2.3. Experimental programs 7

3. Results 8

3.1. Program of 1940-1941 at the National Bureau of Standards 9

3.2. Beltsville vault program with skeleton racks 11

3.3. Beltsville vault program with compartmented racks 11

3.4. Supplementary film rack program 14

4. Discussion 14

4.1. Pressure-load relationship 14

4.2. Effect of film containers 15

4.3. Effect of film racks i 15

4.4. Effect of sprinklers , 15

4.5. Effectiveness of detectors and actuators 16

4.6. Summary 16

5. Conclusions . 16

6. References 17

7. Appendix 17
Fire Effects and Fire Control in Nitrocellulose

Photographic-Film Storage

J. V. Ryan, J. W. Cummings, 1 and A. C. Hutton 2

The results are given of a comprehensive research investigation conducted to determine

the effects of variables such as film load, size and orientation of vent opening, volume of chamber, containers for rolls of film, rack types, and automatic-sprinkler systems on fires in nitrocellulose-film storage vaults, as indicated by internal pressure, temperature, fumes and

flames, and extent of film damage. The data are tabulated and those from an earlier inde- pendent study are included for comparison. The effects of the variables are discussed and

conclusions with respect to the maximum preservation of film are given.

1. Introduction

In some respects nitrocellulose is one of the

most desirable photographic-film bases, especially

for motion pictures. Until recently, when cellu- lose acetate “safety” film came into common use, the vast majority of 35-mm motion-picture film used was nitrocellulose. Unfortunately, although

it is economical and has excellent photographic

qualities, nitrocellulose is very easily ignited, is subject to self-heating and self-ignition ft],

3 gives

off toxic fumes during combustion, burns vigorously, and once well started, continues to burn

on its own chemically combined oxygen even when

submerged in a container of water [2, 3]. Also,

this film goes through a process of decomposition

that depends on time, temperature, and humidity.

A study of this process has indicated that the

danger of ignition by self-heating is almost nonexistent for new or well-preserved film but in- creases appreciably as the film becomes older and

starts decomposition [1], When this film is stored

in large quantities, the danger of explosion is added to the hazards already mentioned. Although

it is virtually impossible to obtain nitrocellulose

film in this country at the present time, the large

quantity of such film in storage still represents a hazard.

Standards for the storage of nitrocellulose film,

based on experiments mads in 1915, listed vault

constructions without sufficient evidence that they

are strong enough to withstand the internal pres- sures likely to be developed under the allowable

load and vent conditions in case automaticsprinkler protection should be inoperative or have

not been installed. Consequently in 1940 the

National Bureau of Standards, at the request of

the National Archives, undertook an investigation of factors that might be expected to affect the severity of and hazards from fires in nitrocellulose-film storage.

1 National Archives.

- Formerly with NBS.

3 Figures in brackets indicate the literature references at the end of this paper.

As the preliminary program of the investigation, a series of experiments were made in two

film chambers on the Bureau grounds in Washington, D. C. These experiments were designed

to serve as a guide for the design of a vault more

nearly the maximum size permitted by the standards, and of its instrumentation, by providing

data on the pressures developed in confined spaces

during fires involving greater amounts of film

than had been used in most of the previous ex- periments. The vault was constructed near Beltsville,Md., and an experimental program set up to investigate the effects of such factors as film containers, racks, and sprinklers in addition to film

load and venting. The over-all investigation was

carried out to provide data essential for the preparation of recommended practices for safe storage

of nitrocellulose film. As many organizations had large amounts of

nitrocellulose film in storage, an Inter-Agency

Advisory Committee on Nitrate Film Vault Tests was formed to plan the details of the remainder

of the investigation. The committee was composed of representatives of interested Government

and private organizations.

1.1. Background

Fires in those places wherein nitrocellulose film was present in quantity have been a problem

since the introduction of this film. Several very

serious fires and explosions have occurred in storage centers [4], In 1910 the U. S. Geological

Survey made investigations on a small scale and. on the basis of their findings, recommended that

not more than about 7 lb of film be stored per

square inch of vent area. In 1915 a special committee of the Committee on Explosives and Combustibles of the National Fire Protection Association published the results of experiments con- ducted on a larger scale [5], Their findings agreed

in general with those from the earlier experiments,

but their recommendations were for less-dense

loading. These findings and recommendations

were used as the basis for standards that were

accepted for many years. However, experience

1
I

from actual fires indicated that pressures higher

than those determined experimentally were being

realized in storage fires. Therefore the National

Bureau of Standards began the investigation

reported herein during 1940. The preliminary

program was completed, but World War II made

it necessary to postpone the large vault program

until after the cessation of hostilities. Some time

after the war it became possible to resume this investigation, and the previously mentioned committee was formed.

2. Experimental Facilities and

Procedure

Two film chambers were used in the preliminary

experiments at NBS in 1940-1941. One was of

steel, and the other was a reinforced-concrete

explosion chamber. The Beltsville vault was most representative of actual storage, having the

form and being about one-half the size of many

existing vaults. Details of the three chambers,

their instrumentation, and of the experimental

programs are given in the following sections.

2.1. Chambers for Preliminary Program of

1940-1941 at the National Bureau of Standards

One film chamber used in the preliminary pro- gram at NBS was a steel cylinder. The other was a reinforced-concrete chamber more nearly

representative of actual storage facilities in that

skeleton racks were installed and the film capacity was much greater than that of the steel cylinder.

a. Steel Chamber

The film chamber for 20 experiments in the 1940-

1941 program was a steel cylinder, inside diameter

2 ft, length 7 ft, with one end permanently sealed

and the other end equipped to allow easy inter- change of steel plates, in which were cut various

size vents. The volume of the chamber was 22

ft 3

. It was provided with pressure taps to which

were connected manometers. Two thermocouples

were installed to obtain interior temperatures.

They were of 18 gage cliromel-alumel wires, with

all but the junction and about 1 in. of the wires

encased in asbestos sleeving. They were placed

with the bare junctions on the longitudinal axis

of the cylinder, one 2 ft 4 in. from each end.

The outside of the cylinder, including the sealed

end, was insulated to prevent rapid heat loss. An ignition source was located about 1 % ft outside the vent to ignite the combustible toxic

fumes liberated. The film was in rolls, on and off reels, both in cans and uncontained. There was

no rack in the chamber, but a steel frame was used

to hold the film 7 in. from the vent opening. Except in experiment 12, the film was ignited by

means of an electrically heated wire placed in contact with film. In that instance a fire of scrap wood was built just outside the vent, and

2

the film in the chamber was ignited by this “exposure fire.” The details of the film load and

vent area for each experiment are given in table 2.

b. Vault

The other three experiments of the 1940-1941

program were made in a reinforced-concrete vault,

the inner dimensions of which were 4 by 4 by 8 ft (volume 128 ft3 ). The walls were 24 in. thick.

An opening was located in each end wall, one

opening serving as the vent and the other as a loading entrance, the latter having been sealed

during experiments. The vent area was varied

by steel plates. Pressure taps and thermocouples were included, which were connected to manometers and potentiometers, respectively. The thermocouples were identical to those in the steel chamber except for placement and number.

Four were placed along the center of the aisle, one each at:

(1) 19 in. from the vent end wall and 10 in. above the floor;

(2) 38 in. from the vent end wall and 32 in. [ above the floor;

(3) 57 in. from the vent end wall and 10 in. above the floor; and

(4) 76 in. from the vent end wall and 32 in. above the floor. The film was loaded on skeleton pipe racks in individual, one-reel cans and was ignited by an j electrically heated wire.

2.2. Beltsville Vault

The reinforced-concrete vault, figure 1, in

j which two experimental programs were conducted : under the direction of the Inter-Agency Committee

was in the form of a cubicle with a door at one

end, an opening in the opposite wall, and an , opening in the ceiling at the same end as the wall

opening. The ceiling opening led to a vertical

vent stack, which simulated the vent of the lower

vault of a two-level building. The inner dimensions of the vault were 4 ft 8 in. wide by 8 ft deep by 10 ft high. The vertical stack was an

additional 14 ft 10 in. high. The walls, floor,

ceiling, and stack were of 10-in. -thick reinforced! concrete. The door and coverings for each vent) were of steel. Both the vertical and horizontal vents were equipped with steel plates that could be adjusted

(

to change the area of vent opening. An experimental cover of steel, weighing 256 lb, was laid over the 504-in. 2 opening at the top of the vertical

stack. It was held in place only by its weight.

The vault door was hung to open inward and

bear on the jamb on both sides, top, and bottom';

when closed. The vault was provided with pipes 1 through the walls to permit the installation or connection of temperature- and pressure-measuring equipment, sprinkler systems, and fire and

smoke detectors.

Ik

ard

sizt

by
Figure 1 . Construction details of 373-ft 3 reinforced-concrete experimental film vault near Bcltsrille. Ma. The vault volume of 373 ft3 was about one-half

the maximum allowed in generally accepted standards. Although the vault was not of maximum

size, it was believed that the experimental results obtained therewith would be of the order of magnitude that might be obtained from experiments

in a maximum-size vault. The vault was designed

by members of the committee and built on the

grounds of the U. S. Department of Agriculture

Research Center at Beltsville, Mil., on a location

selected to provide water supply, shop facilities,

and isolation from inhabited places and valuable

property.

a. Film Racks and Containers

The film loads in these experiments were placed

in various racks and types of containers. The

•>O
containers were either round or square metal cans, each of which held a single 1,000-ft reel of 35-mm

film, or lined, multiple-reel shipping cases of a type approved by the Interstate Commerce Commission. Some of the latter cases held as many

as 10 reels of film. The vertical-storage skeleton

racks and horizontal-storage skeleton racks were

of conventional design. The open-front compartmented shelf racks and the closed-front compartmented shelf racks were designed by members of the Inter-Agency Committee and incorporated

features not available in commercial racks.

The vertical-storage skeleton racks were simple

arrangements of ordinary iron pipe attached to vertical steel frames, in which the film cans rested

vertically on two horizontal pipes. Lateral support and restraint were provided for each film can by the adjacent cans in those instances in which

the racks were loaded to maximum capacity.

Gypsum, board was used to separate adjacent rack

end frames. These racks are shown in figure 2, with film cans in place. The horizontal-storage

skeleton racks shown in figure 3 provided support

to each can by the partial shelves of the racks. In three experiments (4, 5, and 6) the horizontalstorage racks were partially insulated by placing

asbestos millboard or gypsum, board in the three

central stacks on each side of the aisle to enclose

each film, can on all sides except toward the aisle,

Figure 2. Fully loaded vertical-storage skeleton film racks in vault. The horizontal vent opening is at the top.

as shown in figure 4. This was done to simulate

compartmented racks and to determine what

effect would be produced by isolating the igniter can from those adjacent to it. Each open-front compartmented rack consisted

of three vertical rows of compartments, 30 in a row, and stood 6 in. off the floor on sheet-metal

legs. The over-all dimensions were 2 ft 1 1 % in. wide by 6 ft 1 1 % in. high by 11% in. deep. They

were constructed of light-gage sheet steel and

insulated with %-in. gypsum board applied to the

underside of each shelf and the sides and rear of each compartment. The clear space of each

compartment of the open-front rack was 1 1 in. wide by 1 1 in. deep by 2%2 in. high. Each compartment was equipped with a film extractor,

which consisted of a flexible steel strip attached

to the left front corner, from where it curved

around the rear of the compartment to the right

front and passed through a guide. Pulling the

loose end caused the ejection of the film can. The rack is shown in figure 5. Each closed-front compartmented rack consisted

of three vertical rows of compartments, 26 in a row, and stood 6 in. off the floor on sheet-metal

legs. The over-all dimensions were 3 ft 1%6 in. wide by 6 ft ll}i in. high by 1 ft in. deep. They

were of the same general design as the open-front

racks with the addition of an insulated door for

Figure 3. Loaded horizontal-storage skeleton film racks in

vault, experiment 1.

4
each compartment. The door was hung at the

top from a piano-type hinge. The clear space of

each compartment was 1 ] % in. wide by 1 1 % in. deep by 2}&2 in. high. Each compartment was

equipped with the same type of extractor as in the

open-front rack. The rack is shown in figure 6. The skeleton racks were placed along each side

and at the rear of the vault. For the largest

loads, a shelf rack was placed above the vault

door. The compartmented racks, open- or

closed-front, were placed one on each side of the

vault, there having been only two of each available. The type of rack for each experiment is included with the experimental log summary and

in table 3.

b. Load and Ignition

For most of the vault experiments the film load was 5 lb of film per square inch of vent area. In

1 experiment it was 6 lb/in. 2 and in 4 others,

7 lb in.2

. With full- to half-open vents, as used

with skeleton racks, this corresponded to total film loads ranging from 2,520 to 4,970 lb or loads

per unit volume of 6.8 to 13.3 lb/ft3

. In compartmented racks, capacity loads of 780 and 900

lb were used with reduced vent areas. Information regarding the vent and load for each ex- periment is given in table 3. Ignition was achieved by a match in a coil of nichrome heater wire connected to a 12-v d-c

source. The match and coil were placed inside a

Figure 4. Compartmentation of horizontal-storage skeleton racks by means of insulation boards. Figure 6. Closed-front compartmented film racks ca .ti.

Figure 5. Open-front compartmented film rack, showing

film extractors.

304788—56—-2 O
can of film, which is referred to as the “igniter can”. The location of this igniter can was not

the same in every test.

c. Sprinklers

Three types of sprinkler heads were employed;

open spray heads, 165° F spray heads, and 165°

F standard heads. Each installation of sprinklers

consisted of six heads of the same type. The

water-supply line, which entered the vault about

3 ft above the door, fed two distinct pipe systems.

These pipe systems are shown in figure 7, with

open spray heads in place. The center pipe

line with its six branches was used with the two

types of spray heads to form directed spray

sprinkler systems. The branches were directed

so that the centerline of the water spray would

strike the front of the racks at a level two-thirds

of their height above the floor. The two side

pipe lines, to each of which three sprinkler heads

could be attached, were used with the standard

heads to form a standard sprinkler syswem.

When not to be used in a given experiment, the

sprinklers of either or both systems were re- placed by caps or plugs.

The open spray heads were used with the

directed-spray system under “deluge” conditions

in which discharge of all heads was actuated by a “deluge” valve located outside the vault in the

supply line. Each head consisted of a hollow

Figure 7. Pipes for overhead sprinkler systems, with open

spray heads installed, experiment 3.

bullet-shaped nozzle, inside of which was a fixed | piece having a central venturi tube and three ; curved blades. The water entering the head was

separated into two streams by the inner piece; a small central stream through the }g-in. venturi

where its speed was increased, and a larger annular , stream through the fixed blades, which gave it a rotary motion. The central and annular streams

reunited as the}’ entered the %6 -in. orifice, pro- ducing the spray emitted from the head. Each

head was designed to discharge 10 gpm at a pressure of 15 lb/in. 2 or 15 gpm at 32 lb/in. 2 pressure. The 165° F spray heads were used with the

directed-spray system under “wet-pipe” conditions. Each head was designed to discharge 10 gpm through a %6 -in. orifice to strike the outer

surface of a conical deflector plate 1 ){ in. from the

orifice, when operated at a flow pressure of 20

lb/in. 2. The conical deflector was perforated and

deeply castellated along the outer edge to provide

a directed spray of a uniform pattern. The

discharge was actuated in the same manner as that from the 165 c F standard heads.

The 105° F standard heads were installed in | vertical positions above the horizontal pipes.

Each head was designed to discharge 15 gpm

vertically upward through a %-in. orifice, when

operated at a flow pressure of 7 lb/in. 2. The dis- charge was effectively scattered by a deflector

plate 1/4 in. above the orifice. These heads were

used with a “wet-pipe” system, and the discharge was actuated by the melting of a fusible link at or near 165° F, which released the cap sealing the . orifice. The water supply for the sprinklers came from a

fire hydrant through either fire hose or 3-in. pipe I laid on the ground to the base of the vault, thence

up and across the face to the point where it entered

the vault above the door. The deluge valve,

which could be operated automatically by a detector or manually, was located in the vertical

portion of the line about 5 ft above the base of the

vault. The water-flow control equipment, by j which the desired rate of water flow could be set, was inserted in the line between the vault and the

fire hydrant.

d. Detectors Two rate-of-rise detectors were inst alled throughout the first 13 experiments and one of this type in

9 of the other 10 experiments. One detector : element was mounted on the ceiling and was used

to operate the deluge water valve. In those ; experiments in which the deluge valve was opened

manually rather than automatically, or opened

before the experiment began, the detector lighted 1 an indicator light and the time of operation was

noted. The second rate-of-rise detector, when ; used, was mounted near the door to simulate use

| with an automatic door-closing mechanism. The

door closer was not installed, hence the detector

signal w’ent to another indicator light.

6
In conjunction with the use of and for comparisons with the rate-of-rise detectors, each of two

instruments designed to indicate the presence or amount of smoke were included in a few of the

experiments. One smoke indicator was a detector

designed to give an output signal only when the

smoke reduced the transmission of light through a sample of the vault atmosphere by a given percentage. This detector was used to light an indicator

in two experiments; in one of which this was the

signal for manual operation of the deluge valve

and in both of which the times of operation were compared with those of a rate-of-rise detector.

The other smoke indicator was a meter to measure

the smoke density in terms of light transmission.

It was used in the last three experiments, along

with a rate-of-rise detector.

e. Instrumentation

Measurements were made of the pressures and

temperatures inside the vault and of the water

flow through the sprinklers. The times of operation of the detectors and sprinklers were observed.

Pressures were measured at four taps in the

vault, with each tap connected to a manometer

and a gage or at a single tap connected to two

manometers. In order to obtain measurements

over a wide range of pressures, both water- and

mercury-filled manometers were employed.

Temperatures were measured with 18-gage

chromel-alumel thermocouples placed at various

locations. One was 5 ft from the front wall, 5 ft from the floor and centered between the side

wahs; a second was 18 in. from rear wall, side

wall, and roof; a third was 5 ft from the front

wall, 31 in. from the floor, and 12 in. from one

side wall; and the fourth was at the same height

and depth as the third but 12 in. from the opposite

side wall. Each thermocouple junction and about

1 in. of the wires were bare with the remainder

encased in asbestos sleeving. They were connected

to self-balancing potentiometers calibrated to read directly in degrees centigrade. A panel of indicator lights was installed, one light for each

automatic-sprinkler head, and one for each

detector, including the detector that actuated

the automatic operation of the deluge water valve. In view of the potential danger to human life from

toxic gases, automatic motion picture cameras

were set up to record the temperature and pressure

data, as well as the times of operation shown by

the indicator lights. The cameras, indicators,

manometers, potentiometers, and associated equipment were mounted in a truck trailer about 65 ft from the vault. The fact that the tubes from the

pressure taps to the manometers were of considerable length and that they were air-filled rather than liquid-filled undoubtedly affected the

pressure indications. Such conditions would cause amplitude and time lags of undetermined magnitude between indicated and actual pressures

during all fluctuations.

The drop in water pressure at the flow-control

equipment was a clear indication of the operation

of the automatic-sprinkler heads, hence no indi- cator lights were used for this purpose in the last 10 experiments. Because the hazardous conditions

anticipated had not developed in the first 13

experiments, cameras were not used to record

data in the last 10 experiments, but were used

for observations of the vault.

2.3. Experimental Programs

The investigation was composed of three experimental programs, the first of which consisted of the experiments in the 22-ft3 steel chamber and

the 128-ft3 vault on the grounds of the Bureau

in 1940-1941. This first program was designed

for the determination of maximum pressures, although observations were made of temperatures,

combustion characteristics, and duration. The

vents for the steel chamber were 3 by 3% in., 4 by 5 in., and 5 by 8 in., giving vent areas of

10, 20, and 40 in. 2

, respectively. The film load

varied from 20 to 282 lb, giving load-to-vent

ratios from 2.0 to 13.6 lb/in. 2. The vents for the

128-ft3 vault were 7% by 8 in. and lo%2 by 16%6

in., giving areas of 60 and 244.3 in. 2

, respectively.

The loads were 425 to 1,710 lb, to give load-to-vent

ratios of 7.1 and 7.0 lb/in. 2

. The specific information on vent, load, film containers, and some of

the observed data are given in table 2. The second program consisting of the first 13

experiments with skeleton racks in the Beltsville

vault, was designed to study not only the pressure

and combustion characteristics encountered in a

large vault but, especially, the effect of various

control measures on these characteristics and upon

the amount of film destroyed or damaged. Variations were made in the following items: Type and

size of vent, total film load, film containers and

racks, use of thermal insulating material in the

racks, type of sprinkler system, type of sprinkler

heads, and water flow rate. The variations made

in the first two items were designed to give the

desired variations in the ratio of film load to vent

area and in the ratio of film load to vault volume.

During and following each test, observations were made to determine: Pressures developed in vault,

temperatures in the vault, fume and flame

characteristics, operation of detectors and sprinklers, and extent of film damage. The film loads

ranged from 2,520 to 4,970 lb, the vent areas from

360 to 720 in. 2

, and the load-to-vent ratios from

5 to 7 lb/in. 2 approximately. A summary of the

data for each experiment, including load, rack

type, and other variables, is given in table 3, groups I through IV. The third program, which consisted of the final 10 experiments in the Beltsville vault, differed

from the second program in that compart men tod insulated film racks were used rather than the

skeleton, or open, racks. The film loads of 900

and 780 lb for the open-front anil closed-front

racks, respectively, were limited by the si/.es of the racks and the number available. However.
the vent, areas were reduced to keep the load-tovent ratio at 5 lb/in.2

. The load and other data

for each experiment are summarized in table 3, groups V through VIII. Following the completion of the third program,

a supplementary program was made on the

closed-front compartmented film racks for the

purpose of determining the means by which

ignition was established in cans of film adjacent

to the igniter can. The actual compartments

employed in these experiments had not been

involved in previous fire damage.

3. Results

Brief descriptions of the results from each ! program and the supplementary experiments on

the closed-front racks are given here. More

detailed summaries of the experimental logs are given in the appendix. Most of the data and

results have been condensed into tables. Table 1, giving a summary of the 1915 experiments by the

NFPA, is included here for comparison with the more recent results. Table 1 . Summary of data from NFPA experiments of 1915 a

Numbered experiments made in 3-ft 3 steel chamber; “vault” experiment made in 133-ft 5 masonry vault.

Figure 8. Discharge of gas and flames from 22-ft 3 steel chamber during experiment 8 at National Bureau of Standards.

a This table, based on a table and the text of reference [5] at end of this paper.

b Not contained in original table.

c Momentary pressure greater than 300 lb/in .

d No. 12 wire screen inside opening. Pressure dropped to 11 to 12 lb/in. 2 after screen was blown out.

e 25 lb in cans, 10 lb loose for torch.

f 50 lb in cans, 12 lb loose for torch.

s Vent area increased and load-to-vent ratio dropped when window sash blew out at about middle of experiment.

b 1,490 lb in cans, 250 lb on open reels, 160 lb loose.

Experiment Vent

area

Film load Load ratios b

Duration of combustion Maximum record- ed pressure Remarks Amount How contained Load to vent

area

Load to chamber volume

in.'1 lb lb/in. 2 lbIfI 3 min:sec lb/in 2

1 84. 54 50 10 open reels __ 0. 59 16.7 Not taken 0.0 Continuous clear flame of considerable magnitude, no smoke.

2 50. 27 50 ...do . . .99 16. 7 1:00 .0 Do.

3 19. 63 50 ___ do 2. 55 16. 7 1:00 1 Do.

4 9. 62 50 . ...do.. 5. 20 16. 7 1:03 5.5 flame, heavy white smoke.

5 7. 07 50 do 7. 07 16. 7 Not taken 7

6 4. 91 50 10. 18 16. 7 ... do ... 110

7 7. 07 100 20 open reels 14. 14 33.3 do c 20

8 9. 62 100 10. 40 33.3 1:09 .. 8.5 . 9 d 7. 07 50 7. 07 16. 7 d 25 .... 10 9. 62 3. 64 11. 7 at vent end of container and burned without ignit- ing film in cans.

11 9. 62 62 ...do f . 6. 44 20. 7 2:45. .. 9 12 7. 07 62 __ _do f 8.77 20. 7 Not taken 5.5 Cans partially blocked vent

opening, spacer not used.

I 285 1,900 (») 6. 67 14.3 2 to 3:00 0.5 Intensely hot flame over 70

i g 396 6 4. 80 ft long, 8 ft in diameter.

8
3.1. Program of 1940-1941 at the National

Bureau of Standards

The features observed in each experiment of

this program were similar in nature but not in magnitude to those observed in any other experiment of the program. This was true for the steel- chamber experiments and the concrete-vault

experiments. The only features that varied

significantly from experiment to experiment were

duration, intensity, and the recorded temperature

and pressure maxima. Ignition of the igniter roll quickly resulted in the production or liberation of

very large quantities of fumes that were ignited.

The rush of fumes and flames from the vent caused

a loud roar and carried the flames many feet from

the vent opening. Figures 8 and 9 show the steel chamber and concrete vault, respectively, during

the experiments. Most of the data obtained in each test is given in table 2. Table 2. Summary of data from NBS film-fire experiments of 1940-1941

Experi- ment Chamber volume

Vent Film load Recorded maxima

Approxi- mate

duration

of combustion Dimensions Are3

Containers Weight

total

Load ratios

Pressure Temperature Type Number Load to vent Load to volume

ft 3 in. in. 3 Lb Ibtin.t lb!fit Iblin.2 °F min: sec ! 1 99 3X3^3 in 4 20 2 0 0 91 785 1:25 la 22 3X3f$ 10 do. __ 4 20 2,0 .91 0.7 945 1:22 2 22 3X31$ 10 __do__ 10 48 4,8 2. 18 1. 7 1, 113 1:22 2a 22 3X31$ 10 do_ _ 10 46 4.6 2. 09 2.4 1,304 1:20

3 22 3X31$ 10 do__ 14 68 6.8 3.09 4.2 1,155 1:35

4 22 3X31$ 10 .. __do_ _ . 20 100 10.0 4.55 14.0 1,325 1:30

5 22 4X5 20 _do._ _ _ 20 100 5.0 4. 55 1.8 1,951 1:33

6 22 4X5 20 .do. - . ... 28 140 7.0 6.36 7.8 1, 325 1:25

7 22 4X5 20 Reels in .cans . _ 28 140 7.0 6. 36 2.2 1,029 2:20

8 22 5X8 » 25 do__ __ 56 280 11.2 12. 72 7.8 1,240 2:08

9 22 4X5 20 Cans, no reels 56 271 13.6 12.31 11.8 1,410 2:30

10 22 4X5 20 do__ 28 140 7.0 6. 36 2.9 1,240 2:05

11 22 4X5 20 _ ___do_ 72 140 7.0 6. 36 4.9 1, 586 1:30 12 22 4X5 20 do._ 28 140 7.0 6. 36 4.9 1,132 1:20 16 22 5X8 *37 do. __ _ 56 280 7.6 12. 72 9.3 2,187 2:05

17 22 5X8 40 do__ _ 61 282 7.0 12.81 11.5 1, 198 1:30

18 22 5X8 40 --- _do_ . 62 280 7.0 12. 72 4. 2 1, 113 2:46

19 22 5X8 40 do_ __ _ 53 275 6.9 12. 50 3.0 1,198 2:05 20 22 5X8 40 do_ _ 55 280 7.0 12.72 9.5 1.494 2:00

21 22 4X5 20 do_ — 47 141 7.0 6. 41 2.3 1,240 3:00

13 128 71$ X8 60 do_ 150 425 7.1 3. 32 .93 1,157 3:20

14 128 15J4X1634 * 188 _ __do_ __ 335 1,710 9. 1 13. 38 12.3 1,859 2:10

15 128 15J4X16H 244 __ _do _ 326 1,686 6.9 13. 18 12.4 1, 498 1:20

a Rectangular vent partially blocked by film or cans; effective area of opening reduced thereby.

Figure 9. Discharge of gas and flames from 128-ft 3 concrete chamber during experiment 14 at National />. <<: >
Table

3.

Summary

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data

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3.2. Beltsville Vault Program With Skeleton

Racks

The features observed, as well as the temperature and pressure data, varied appreciably from

experiment to experiment. Following ignition of

the igniter roll, fumes were produced and escaped

from within the vault in clouds that ranged from

light to very heavy. In 5 (9 through 13) of the

13 experiments, only 1 (Xo. 9) of which included

sprinkler protection, the fumes became ignited

outside the vault. In 1 of these 5 (No. 12) the

flame lengths reached 100 ft and film was thrown

over 350 ft, both distances horizontally. Flames

and ejected film from the vertical vent reached

estimated heights of 70 and 500 ft, respectively,

in yet another (No. 11). The differences from

experiment to experiment were brought about

largely by the use of different types of sprinklers

and regulation of the water-flow rate. No

sprinklers were used in 4 of the experiments (10

through 13). Table 3 contains much of the data

from the individual experiments, arranged in groups according to the type of sprinkler used.

The data from this program are given in groups I through IV. The recorded temperature maxima

may have been less than the true maxima due to the limited number of thermocouples and their

locations in the vault as well as the possibility of wetting of thermocouple junctions in sprinkler

discharges. However, the tabulated temperatures

give an indication of the order of magnitude that

might be expected. Discharges of dense fumes

and flames from the vertical and horizontal vents

are shown in figures 10 through 14.

3.3. Beltsville Vault Program with Compartmented Racks

The features observed in the individual experiments with compartmentecl racks varied some- what from experiment to experiment. In only 1 of the 10 experiments were the fumes ignited.

The fumes that escaped from the vault in the

other 9 experiments were of light or moderate

intensity. Table 3 contains much of the data

from the individual experiments. The amount

of film damaged was very low in all but one experiment, No. 23, in which open-front compartmented

racks were employed without sprinkler protection.

With the closed-front racks there was limited

spread of ignition from compartment to compartment, but almost exclusively in a downward

direction from the igniter roll.

11
Figure 10. Discharge of dense fumes from Beltsville vault during experiment 2, vent cover in place on vertical vent. Figure 11. Discharge of flames about 60 ft above vertical vent after vent cover blown off, experiment 11 in Beltsville vault.

Figure 12. Discharge of very dense fumes from horizontal vent just as ignition of fumes initiated at vent, experiment 9.

12
Figure 13. Appearance during experiment 9 about 10 sec after that in figure 11, showing that dense fumes were almost completely burned.

Figure 14. Violent discharge of flames, film cans, and film from horizontal vent during experimt nt 1

1

13
3.4. Supplementary Film Rack Program

The closed-front compartmented film racks had

been designed with the intent that they should be

capable of containing the fire damage to a single

compartment—that of the igniter can—without

the aid of sprinklers. However, they failed to do

this (experiments 21 and 22), and several supplementary experiments were made in which these

racks were set outside the vault so that the

mechanics of the flame spread could be observed.

A thermocouple junction was placed beneath the can in the compartment above the igniter and

another on the top of the can below. As in the

vault experiments, flame spread was in a downward direction. As the film in the igniter can

burned, the door to the compartment below

opened slightly, followed shortly by ignition of the film below. This chain of ignition (film

above igniting that below) repeated several times

and then stopped for no apparent reason. The

temperatures measured on the cans below the

igniters were consistently low which indicated

that ignition of the other film was caused by some means other than heat transfer through the

insulated shelves, probably by flame penetration

from above.

4. Discussion

The storage of nitrocellulose-type film presents

greater hazard than that of other films. The

amount of film destroyed as the result of a

nitrocellulose-film fire in a storage facility, the

pressures developed, and the ensuing hazards to

life and property are all dependent on the total amount of film in the vault or chamber, the ease with which ignition spreads, the size and type of

the vent or vents, the density of loading, and the

effectiveness of various fire-control devices

employed.

4.1. Pressure-Load Relationship

The 1915 experiments by the NFPA, as re- ported by Stewart [5], led to the conclusion that

the maximum loading density of film on bare

reels that did not produce prohibitively dangerous

pressure was approximately 7 lb/in. 2 of vent, and

to the recommendation that actual loadings be

kept somewhat lower to be safe. Stewart gave

a plot of part of his data and a curve through it but did not present a formula to express this curve. Various formulas have been suggested

to express the relationship between pressure and

film load.

Figure 15 is a plot of the data obtained from

experiments with film on bare reels or loose film. It includes data from NBS experiments and

Stewart’s [5] experiments except two of the latter

in which extreme pressures of short duration were

pe

ra

ar

tli

ank

It

wl

to

an

pr

lie

ca

ev

tli

I'd

rt: w

or

ra Figure 15 . Pressure as function of load-to-vent ratio for film not in containers.

attributed to temporary reduction of vent area through partial obstruction by film. The curves were plotted from formulas derived by least- squares analyses of the data. The solid curve

represents the relationship

P=0.135 Zv

2 - 18

I derived from data obtained with the load-tovolume ratio of 16.7 lb/ft3

, indicated by the circles] The dashed curve represents the relationship

apK

St

Cl’

P

Ik

kj

si

do

01

til

01

cs

ra P=0.033 iv

2 - 59

derived from data obtained with the loacl-to-volume

ratio in the range 2.2 to 4.6 lb/ft3

, indicated by !" squares. The triangles indicate data from twt

experiments in which the load-to-volume ratic,!

'

1 was 33.3 lb/ft3

. In each formula, P is pressure

in pounds per square inch, and Lv is load-to-veni

ratio in pounds per square inch.

It should be borne in mind that the formulae

and curves are intended to apply to only those i cases in which the cellulose nitrate film is loose or on open reels, is stored without automatic

sprinklers or equivalent protection, and is so placed in the vault or chamber that the ven

will not be even partially obstructed at any time

The formulas do not include any extra margin o

factor of safety.

i

14
4.2. Effect of Film Containers

Two of the several factors that determine the

peak pressure in a film vault during a fire are the

rates at which the gaseous combustion products

are generated and at which they escape from the

chamber. The latter is related to the vent size and the former to the rate at which the film load

burns. The individual reel, roll, or unit of film

burns very rapidly. However, the ease with

which the ignition spreads from roll to roll will control the over-all rate at which the film burns

and gases are liberated. Reduction of thisrate will produce a reduction in pressure within the chamber. Although none of the film cans and shipping

cases used in these experiments prevented the

eventual destruction of the film they contained,

they did retard the spread of combustion and

reduce the pressures observed. The experimental

results of group I indicated that the ICC cases were somewhat superior to the metal cans, round

or square.

4.3.

Effect of Film Racks

The results obtained from the use of skeleton

racks in various experiments without sprinklers

appeared to indicate that the racks alone were

not of significant value in reducing the extent or severity of the fire, or the gas pressure. However, these racks provided spaces between cans or groups of cans and a more uniform distribution of them throughout the vault than would be obtained

by stacking the film can-on-can on the floor. Rack

storage permits air circulation, which lessens the

danger of self-heating and self-ignition in storage over extended periods of time.

With sprinklers the skeleton racks were effec- tive in positioning the cans in a way that per- mitted the water to get to at least part of the

exterior of each can. The horizontal-storage-type

racks appeared to have been more effective because

water was retained on the flat tops of the film

containers.

The performance of the insulated open-front

compartmented film racks when used with sprinklers was appreciably better than that of the

skeleton racks with sprinklers. The pressures were of the same order of magnitude as those in the experiments with skeleton racks and sprinklers,

but the amount of film destroyed was significantly

lower. When used without any sprinklers, the

open-front compartmented racks failed to prevent

the complete destruction of all the film. The results obtained from experiments with the

closed-front racks, although not fully satisfactory, were the most encouraging of all. In experiments

19 and 20 with sprinklers, only the ignitor cans were destroyed, and only 1 and 2 adjacent cans of

film, respectively, were slightly damaged by heat.

These cans were either immediately above or below the igniter cans. The remainder of the

film in the racks was not affected. In the experiments without sprinklers (No. 21 and 22), 5 and 8 cans of film were destroyed, respectively. In each

instance the flame spread was vertical only, there

being no spread sidewise or across the aisle. Except for one, all the cans in which film was

destroyed were below the igniter can. This singularity of direction of flame spread would indicate a single or relatively small number of defects in the design or manufacture of this type of film rack.

The only routes through which flames could have

passed from one compartment to another were the

clearances between parts of the door hinge and

thin gaps between the shelf and the rack walls,

which were observed in some compartments to have been in intimate contact only at the spotwelds by which they were joined. The preponderance of downward spread appeared due to deflec- tion of flames in that direction by the partially

open door and, possibly, by the lip of the film-can

lid. The most logical explanation for the fact that the spread of ignition w

T as stopped before

reaching the bottom of the rack seems to be that a shelf was reached that fit tightly enough to prevent the penetration of sufficient flame to the

compartment below to ignite the can of film

therein.

4.4.

Effect of Sprinklers

With the skeleton racks, the amount of film

destroyed when protected by directed-spray

sprinklers was less than when protected by standard sprinklers in spite of the fact that the standard

sprinklers used as much as twice the amount of water per head as the directed-spray heads. In

4 experiments (3 through 6) in which the former was used, the percentage of film destroyed ranged

from 2.2 to 14.2, average 7.7. In 2 experiments

(1 and 2) of the standard sprinklers with identical

racks and cans, and essentially equal loads, the

percentages were 27.8 and 37.1. The high (92.9)

percentage of film destroyed in experiment 9. with

sprinklers, appears to have been attributable to other factors, such as load density and can position, rather than to the sprinklers. The sprinklers

appeared to have been effective in preventing pres- sures as high as the 3.0 lb/in.-’ observed in experiment 12, without sprinklers, which was very

similar to 9 in other respects.

Although the film destruction in experiments

with sprinklers and skeleton racks was not eonfined to the igniter can, neither was it complete in any such experiment. The range of percentage

destroyed was from 2.2 to 92.9. average 24.

S

However, in experiments without sprinklers, the

burnout was less than total only with the closedfront compartmented insulated iilm racks
4.5. Effectiveness of Detectors and Actuators

The fusible-link sprinkler heads operated in as

little as 26 sec after the current was applied to the

igniter. However, in 8 of the 10 experiments in which they were used, from one to all of the fusible

links did not separate. The vault temperatures in one of these experiments did not exceed 150° F

because the igniter roll did not flame but merely

decomposed rapidly, without involving any other

rolls. In the other experiments with fusible-link

sprinklers, the maximum recorded temperatures

ranged from 666° to 1,738° F and yet some

sprinklers did not operate. Factors that probably

affected the behavior of the fusible links were (1) the local variations of temperatures within the

vault, which in experiment 3, with sprinklers, were

observed to have been as great at 1,685 deg F

between thermocouples that were about 7 ft apart

and at different levels, and (2) the spray of water

from operating sprinklers that may have fallen on

and cooled the fusible elements of others not vet in operation. Also, this behavior may be attributed

in part to the very short duration, often a few

seconds, of the high temperatures. Although

neither the mass nor the specific heat of a fusible

link was high, there would have been some short

time required for transfer of sufficient heat to the

link to raise its temperature to the fusion point.

There was no indication that the failure of any

sprinkler to operate could be attributed to defective materials or manufacture.

The temperature rate-of-rise detectors, in conjunction with the deluge valve and open sprinklers,

operated in from 18 to 33 sec and, in the experiments in which the detectors merely gave a signal

for comparison with other detectors, operated, or “alarmed”, in from 10 to 45 sec, averaging 21 sec

for all experiments.

The smoke detector used in 2 experiments (14

and 15) gave signals at 20 and 23 sec, respectively,

and the smoke meter, which operated in 2 of the

3 experiments (21, 22, and 23) in which it was used,

reached full scale (indicating a 50-percent loss of

light transmission) at 14 sec in each instance. In

the third experiment the intake was obstructed,

thereby preventing fumes from entering.

The deluge valve was operated manually or by

the rate-of-rise detector. It was observed that

4 sec elapsed between the detector signal and the

start of water discharge from the sprinkler heads.

From the data of those experiments in which more than one type of detector or detector- actuator were used, the following comparisons were obtained: (1) The period of time for the rateof-rise detector to operate was 36 to 78 percent,

average 66, of that for the first fusible-link sprinkler to operate in the same experiment; (2) the

period of time for the smoke detector to signal was

70 and 83 percent of that for the rate-of-rise

detector in two experiments; (3) the period of time for the smoke meter to reach full-scale indication was 64 and 93 percent of that for the

rate-of-rise detector to signal.

4.6. Summary |

c(

L

|| The results obtained from the two programs in the Beltsville vault showed the desirability of - sprinkler protection with the types of racks

employed. With the skeleton racks the directedspray system appeared to be superior to the

standard system. With sprinkler protection, the f results obtained indicated the superiority of the

compartmented insulated racks over the skeleton

racks. Of the compartmented racks, the closedfront type was better than the open-front type, j

,, specially in experiments without sprinkler protection (group VIII).

g

5. Conclusions

t a The conclusions are based not only upon the j

(, results of the experiments but also upon considerations of general safety and the protection of nearby B property. Some of these are concerned with the , t protection and preservation of the film in a vaidt t wherein a fire may start; the others with the

prevention of fires or of their spread beyond the

vault.

It was concluded from the results obtained from j!

I

1 a limited number of experiments in a vault of about one-lialf the maximum size allowed in generally accepted standards that: i 1. Each vault for the storage of nitrocellulose

film should be provided with a vent of sufficient area to prevent the development of dangerously

high pressures during a fire. I 2. With closed-front compartmented racks and !i a film load of 5 lb/in. 2 of vent area, pressures as highas0.25lb/in. 2 wereobserved. Vaults, including 1 doors, should be designed for such pressure, when

they are to be equipped with such racks.

3. If open-front compartmented or skeleton film

racks are employed and the film load kept at or below 5 lb/in. 2 of vent area, pressures as high as 1.0

lb/in. 2 may be developed during a fire, and the \ should be designed accordingly.

4. Temperatures observed were sufficiently high ! that only masonry or other equally noncombustible I construction should be used for film vaults.

5. The film should be stored in close-fitting metal , cans, or containers giving equal protection, placed on racks within the vault.

6. The film may be completely destroyed, unless

the vault is equipped with closed-front insulated

compartmented film racks or adequate automaticsprinkler protection. The closed-front compartmented racks employed should be so constructed to prevent the spread of fire from one compartment,

to another. By adequate sprinkler protection is meant one sprinkler head, preferably of the

clirected-spray type, for each 60 ft3 of vault.

7. The minimum destruction of film was obtained by the use of closed-front compartmented | racks and automatic sprinklers of the directedspray type.

16
It was further concluded from the data and from

considerations of safety and protection of property

that:

8. The film in a vault or group of vaults represents a hazard to the surroundings so that vaults

should be located where they may be expected to remain isolated from valuable property.

9. The vaults used should be equipped with

vertical vents or means to deflect the discharge

hi a vertical direction. The minimum dimension

of the vent should be greater than the maximum

dimension of the film containers to be stored. The

throat edges of the vent should be beveled or funneled at approximately a 45° angle to prevent

film containers sticking in and partially reducing

the vent opening.

10. Any cover on the vent should be so designed

and constructed that it will open before the in- ternal pressure rises to 0.25 lb/in. 2

. 11. Any device such as electric or heating equipment that might ignite film should be placed and

enclosed in such a manner that contact with film

is not possible.

6. References

[1] J. W. Cummings, A. C. Hutton, and H. Silfin, Spontaneous ignition of decomposing cellulose nitrate film,

J. Soc. Motion (Picture and Television Engrs. 54, No. 3 (March 1950).

[2] R. A. Mitchell, The 35-mm projection positive film, Intern. Projectionist XXV, No. 2 (Feb. 1950).

[3] D. W. Wood, Celluloid dangers with some suggestions,

Red Books of British Fire Prevention Committee—

No. 179 (1913).

[4] Fox film storage fire, NFPA Quart. 31 , No. 2 (Oct.

1937).

[5] F. J. T. Stewart, Fire tests of nitrocellulose motion

picture films, NFPA Quart 9, No. 1 (July 1915).

[6] Standards of the National Board of Fire Underwriters

for storage and handling of nitrocellulose motion

picture film, NBFU Pamphlet No. 40.

7. Appendix. Observation Details

The logs of observations made during and after each experiment are summarized. Where the observed behaviors within a program were similar,

and the number and range of variables were

limited, the logs are combined into a general dei scrip tion.

7.1. Program of 1940-1941 at the National

Bureau of Standards

The features observed in all the steel-chamber

I experiments were similar, differing only in degree

and elapsed time. The first flames or fumes were

observed about 10 sec after the igniter current

' was turned on. The discharge of flames and

fumes, which indicated rapid combustion, continued for periods of from 80 to 200 sec and

reached its peak at from 40 to 105 sec. The

discharge was marked by flames that reached

lengths of 20 to 80 ft (fig. 7), a loud roar, and

occasional blasts, the latter apparently caused by

explosions of individual film cans or variations in

pressure resulting from temporary obstructions

of the vents. The rush of gases was so rapid in some instances that the flames were extinguished.

The maximum recorded temperatures iri the

chamber ranged from about 785° to 2,190° F, and

the maximum recorded pressures ranged from. 0.7 to 14.0 lb/in.2

. In experiment 11, the lid of a film can was blown through the vent. In experiment

12, with ignition from a fire outside the vent, the

first flames from within the chamber were observed at 9 min 30 sec, but the behavior thereafter

followed the above pattern.

The features observed in the 128-ft3 vault

experiments were similar to those in the steel- chamber experiments but of greater magnitude in some respects. The first flames issued from the

vent about 16 sec after ignition. The discharge

reached its peak at about 60 sec and had a duration of about 130 sec. The flames reached lengths

of 50 to 100 ft or more (fig. 8), and film and cans were blown out the vents to distances up to 300 ft. An estimated 100 lb of film was blown out in experiment 14. In experiment 15, a tree 50 ft from the vent and several feet from the center of the flame path was scorched from the ground up

to a height of about 22 ft. The maximum re- corded temperatures were 1,160° to 1,860° F, and

the maximum recorded pressures were from 0.93

to 12.4 lb/in. 2

. In 2 of the steel-chamber experiments, 8 and 16. and 1 of the concrete-vault experiments, Xo. 14,

the vents were partially obstructed by film or

film cans. This resulted in lower vent areas and

higher load-to-vent ratios than planned for the

particular experiments.

7.2. Beltsville Vault Program with Skeleton

Racks

Because of the increased number of variables

introduced in these experiments, as compared with

those at NBS in 1940-1941, the results of each

experiment are summarized individually. They

are not given in numerical order, but are grouped

by related items among the variables. The vertical vent was used in all experiments except 9 and 12, as noted.

Group /. The following are summaries of results

of the experiments in which six 165° F standard

sprinkler heads were employed:

Experiment 1. Loaded in horizontal-storage skeleton racks to provide load-to-vent ratio of 5 lb/in.2

, water flow

set for 15 gpm per head. At 20 sec, rate-of-rise indications

for simulated door-trip and deluge-valve operations; 27

see, first sprinkler operated; 45 sec, blast inside vault: 50 sec, fumes from vent; l min 55 sec, dense brown fumes

from vent, cover was lifted periodically (indicating pres- sure of about 0.1 lb/in.2 ), relieving pressure; 4 min. fumes

diminished; 10 min, water turned off. Actual water flow 15.0 gpm per head, six operated.

Apparent duration of combustion 7 min. Automatic camera failed to record pressures but visual observation ot about 0.2 lb/in. 2 noted. Maximum recorded temperature

1,274° F (090° C). Only one-third as many cans of flint burned out in rack containing igniter can as in opposite

rack.

17
Experiment 2. Loaded in horizontal-storage skeleton

racks to provide load-to-vent ratio of 5 lb/in. 2

, water flow

set for 22.5 gpm per head. At 20 sec, first fumes; 45 sec, rate-of-rise indication and light blast; 46 sec, door-trip

signal received; 1 min, first sprinkler operated; 4 min 30

sec, very dense fumes; 7 min, fumes nearly ceased; 10 min, water off. Water valve reopened at 10 min 22 sec, shut

finally at 15 min 30 sec. Actual water flow 25.2 gpm per head, five heads operated.

Apparent duration of combustion 7 min, maximum re- corded pressure 0.15 lb/in.2

. Only about half as many

cans of film burned out in rack containing the igniter can

as in opposite rack. The discharge of fumes, shown in figure 9, was very dense. Experiment 7. Loaded in vertical-storage skeleton pipe

racks to provide load-to-vent ratio of 5 lb/in. 2 with 1,000- and 2,000-ft reels in ICC cases, water flow set for 20 gpm

per head. At 23 sec, first fumes; 25 sec, deluge valve

operated, door-trip signal received; 35 sec, sprinklers

operated; 45 sec, dense fumes from vent; 2 min 30 sec, all fumes ceased; 10 min, water off. Actual water flow rate 26.0 gpm per head, four heads

operated. Apparent duration of combustion 2 min. Maximum recorded pressure 0.15 lb/in. 2

. On the average, the fumes were of moderate density. The only films burned out other than those in the ICC case containing

the igniter can were in two cases in the opposite rack and

below the level of the igniter can. Maximum recorded temperature about 1,521° F (827° C). Experiment 8. Loaded in vertical-storage skeleton pipe racks to provide load-to-vent ratio of 6 lb/in. 2 with 1,000- and 2,000-ft reels in ICC cases, w'ater flow" set for 20 gpm

per head. At 19 sec, first fumes; 21 sec, deluge valve

operated, door-trip signal received; 26 sec, sprinklers

operated; 35 sec, voluminous dense fumes from vent; 2 min 10 sec, fumes ceased; 10 min, w'ater off; 12 min 20

sec, w'ater back on; off again at 14 min 10 sec. Actual water flow 23.9 gpm per head, five operated.

Apparent duration of combustion 2 min. Maximum

recorded pressure 0.18 lb/in. 2

. On the average, the fumes

w'ere light. Flame and some film came out the vault scupper early in the test. Maximum recorded temperature 1,409° F (765° C). Approximately 15 percent of the

film that burned out, including the igniter film, wr as in the rack containing the igniter can. Experiment 9. Loaded in vertical-storage skeleton pipe

racks to provide load-to-vent- ratio of 7 lb/in. 2

, horizontal

vent, w'ater flow" set for 15 gpm per head. First fumes,

door-trip signal and deluge-valve signal received all at 23

sec; sprinklers operated at 29 sec; 40 sec, dense fumes from

vent; 48 sec, more sprinkler heads opened; 1 min 30 sec, film ash from vent with fumes; 2 min 15 sec, fumes ignited; 2 min 30 sec, flame length 50 ft; 3 min 30 sec, flames licking up back of vault stack; 6 min, 10 ft flames; 10 min, 15 ft flames ; 14 min, area of concrete about 3-ft diameter on back

of vault stack spalled ; 16 min 30 sec, w'ater supply increased

to maximum rate ; 38 min, water flow reduced to initial rate. Actual water flow" 14.8 gpm per head, until increased to 24.3 gpm per head at 16 min 30 sec, six heads operated.

All but about 7 percent of the film w"as burned out. Nearly

all of the unburned film was in the bottom racks on the side opposite the igniter can. The fire could not be controlled by the initial wr ater flow" and only after several minutes, if at all, by the maximum flow" obtainable. However, the duration of combustion indicated that the sprinklers retarded the rate of combustion. The maximum recorded temperature and pressure w"ere 1,562° F (850° C) and 0.22

lb/in.2

, respectively. Figure 11 show's the cloud of fumes

just as their ignition started at the vent. Group II. The following is a summary of the

experiment in which six 165° F spray-type sprinkler heads were used in a directed-spray system.

The vertical vent w

T as employed.

Experiment 5. Loaded in horizontal-storage skeleton racks to provide load-to-vent ratio of 5 lb/in. 2

, water flow

set for 10 gpm per head. Gypsum board or asbestos millboard wr as used to insulate top, bottom, rear, and each

side of each can in the central three sections of racks on

each side. At 15 sec, first fumes; 20 sec, deluge-valve 1 operation simulated; 21 sec, door-trip signal received; 32

sec, first sprinkler operated; 3 min 9 sec, fumes ceased;

10 min, w'ater off; 11 min, on again; off at 15 min 30 sec. Actual water flow 11.4 gpm per head, three operated.

Apparent duration of combustion 3 min. Maximum

recorded pressure 0.12 lb/in. 2

. Fumes were heavy during

first 3 min but average only moderate. Maximum re1 corded temperature 1,553° F (845° C). The can immediately opposite to the igniter can was left partly open with a

loose end of film outside, which served as a secondary

igniter. The amount of film burned out adjacent to this secondary igniter was nearly twice that adjacent to the primary igniter. One-fifth of the total amount burned out was in an end rack. Group III. The data in this group are from

those experiments in which six open-spray sprinkler

heads wr ere used. They w'ere operated by an

automatic deluge valve, which was actuated by a

rate-of-rise detector. The vertical vent w

r as used.

Experiment 3. Loaded in horizontal-storage skeleton racks to provide load-to-vent ratio of 5 lb/in. 2

, water flow , set for 15 gpm per head. At 20 sec, first fumes; 22 sec,

| sprinkler deluge valve operated; 45 sec, voluminous fumes; t

I min 30 sec, pressure 0.15 lb/in. 2 and greater fumes; 3 min

45 sec, fumes nearly ceased; 10 min, water off. Actual w'ater flow 14.7 gpm per head. Apparent ) duration of combustion 6 min, automatic camera failed, t but visually observed maximum pressure was 0.15 lb/in.2

, All film in same vertical stack as igniter can burned jf out. The only other reels of film burned out were in the » stack on either side of the igniter can. Maximum re- >. corded temperature 1,850° F (1,010° C). Experiment 4- Loaded in horizontal-storage skeleton ' racks to provide load-to-vent ratio of 5 lb/in. 2

. Asbestos 9 millboard, bfi in. thick, w'as placed to insulate the top, bottom, sides, and rear of each film can in the stack j) containing the igniter can and in the stack on each side of L

it. Water flow set for 15 gpm per head. At 10 sec, I

1 first fumes; 18 sec, deluge valve operated and door-trip

signal received; 1 min 10 sec, fumes out vent; 10 min, still 3 fuming steadily; 16 min, fumes ceased; 16 min 30 sec, door

opened; 18 min 10 sec, water off. Actual water flow" 14.8 gpm per head. Apparent . duration of combustion about 16 min, maximum recorded

pressure 0.03 lb/in. 2

, maximum recorded temperature 676° ' F (358° C). On the average, fumes were moderately light. ! The only' film burned out, other than the igniter can, was a

f full stack adjacent to that immediately opposite the igniter can.Experiment 6. Loaded in horizontal-storage skeleton

j racks to provide load-to-vent ratio of 5 lb/in.2

; jKe-in. !, asbestos millboard used to insulate the top, bottom, sides,

| and rear of each can in the stack containing the igniter can and in the stack on each side of it. The three central ,, stacks immediately opposite w'ere similarly insulated with , ^i6-in. gypsum board. Water flow set for 10 gpm per j- head. At 19 sec, deluge valve operated and door-trip

signal received; 45 sec, first fumes; 1 min 45 sec, steady

fuming; 2 min 45 sec, fuming ceased; 10 min, water off; on again at 11 min, off at 15 min 38 sec.

j Actual w'ater flow" 10.2 gpm per head, maximum recorded i» s: pressure 0.10 lb/in. 2

, maximum recorded temperature : 1,591° F (866° C). Fumes were of light to moderate : intensity, short duration. Nearly all the burned out film j was in the rack opposite the igniter. However, the total : amount was small. Group IV. The following are summaries of the

observations from experiments without sprinklers. ; However, the supply pipes remained in the vault

and water was circulated through them and dis- | charged outside the vault to protect the pipes

18
, from the high temperatures anticipated. The

deluge and door-trip signal indicators were not connected.

Experiment 10. Loaded in horizontal-storage skeleton racks to provide load-to-vent ratio of 5 lb/in. 2

. At 20 sec,

first fumes; 42 sec, dense fumes from around door and both

vents; 55 sec, vertical vent cover blown off; 1 min 4 sec, fumes from stack burst into flame; 1 min 30 sec, 50 ft flames from stack; 2 min 20 sec, flame length down to 10

ft: 2 min 35 sec, burst of flames at least 50 ft high; 3 min,

only slight fumes, no flames.

Tire film in the vault was completely destroyed. At

the height of activity, a few film cans were blown out the

stack to an estimated height of 100 ft. The maximum

recorded temperature was 2,134° F (1,168° C). The

temperature indicated by the highest reading thermocouple was over 1,832° F (1,000° C) for a period of 1 min 44 sec. The maximum recorded pressure was 1.01 lb/in.2 . In

addition to the flames from the stack, flames issued around

the door late in the period of combustion. After the exper- iment, the door was found to have been warped. The

. apparent duration of combustion was about 2 min 30 sec. Experiment 11. Loaded in horizontal-storage skeleton

racks to provide load-to-vent ratio of 7 lb/in. 2

. At 17 sec,

first fumes, 35 sec, very dense fumes; 1 min, vent cover blown off and fumes burst into flames; 1 min 12 sec, mercury manometers blown out; 1 min 30 sec, pressure re- duced; 2 min 10 sec, only slight flames.

All the film was destroyed. The maximum recorded temperature was 2,088° F (1,142° C.) The gage pressure

; rose from near zero to a maximum of 18.3 lb/in. 2 in a few

seconds. The manometers were blown out, the maximum

being read from a gage. The high pressure was believed due in part to possible jamming of film cans in the vent

stack. The maximum flame height was estimated at 70 ft above the top of the stack, somewhat higher than

shown in figure 10. Film was blown from the stack to an

estimated height of about 500 ft. Experiment 13. Loaded in ICC shipping cases on verti- cal-storage racks to provide load-to-vent ratio of 7 lb/in.2

. At 35 sec, first fumes followed immediately by vent lid being blown off; 50 sec, fumes from vent in puffs; 1 min 4

sec, fumes ignited; 1 min 30 sec, 20 ft flames; 50 ft or greater

flames from 1 min 50 sec to 2 min 45 sec; 4 min, 15 ft flames; 4 min 55 sec, sound of burst heard; 6 min 20 sec,

all flaming ceased.

All the film was destroyed. However, the insulated ICC cases retarded the rate at which the film burned. The

combustion continued for approximately 6 min, much

I longer than in the other experiments without sprinklers.

The maximum recorded pressure was only 0.35 lb/in. 2

, but

this pressure continued for a longer period than previous

! maxima.

Experiment 12. Loaded in vertical-storage skeleton pipe

j racks to provide load-to-vent ratio of 7 lb/in. 2 and load-to-

| volume ratio of 13.32 lb/ft3

, horizontal vent. At 30 sec,

i first fum.es; 35 sec, first flames; 40 sec, fumes from around

i cover of vertical vent; 1 min 10 sec, flame from horizontal vent 75 ft long and flame from around door and cover on

vertical vent; 1 min 15 sec, flames from horizontal vent

100 ft long; 1 min 20 sec, film being blown from vent; 1 min

40 sec, flames only 50 ft long; 2 min, only 25 ft; 3 min 15

, sec, flames almost ceased.

All the film in the vault was burned. Film was blown

through the vent to distances up to 350 ft from the vault and flame length was at least 100 ft. The maximum

recorded pressure was 3.0 lb/in. 2 and the maximum

recorded temperature exceeded 2,192° F (1,200° C), the

full scale of the potentiometer, for a period of 40 sec. Figure 13 shows the discharge of flames and film during

: this experiment.

7.3 Beltsville Vault Program with Compartmented Racks

This portion of the investigation was composed

of the film-vault experiments in which special compartmented film racks were used. These racks were described in 2.2 a. They held much less film than the skeleton racks. Therefore, the load to vault-volume ratios were low. However, the vent

area was adjusted to give a load-to-vent ratio of 5

lb/in. 2 in each experiment. The vertical vent was

used throughout. The results of the experiments

are given in groups rather than in numerical order.

As stated in section 2, these groups were determined on the basis of the variables, primarily the

type of sprinkler used. In order to avoid possible

confusion, the group numbers are in continuation

of those in 2. Group V. The following are summaries of the

experiments in which six 165° F standard sprinkler

heads were installed.

Experiment 18. Loaded in open-front compartmented

racks. Water flow set for 15 gpm per head. At 16 sec, deluge-valve signal received; 32 sec, sprinklers operated: 43 sec, first fumes observed, 1 min, dense fumes; 2 min. very little fumes; 6 min 5 sec, water off. Actual water flow 15.6 gpm per head, two heads operated. Maximum recorded pressure and temperature

0.06 lb/in. 2 and 1,321° F (716° C), respectively. Apparent

duration of combustion less than 2 min. No film other than that in the igniter can burned out. Experiment 20. Loaded in closed-front compartmented

racks. Water flow set for 15 gpm per head. At 32 sec,

first fumes; 35 sec, deluge-valve signal received; 51 sec, sprinklers operated; 1 min 30 sec, very light fumes from

vent and around door; 3 min, fumes from vent only; 5 min

1 3 sec, water off. Actual water flow 16.3 gpm per head, two heads operated. Maximum recorded pressure and temperature

0.07 lb/in. 2 and 666° F (352° C), respectively. Apparent

duration of combustion about 3 min. Only the igniter

roll burned. The reel immediately above was slightly

damaged by heat as were the doors of a few compartments

below. Despite the closed fronts, considerable water

entered the compartments and remained there, but none

got inside any of the film cans. Group VI. The following are summaries of ex- periments in which six 165° F sprav-type sprinkler

heads were installed in a directed-spray system.

Experiment 16. Loaded in open-front compartmented

racks. Water-flow valve set full open. At 25 sec. first fumes; 35 sec, heavy fumes from around door; 45 sec, light fumes from vent; 3 min, light steady fumes from

around door; 8 min, fumes decreasing. For some unknown reason the “igniter” roll of film did not fully ignite but went into a rapid decomposition, which

did not cause any recorded vault pressure or heat damage.

The maximum recorded temperature of 147° F (64° C)

would not be high enough to cause any of the sprinklers to

operate.

Experiment 17. Loaded in open-front compartmented

racks. Water-flow valve set full open. This was a repeat

of experiment 16 with a new igniter roll. At 10 sec. deluge-valve signal received; 28 sec, first fumes and

sprinkler operation; 37 sec, dense fumes from vent and

door; 2 min 15 sec, decreased fumes; 3 min, practically no

fumes; 6 min 5 sec, water off. Actual water flow 17.6 gpm per head, four operated.

Maximum recorded pressure and temperature 0.13 lb in.-' and 1,738° F (948° C), respectively. Apparent duration

of combustion between 2 and 3 min. About one-fourth

of the film in the same rack as the igniter can was slightly

damaged by heat. However, one-third of the film in the

opposite rack was either burned out or severely damaged

by heat.

19
Group VII. Tlie following are summaries of experiments in which six open spray heads were

used in a directed system. The deluge valve for the sprinklers was operated manually following a

signal caused by the operation of a rate-of-rise

detector or smoke detector.

Experiment 14- Loaded in open-front compartmented

racks. Water flow set for 15 gpm per head, to be started on rate-of-rise signal. At 20 sec, first fumes; 23 sec, smoke-detector signal received; 33 sec, deluge valve operated following rate-of-rise signal; 1 min, most of fumes

coming from door; 5 min 13 sec, water olf. Actual water flow 14.7 gpm per head. Maximum re- corded pressure and temperature 0.06 lb/in. 2 and 536° F

(280° C), respectively. The igniter roll was the only film destroyed. Three other rolls were slightly damaged by

heat or water. Experiment 15. Loaded in open-front compartmented

racks. Water flow set for 15 gpm per head. Deluge valve

to be operated following smoke-detector signal. At 20

sec, flames, fumes, and smoke-detector signal; 24 sec, deluge valve operated, rate-of-rise signal received; 1 min,

heavy fumes from around door as vent cover lifted

;

5 min 3 sec, water off. Actual water flow 15.1 gpm head. Maximum recorded

pressure and temperature 0.10 lb/in. 2 and 1,724° F (940°

C), respectively. Seven rolls of film were burned out,

six others were slightly damaged by heat in the rack

opposite the igniter can, and seven were slightly damaged

by heat and three by water in the same rack as the igniter can.Experiment 19. Loaded in closed-front, compartmented

racks. Water flow set for 15 gpm per head. The deluge

valve was to be operated following rate-of-rise signal.

No smoke detector. At 11 sec, sprinklers on; 20 sec, fumes from door; 1 min, slight fumes from vent; 2 min,

very slight fumes from door; 3 min, water off. Actual water flow 15.2 gpm per head. No recordable

pressure, maximum recorded temperature 1,087° F

(586° C). The igniter film was burned out, but the film

in the compartments immediately above and below were

only slightly damaged by heat. No other film was

damaged.

Group VIII. No sprinklers were installed in the vault for these experiments. However, a rate- | of-rise detector was installed to operate a signal,

and a smoke meter was installed to determine the

fume-density characteristics inside the vault. Experiment 21. Loaded in closed-front, compartmented | racks. At. 14 sec, smoke meter off scale (over 50-percent reduction of light transmission); 18 sec, flash of flame; 22 sec, rate-of-rise detector signal, and vent cover dis- placed; 1 min 10 sec, first fumes outside vault; 2 min,

fumes from vent and door; 14 min, continued fumes from

door; 20 min, slight fumes from vent. Four cans of film below the igniter can were burned out. The fifth below' and the first, above the igniter can were

slightly damaged by heat.. None of the others was affected. The maximum recorded pressure and temperature were

0.09 lb/in. 2 and 968° F (520° C), respectively.

Experiment 22. Loaded in closed-front, compartmented

racks. At 15 sec, flash of flame; 18 sec, rate-of-rise signal;

1 min 25 sec, dense fumes from vent; 3 min 50 sec, vent i cover blown off by explosion with flash of flame; 7 min,

steady fumes; 18 min, very light fumes. The smoke meter did not operate because of a clogged

filter in the sampling line. The can of film immediately

above the igniter can and the six below it, were burned out. The seventh below was slightly damaged by heat, but I no others were affected. Maximum recorded pressure and temperature were 0.25 lb/in. 2 and 1,256° F (680° C), respectively.

Experiment 28. Loaded in open-front compartmented

racks. At 11 sec, puff of fumes; 14 sec, smoke meter

off scale; 15 sec, rate-of-rise detector signal received; 35 sec, fumes and flame out vent; 1 min 30 sec, 30- to 40-ft flames from vent; 2 min 30 sec, 5-ft flames; 3 min, flames

ceased; 3 min 30 sec, slight, fumes.

All the film vr as destroyed. Maximum recorded pressure , and temperature were 0.95 lb/in. 2 and 2,169° F (1,187° C), respectively.

| Washington, July 29, 1955.

20

U. S. GOVERNMENT PRINTING OFFICE: 1950
BUILDING MATERIALS AND STRUCTURES REPORTS

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“Knap Concrete-Unit” Walls * BMS95 Tests of Cement -Water Paints and Other Waterproofings for Unit-Masonry Walls 30(4 BMS96 Properties of a Porous Concrete of Cement and Uniform-Sized Gravel * BMS97 Experimental Dry-Wall Construction With Fiber Insulating Board * BMS98 Physical Properties of Terrazzo Aggregates * BMS99 Structural and Heat-Transfer Properties of “Multiple Box-Girder Plywood Panels” for Walls, Floors, and Roofs * BMS100 Relative Slipperiness of Floor and Deck Surfaces * BMS101 Strength and Resistance to Corrosion of Ties for Cavity Walls * BMS102 Painting Steel 150 BMS103 Measurements of Heat Losses From Slab Floors * BMS104 Structural Properties of Prefabricated Plywood Lightweight Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by the Douglas Fir Plywood Association.. * BMS105 Paint Manual with particular reference to Federal Specifications $1.50

B MS106 Laboratory Observations of Condensation in Wall Specimens 15(4 BMS107 Building Code Requirements for New Dwelling Construction * BMS108 Temperature Distribution in a Test Bungalow With Various Heating Devices 15(4 BMS109 Strength of Houses: Application of Engineering Principles to Structural Design 700 B MSI 10 Paints for Exterior Masonry Walls 200 BMS111 Performance of a Coal-Fired Boiler Converted to Oil 15(4 BMS112 Properties of Some Lightweight-Aggregate Concretes With and Without an Air- Entraining Admixture 150 BMS113 Fire Resistance of Structural Clay Tile Partitions 150 BMS114 Temperature in a Test Bungalow With Some Radiant and Jacketed Space Heaters 250 BMS115 A Study of a Baseboard Convector Heating System in a Test Bungalow 200 BMS116 Preparation and Revision of Building Codes 200 BMS117 Fire Resistance of Walls of Lightweight Aggregate Concrete Masonry Units 250 BMS118 Stack Venting of Plumbing Fixtures 250 BMS119 Wet Venting of Plumbing Fixtures 250 BMS120 Fire Resistance of Walls of Gravel-Aggregate Concrete Masonry Units 150 BMS121 Investigation of Failures of White-Coat Plasters 300 BMS122 Physical Properties of Some Samples of Asbestos-Cement Siding 200 BMS123 Fire Tests of Wood-Framed Walls and Partitions With Asbestos-Cement Facings * BMS124 Fire Tests of Steel Columns Protected With Siliceous Aggregate Concrete 150 BMS125 Stone Exposure Test Wall 300 B MS126 The Self-Siphonage of Fixture Traps 200 BMS127 Effect of Aging on the Soundness of Regularly Hydrated Dolomitic Lime Putties 150 BMS128 Atmospheric Exposure Tests of Nailed Sheet Metal Building Materials 200 BMS129 Fire Endurance of Shutters for Moving-Stairway Openings 100 BMS130 Methods and Equipment for Testing Printed-Enamel Felt-Base Floor Covering 150 BMS131 Fire Tests of Gunite Slabs and Partitions 150 BMS132 Capacities of Plumbing Stacks in Buildings 250 BMS133 Live Loads on Floors in Buildings 250 BMS134 Fire Resistance of Concrete Floors * BMS135 Fire Tests of Steel Columns Encased With Gypsum Lath and Plaster 150 BMS136 Properties of Cavity Walls 150 BMS137 Influence of the Wash From Bronze on the Weathering of Marble 150 BMS138 Effect of Edge Insulation Upon Temperature and Condensation on Concrete-Slab

Floors 200 BMS139 Studies of Stone-Setting Mortars 250 B MS140 Selected Bibliography on Building Construction and Maintenance 300 BMS141 Fire Endurance of Open-Web Steel Joist Floors with Concrete Slabs and Gypsum

Ceilings 200 BMS142 Frost Closure of Roof Vents 250 BMS143 Fire Tests of Brick Walls 350

BMS144 Sound Insulation of Wall and Floor Constructions 400 Supplement to BMS144, Sound Insulation of Wall, Floor, and Door Costructions 50 BMS145 Fire Effects and Fire Control in Nitrocellulose Photographic-Film Storage 200

•Out of print.