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PUBLICATIONS

REFERENCE

AlllOt. DMfiS3S ( 5- 3100-1

Literature Survey on Drop Size

Data, Measuring Equipment, and

A Discussion of the Significance

of Drop Size in Fire Extinguishment

Warren 0. Hayes, Jr.

Revised Edition

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Gaithersburg, MD 20899

July 1985

Prepared for: U.S. Federal Emergency Management Agency

Washington, DC

Interagency Agreement

^W-E- 1 239, Task Order 4

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1A Work Unit No. 61 21

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85 - 3100-1

1985

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NBSIR 85-3100-1

LITERATURE SURVEY ON DROP SIZE

DATA, MEASURING EQUIPMENT, AND

A DISCUSSION OF THE SIGNIFICANCE

OF DROP SIZE IN FIRE EXTINGUISHMENT

Warren 0. Hayes, Jr.

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Gaithersburg, MD 20899

This report has been reviewed in the Federal Emergency

Management Agency and approved for publication. Approval

does not signify that the contents necessarily reflect

the views and policies of the Federal Emergency Management

Agency.

July 1985

Prepared for; U.S. Federal Emergency Management Agency

Washington, DC 20024

Interagency Agreement

EMW-E-1239, Task Order 4

Phase 2

FEMA Work Unit No. 6121

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

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

Page

Abstract 1

1. INTRODUCTION 1

2. LITERATURE SEARCH 3

2.1 The Search for Existing Data 3

2.2 The Search for Measurement Apparatus 4

3. BACKGROUND MATERIAL 8

3.1 Mechanisms of Extinguishment and the Effect of

Firefighting Techniques 8

3.2 Dynamics of Extinguishment 12

4. REFERENCES 19

5. ADDITIONAL READINGS 20

APPENDIX 25

iii

LITERATURE SURVEY ON DROP SIZE DATA, MEASURING EQUIPMENT, AND A

DISCUSSION OF THE SIGNIFICANCE OF DROP SIZE IN FIRE EXTINGUISHMENT

Abstract

The literature was searched for information on the size of water droplets

from fire fighting equipment, on instrumentation and techniques for measuring

droplet size in dense sprays, and on the significance of droplet size in water

sprays used for fire extinguishment. From the information on drop size

analyzers gathered, it is likely that analyzers using a shadowgraphic method

to measure drop size are best suited for drop size measurements in water

sprays from fire hose nozzles. The effects of droplet size in water sprays

used for extinguishment in confined and unconfined spaces and with and without

counterflowing air currents are discussed.

1. INTRODUCTION

This literature survey was conducted to obtain technical information

related to fire suppression with water sprays. Technical publications dealing

with water spray formation, water spray measurement, and fire extinguishment

tests were sought. Special effort was made to find data on drop size

distributions produced by 1-1/2 inch fire hose nozzles. This literature

search was initiated with computer searches of the following indexes, the

descriptions of which are in the appendix:

1
(1) INSPEC - Information Services in Physics, Electrotechnology,

Computers and Control

(2) NTIS - National Technical Information Service

(3) BHRA - British Hydromechanics Research Association

(4) COMPENDEX - The Engineering Index

(5) TRIS - Transportation Research Information Service

(6) POLAB - Pollution Abstracts

The computer search was followed by manual searches of the Engineering Index

for the years 1955 through 1969 to complement the computer search of

COMPENDEX, The Building Research Establishment References to Scientific Literature on Fire for the years 1950 through 1980, and the NBS Fire Research

Information Service subject file. Lastly, telephone discussions were held

with the following; two staff people in college fire protection curriculum,

three people on the NFPA fire hose committee, two technical people with companies manufacturing hose nozzles, two federal fire researchers outside of

NBS, a fire researcher in the Building Research Establishment in England, two

federal aerodynamic engineers, and several people in industry doing droplet

analyses and droplet measuring research.

As a result of the index searches and telephone discussions, nine books,

twenty-six reports, thirty-four articles, and two standards were identified

2
and reviewed. Only those discussed are cited, but the remainder are included

in the bibliography.

2. LITERATURE SEARCH

2.1 The Search for Existing Data

The search for existing data on droplet size of sprays from fire hose

nozzles yielded only one document, the summary of which follows. Savage and

Freeman [1] reported the results of their drop size measurements in sprays

from nozzles used in the extinguishment of fully developed room fire tests of

Hird [2]. The fog nozzles were of the impinging jet type. This means that

the nozzle was designed to direct pairs of jets to collide exterior to the

nozzle to form the spray. The aforementioned nozzles were operated at 552,

1551 and 3147 kPa (80,225 and 500 psi) pressure and with flow rates of 1.14,

3.41 and 5.68 m /s (5, 15 and 25 gpm) . The orifice size was held constant at

1.59 mm (1/16 in), and therefore, the flow rate was varied by changing the

number of pairs of jets. The technique for determining drop size was one of

collecting samples at selected points in the spray pattern in shallow glass

dishes containing a layer of castor oil, making contact photographs of the

dishes filled with droplets, projecting the photographs for enlargement, and

measuring the image sizes with a template.

The following table was extracted from their report. The values are

weighted for volume distribution of the water within the overall spray pattern

from the nozzle.

3
Mass-Median Drop Size (ym)

o Flow (m /s) Pressure (kPa)

552 1551 3147

1.14 550 390 320

3.41 850 620 610

5.68 540 590 540

Unfortunately, the nozzle here characterized is not of a type commonly used

for fighting fires in the United States. Most of the fog nozzles used in this

country generate droplets by impaction of the hose stream with a plate within

the nozzle.

The technical people working for fire hose nozzle manufacturing companies

who were contacted by telephone did not reveal any results of drop size distribution measurements they have taken on their own nozzles or others.

2.2 The Search for Measurement Apparatus

The search for information on droplet size measurement apparatus was much

more fruitful. The recent interest in energy conservation has intensified

resarch in the measurement of droplet size and velocity even more so than did

spray drying in previous years. Spray drying is a process that has been found

very useful for generating many powdered materials such as Instant coffee from

solutions. The interest in droplet size related to energy conservation is in

the development of fuel spray nozzles for improved combustion efficiency. The

4
interest in such spray characteristics is not just of recent times, but rather

a revival prompted by more recent improvements in measurement technology.

Jones [3] wrote a comprehensive review of the methods for measuring droplet

size in dense fuel sprays, which he defined as droplet concentrations in

excess of one drop per cubic millimeter. He described most of the known

mechanical, electrical and optical methods. The mechanical methods include

droplet capture on slides coated with powders, or in pools of immiscible

liquids like that used by Savage and Freeman [1], cascade impactors, freezing,

and sedimentation, the electrical methods include gapped electrodes, charged

wires and hot wire anemometers and the optical methods include high speed

photography, holography and laser defraction. Fifty references are cited.

Azzopardi [4] subsequently published a much more comprehensive review in

which he divided the droplet size measurement methods into the following

categories: photographic, impact, thermal, electrical, optical, time of

residence, and indirect via velocity. He further tabulated the methods with

regard to their characteristics which included whether they provided number or

mass flux data, single particle or cloud average counting, size distribution

or mean size, and temporal or spatial distribution. The size range,

disadvantages, advantages and references for each method are given. One

hundred and thirty-one references are cited.

Chigier [5] followed with an extremely comprehensive review of drop size

and velocity instrumentation. The main focus of this review however, was on

optical methods such as holography, laser doppler anemometry (LDA) and laser

transit anemometry (LTA) . It also discussed a phase discriminating sampling

probe that withdraws samples isokinetically and even briefly mentioned still

5
and motion photography, and high speed video. Forty-five references are

cited.

Not mentioned in any of these reviews but worthy of note is the work of

Semiat [6] who simplified the formation of a laser beam interference fringe

pattern with use of a Ronchi grid. A Ronchi grid is a glass plate with

equally wide alternating clear and opaque lines. When the grid is placed in a

laser beam, the identical pattern is transmitted. An interesting feature of

this technique is that crossed grids allow for the measurement of two-dimensional velocities.

It is evident from the number of fundamentally different methods of

measuring droplet size here mentioned that there are numerous pieces of apparatus in existence. Improvements in signal acquisition and processing and

miniaturization of computers have greatly simplified the process of obtaining

droplet analyses of sprays. Even one of the oldest methods, photography, has

attracted new interest because of the advent of image analyzers which digitize

video images. Many of the pieces of apparatus were, however, not studied in

detail by this author simply because they lacked provision for or because of

the anticipated complexity of providing protection of the electronic and

optical elements from the environment accompanying the production of sprays

produced by some of the equipment of interest. The reader is reminded that

fuel sprays for internal combustion engines are only a few hundred cubic

centimeters in volume, and therefore very different from sprays that fill

entire rooms for fire extinguishment. As one would expect, tradeoffs must be

made.

6
Equipment that will measure drop size distributions of sprays from aerosol

cans usually will not do so for sprays from fire hose nozzles and vice versa.

Holographic equipment will capture action in very large volumes of space but

obtaining a droplet size distribution analysis from the hologram is very

laborious. The hologram like a 35 mm camera slide must be used to reconstruct

(project) with use of a laser light source the captured image into space. The

reconstructed object must then be manually analysed with use of a telescopic

type lens system with a drop sizing reticule and this must be done plane by

plane through the volijme. Equipment that will analyse clouds of drops by use

of Fourier transform lens focussing of diffraction patterns from each drop in

the cloud onto a specially patterned detector is very good for quickly

obtaining drop size averages from fairly large volumes of spray. This type of

equipment does not, however, allow one to view the drops being measured or to

obtain drop velocities. Shadowgraphic equipment that automatically will

perform the laborious process of calculating the droplet size distributions

usually will do so for only a small slice of the spray patterns at a time, and

therefore, one must systematically take many samples of the whole pattern or

part of the pattern for symetrical sprays. The size of the volume into which

the sample can be placed also is important when one may want to include

sources such as flames and hot surfaces that generate counterflows that would

interact with extinguishment sprays.

Drop analyzers that use the shadowgraph technique, with a strobe light

source and video monitoring and recording of individual drops are probably

best suited for studying water sprays from fire fighting equipment. Images

from individual drops ranging in size from 8 to 10,000 pm may be digitized and

then sized and counted as directed by accompanying software which then can

7
analyze the data and provide arithmetic, surface, volume, weight and Sauter

mean diameters and size distributions. The addition of a multiple strobe

feature can also provide the capability of obtaining droplet velocity data.

Furthermore, it has been demonstrated to measure droplets Immersed in propane

flames

3 . BACKGROUND MATERIAL

3.1 Mechanisms of Extinguishment and the Effect of

Firefighting Techniques

Water probably has been the primary fire extinguishant used by man since

he learned to use fire. The delivery of water for the extinguishment of

unwanted fires has changed over the years from hand transportation in buckets

to flow through hoses supplied by pumps. The form of the water used has

changed from bucketfuls to sprays. For many years between the use of bucketfuls and the use of sprays, solid hose streams were used. Thus the main topic

related to extinguishment in the fire literature of this period was the transport of water from its source to the fire at a sufficient rate and in sufficient quantity. Nothing was said about the form of the water delivered.

Sprays as opposed to solid streams were used but only in automatic sprinkler

systems and only for the purpose of distributing the water throughout the

space for which the protection was designed rather than for the benefit

provided by the state of division of the water.

The earliest discussion advocating the use of sprays consisting of very

small droplets of water for manual firefighting was by Lloyd Layman [7] who in

1954 originated the "indirect method of fire attack". The method was devised

as a result of experiments in the extinguishment of fuel oil fires in merchant

8
marine ship machinery spaces. Layman directed these experiments during World

War II at which time he was Commandant of the U.S. Coast Guard Fire Fighting

School. The method proposed that sprays consisting of very small water

droplets be injected into confined spaces containing fires. The conclusion

drawn from the test results was that the rapid generation of steam within a

confined space created a violent atmospheric disturbance within the space.

Put a little differently, the rate of evaporation is directly proportional to

surface area of the water that is exposed to the heat and for a given volume

of water is inversely proportional to the droplet diameters squared.

Therefore, the smaller the droplets, the higher the rate of evaporation. The

O O evaporation of water absorbs 2.26 x 10"^ MJ/m"^ (8100 Btu/gal) and is

accompanied by a volume expansion of approximately 1700 times the original.

The rate and magnitude of the expansion of the water to steam apparently

creates great turbulence which contributes to the distribution of the

remaining droplets of water to much of the remaining heat in a confined

space. The steam displaces a large volume of the air required to sustain

combustion in the space and consequently the fire is suppressed.

The National Board of Fire Underwriters [8] subsequently supported a more

detailed investigation of the use of finely divided water at the Underwriters

Laboratory. For this investigation a test chamber with an approximately one

square meter base and approximately two meters in height was constructed of

galvanized steel with a removeable top, adjustable vents and a spray port on

the sides near the bottom. Nineteen spray nozzles were characterized for

droplet size distribution at various water pressures and at various distances

from the nozzle. Test fires using 237 mil of gasoline, kerosene, or ethyl

alcohol were burned in sheet metal pans approximately 150 mm square by 50 or

9
150 mm deep or 300 mm square by 300 mm deep placed on the floor of the

chamber. Fires of small wood piles also were Included in the tests. Water

sprays from each or some combination of the nineteen nozzles were directed

toward the fires from approximately 3 m directly above or horizontally through

the side port approximately 250 mm above the floor.

The conclusions were as follows: (1) That these flammable liquid fires

were extinguished predominately by dilution of the air supply with water

vapor. (2) Up to a point, reducing the droplet size of the water spray is

beneficial. (3) Sprays directed down from directly above with droplet

diameters less than 150 pm did not extinguish the fires because they were

repelled by the fire plume. (4) The same sprays were effective when directed

from the side. (5) There was a definite increase in the amount of water

required when the droplets were larger than 300 pm. (6) Confining the fire

to the burn compartment was a very important factor in the effectiveness of

the water spray. (7) Wood fires had a strong tendency to rekindle after the

spray was stopped.

Several investigators subsequently concluded that the mechanism of extinguishment of diffusion flames in other than the confined spaces used in the

Layman and the National Board of Fire Underwriter Tests was by cooling of the

fuel. Bryan’s [9] tests of the extinguishment of wood cribs demonstrated that

the resistance to extinguishment depended more on the heat content of the fuel

than on the rate at which it was generating heat. Rasbash [10] concluded from

his extinguishment experiments with pool and wood fires that the best way to

extinguish a fire was to assure that the water reach and cool the fuel. He

also stated that for most fires the droplet size of the spray was not usually

10
an important factor. He did acknowledge that it was not clear whether room

fires were more efficiently controlled by cooling of the fuel or by cooling of

the flames. He believed that investigations up to that time had not been

systematic enough to allow one to draw conclusions about how the

extinguishment mechanisms operate during real room fires. Lacking were data

on critical flow rate and quantity of water required.

It is obvious from the aforementioned works that different fire

situations require different fire fighting tactics. Cooling of the fuel is

the surest method for most situations, but smothering by the displacement of

air with water vapor is very effective under certain conditions which have

been characterized only as confined. Droplet size must be important because

the droplet must have enough momentum to overcome the resistance over the path

that it travels and because in many situations it must not evaporate before it

reaches the fuel. The waterspray path is dependent upon the available access

to the fire, the available equipment, and the firefighter's choice of attack

position. The firefighter's preference for position of attack would be upwind of the fire so that the smoke and heat would be blown away from him and

so that the wind would help carry the water spray to the fire. Furthermore,

the usual technique for applying water to a fire, excluding the situation of a

fire in a confined space, would be to direct the spray at the base of the

fire. As the base of the fire recede as the near part of the fuel is

extinguished, the spray would be directed to follow it with due consideration

of the burning characteristics of other fuel in the direction that the fire

was being chased. The latter simply alludes to the fact that air entrained In

the spray tends to blow the fire, persisting beyond the area of spray

impaction, in the direction of the spray, and that the firefighter will not

11
intentionally cause the fire to be blown toward highly flammable material if

it can be avoided. The same consideration would apply to trapped occupants.

For intense fires in confined spaces, the technique used initially might be to

direct the spray to the upper part of the space from a low level opening.

Since the hot gases from a fire tend to concentrate near the ceiling in a

confined space, this tactic assures that the maximum amount of water is

converted to vapor , a process which absorbs heat and displaces smoke and

thereby provides better visability of and accessability to the base of the

fire. This type of fire is frequently underventilated, lacking oxygen, when

extinguishment is begun and has been known to flash when air currents created

by air entrainment in the spray have ventilated the fire. In both of these

situations, travel of the spray would probably be aided rather than impeded

by currents of air. If however, the wind were to change, or simultaneous

attack from other positions chase the fire toward the firefighter, or the

firefighter be forced by inaccessibility of a better position to take a

position requiring directing of the spray counter to the fire plume, the spray

stream would have to be strong enough to overcome the counterflows. Dynamics

of sprays are covered in the next section of this report.

3.2 Dynamics of Extinguishment

The relationship between spray momentum and gaseous counterflows has been

discussed by several authors. The earliest discussions related to the process

called spray drying, a technique for converting solutions or slurries into

powders. Lapple and Sheppard [11] published a comprehensive theoretical,

mathematical analysis of particle trajectories in a variety of air streams.

The interest in this case was in suspending droplets in an air stream for the

time required for them to crystallize or dry.

12
Kalelkar [12], Yao [13], Dundas [14], Liu [15] and Beyler [16] theorized

about the interaction of spray droplets and fire plumes as related to automatic sprinklers. All of these authors based their discussions on a balance

of forces relationship between a moving droplet and a moving air stream. For

the simple case where the drop is falling straight down through an air stream

moving straight up the balance of forces may be expressed as follows:

m

dt

dv

d = mg -

where m = mass of the drop (kg)

v^ = velocity of the drop (m/s)

t = time (s)

2

g = acceleration of gravity (m/s )

= density of the air stream (kg/m )

Cq = drag coefficient of drop

* fCNug) = f — ® - 0.44 [11]

for 500 < < 200,000 where = diameter of drop (m)

Ug = viscosity of air stream

(kg/m-s)

13
o Aj = largest cross sectional area of drop normal to air stream (m )

= velocity of drop relative to air stream (m/s)

Solving for v^ in fire extinguishment sprays is difficult for the following

reasons

1) The motion of the droplets in fire extinguishment is a three-dimensional

problem rather than the one-dimensional problem given as the simple

case. The thrust of the fire driven air current varies threedimensionally with location and conditions in the compartment fire even

without the disturbing forces that accompany extinguishment. Furthermore,

the conditions vary as the characteristics and location of the burning

fuel Involved change with the progression of the fire.

2) The approximation of the drag coefficient previously given was determined

from experiments with single drops rather than the dense clouds of spray

associated with extinguishment. One would expect that in a dense spray

many drops would be in the wake of others and that the drag in such a

situation would be different from that for a single drop, but such a

determination apparently has not been made. Of course, evaporation from

the many drops in the cloud would raise the water vapor level in the cloud

which in turn would reduce the rate of evaporation from the drops which

does have an effect on drag. Drag on drops has two components, friction

drag and pressure drag. Yuen [17] found that evaporation from water drops

always reduces the friction drag. The pressure drag is not affected by

evaporation at Reynolds numbers below 20, but at that point it begins to

14
increase with Reynolds number. He determined that the increase in

pressure drag will equal the decrease in friction drag when the Reynolds

number reaches 1000 resxilting thereafter in increasing total drag.

Evaporation also reduces the size of the drop which reduces the cross

section of the drop and thereby reduces the drag.

3) The cross section of the drop varies in flight because the shape of the

drop oscillates between a teardrop and horizontal ellipsoid. This

instability is worse for larger drops.

The spray from a sprinkler is probably the most extreme interaction of an

extinguishant and a fire driven counter flow and, therefore, the most difficult

to predict. The reason is that the active sprinkler usually is to the side of

the vertical axis of the fire where the plume is the strongest.

Thomas and Rasbash have done studies on the characteristics of sprays

from fire hose nozzles. Thomas [18] derived a formula for predicting the

throw of spray from a fire hose nozzle in the absence of wind from data taken

from a NFPA report [20]. The formula is as follows:

t = 2.32 + 0.85 r + 2.15 a + 0.36 p + 1.03 ra

where t = log^^Q throw (m)

r = logj^Q flow rate (m'^/s)

_ T _ tan( total spray cone angle)

a - J-og]^o 4

15
- pressure(KPa)

P “ '°Sio Too

Blasbash [19] discussed penetration of spray to the "seat of the fire" as

affected by drop size, thrusts of the spray and of the fire plume, the wind,

and gravity. For example, the critical spray "thrust" (i.e. its spray

momentum per unit area at the flame) to just penetrate the flame from above

was suggested by Rasbash [19] to be related to the flame height as follows:

= 0.5 p g X

where = critical thrust (N/m )

p = density of air (Kg/m^^

g

= acceleration due to gravity (m/ s

^

X = height of flame prior to spray (m)

One can then use the following relationship between flame height and heat

release rate as determined by McCaffrey [21] to determine this critical thrust

in terns of heat release rate
X = 0.2 Q

2/5

where x = flame height (m)

Q

= heat release rate (kW)

Rasbash [19] also determined that the spray thrust from a nozzle was related

to reaction of the nozzle in the following manner.

Spray thrust = R/A = CP^'^F/A

where R = nozzle reaction force

A = cross sectional area of the spray at the plane of interest

P = nozzle pressure

F = nozzle flow rate

C = a nozzle constant

He also made the very interesting statement that the spray thrust was entirely

converted to momentum of the entrained air stream within about six feet of the

spray nozzle. Purington [22] gives a relationship to estimate spray nozzle

reaction in terms of flow rate. The above relationships give some sense of

the factors influencing the dynamics of water sprays in fires.

17
4. CONCLUDING REMARKS

The extinguishment of room fires is a very complex phenomenon. The

literature suggests that the strategy for the majority of fires should be to

cool the fuel rather than smother the flame. This is in spite of the fact

that most unwanted fires are already in a ventilation controlled stage when

extinguishment is begun [23, 24]. Water must reach the fuel to cool it. Most

of the theoretical and experimental work thus far has dealt with penetration

of the fire plume by water spray. This itself is a very complex problem

because of the variability encountered in the burning characteristics and

arrangement of combustible furnishings, the ventilation characteristics of the

space, the difficulty of dealing with the three-dimensional motion of both the

droplets in the water spray and the fire driven counter air currents, and the

reaction of the fire to the extinguishment process.

To apply existing knowledge of extinguishment dynamics to real life fire

fighting requires more information on the drop size and velocity distributions

from hose nozzles. This report identifies available techniques for the

measurement of nozzle spray characteristics, and contains a literature

bibliography on the subject, and on the research studies of the dynamics of

water sprays on flames.

18
5. REFERENCES

[1] Savage, N., and Freeman, S., The determination of the drop sizes of high

and low pressure water sprays. F.R. Note No. 373/1959, Fire Research

Station, Borehamwood, Herts, 9 p.

[2] Hird, D. , Pickard, R. W. , Fittes, D. W. , and Nash, P. , The use of high

and low pressure water sprays against fully developed room fires. F. R.

Note, No. 388/1959, Fire Research Station, Borehamwood, Herts, 23 p.

[3] Jones, A. R. , A review of drop size measurement - The application of

techniques to dense fuel sprays. Prog. Energy Combustion Science, Vol.

3, Pergamon Press, (1977) pp 225-234.

[4] Azzopardi, B.' J. , Measurement of drop sizes, Int. J. Heat Mass Transfer,

Vol. 22, Pergamon Press, Ltd., (1979) pp. 1245-1279.

[5] Chigier, N. , Drop size and velocity instrumentation. Prog. Energy

Combust. Sci., Vol. 9, Pergamon Press, (1983) pp. 155-177.

[6] Semiat , R. , and Dukler, A. E. , Simultaneous measurement of size and

velocity of bubbles or drops; a new optical technique, A. I. Ch E Jour,

Vol. 27, No. 1, (Jan. 1981) pp 148-159.

[7] Layman, L., Attacking and extinguishing interior fires. National Fire

Protection Association, Boston, Mass., Third Edition, (1958) 149 p.

[8] The mechanism of extinguishment of fire by finely divided water, NBFU

Research Report, No. 10, National Board of Fire Underwriters, N. Y.

(1955) 73 p.

[9] Bryan, J. , The effect of chemicals in water solution on fire extinction.

Engineering, pp. 457-460, June 1945, p. 474, June 15, 1945, pp. 497-500,

June 22, 1945.

[10] Rasbash, D. J. , Rogowski, Z. W. , and Stark, G. W. V., Mechanisms of

extinction of liquid fires with water sprays. Combustion and Flame,

(1960) pp. 223-234.

[11] Lapple , C. E. and Shepherd, C. B. , Calculation of particle trajectories.

Industrial and Engineering Chemistry, Vol. 32, No. 1, (May 1940)

pp. 605-617.

[12] Kalelkar, A. S. , The dynamics of large deforming liquid drops in strong

vertical air-streams, FMRC Ser. No. 18792, Factory Mutual Research

Corporation, Norwood, MA (April 1970) 19 p.

[13] Yao, C. and Kalelkar, A. S., Effect of drop size on sprinkler

performance. Fire Technology, (November 1970) pp. 254-268.

[14] Dundas, P. H., Cooling and penetration study, FMRC Ser. No. 18792,

Factory Mutual Research Corporation, Norwood, MA (May 1974) 56 p.

19
[15] Liu, S. J., Analytical and experimental study of evaporative cooling and room fire suppression by corridor sprinkler system, Nat. Bur, Stand.

(U.S.) NBSIR 77-1287; (1977 November) 56 p.

[16] Beyler, C. L., The interaction of fire and sprinklers. Nat. Bur. Stand.

(U.S.) NBS-GCR-7 8-121; (1977 September) 78 p.

[17] Yuen, M. C. and Chen, L. W., Dynamics of evaporating water droplets,

NU-ME/AS No. 75-1, Northwestern University, Evanston, IL (May 1975)

24 p.

[18] Thomas, P. H. and Smart, P. M. T., The throw of water sprays, F. R. Note

No. 168, Fire Research Station, Borehamwood, Herts, England, (May 1955)

3 p.

[19] Rasbash, D. J., The extinction of fires by water sprays, Fire Research

Abstracts and Reviews, Vol. 4, January and May 1962, Nos. 1 and 2,

pp. 28-53.

[20] Out of print and not available. Studies of fire department fog nozzles.

National Fire Protection Association, 1952.

[21] McCaffrey, B. J. , Purely buoyant diffusion flames: some experimental

results, Nat, Bur. Stand. (U.S.) NBSIR 79-1910, (1979 October) 49 p.

[22] Purington, R. C. , Fire fighting hydraulics. New York: McGraw-Hill Book

Company; (1974) p, 371.

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[24] Fried, Emanuel, Chapter 6, Ventilation, in Fireground Tactics, H. Marvin

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24
APPENDIX

Computer Indexes

1. INSPEC (Information Services in Physics, Electrotechnology Computers and

Control) corresponds to the three Science Abstracts printed

publications. Electrical and Electronics Abstracts, Computer and Control

Abstracts, and Physics Abstracts.

2. NTIS (Dialog Information Retrieval Service) The database consists of

government sponsored research, development, and engineering reports as

well as other analyses prepared by government agencies, their contractors

or grantees.

3. BHRA (British Hydromechanics Research Association) contains records from

the ten BHRA - produced abstract journals and other sources providing a

comprehensive source of information on all aspects of fluid engineering

and behavior and application of fluids.

4. COMPENDEX (The Engineering Index) contains abstracted information from the

worlds' significant engineering and technological literature.

5. TRIS (Transportation Research Information Service) is a composite file

whose records are either abstracts of documents and data holdings, or

resumes of research projects that are relevant to the planning,

development, operation, and performance of transportation systems and

their components.

25
6. POLAB (Pollution Abstracts) is a leading resource for references to

environmentally related technical literature on pollution, its sources and

its control. The database corresponds to the printed Pollution Abstracts.

26
NBS-114A (REV; 2 «ac)

4. TITLE AND SUBTITLE

Literature survey on Drop Size Data, Measuring

Equipment, and A Discussion of the Significance of Drop Size in

Fire Extinguishment.

5. AUTHOR(S)

Warren D. Hayes, Jr.

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions) 7. Contract/Grant No,

NATIONAL BUREAU OF STANDARDS EMW-E-1239,Task 4, Phase

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

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

U.S. Federal Emergency Management Agency

Washington, DC 20024

10. SUPPLEMENTARY NOTES

1 1 Document describes a computer program; SF-I8S, FlPS Software Summary, is attached.

U.S. DEPT. OF COMM. 1. PUBLICATION OR 2. Performing Organ. Report No. , 3. Publication Date BIBLIOGRAPHIC DATA

REPORT NO.

July 1985 SHEET (See instructions) NBSIR 85-3100-1

11. ABSTRACT (A 200-word or less factual summary of most sigrtificant information. If document Includes a significant

bibliography or literature survey, mention it here)

The literature was searched for information on the size of water droplets

from fire fighting equipment, on instrumentation and techniques for measuring

droplet size in dense sprays, and on the significance of droplet size in water

sprays used for fire extinguishment. From the information on drop size

analyzers gathered, it is likely that analyzers using a shadowgraphic method

to measure drop size are best suited for drop size measurments in water

sprays from fire hose nozzles. The effects of droplet size in water sprays

used for extinguishment is confined and unconfined spaces and with and without

counterflowing air currents are discussed. This report supersedes the

January 1985 edition (NBSIR 85-3100)

12. KEY WORDS fS/x to twelve entries; alphabetical order; capitalize only proper names; and separate key ^orbs Sy te- co or t

drop size measurements; fire extinguishment; fire fighting; fire hoses;

room fires; spray nozzles; water

13. AVAILABILITY

j, I Unlimited

I I For Official Distribution. Do Not Release to NTIS

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

I Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OP

PRiS'^ED P* 3ES

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