An Assessment of Correlations

Between Laboratory and

Full-Scale Experiments for the

FAA Aircraft Fire Safety Program,

Part 2: Rate of Energy Release in

Fire

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

July 1982

Sponsored by;

U.S. Department of Transportation

Federal Aviation Administration

" QC " nical Center

itic City Airport, NJ 08405

.U56

32-2536

1932
J3II
NBSIR 82-2536

AN ASSESSMENT OF CORRELATIONS

BETWEEN LABORATORY AND

FULL-SCALE EXPERIMENTS FOR THE

FAA AIRCRAFT FIRE SAFETY PROGRAM,

PART 2: RATE OF ENERGY RELEASE IN

FIRE

aiA«oNja« wnnuji

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lilBJlAJlT AUG 1 9 1982

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James G. Quintiere

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Fire Research

Washington, DC 20234

July 1982

Sponsored by;

U.S. Department of Transportation

Federal Aviation Administration

Technical Center

Atlantic City Airport, NJ 08405

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

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
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AN ASSESSMENT OF CORRELATIONS BETWEEN LABORATORY AND

FULL-SCALE EXPERIMENTS FOR THE FAA AIRCRAFT FIRE SAFETY PROGRAM,

PART 2: RATE OF ENERGY RELEASE IN FIRE

by

James G. Quintlere

ABSTRACT

The rate of energy release in fire is discussed. The significance of

calorimetric measurements of energy release for materials is related to thermodynamic parameters, namely heat of reaction and stoichiometric coefficients.

It is shown that a common set of parameters is necessary to express ignition,

flame spread and mass loss due to combustion and heat transfer in fires. The

relationship of ignition and flame spread to rate of energy release in fires is

presented along with a presentation on upward spread.

Key words: calorimetry, correlations, energy release, flame spread, test

methods
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TABLE OF CONTENTS

Page

INTRODUCTION 1

Purpose 1

Background 1

DISCUSSION 2

Idealized Calorimetry 2

The Role of Fire Parameters 6

CONCLUSIONS 11

REFERENCES 13

i
LIST OF ILLUSTRATIONS

Figure Page

1 An Idealized Calorimeter 14

2 Flame Spread Example 15

3 Igniting Flame Heat Flux (ASTM E-84 and Bunsen Burner Test) 16
NOMENCLATURE

A area

B Spalding mass transfer number

c specific heat of solid

c^ specific heat of gas at constant pressure

C flame spread modulus (Eq. 28)

g gravitational acceleration

h heat transfer coefficient

h enthalpy

h° enthalpy of formation

height of window or door

k thermal conductivity

L heat of gasification (Eq. 20)

n exponent of (See Eq. 8)

m mass

Pr Prandtl number

q heat transfer

Q energy release rate

r mass air to fuel stoichiometric ratio

Re Reynolds number

t time

T temperature

u velocity

flame spread velocity

W width

X space coordinate

Y, mass fraction of 1

ill
a entrainment constant (Eq . 2)

6 flame height coefficient (Eq. 8)

AH heat of vaporization

V

AH heat of reaction

y viscosity

V kinematic viscosity (y/p)

p density

T flame spread time (Eq. 106)

Subscripts

a air

b burning

e entrainment

f fuel

g gas

o reference state or opening

ox oxygen

p products

py pyrolysis

s surface

V vaporization

w wall

Superscripts

( ) per unit time

(

)

’ per unit length

( )” per unit area

IV

I
INTRODUCTION

PURPOSE .

The purpose of this report is to illustrate theoretically the various factors

that govern rate of energy release in fires. These factors can be expressed in

terms of various parameters and depend on fire phenomena. In a heuristic and

qualitative fashion it will be shown that there is a set of parameters or "properties”

common to the various phenomena which comprise rate of energy release. The

measurement of these parameters would provide the information needed to predict

energy release rate with mathematical models. Only through this process will

rational scientific correlation emerge between laboratory test data and fullscale fire tests.

BACKGROUND .

The rate of energy release (Q) in a fire is the most significant parameter governing fire growth. This can be illustrated by an experimental

correlation for predicting the temperature rise (AT) in compartment fires

given by McCaffrey et al. [1]:

At

T

o

( 1)

The other parameters in Eq. (1) relate to property and geometric variables and

are given in Ref. [1]. The main point is that AT depends on Q . Temperature

is the principle indicator of hazard in terms of human discomfort, burn injury,

ignition of other objects and the potential for flashover. Temperature

difference is also the promoter of air flow into the fire and Q is a manifestation of the rate of fuel constimed and products released from the fire source. Although the quantity of particular products formed depends on the material burning

and other factors, the rate of evolution of products and oxygen consumption will be

proportional to Q. Hence Q gives rise to temperature directly and other fire

products indirectly, all of which combine to impose a threat to people and property.

The need to measure the energy release rate from combusting materials has

led to the development of several apparatuses. Smith [2], Tewarson [3], and

Parker [4] are among those who have developed devices to measure the transient

rate of energy and other products of combustion from burning materials. These

devices are flow-through systems in which measurements in the gas stream flowing

from a burning specimen are used to infer the energy and product releases of

the material. To put this process in perspective and to demonstrate the

relationship of the measured quantities with physical properties will require

some analysis. Two issues must be resolved for test method data to have

meaning in full-scale fire analyses and correlations. The first issue is the

meaning and limitations of the test data collected. Specifically the meaning

of energy release rate and its dependence on heat flux, temperature, oxygen,

configuration, orientation and scale must be understood. The second issue

is to understand the nature of energy release in full-scale fire scenarios

and to understand the contributions of ignition and flame spread to that overall

process

1
DISCUSSION

IDEALIZED CALORIMETRY ,

The meaning of the expression "rate of energy release" in a transient

calorimetry apparatus will be considered. An analysis for an idealized solid

fuel will show the relationship of energy release rate to thermodynamic properties.

Although more realistic fuels may change the details of this analysis, the general

form of the results should not vary. The ideal system to be analyzed is typical

of devices being used to measure energy release rate. A schematic is shown

in Figure 1. The following assumptions are made:

(1) gas phase transients are negligible, ^ = 0,

(2) all gas species have Identical specific heats, c , (3) the combusting fuel is a vaporizing solid with n§ char yield.

The stoichiometry of the combustion process is given in terms of mass by

1 g fuel + r g air - (1 + r) g of gaseous products (2)

Enthalpy relationships for each constituent are given below:

fuel

h^ = h° + C (T-T^) , T £ T^ (solid phase) (3)

h. = h° + c (T -T ) + AH + c (T-T ) , T > T (gas phase) (4)

f f 'vo V g'v — V

where c is the specific heat of the gas,

c®ls the specific heat of the solid,

AH^ is the enthalpy difference due to the change from the solid

to the vapor phase,

and T^ is the vaporization temperature.

air

h = h*^ + c (T-T ) (5) a a g o products

h = h + c

P P g

(T-T ) o(6)

The heat of combustion, defined as positive for an exothermic reaction, is

given by

Ah = - (1+r) h° + h? + rh° (7)

p t a for the solid fuel at the reference state T^. The AH is exactly the quantity

that would be measured in an oxygen bomb calorimeter assuming a negligible

change in molecular weight of the initial gas state and the final mixture state

at T . It is also the heat transferred in a flowing system per unit mass of

soliS burned when the exiting gases have cooled to T^. This is the intrinsic

2
property that underlies the energy release rate. For a complex comhustion

process Involving charring and transient conduction losses, the “

J

^ with time. Nevertheless, a good measurement technique should be caPaW®

recording a transient AH consistent with thermodynamic principles. An

extension of the following analysis should be able to consider these

transient factors.

Conservation laws are applied to the gas enclosed by ^c dashed

in Figure 1. The inlet and exit states are assumed to be well mixed and

therefore uniform. As assumed, the time rate of change of the gas properties

within the volume are negligible.

Mass conservation

m = m + m ( 8 )

Fuel specie conservation

Y m - m - - (9)

where m is the gaseous fuel production rate and m^ is the burning rate.

V

Product specie conservation

Yp m = (r + 1)

Air specie conservation

Y m - m^ = - rm^

( 10)

( 11)

or

Oxygen specie conservation

ox m - 0.233 m = -0.233 rm^

Energy conservation

ihh(T) - TMv^ *^w ^ ^ ^ "" f,gas

( 12 )

(13)

where h(T) = Y^hj(T) + Yphp(T) +

q is the net heat transfer rate to the solid fuel,

and e is the rate of heat transfer lost to the apparatus walls, w

3
By utilizing the enthalpy relationships (2-7) and solving for the specie

concentrations at the exit in Eqns. (9-11) the energy equation (13) can be

written as

(lii + m ) c (T - T ) = HL [AH + c(T - T ) + AH ] a V g o' b ^ V o V + m c (T - T)-q - d (14)

py g V o' ^s

^ ' ' Here T was taken as T , and unburned fuel is allowed to occur at the exit if

9- O

^ insuffxcient air is supplied or if the pyrolysis rate is too great;

m = m - m, (15)

py V b

' '

is the excess fuel.

A final form of the gas-phase energy equation is developed by considering

an energy balance on the solid fuel. For a coordinate system fixed to the

regressing solid-gas interface with x taken positive into the solid,

^ 9T .„ 9T , 9^T

(16)

holds within the solid with T = T at x vaporizing interface

q" + k

s 9x x=o AHV

0 and T = T as x At the

o

(17)

holds for solid and gas flowing across the interface with flow rate per unit area and at the temperature T . The restriction that steady state holds in

the solid, i.e. T=T(x) only, leaSs to

and

T = (T -T ) e V o + T

o (18)

q = m [Ah + c

s V V

(T -T )] V o (19)

If transient conduction were considered it is apparent that time-dependent

terms would occur in Eqns (18) and (19) . The effective heat of

gasification, L, is a useful fire parameter defined as

L X

m

V

( 20)

4
and for this example.

L = ah + c (T -T ).

V

' V o

( 21 )

In general L would depend on time due to any transient effects in the solid.

Eq (19) is substituted in Eq. (14) to yield

Cg <T-T^) = \AH - Apy[A\ + (c - Cg) (T^ - !„)] - % (22)

As stated earlier if the exit gases are cooled to T^, and if 111^^

= 0, the rate

of heat lost is

w “b

AH (23)

T=T

o m =0

py

Hence all of the energy released by the chemical reaction Is manifested as a heat

loss. This clearly shows the significance of tt AH as the energy release rate for

the combustion process. Although this analysis assumed lack of transients in

the gas and solid phases, the equations apply at any instant of time and

Chanies In the natLe of the gas-phase reaction are still allowable. For example,

the chemical composition of the gaseous fuel can change as the burning process

^ proceeds in time. This would reflect changes in the values of the stoichiometric

ratio, r, and the enthalpies of formation, h° and h^. Hence AH could change with

t ime

The utility of AH is clear but its measurement needs some discussion. The

measured "rate of energy release" (Q) must be shown to be m^AH. ^

^herma

method to measure energy release must not only measure

energy flow rate through the apparatus but it must also eliminate or account

for the heat losses to the walls. For m^^ - 0, i.e. surricient

Q

= AH = (m + m ) a V =g (T-T„) + %

(24)

The terms on the right-side of Eq. (24) must all be known to give an accurate

measurement for Q or AH. The difficulty to account for the heat losses to the

surroundings under transient conditions is a disadvantage of the thermal

method

An alternative method to determine Q is to utilize the empirical result

that the heat of combustion per unit mass of oxygen reacted (AH^^) ^ constant for most materials. This has been demonstrated by Huggett [ ]. n terms of the present example it follows for Eq. (12) that

AH = 0.233r AH (25) ox The stoichiometric ratio, r, can be determined from Eq. (12) by

of mass flow rates, mass loss rate of the fuel and oxygen concentration at the

exit provided sufficient air is supplied for combustxon. Hence both AH and are found without any thermal measurements. A nominally constant value tor

Ah is 13 kJ/gO„.

ox 2:

5
THE ROLE OF FIRE PARAMETERS.

The parameters AH, r and L are of fundamental Importance in arriving

at the overall energy release rate in full-scale fires. The dependence of

these parameters on environmental conditions and effects of size, orientation

and configuration must be known. The data of Tewarson [3] suggest that

variations in ambient oxygen concentration and external radiant heat flux

lead to little variation in AH for a given material. Ultimately, these

parameters must be clearly demonstrated to represent material properties

in the main, and weakly dependent on the fire conditions and processes.

If that can be shown, they will have great utility.

More data and analysis are required to fully establish whether these

parameters are complete and sufficiently fundamental. If they depend strongly

on many factors, then their utility is diminished. Since most predictive

analytical relationships in fire require a knowledge of these and other similar

property parameters, a theoretical basis for understanding the performance of

real materials in fire may not then be possible. Reliance of material evaluation

would be purely empirical. Alternatively the establishment of a general property

basis, consistent with current theoretical methods, offers the means of

predicting and correlating results in full-scale scenarios.

FLAME SPREAD EXAMPLE . The steps necessary to understand the release of

energy in fire will be illustrated. This process will demonstrate the role

of the parameters introduced above and the various influencing factors. A

one-dimensional flame spread process will be considered for a material of

width, W. An external radiant flux distribution will be imposed on the

material at a sufficient initial value to cause piloted ignition. The

example is Illustrated in Figure 2. The material will be assumed to be thick

so that burn-out will not be considered. In general, the prediction of

extinction and its dependence on other variables must be considered to fully

describe the process.

The energy release rate is given by

Q

= W i

AH dx (26)

where m^ depends on time and position. The material will ignite in time t^

corresponding to q"(o) and spread to the minimum flux required for piloted

Ignition, qQ shortly thereafter. That transit time will be considered

negligible. Flame will now spread (at a relatively slow rate provided this occurs on a "floor" or laterally on a "wall") between x^ and Xg. At x the

minimum flux for spread, q

" , will be encountered and the spread will cease

The position of the flame ?font is given by

where

x,-x =

f o dt (27)

( 28 )

6
at most. The flame spread parameter C can be found from theory or experiment

along with the limiting heat fluxes [6]. The pyrolysis rate is given by

^f +

^e ^s

V

(29)

where q” is the flame heat flux,

and q” is the surface radiative loss,

s The flame flux is not generally predictable for realistic fire conditions

since it depends on scale, orientation, ambient conditions and similar

variables. In principle it can be predicted; however, progress has been

limited to simple materials and configurations.

In order to simplify the results for this example assume that qj is a constant and that q^ and q^ 2 represent mean values in the ignition and

spread zones. Also assume ra" = m" or sufficient air is available.

V b

Q

W X + W

o

* If * II I * If ^f-^s %,2

(t-t. ) (q”o,ig-^e,2^

for t , < t < t when x^=x . ig — — e f e

(30)

If the process were to become air limited then

m

0 = (^) AH (31)

where m Is the rate of air flow to the fire,

a This relatively simple result shows the various factors controlling the

evolution of energy in a fire. There will be ignition after sometime over a region defined by qo,ig’ ^ characteristic of the material for the most part [6].

Subsequently, flame will spread depending on time and other factors (eg. C)

The roles of the "property" parameters: AH, L and r are clearly shown. Finally

the extent of spread will be limited by the minimum external flux needed to

sustain spread q^ ", The significant effects of all the other variables have

been contained in*q*J. Questions of the invariance of parameters like AH still

remain, but the structure of the example is still valid. The variation of Q

in time is also shown in Figure 2. Of course, in a more realistic case,

burn-out will occur, and the resulting curve would give smaller values for Q

with decay to zero eventually.

The maximum value for Q from Eq. (30) can be written as follows:

Q

= w + w (32)

The first term results after ignition, and the second term represents the

flame spread process up to the extinction position Xg. For a given material

and external heat flux distribution, these distances (x^ x^) can be determined

provided the parameter q and q

" are known. Figure 3 displays initial

o , xg o , s

7
distributions imposed on a specimen in the ASTM E-84 Steiner tunnel test and

^ on a specimen in the Bunsen Burner test method. If a value of qo,ig “ 2 Vl/cva

is considered, then ignition would occur over 1.5 m in the tunnel and over

5 cm in the Bunsen Burner test. Eq. (32) would suggest that the energy release

rate per unit width (Q/W) would therefore be 30 times greater in the tunnel

test. If the material has a minimum flame spread heat flux of 0.5 W/cm^, flame

propagation will occur for considerable distance in both tests. This discussion

only serves as a illustration in understanding the effect of initial heat flux

conditions. It applies to test methods and full-scale fire simulations. For

the tests in this discussion, the vertical orientation in a Bunsen Burner test

or the wind-driven ceiling spread in the tunnel would add comple?cities not

considered. The forward heat transfer in both cases would result from flames

extending far beyond the initial ignition zone (x^) and in fact would contribute

additional heating to q'g. The resulting spread velocity would depend on x and

this flame heating distance. A general solution to this problem does not yet

exist, and the differences in scale in the two tests do not alone constitute

a basis for differences in flame spread that might be observed. Nevertheless a simple model will be described for upward flame spread in order to illustrate

the variables on which this type of flame spread depends.

FLAME SPREAD ON A VERTICAL SURFACE . The model considered is based on concepts

involving a prediction of flame height (x^) in terms of pyrolysis length (x ) based on entrainment, Spalding’s treatment for predicting burning rate, ^ and a flame spread model based on conduction in an inert solid. The

analysis follows:

Flame height is determined by equating air required for combustion with air

supplied. For r, the effective mass stoichiometric air-fuel ratio, the air

supplied is

m' = r mi (33) a f

where m^ is the fuel produced per unit time per unit width. The mechanism for

air flow into the boundary layer is considered to be by entrainment with the

entrained velocity

u = a u (34)

e where a is the entrainment constant and u is a characteristic velocity in the

boundary layer. The characteristic velocity follows from a momentum balance

neglecting the wall shear stress and treating the flame zone at a uniform flame

temperature T^

u =

>J2 1 - T^/T^ gx

(35)

Then

m

a

P u

a e dx

8
or 3/2

*; = 3 “Pa >J2 a - Ta/^f> « ’'f

( 36)

The fuel production rate is assumed to be governed by the convective heat

transfer process alone. The effect of flame radiation or external radiation

must be eventually added for completeness. From simple mass transfer

principles [7]

m'; = - )ln(l + B) (37)

t cP

where B is the Spalding mass transfer number and h will be based on turbulent

boundary layer flow with u (Eq. (35)) as the characteristic velocity.

or

h = 0.0292 - Re Pr^^^

X X

2/5

h = 0.0292 2 1 - Tat/T. g

V4/5

1/3 1/5

Pr X (38)

Then

Substituting

- Joj

m'^ dx

appropriately into Eq. (33) and solving for x^ gives

(39)

Xf = 6 Xp

4/5

where

3 = I (0.0292) (6/5) (3/2)r 2/3 2/15 ^2g(l-T^/T^) ^

1/15

(40)

2/3

Jln(l+B)

For polymethylmethacrylate (PMMA), B - 1.4 and r - 8; also taking a 0.1,

1.2 kg/rn, V = 20 x 10^ m^/s, Pr = 0.7 and 1 - T^/T^ = 0.75 yields

a f

Q 1 ^7 1/5

3 = 1.67 cm

If r were taken at four times stoichiometric then

of flame radiation would also increase 3. Orloff,

derive from PMMA flame spread experiments

3 = 4.3 cm^^^. The inclusion

deRis and Marksteln [8]

0 78

x^ = 5.3 X * (in cm units)

f P

The results of this simple analysis are in remarkable agreement.

The flame spread rate is determined by Eq. (40) and the results

(41)

from

9
Orloff et al. J8] that

X

_JP T

iln n n-1 (42 a)

where n = 4/5 and the transit time between x and x- is

P f

'

T = 2 (Tp-T^)^/(qP^ (42 b)

where kpc is the thermal inertia of the solid, T in its pyrolysis or ignition

temperature and q^! as from Eq. (37) is ^

’ —

_ • I! T _ m. L =^

( 1) „L Und+B). h(x )

1 p

(43)

Substituting Into Eq. (42) yields

jjE- = f . (44)

where f depends on the properties of the solid fuel: kpc, AE, r, L, T and

other less variant quantities. In a complete model, radiation parametirs

would also appear. Ignoring the dependence in the logarithmic term, the

pyrolysis front grows as

X ^ (45)

dx ^

'^'^P 3/2 and '\j t . Hence the spread rate increases with time and clearly depends

on scale or the extent of growth of the front (i.e. the pyrolysis length)

A simpler example will be used to illustrate the effect of a fixed flame

source as an ignition source and continuing source of heat. This is based on

an idea by Parker [9] to explain the ASTM E-84 tunnel test behavior. Consider

n = 1 and flame lengths are additive with x the flame length of the igniting

source. Also assume Instant ignition so that at t=0, x =x . In place of Eq. (42)

p o approximate

dx

I dt

%

x^-x

f P (46)

where T or q^ is considered independent of t. The solution is

6 exp\ T / t - 1 X = X

P o 3-1 (47)

and

dx

_J

dt

J1 = X 6 oT

exp (¥) (48)

10
The results clearly depend on scale and on the length of the Igniting flame.

The quantity 6 increases with B and in general can be considered proportional

to the ratio of energy release per energy required for burning. For large

B, flame spread by Eq. (47) is indefinite. For small B <1» the spread reaches

a limit of x /(1-B). In small scale tests the minimal effects of flame

radiation could result in B '^1> but for the same material tested in a larger

scale, B could effectively be larger than 1. Another view of B stems from

considering that most materials will not burn unless an external radiant

source supplies energy. Hence the burning rate expression may be represented by

ifi IIf

(49)

where the second term represents the external flux contribution to mass loss

rate, and m^ is the burning rate at zero external flux. For many materials

ni" is negative, implying burning takes place above some critical heat flux.

Using similar arguments to arrive at x^ as before, but replacing Eq. (37)

with Eq. (49), yields that

Xj = B Xp

2/3

where B now is proportional to (m” + —

)

2/3.

For ease in illustration, consider the 2/3 power to be approximately 1.

Then from Eq. (47) it is clear that flame spread will stop or grow

exponentially depending on the value of m" + q^/L, i.e. flames will not

propagate if this value is small enough. Hence, especially for materials that

do not sustain burning without external heating, q^ must be large enough to

promote continued spread.

CONCLUSIONS

This analysis has attempted to illuminate the processes that relate to

energy release in fire growth. Heuristic models have been presented for some

of these processes in order to show the significant variables that govern them.

Techniques for measuring rate of energy release using calorimetry devices only

make measurements for a fixed sample size. The interpretation of these

measurements into an effective heat of combustion property has been shown. Also

the pitfalls of measuring rate of energy release by thermal techniques have

been discussed. The oxygen consumption technique offers a more accurate

approach. In fire growth the total energy release process will depend on more

than just calorimetry data since the processes of ignition, flame spread and

extinction play a role. Although complete models for predicting these processes

have not been developed, it is clear that a set of parameters is common to

current models. The analyses presented have illustrated these variables.

More complete solutions Involving flame radiation effects will add some additional

parameters. The list of relevant parameters follows:

11
1 . 2 . 3.

4.

5.

6 . 7.

Heat of reaction, AH.

Stoichiometric air to fuel ratio, r. Heat of vaporization, L.

"Creeping" flame spread coefficient, C.

Minimum radiant flux for ignition,

Minimum radiant flux for flame spread^

q Thermal inertia, kpc.

There are likely to be additional parameters related to fire growth as models become more complete and specific. Also some of these parameters

are dependent on time and environmental conditions so that their most

appropriate representation needs to be decided. Nevertheless they are measurable for many materials as demonstrated by the work of Tewarson [3J

and Quintiere [6]. It should be emphasized that the intended application

of these parameters is equivalent to, but hopefully more general than,

simply measuring energy release rate per unit area [2]. In any case any

attempt to short-cut correlation analyses between test method data and large

fires by ignoring important features of a particular fire scenario will

not be successful. For example, a comparison of energy release data

from a calorimetry device with temperatures in full-scale fires without

concerns for flame spread could be deficient.

12
References

1. McCaffrey, B. J. , Quintlere, J. G. , and Harkleroad, M. F, , "Estimating

Room Temperatures and the Likelihood of Flashover using Fire Data

Correlations," Fire Technology , Vol. 17, No. 2, (May 1981) p. 98.

2. Smith, E. E. and Satija, S. , "Release Rate Model for Developing Fires,"

The American Society of Mechanical Engineers, ASME paper No. 81-HT-4, (1981).

3. Tewarson, A., "Physico-Chemical and Combustional Pyrolysis Properties

of Polymeric Materials", National Bureau of Standards Report,

NBS-GCR-80-295 (Dec. 1980).

4. Parker, VJ. J. , "Calculations of the Heat Release Rate by Oxygen Consumption

for Various Applications", National Bureau of Standards, NBSIR (to be

published)

5. Huggett, C. , "Estimation of Rate of Heat Release by Means of Oxygen

Consumption Measurements", Fire and Materials , Vol. 4, No. 2 (1980) p. 61.

6. Ouintiere, J. , "A Simplified Theory for Generalizing Results from a Radiant Panel Rate of Flame Spread Apparatus", Fire and Materials , Vol. 5,

No. 2 (1981) p. 52.

7. Spalding, D. B, "The Combustion of Liquid Fuels", The Fourth Symposium

(Int.) oil Combustion, The Combustion Institute, (1953) p. 180.

8. Orloff, L. , deRis, J. and Markstein, G. M. , "Upward Turbulent Fire Spread

and Burning on Fuel Surfaces", Fifteenth Symposium (Int.) on Combustion,

The Combustion Institute, (1971) p. 1329.

9. Parker, W. J. , "Correlation of ASTM E-84 with Full-Scale Room Fire

Tests", National Bureau of Standards, NBSIR (to be published).

13
Products

out,

m,

T,

Yqx

iH

Figure 1-

An

Idealized

Calorimeter
T

W

Ignition occurs over 0 to xq in tjg

Flame spread occurs up to x=xe

Figure 2 - Flame Spread Example

15
Figure 3

DISTANCE FROM BURNER (m)

X3

-I

U.H

<

UJX

(a)

X

6 -

5--

4

-

3

-

2 -

1 -

0 >

0

A

Horizontal sample

J I I A I ; I I I L. 123456789 10 DISTANCE FROM THE SAMPLE EDGE, x |cm)

(b)

XZD

6 -

5

-

4

-

3

-

A

A

A

Vertical sample

I

0 I I

I 1 I I I I ! I 01 2345S789 10 DISTANCE FROM THE SAMPLE EDGE, x |cm) (c)

- Igniting Flame Heat Flux for the ASTM E-84 Steiner Tunnel Test (a)

and the Bunsen Burner Test, (b,c).

16
NBS«114A (REV. 2 .80 ) U.S. DEPT. OF COMM.,

BIBLIOGRAPHIC DATA

X. PUBLICATION OR

REPORT NO.

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

SHEET (See Instructions) NBSIR 82-2536 DOT/FAA/CT-82/108 July 1982

4. TITLE AND SUBTITLE

An Assessment of Correlations Between

Laboratory and Full-Scale Experiments for

the FAA Aircraft Fire Safety Program, _ Part 2; Rate of Energy Release in Fire

5. AUTHOR(S)

James G. Quintiere

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

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

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

Federal Aviation Administration

Technical Center

Atlantic City, N.J. 08405

10. SUPPLEMENTARY NOTES

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

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document in<^qdes a^sigryficant

bibliography or literature survey, mention it here) The rate of energy release in fire IS discussed.

The significance of calorimetric measurements of energy release for materials is

related to thermal-dynamic parameters, namely heat of reaction and stoichiometric

coefficients. It is shown that a common set of parameters is necessary to express

ignition, flame spread and mass loss due to combustion and heat transfer in fires.

The relationship of ignition and flame spread to rate of energy release in fires is

presented along with a presentation on upward spread.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Calorimeters; correlation; energy transfer; fire tests, flame spread. Ignition; mass loss; test methods.

13. AVAILABILITY 14. NO. OF

PRINTED PAGES

[X^] Unlimited

24 1 1 For Official Distribution. Do Not Release to NTIS

r 1 Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

15. Price 20402.

[X] Order From National Technical Information Service (NTIS), Springfield, VA. 22161 $6.00

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