AIVC 11899
CH-99-1-3
Predicting the Position of the Smoke Layer
Interface Height Using NFPA 928 Calculation
Methods and a CFO Fire Model
William N. Brooks, P.E.
ABSTRACT
NFPA Standard 92B presents computational methods for
determining the position of a smoke layer in a large-volume
space. Although NFPA 92B is a guide to smoke management
design, the methods have been adopted, with certain modifi­
cations, by model building codes and are mandated for use in
atriums and large-volume spaces. This paper makes use of a
recently developed CFD fire model to assess the NFPA 92B
calculation methods. A total of 13 simulated tests were
conducted. Results suggest that the NFPA 92B Equation 9
method may not predict the fastestfilling of an enclosure within
the range of aspect ratios provided in NFPA 92B.
A- PLUME RISING TO CEILING
- - -
·-
___,{_
L.: -,
-,
'
\ 'tt /.
� --
INTRODUCTION
-
\\-
Prediction of smoke layer interface heights in large­
volume spaces is essential to certain building fire-protection
and life-safety strategies. Predicted positions of the smoke
8- SMOKE LAYER FORMS
layer interface height can be applied to egress design or to
property conservation.
Figure 1 depicts the development of the fire plume, the
formation of the smoke layer as the fire plume radiates
outward to the surrounding walls, and the smoke layer
descent. Figure
2
illustrates a cross-sectional view of an
atrium with a descending smoke layer. The terms used are
defined
as
H
=
highest point of smoke accumulation
z
=
height of smoke layer interface
ZcR
=
critical (design) height of smoke layer
interface
Zt
I
::..
\-1
follows:
=
limiting elevation (defined as the height of the
luminous flame)
William N. Brooks is fire protection department manager, Peter F.
C - SMOKE LAYER DESCENT
Figure
1
Smoke filling of atrium space: (a) plume rises
to ceiling; (b) smoke layer forms; (c) smoke
layer descends.
Loftus Division, Eichleay Engineers, Inc., Pittsburgh, Pa.
THIS PREPRINT IS FOR DISCUSSION PURPOSES ONLY, FOR INCLUSION IN ASHRAE TRANSACTIONS 1999,
V.
105, Pt. 1. Not to be reprinted in whole or In
part without written permission of the American Society of Heating, Refrigerating and Air-Conditioning Engineera, Inc., 1791 Tullie Circle, NE, Atlanta, GA 30329.
Opinions, findings, conclusions, or recommendations expressed in this paper are those of the auttior(s) and do not necessat11y reflect the views of ASH RAE. Written
questions and comments regarding this paper should be received at ASHRAE no later than February 13, 1999.
METHODOLOGY
Four calculation methods are used to predict the position
of the moke llyer interface in a total of 13�imulated test cases
usi,� steaQ.Y,;:�tate heat release rate fires.
--Method t:__._:_NFPA 92B, Equation 9 (calculation method
for regular spaces described in the 1996 BOCA Code)
•
H
Method 2-NFPA 92B, Equation A-26
A:ARJ.A OF
ATRIUM
Method 3-NEPA.92B, Equations 14 and 15, adjusted
for s�oke layer temperature
Method 4--Large eddy simulation CFD model
•
Table
t ·is a: 'US! of the individual test cases-. With the
J
exception of Test-No. 10, the selected aspect ratio are consis.
,, . ,
Figure 2
'· i
: u, '<
. t�
:
t�
'
..
t
H-Highest point of 'smoke accumulation; 1.; ·
: z_:_Height of s �oke layer' interface; Zcrn Ctitical
(design) height of smoke·· layer '\
·, interface;J ·zrL7miting elevation (height"of
·
' 1 ;;, : ·
c
llJmirlbus flame)•
·
'' ·
I
.I ..
;,
"i•
'
'. ···. (;_.;It. •. If.:,-.� i, '
'• ' '
A
ltoriZontal cross-sectional area' of atrium
Aspect ratio
A!H2 /·.
=
'
:.
'
·:::: ·_; . 7 �
'
b :>=?- t
·
-
ii ' --- '.� t .,,;t,.1M
f..TP'PA. <:st�ndarcl 101 (Lifej?Jei ·:r coae) ·1aifrl'\Iir1996
BOCA National Build1��g Coile (Jio't� {ij96)\1ke..th'e NFPA..
·
Sta1,1
_ dard 92B metliodolog;y in � mannex; that link� p�e position
of the smoke layer at a particular tfme to the requirement for
a smoke management system (see BOCA Code, Section
922.2, and NPP.A l 01, .Sectiop. 6-2A1;). The llnJform·Building
Code (ICBO 199?)J;l9es not �til��e-�tj.rne c<;msideration in its
large-volume desi� criteria. I.nstead � sms>�e exhau�t systel!l
mu t be capable of1milntainfog an interface height 3".1 m (10
ft) above the high'e t walking sllrface'in the"'sin6ke
' ione (see
ICBO Code, Seotibn 905;5.2. l). Therefore,itbe time-of smoke
layer descent is a critical factor in NFPA l@l!:and the BOCA
Codei design but is not relevant to ICBQ Code design.
,
A �tevi�,�s P.�per ,�y t?e u�or,@roo�� 1��7) showed
�
:!
.
.
th t the two desWJ
.meth9ds m the BOCA COde produce
.
: ·1 v r
i�
;
results that vary significantly. In fact, ari exampTe iri the·19'93
'
Comment a,: (B'dcA i � 9�) ��s us�cfto ill��trateiffi·ka sm��e
re9�i.....;�d,·v:h
manageme�t
in)1the c"af ic'Uia
ti �n �ethod
'f .
:
t
. 1ft.J,:1.
�
for regular spaces is used, while a smoke management sy. teJP
·
is not required when the calculation for irregular spac�· 'is
used.
. :::;.d
·
·
s;.�i��-·i �
r
• .
.
•
•
.
2
.'
,,
Test No. IO.represents a more· slender aspect ratio that is.
not contemplated by_ NpP� 92B or the 19,96 _BOCA Code. It
h�.�.�ee� inclu�� for sensitivitr P�Tos��·
,
All of the cases assume ,a fl.� hotjzontal ceiling and. a
uniform square hoi;izontal cross-sectiona' l area y.-ith vertical
,rr.. . !.
l•
�·
r J.
sideS:
;
f
.. rt.
•
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It,..,
CALCULATION METHODS
·:·t '.�-
1
. ..
�·C;.i.HI
···,
.•
. r
,,
·,�
J
' "'
... ·
..
Methods 2 and 3 :can be defined as zone models, which·
predict. well·defiried srnpke laytm positions !atl any' given time
and·distirict-differentiatinn,between the smoke lay.en.and the
clear<allr b�low. Smoke layer interface positions are assun;ied
,·
,, • .
•
' '
1 ; r.-..
•
�·i
,'_':nn )
. , , JJJ'.
-: .
TABLE 1a'
J '-'
'
-
·
"
""'
··�selec,t��fT�lC�ses i· ,,,, ·
' .t� leh� 'J:e�t �oi\<!ii�o�s Sf U�I�])
:-.::i ... .�.:
,
·.-
-.
' •
·)
'
.
. ..
•
..<i
�
,,
-
l _j
!1
rr:
••
'1
-
,,.,r
•
.
• 'I
"iHeatRelcase
"Test No;, Aspect Ratio r!Area'(m2): Height (m),,: Rate (kW)
I:
''1 'l
: ,, '.l• '1
."..'2':""
,-3,
'
.�
A large eddy simulation, fornp\itaifoti'a! fluid° <iyniirrt'ics
(LES. CFD) model:(McGra.ttan �t,al.�1199�) is usell.'in an
attempt to reconcile:the differenc.:e_s among a.number qf ca
_ - lc.:ulation methods.
"
;,
.
tent with NFPA.92B and the 199(iJ;�oCA Co4.e�J:Iea.t rel_(!ase
rates include the range of fire sizes'that are mandated for use
by the BOCA Code (2110, 4640, kW) and tlie ICBO Code
(5275 kW):-Selected areas represent
th� author's·opinion as to
o}
where the design methods will be most widely utilized.
•·· •·
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···�·
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10
11
12
13
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,
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1
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,
,,
r
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. :•
or:r?��o
'1
:: :14:.:r;1),
•Ii
14"'"J u•
'l
14
0.9
0.9
..•
-�
,
0,9 I
0.5
Y;
·
·
'''·3'0'.5 '
9#Q�"
"
,
. t ""i:; :'0;9 ;; ...
.
..
;. S>l..
.
•" 00.9
.
.
·
·-1'9'303
'10''..i' 11.
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921 J
• 9i7:y
---
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-
9391,,i!·
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.
.
1
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·1'>l8:3·0.i'.
·
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1'.le?OO.�J fiS�3':1
43 1
�.672
:,r167:Z.
' i
,,0.
464�
�'
4640\_ ·-.
,,
\
'
·_4400:
,,
1,�7:)8
.,
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544
Je
25'�9 JJ, '"· ·4400 ur·
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4640
43. l
96 93
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464Q
2t 10
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2110
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929
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CH-99-1-3
;1
TABLE 1b
Sel�cted Test Conditions
.1._
I
10
100,000
2
0.9
100,000
0.9
,100,000
10
10,000
31.5
;2000
0.9
10,000
.105,,
2000
0.9
10,000
105
4400
14
10,000
27
4
5
J
6
7
'i:.·8
,.
!'
H�il't Release
Height (ft) Rate (Btu/sec)
1
3
.·.r
.
9
.
,.!J ;:: �...
I
J
10
11
12,, . .. ........
L�·
100
2000
333
,
4400
'·,4170
.)4
14
.�p.900
L100,000
·o.5
10�000
141.5
4400
14
�80,000
141.5
14,900
0.9,
18,000
141.5
9,200
18,000
i·Ml,�
·-
( ··O�-��t{·
.
•
....
�
[ ;-·,!·
85
·
I "'./l�·;.
·
.
,, '
,
4170
520
('.,,.
•
to be level and to fill atnum: volumes much like an mverted
.
versio_h of wate� � l�n'g a '. bo
' cket.
')
1-,;
,
•
I
)
'
"'•
j
·
(
1
0
j
. .
ll; '.
Method 1 is also a zone model, with the excep'tion th�t it
does not define the position of the smoke layer interface'.
Instead, the results of this calculation ffeeJ�pc;I are,tq . be viewed
as the first indication of smoke, or �- oegin.i}ing of the transi­
ti(m between clean air andceontaminated all:. (NIWA 92B,
Figures Hhrough4.and:accompanyingidemnitions). ltdoes not
assess the .quality:of:the:environment at·the fransi.tion point;
only that this is the:point where· the transition begins to occut.
Method 4 is the LES CfP: m<:>QeL, relying on a much more
precise calculation
t!te characteristics of
the atrium enviJ-.on ,qien.t: �i&"inedi0:�1 ��1�to d�e the posicl101
;:{:!!' . 11 c .. .,, ..: 9 , �. J 'F..,.h. , ·•
ti.Q.n \YQI}!"�. tern �r��e �l!!IE_ge_ 9c,cur§_ as�a res��� of p�_ u�e
in.ter{l.c;won wi�h the ambient air.
1 ITher�.is norsta'n'dilra to define .the -position of the �moke
t�?l�.J�������o:e�i�JiJ�
J
(1)
�
height from the floor to the smoke interface (m),
=
time for the interface to extend to Z (s).
=
H
=
height from floor to flat ceiling (m),
=
horizontal cross-sectional area of the space being
filled (m2).
= steady-state heaf release rate (kW),
A
4400
}3.p
Z
Q
2000
60
1.1 1 - 0.28 ln [(tQ113!H413)/(A/H2)]
=
where
(Selected Test Conditions [IP Uni�])
Test No. Aspect Ratio Area (ft2)
ZIH
Equation 1 is a correlation, representing a "curve fit" of a
limited number of fire tests {NFPA 1995).
Method 1 does not readily lend itself to a hand-calculated
solutio.n for t, given a particular value of Z/H. It is for this
reason that it would most often be used in a "pass-fail" manner,
as presented by the BOCA Code to determine if the smoke
layer interface has reached the•critical height (design objective
level) in a given period of time. (The 1996 BOCA National
Building Code and the 1997 NFPALife Safety Code define this
period.of time as 1200:1-'<!Conds,)
?.:1
·:'-''
The usefulness of, this method is presruited by the 1996
BOCA National Building Code as a sin.gle�pqint "test" to
determine if the smokie layer interfac�-.has reached a given
point (Z/H) in a defined time period. Ho,wever, with some
manipulation, the use of the method can be expanded to graphically plotthe P �ti t\O� ?r{ the ]ayer at 81}� �iven ?me.
'"
; , .
\
,
Method 2-NFPA 928, Equation A.;26
\
,
The. poi;jtion.of
the s�oke 1ay1er int�rf.:!!c.cr, ?i �s J?redi,cted
\
. '1,{...
1 •
' .
t ... ·,f
�·}
at.an}'..llme usu�� ijiefollovieng equation:. . .
..
.
,,
.·
•
.·
•
•
.
•
•
•
•
•
'
•
! ,•
�...
'
t
....
'
-
''\l
Zffl ,:,,:tf +[2kv(tQll3tfl'V·3Y/g(AfW)]}�312
'{'�..!·:�:Ji':� '1:1:�::
whereJ,;
z
r
"
.
:
.
_
�,i
•.
>".· .r.:.:).:J
J
Q,
'
.
;l�
. 2·'.
,
..
;::.Ji:
,
;,T
. ·=
.
(,.•
' .: ;:.i
",
·1J
. .. ·�
·'
;:
;::: �e for the ihierfabe to extend to' Z'(s), '' ..
'
L
=;=
<,
'
•
frounio6; tb flat ceilirig (m), ·1' '
:..
:
i�
o
O •
"
.r
�'
1
�tef,lCIY,�,state he�t re�ease ra�e (k\Y),
:
�
(2)
l. J
;', 'k::·height from theTflfuor to.the smoke iliterface (m),
i{ve ·� height
'
·
•
. , · ,_:.. .
•
·;
· •
·
. . ,co
11' ·• �:
:j
ri
inteffa
�: KD.1,..ift".'�
riiber Ofpintii7
. a�fii
iis op16:°\ITiB-a
fay�r
,
.. r ..
• &;'\ fa-a
I
.
are·· proposed ·(ehow 1995; Soderbom,
numQtr of metlro
(
:;:t
,. '
'
I' I'
•
1-9 92; He et aL- 19�8) Experimeiital..prograrri.s use .combinatio.lLQf 1yj�t,1.al ...9.P.s�atjon
_ s, Uf�W.Q..�oup!�. tree�, �d·}�ght
�bscutation mbasurement equipment record the p.osition of
the sl}ioke lay"fr"at�y �veri time (Yamanii.and Tan'afca 1985).
;nrer�fo;e,' me' re-sutt'S:-oftbtn:aicµlations will �ary �n-that they
may be predicting.different-pneriome'n a Th�t is, Method l is'
p:r�dkti,ng '.'.first in_�lJ�aJj.gl_l _of�smqk�,·� M;etho_ds �.i111d 13 111".f!
predi'et:ing si.Jllila r· smoke la�r' positions,, and Method 4 is
t WOWcfbe made in an ej<.permuch·like visuaJ o6�rvations
�
.
:
- �imemal��ro-gt:nn;· -�-·
-'·
A., c
Methot( 1-NFPA 9_�!3. _E�u�tjor:t�
Basic Calculation; Method. '!fhis method relies on an
integrative apptdach that utilizes the following NFPA 92B
. '·
plume mass flow rate correlations:
to
; .
:
CH-99-1'.a
'.
·
'
; ,i'
·
_
�on of the smoi(J l�yer-intert'�c�, Z, is predicted
The -posi
at any time
...._
·
'
mi�ng Jbe''following eq��tjon�_.i_
·
··
1
.....
-ihorizontal cross-sectional atea of tbe spac¢. being
'1filled/in2);.'-'.0"
;
;jl
'
·=
::::
�
•
'
•
•
entrainment oonstant (use 0.064 m413t[s-kW113]).-
•
"
'
. · 1 �tho g E<J ilati°'J ' 1
;;
�\
h i� �as�o? a.��b�t �f. a ��be� of.
ffi:�. �ts, Equ�ti�n �:· acco�ding tb,�A 92B; is a theoreticfill!'.
based equ'Ationrfor : inoke fillin� "aen.ved usi.I)g the law� of
c �seNhtio·� �·of'hiass .an.d" 'en·erg'j t?, detennin th� additional
vol�� bbing supplied to'the up#er la)'.'erf,. (NFPA 1995, Appen·u�
·· :J.I ·1·
;�· ·· 11· ' - · ,. , . ,,,.
?
f
··.,
aiX" i\-3-6,L..2).
..
�
�
•
•
I
'':
I•
a
'
• • •
..; !,
•I
••
j/
,•••
•
'J
i
Method a.......NFPA 928, Equations 14 and 15,
��jµsted for �woke :Layf!r Jempera� ure
,,
3
Lm
:1
= 0.071Q/3z513 + 0.0018Qc (NFPA 92B, Eq. 14)
Vl:'.?ere
m
Qc
where
''li''
• .
= mass flow rate in plume at height Z (kg/s)·and·
(3)
J'
i,
,
'·
= convective portion of heat release rate (kW),
:-
·'
(4)
.I ,.
and
m = 0.032�?5z (NFPA 92B, Eq. 15).
(5)
Equations 3 and 5 define a mass rate of smoke:]Jroduction.
Equation 3 is to be.used above the limiting elevation, calcu­
lated as follows:
z1 = 0.l66Q/15 (NFPA 92B, Eq. 13).
jA (6)
Equation 5 is to be used at or below the limiting elevatiolj:
Calculating 'tile
position is not straightforward as is
the case with Methoos 1 and 2. Method 3 requires the following iterative calculation procedure:
layer
·
1.
2.
CalcUlate smoke mass production (m) using Equation 3
based on the ceiling height (H'),
Convert smoke mas.s production (m) to smoke volume (V)
using the folloWing;equation:
,
where
v
p
3.
4.
-.., ... .:.. .
. ll = m/p
·�
-
(7)
= volumetric rate of smoke production (m3/s) and
.;
· in.;:.
'1'
= density o('rnoke0(Rg7rri3f .:- '.
,..
.
.
.
l-1
,.
,
.
·�
-:.:
'.
Smoke LayertTemperature Correction
NFPA 92B provides no guidance regarding the ti�e otthis
calculation method. The 1996 BOCA Code Commentary.
iil us trat� the''iterative na"iure of the calculation but fai1s
adjust the volume of smoke production based on a smoke
density correction. As reportc;:d previously(Brooks 1997), tl'fe•
BOCA Code biregular ceiling calculation method is.based on
smoke density at21 C (70°F). Therefore, the resulting c<iku­
lations .will represent the·, slowest filling· of the volume (i.e.:, !
smoke with1 the greatest density win occupy the smallest'
•:Jf
,•r
, ' '
volum� per kg).
In order to determine the 'sensitivity of the calcultRioni:
method tQ ..smoke density, the' smoke layer temperature is
assumed·fa1be:uniform and equal to the average temperature:
. . 1,
of the plume centerline.
Adjusting the layer tempera:rure will result in ·a decrease'
in smoke density and will increas'e -th� volume ·elf sm()i(e
produced. The increased smoke volume will mean faster fill,··-·
ingiof the atrium;r
For eachtest case, an average plume temperature is calcu· ·,_
lated using the folldwing method:-;.:�··
'it;;·
°
, �
fl
1.
I
•
�1 <"
'tt)
• ••
Subtract the incremental smoke layer depth (dZ) from the
ceiling height (H). The new height becomes the smoke
layer interface height Z.
5.
Calculate smoke mass production based on the smoke layer
height (Z).
6.
Repeat steps 2 through 5 until the smoke layer interface
height descends to the limiting flame height (z1). At this
point, calculate the smoke mass production (m) using Equa­
tion 5.
' ;L ,,
whe�e,
T cl
•
i·
., (!•,-. ....
1
elivilion (Eq\iitfio�:
6)�'
.
�--
•
T CL= TA+ 25(Q/1 3/(Z-Zo)513) (Klote 1994)
• /''
_
.
.
;-1
. .,,
"·
·:
1C
·'·
•
.
..
'=· �plume1cepferline temperaturei(l'�y,. .
:
I'
•
I
(8)
·,
•''' .
·1 :'•
-:r
For the atrium heights and heat release rates considered in
this analysis, the virtual origin Will be assumed to be at floor
level.
,fi ·''- ''
2. Calculate average plume/centerline temperature:
..
where
TAVE
TH
T1
3.
(9)
.
'
= average pilll'Jl centerline temperature (°C),
= plume cei;it€rurie temperature at height H,
= plume,,C�nterline temperature at limiting elevation.
.,.�
-,r.u
,�
Calculate smoke density, using the average plume temper-
The calculation method results in instantaneous distribu-�
· ,i;ltute:
/
,
tion of smoke under the entire ceiling surface, without regard_,:.. ..-- · ·
, ,..,,
to transport time from the fire to the.ceiling.or wit1toUi·regard
.,.. ,..,..-v
. P = �lRT .
to the time required for th"e smok�ovement horizontally
wl,l.en(
under the cei li ng surface. The method also fails to �ccount for .
= absolute pressure (101;325 Pa),
p
any horizontal entrainment tha t may occur as the smoke·:,
R
=
,g�. con�tant
(J/kg
K),
moves ,radially outward from ,.the ppint,,where. �e plume
,\
- __)\'i� -�
1F"\
. '.
centerline impinges on'"the ceiling.
= ap�olµt1< temperawre.(K)F 27,3 .+.J'AvE·
T
.
..·
4
;(
• ,.
·;•,
Distribute the'silloke v<lilinie uit'lfoimly'u'nder the ceiling
surface area (A) by dividing the smoke volume produced in
the first time period (1 second) by the area of the atrium.
This value becomes the incremental depth of the smoke
layer.
·
l
0
Calculate the plume centerlirie temperature at ilie ceiling of
the atriuni''.inctat the fire's liin1ting
>
. .
•
.
.
•
1•
(10)
'·
CH-99•1-3
4.
The value for Equation 10 is inserted in "Equation 7 and
, , ,remaiJ;is constant for the entire calculation period.
' )_
··'
Method 4-Large Eddy Simulation CFO Modef
.
:
tt
"
The large eddy simulation CFO model (McGrattan et al.
1997) has been developed in conjunction with National Fire
Protection Research .Foundation at the National Institute of
Stap9ards and Technology. The model is seen as a valuable
tool to redµi.:e the overall costs offire1experiments by devel­
oping computational methods· to predict fire phenomena.' In
addition to predicting and evaluating experimental results, the
mode� �s able to assist in pliµming experimental pro'grams.
il\terface position:as it descends. Also note the linear nature·of
the descent as the interface descends below the 7 m (23 ft)
height, corresponding to ZIH 0.26. The dashed line reprf.::
sents the:<Yamanatranaka predicted filling. Figure 3 most
closely represents Test 5 presented in this dise.ussion.
=
CALCULATION RESULTS
I
Figure 4 illustrates predicted volume filling for each of
the 13 tests. In this figure, the Method 3 calculations were
performed without layer temperature c,o,�ection. Note the
Fgr:;this analysis, the LES CFO model is,li>eing.used in
plaq� of 13 fire experiments. While the validation ofthe model .
is still in process, its use appeared to present .an interesting
opportunity �o simµla,te fireJ:mnditions in order, to compare the
rt<�µl� from the thre� ,zone models to the LES CFD model.
e
..
-.,1
......
::C • I
(.!)
LI.I
::c
a
I
�a
I
�fl:' '"TEMPERATURE
.�
o
l,1
I•
;J'.:1 '
\<,r:'j, _
•
:ii
\ .:
Q,0
,
•
� a.::o-:--�----!
•· .•l'·
'
...
l•JJ,
0
Figure 3
1---·..
j
\a
'
10
i '
�
1.00
t.
---CALCULATED BY EO(ol
A •
Figure 3 illustrates the differences among observed data
in a fire experiment (Yamana and Tanaka 1985). The test data
represent the fillingooh,24 m (18.7.ift),by,30.m.(98.4 ft) by
26.3 m (86.3 ft) high enclosure. T�e aspeHt �atio f.t,!/H2),is1.04. "
No mecha} �al V�l�tjl.��on, i us d q�ring fhe}e,st. �he fire
r
}
. t�1}?e_ 1300 kW·
has a steaay-state heat release rate re�wc�d
(1232 Btu/s). Note the difference among tlie photometer
thermocouple, and visual' observatioi\s; of 'the' shloke layer'
THERMOCOUPLE
"'
PHOTOMETER
EYE
0
I
J!O
I
•
A-1
[]()
-
� q 1!ffi g �
1
o�
0
Cl
The LES CFO model predicted the position of the smoke
layer interface in each of the 13 cases. Since there is no· math-·
ematically defineci methocl to determine the smo� fayer inter­
face position, the LES CFD: modeler visually observed the:,
,� -the atrium �nclosures. In, a,.�1vnse, the i
s �J-�t�
.
observatiop pt the !Jmoke layer mterfacc descent u1ang
the
.
LES CFD° m0Ci1e1 is somewhat similar to observing" an actual
test.
I
:J• .
�
0
25
0
5
0
.
10./
I
, J
10
TIME cmrn)
Yamana/I'anaJca,..cxperimental results. Aspect
Ratio
1.04, H ·,;,, 26. 3 m (86.3 ft); Heat
�.{f.e.�f!04�/?-a,�� =}�q<J..k,W (1232, Bt'!(s).:
=
l
,;•
,) '
1') '
·
•
"•[;";_ •;.';::_
� \( ,"•
;.J
.,. ,
0.80
.
0.70
i
j
0.60
.,... ,,,,!'ii� 0.501 ['" '"
• _....,.._ •
;�:�,·�•'Ji..
�u.
I
•·-•
o.49* rrt�h
0,20
ME'T
O, 10
0.00
4
CH-99+3
.
.
,
�
•'
.
!o,
..
,1�
•;
.
••'
I
la
I
��
40
50
60
NORMALIZED '.ffMF:
90
:
.H
•
'ioo
.!'.
(,j
110
I.:
:,.!'
'--' �1
�··
==
30
•.
0
•: , ...·· ;
D 2 INFPA 928, EQ A·2
I ·, \1 l � •
�.
ETHOO 1 (NFPA 928, ea
,,oill!
Figure
"!1
,. ·
'
.
.
I
,-.
120
' '
·/
.
..
'
.,
)
'
i'
''
Calculation methods 1, '2, ''iifiii 3.· (Cdlculation method 3 riot adjusted'fo r smoke lqyer temperature; Meth�J 3·:.
,, r· '
'
calculaiions id'in.tifiea bjiest n'Umher.) "
\
5
clustering of the Method 3 curves around the Method 2 curve� :.: .. longer predicts the fastest filling of the atriums. Tests 4 and 7
Also note the position of the Method 1 curve. For these calcu-;r,,, now fall closer to the origin than the Method 1 curve. The
lations, the Method 1 curve represents the fastest predicted.
Method 2 curve now represents nearly the slowest filling rates.
filling of the atrium volume.
Figure 6 -compares the results from the LES CFD--simul
Figure 5 also illustrates the predicted filling i'at�s, but in
lations to . Methods' 1 and 2. The LES CPD results · are
this instance, �moke densities have been adjusted based on the, 1 trendlines derived from the raw data observed from the LES
calculated average plume temperature. Note the shift of the
CPD simulations (see Table 2 for LES CFD �Qserved data).
Method 3 curves toward the origin. Note:�so that Method 1 n�
The LES CFD simulations s�
_ ()W the general dJstribution of the
•
,)_
1.00
__
--0.90
1
.
,
o.80
0.70
�
�
0.60
�
�
\.<'
i
=
0.50
0.40
0.30
""
0.20
METHOO
1,:
0.10
METHO
'
0.00
0
Figures
1
•
10--·-·- 20- ----30
�_'� i
.i�
----
.
,-,
- -40-
.
. -50- - -.
60-- - - - --70NORMA�IZED TIME
80------ 90----
100- -
.
)
'
I
J20
,110
•
I,
-
- -
--·---
·•
I
Calculation methods ·1,1;:2.iiaiirJ i· (.Cafoulatfon ·m.ethod J.;�aajuste(f1"(ir ,s'mqke
- --,�- - layer ,t�mperature; Method· 3
calculations identified by:t:est nuinber.r - '�
�;- . --- . "r1
--- · I
"
. - --�--'- -- + ___ ....,
.
.
-
·---- . - --
-·--- -
.'
· -- -
· -
'.· :1
1.00
-
::c;
• ,•.,II
I •
Jt1
0.90
-
-
·�-
••
.
--
r
,.
0.80
-
I!
,
·-·--·--
•l I
0.70
.
·'
·"""--··
i.
,
.
'·
0.60
.
--�,,,·-
.. �. ,:'
0.30
r
�.
r
•
·--
··-· . -
..
,·�:·1Jd;.·:';,i.--{
-'
J
•
•1,,·
i"- ..:-.•
;- .
'. ,-,
•
( ..:.
i."
,
r.,.
I
....
-
.
.. _ .
---
•'· j.\
.
trL_
----
:..-===-===-�-=----: .
0.20
�
Lt �:·
0.60
0.40
•.. =.i
- .. --
;_
!
-:.
-
'
�
..
; II
·�
·.· :·
0.10
0.00
0
10
20
30
40
60
60
' 70
NORMALIZED TIME
Figure 6
6
90
_L
,•
:x: l:::::;
". 100
· · ---
'•·I.��; ·,;L_,
I
'10, r
•-
'12.0
•
..--.-- •
....
�
'•'
_
. '
'•
Calculation methods 1 and 2. (Compared to large ed.<;J,y simµJatioh C.fQ prMi.fte d c),1,rve�;_ LeS.- CF!) q.�rves
identified by test number.)
·
CH-99-1-3
TABLE2.
LES CFO Experimental Observations
.
Test 1
.,
Height (Z)
Height'(Z)
Time
m
ft
sec
.m
30.5
100
,,82 •::
0
9.6
'25
20
66
15
49
7.5
25
10
95
85
75
65
SS
20
3
70
10
2
7
32.1
0
333
75
312
279
24
16
110
246
130
180
sso
213
148
115
J 821:,.
•
''1700
30
220
20
290
16
280
.. 10
7
4"oo
450
..
Heighf (Z) · ·: ',"
Time'·
m
ft
sec
32.l
105
0
24
79
16
52
Time
9
30
16
75
22S
246
s
10
250
250
so
164
450
40
148
131
600
180
llS
8.2
800
7 ·:
6
900-·,_,
98
82
1100
20
66
1300'
49
lSOO
1.
180Q
"' '·
27
_
___ ..
.. 5
16
4
_,.
�.
2
23
20
13
'
.,
-,
-
10
7
0
·-
20
.-
35
45
63
90
125
300
350
Time
m
ft
sec
43.1
141
0
30
98
65
22
72
2
7
36
150
375
900
"''
800
·1800 "'
·'
10
• ·
33
'·Tbne
..
sec'· ..
0
25
50
135
150
Test 11
Height (Z)
ft
m
43.1
141
30
98
22
72/
10
sec
�-·
,,../)2.6
.
Time
ft
8
150
43 '
75
Test 10
310
Height (Z)
m
(;_-66
. . Height (Z)
m
:·rt'
· '·"-'·
Test7
750
20
.-·
215
7
2
375
2S
CH-99-1-3
3
100
213
1.
0
26
90
20
Height (Z)
11
85
0
Test 13
Time.•
8
279
6
10
ft
72
85
_.; 33:
900
60
200
10,.,.
7
'
150
23
lS
2
102
7
30
700
31
0
3S
10
22
75
4S
3
30
312
7
30
400
141
333
2
500
43.1
101.6
250
16
. . 13
310
,-·
72
23
2S.9
150
22
7
Height (Z)
33
so
12S
5
m
45
141
Test 9
80
Test6
'
Test3
sec
30
5
�
1900
ft
79
23
2·
r200
0
98
43.1
39
30
sec
m
0
]S
Time
ft
sec
52
sec
105
7
6
850
Time
52
9
350
Height (Z)
55
9
300
ft
m
sec
1400
65
12
Height (Z)
Time
ft
Mi
I
160
Height (Z)
Time
98
95
�eight (Z),
Tests
l®O
m
46
90
6
1750
ft
66
14
16
131
20
60
s
40
30
18.3
500
600
25
m
0.
35
164
35
sec
23
so
45
..
,17 .
1000
Height (Z)
101.6
Time
200
280
33
ft
'
! ·,
Test 12
Tests
31
Test2
m
,.
Test4
�-
33
13.
.. ,�
Time
,•
·1
sec
o·
250
600'
I
/1450,
1825
..
,
.....
.
,
_.
�·
....
.'I
.
.
,
.
'
·,··
7
simulated filling curves. Note the similarity to the Figure 5
Please refer to Figure 3, which illustrates the results from
curves in that Method 1 does not predict the fastest filling rate
a fire experiment in an enclosure very similar in aspect ratio to
LES CFD results
7
the 0.9 aspect ratios assessed in this analysis. It would appear
predict filling times that are 50% faster than the Method 1
that the Figure 3 test most closely approximates Test 5. Note
Figures 7 through 10 compare all of the calculation meth­
mated by the Method 2 and Method 3 calculations, but the
for five of the tests. In fact, the
for Test
that the Test 5
predictions.
times. The LES CFD observations also·reflect the linear nature
LES CFD predictions
of the smoke layer interface descent observed in the Yamana/
are shown as individual points. These points are the raw data
points reported by the
LES CFD observer during the observa­
Tanaka experiments.
,., ...
Figure 9. Only two cases represent aspect ratios of 1 0. In
tions of the test simulations.
Figure 7. Methods 1 , 2, and 3 approximate the LES CFD
calculation from ZIH
faster filling than the
=
LES
both cases, Method 1 predicted filling times with reasonable
ZIH O.i Method 1 predicts
CFD observed points; but Methods
1 .0 to
accuracy. Method 2 does not appear to be reliable for these
=
cases. Method 3 compares favorably to Method 1 and the LES
CFD in Test 4 �µt does not predict Test-J. with a similar degree
2 and 3 predict slower filling rates. Due to ' the- asymptotic
nature of the Methods 2 and 3 curves, the predicted smoke
of accuracy,"'
LES
layer interface arri val times begin to diverge frmn the
... . Fi��
CFD calculations below a value ofZJH = 0.3. Note the div�.,.,
-gence of the Method 2 calculation fi:gµt the LES- t::FD observations as ZIH decreases.
·
•
.
LES CFD· observed points.
However; .�. the
mar�.
=
}.l:h the LES CFD resttlts"for each case. Method 3 predicts the
r.;;·
Test 7 filling reasonaoly adequately, but it overpredicts filling
tjmes for the other cases.
H
with the proper characteristic shape. Below Z!H
=
-
0.3, the
Method 3 curve's asymptotic shape begins to differ from the
LES CFD
observed points. Method 2 represents midpoint
values for these six tests. Note the linear nature of the
LES
CFD observed data as ZIH approaches 0.25 to 0.2. Until this
point, Method 2 and Method 3 produce results that are reasonably close to the LES CFD observations.
depict
w
overpredict fi��ng times by a wide
For ne�ly a of the . , ANALYSIS
\
0.9 caSes, the Method . . 3 predibtions prbdUce· curves ...1 '
A/f/2
LES CFD· observations
Method .2 'appears to be unsatisfactory and fails to correlate
�
height of the atrium i ncreases, the Method 1 curve begins to
10. All of the
substantially, faster filling than the Method 1 calculations.
Figure 8. The Method 1 calculation again predicts faster
filling than the
are closely approxi­
Method 1 calculations predict significantly shorter filling
ods by separating the test results into the four selected aspect
ratios. On each of the four figures, the
LES CFD observations
•
•
Although the LES
, ,
,1
. , , .,.
1 '
'
CFD mo\fol ma ridt be'fully validated
y
based on the number of full-scale fire tests, its predicted results
have been used as a comparison to zone model calculation
methods provided in NFPA 92B.
It appears that the currently ava.i:lable calculation methods
f,
may not be useful over the full ran e of aspect ratio defined
in NFPA 92B. The reasons for tliis are not known, but the
"'
'lf
/f
1 .00
i
·' '
0.90
I
o_ao
I
l
0.70
!i:'
�
�
�
g
/'
0.60
_.,,,
0� 50
J
'
:
/
/
i
'
0.40
. .. . .
- · """ ·
0. 30
,· Ix TEST t o fO.s. 43.1. 46401I
0.20
0.10
"
Figure
8
7
.
0.00
0
10
20
30
Summary of results. Aspect ratio =
. ,40
50
' 1'"'so;.
,_-·,
'70
NORMALIZED TIME
80
'>
90 '."; · . _10,0,
' • , 1 1!>',. '.
": . '
o J 20_ \\'\I\
0.5. (LES CFD data represented by individual points.)
CH-99-1 -3
1 .00
J.. .
. · .
0.90
·.
0.80
·,
, 0.70
J !
,, 1
"E
�
I
· ·.
0.50
ti ·
1.
. • I '. ,
0.60
0.40
I •
'
,
.
ll
.
.
,
' .
.
·
:;r.'
1,
, t TEST :}:10.9; ,1 ()1 .6, 4640)
' I
.ln 'TJ
'
I
- TEST 5 10.9, 32. 1 , 2 1 1 0)
c TEST 6 10.9, 32. 1, 46401
. .. :rE�T .12:10.9, 43 . 1 , 9693)
,r; - TEST
1 3 1 0.9, 43. 1 , 544)
'J,
METHOD 2
.� : .
I C• t
,,
'
1 \;:0.30
I•
2
o.2p
. '·
'"
,0
�
..
(�
��
_,
,,..
_�
,�
••�
-�,_,_�........
. ,,_,_
.., �
;-..-...�
c;.-.
�
....
-+'
.. c,...,
�
r;
.......,.
..
o.oo +-��--+���....,�
�
-+
�
, �
::-1'.'
;�
0
10
110
50
7Q ,
30
20
40
60
.:\,p,�; ; I .90
,1 00
120
., ,
I '.• .
Figure 8
' 1.:.>.
·� T
,,
,,
Summary of results. Aspect ratio
frid�viduall�. i1de1'f:.�ified.) ;
i:) ··-x:
1
t
A
i'
1J
,,:. . ; Oi90
n
' �_,
; _,,,., _ � �
,
i ;_.
r
.
[ ' NORMALIZED TIME.
'....! '
t'
,
-
' I �·-
'_1
1l"
:
�
.1
J'
·1 t
.
r!!
' ; ' J -.
I ;·
,
I
·1
... •
!
")
,,
.
.f
�H
;
�I
t
'
0.9;-(f!BSfocFD ��tg iep.f��e!l��d b>' )��ividuaf,points; Method_) 1 �urv;s
.
,
=
'
�-'.I :
1 .00
.. ·
·�·
x TEST 2 10.9, 1 0 1 .6, 2 1 1 0)
q r.1.ff1
l...!
,
. .�.' ' t
·<[J
,. ,
l .
�' f �
...J t •
t0
�1 '
. .--:. :.. 1
£
-�-�.1 _:
.
J
•
rJ,
r ,
.' J j
.
,,; , !
Jt.
. . . ..
, , T•1
.i
.
.J
;_; "J . C ' ;f�C"l1
!:
·n
'.
i. �
• J
j,
•:
'
: /'!�'
,
·,,
:)
.
...
{
..
0.80
0.70
0.60
�
�
i
0.50
c TEST 1 110, 30.5, 2 1 1 0)
+ TEST 4 110. 9.6, 21 lOI
0.40
I
0.30
,1
0 . 20
0.10
:�···
:.I' '
60
:
Figure 9
Summary of results. Aspect.ratio
individually identified.)
c
CH-99-1 -3
.
=
.
. . . ..
70
80
90
100
110
120
NORMALIZED TIME •
'
JO.
,
i· .
(LES CFD data represented by individual points; Method 3 curves
,
9
1.00
·1:
0.90
I
o.eo
I
·1
"t . 1�
·�
.
0_10
�
I
) :�
. ;' •
I
. ..
•It.
I
I';. ·
� 0.50
,.
;l;
�
j
• I
·..
(I
0.60
'
I'...
0.40
• TEST 7 114, 8.2, 46401
• TESt 8 114, 1 8.3, 44001
6 TEST 9 114, 25.9, 4400)
�TEST 1 1 114, 43.1 . 1 57181
0.30
0.20
_
-, , . ;
0.1 0
O.IJI!
�
80
-
-
•
-
, .·
90
• /',-"'"f� •ti1
.
.
110
100
1 20
.
•
; 'j . i!'"
Figure 10 Summary of results. Aspect ratio = 14. (LES CFD points reP.resented by indi�i41ftfl ppints,�., Method
3 curves
1·
.. . ,
---- 1• . .
"·
--· indfviaually identified. )
·
��� �
�
·
_.
�s .represent�g the
ces_- e signifi .!ht for. as�b.Cha
diff
sho�� _slr1:1£�Un�s (�pei(t�tio =:. 14).
cases, Method. I overpredids fillilig 'times by a significant
margin. In other cases, Meth11>d 1 unde!predicts fiHirtg ".tiines
. i 'i
: -· .
by a s�giiificarit margiii. .J ;1 .
....I� '· : '
� ti _ .
: J '- /,f. 1!llJ
(-lJ � i ' • · &.J
;!] ')),,
r
i ts fr<;>.xn :.the .LES
� p co���es, �e a,n:,9�t� P.9 �
CFD model with a number of curves representing mq4ifica' -· n
.:. : _J;Ji�ttiod 1.:§eems_J() projlij¢� a sroo�i��er fii_un&;�ufv�::
¢at exhibits.th� li_{lear nature ofthe r_ate of filling at ZJ# ':.! 0:3
'and bdow. However, i! appeats tha� the_selection _9f �n Loitial
term " of 1 . 1 1 limits the usefulness of this method. Iii some
• ;
r
· ;rtfi�
�
.•'
'
.1
tiqn� t!J . th� initial. tqrm o� the Equati_qn_. L Foi;. refe:rence .
. ' , · ..
;(
, ,,,
. . , i.
. ·).
, .
f
,
�.
.L
• '"
Ii•
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Figure 11 Me_thod 1 curves with q_<Jj1Jstedfirst terrµ_y�. LES CFD obser�fiH°.'!k (J,.E�. .Clf� �P.!a_points,.,)1,� t'i
10
-·-
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r:J. 1 � . : i� ,�(.1: • ..,
· : "' ' ;,.;rEST,& f0.'9/32.1-. 2:1;101 ' .' '
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J'--', -'- -"--'---_;,,;_------"'
-lffi lM''r-'i-'1r..,_,'<-o. 70 +.. .
:� ( . ·:.rJ; ,,,,; . �P!JE�f_6 f9!"9,·:��At4:640� f lEST_�l1.f;;�.2::�64Jl} ,
:,
,
0.60 +----1+1'1--T-'l-'<-..,_..-'...-:..._�---��-�-----j
• TEST 8 114, 18.3, 44001
u·J�!-rEST ·a ,.,�: 2s.s: '*ioop ( J
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u .:- � 1r:�; . .
0, 50 t---t�l'illll'r-"r'6"'"'""'�.-�°'------;:-o-;-�
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.
CH-99-'1 -3
purposes, the curve noted " 1 . 1 " approximates the Equation 1
curve. The additional curves represent Equation 1 initial term
values from 0.85 to 1 .35. Note that each of the LES CFD test
observations appear to follow one of the adjusted Equation 1
curves. From this observation, it would appear that the adjust­
ment of the initial term of Equation 1 for a particular combi­
nation of aspect ratio, height, and fire size could result in a
calculation method that would reflect the observations from
the LES CFD experiments.
Table 3 is a presentation of the test cases, separated on the
basis of fire size, aspect ratio, and area. Each of the 1 3 test
cases is represented by an entry. Although a number of addi­
tional LES CFD tests would be_required to provide entries for
each configuration and fire size, it appears that some general
observations can be made.
1 . As the aspect ratio increases, the initial term decreases.
. -2. As the area increases, the initial term increases. , ·
3. As the fire size increases, the initial term decreases.
TABLE 3
Adjusted Initial Term Values for Method 1 Calculations
Aspect Ratio
Area
are based on the observed
The following conclusions
'
differences betweeh thi LEs CFO observations and the other
calculation methods.
1 . Metlwd 2 (NFPA .92�,- Equatien A-26) is not«a· reliable:j .
d
': r pg: iptor of sino,iq! layer positionoiexceptfor a narrow range
of atrium sizes. The results from thi!!;equatiqp., wiJJutµ.<e!y
underpredict filling times by a wide margin using the
Joni'biilations of hea-rre1ei: e ratei, heiglits��an<l arefil'lli. this
:K) t""': ! ; -/' '
) "" r.t7 ' J. (f :�
J ·J u 1
t• �::... ..
·h:..·�tudy.
'
:
2 .-·:i;·'Methbd' 11 {NFPA' 1-�h1l E�u�ti'oA 9) d�fh�(�rodu6�
"conservative" results (that is, results that can be relied on
to predict filling times -that are faster than would be
produced in actual experimental conditions). in all of the _
cases that are foreseeablf 1yii�� ;t?�- ��PfcaPle range of
aspect ratios. Method 1 ap�,to, predi9� pmch faster fill­
ing times for certain 0.9 aspect ratips anq-much slower fill­
ing times for an aspect ratio .0fd4FAn!;adjusJ1netltof tlie
initial term is suggested in'orderto:make'the method a reli­
able indicator of smoke layer p6sl.dort. ,,.
: �· � . �: . · ; j ; ,: r2:; ;- •
,
3. Method 3 produces reason!:lble results f� �pect ratios up to
1 0. However, at aspect ratios, greater :than 10, Method 3 is likely to underpredict the<time of arrival of the smoke layer
interface by 100%: A oorreetion°fadoi:' (or method) for
'
ruy
Method 3 is beyond the scope�oflhis art
- - ----- - . -· ::sis. ; . e4. High aspect ratio spaces do nqt appear to fill in accordanc
with previously accepted: zone model assumptiohs. µe­
reasons for this behavior are not known.
9300
.
.
RECOMMEN DAT IONS . .
1.
1 700
'
-
CH-99-1 -3
,,.
..
_,_/
Area
/ 0.5
2 600 0,, .-·
-·· 93
.
@
Aspect Ratio
-
4700
I
1 700
93 0
·.
•I
,
.
� ��
I "\,
, f-.
0.9
10
1.3 4
1.1
\ ' ) ',
1.22
n 0; Heaq_�1elease Rat,e -.
'
93 0
9700 kW
Aspect-Ratio
' 0.9
0.5
10
14
-·
4 700
r
�
- �'{
1 700
93 0
·,aAl.12
,_
�
·'
.
15700 kW
Heat Release Rate
Aspect Ratio
0.9
0.5
10
14
0.98
2 600 0
-
: 0.9 7
Heat Rel�,� �ate
2 600 0
Area
' '· · i
.
,4500.. kW_
0.8 7
· ·
9300
I"!
\i_,,··. �
L2
1.18
Area
' "!: '
,
,
1 700
14
1
,,
·. -
·;
2110 kW
Heat Release Rate
'
·
. -
"
93 0
:.:. f
j .
(�
A standard definition of smok�_ layer interface should be(Ji.
developed. This definition should be expressed in mathe� .,
matical terms in oi:der to
experi- .(. .
'
" evaluatel _(or. �r�valuate)
mental data prevrously couet:fe and to eVah.i'ate future '
_
1.13
4 700
•
·
14
10
0.9
0.5
2 600 0
•• ,,��- ·
CONCLUSIONS
544 kW
Heat Release Rate
9300
4700 .
1 700
. _, _.9 �0
t
'
,
�
. \.�
}�
•I'
11
experime11tal data. The definition would be particularly
useful in CFD simulations where mathematic functions are
utilized to determine the characteristics of discrete cells in
an enclosure.
2.
Additional LES CFD simulations would be useful for
aspect ratios between 0.9 and 10. The data will be useful to
further validate present Wlle models or can be used to
develop improved zone models that can be used for the next
several years.
ACKNOWLEDGMENTS
The author would like to thank Mr. Kevin B. McGrattan
for his assistance in the preparation of this paper. Mr. McGrat­
tan spent many hours working with definitions, assumptions,
and procedures in order to produce the data from the 1 3 exper­
iments. Without his help, this effort would not have been
possible.
REFERENCES
BOCA. 1996. 1996 BOCA National Building Code. Country
Club Hills, Ill.: Building Officials and Code Administra­
tors International, Inc.
BOCA. 1993. The BOCA National Building Code/1993,
Commentary Volume 1. Country Club Hills, Ill. : Build­
ing Officials and Code Administrators International,
Inc.
Brooks, W.N. 1997. Comparison of "regular" and "irregular"
methods of calculating smoke layer interface heights in
1996 BOCA National Building Code. ASHRAE Trans­
actions 103(2): 554-568.
12
Chow, W.K. 1995 . A comparison of the use of fire zone and
field models for simulating atrium smoke filling pro­
cesses. Fire Safety Journal 25: 337-353.
He, Y., P. Fernando, and A. Luo. 1998. Determination of
interface height from measured parameter profile in
enclosure fire experiment. Fire Safety Journal, 3 1 (1):
19-38.
ICBO. 1997. Uniform building code. Whittier, Calif.: Inter­
national Conference of Building Officials.
Klote, J.H. 1 994. Equation 10, Method of predicting smoke
movement in atria with application to smoke manage­
ment. NISTIR 5516, Building and Fire Research Labo­
ratory, National Insliluli: of Standards and Technology,
Gaithersburg, Md.
McGrattan, K.B ., H.R. Baum, and R.G Rehm. 1 998. Large
eddy simulations of smoke movement. Fire Safety Jour­
nal, 30: 161 -178.
McGrattan, K.B., H.R. Baum, and R.G Rehm. 1 997. Large
eddy simulations of fire experiments. ASME Heat
Transfer Conference Proceedings.
NFPA. 1995. NFPA Standard 92B, Guide for smoke manage­
ment systems in atria, covered malls, and large areas.
Quincy, Mass.: National Fire Protection Association.
NFPA. 1997. NFPA Standard 101, Life Safety Code. Quincy,
Mass. : National Fire Protection Association.
SOderbom, J. 1992. Smoke spread experiments in large
rooms. Experimental results and numerical simulations.
Swedish National Testing and Research Institute Fire
Technology SP Report 1992:52.
Yamana, T., and T, Tanaka. 1985. Smoke control in large
scale spaces, Part 2: Smoke control experiments in a
large scale space. Fire Science and Technology 5(1):4154.
CH-99-1 -3