HomeMy WebLinkAbout1993/04/12 Board of Appeals & Advisors Agenda Packet
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OlY OF
CHULA VISTA scANNED
BUILDING AND HOUSING DEPARTMENT
CODE ENFORCEMENT DIVISION )
7/¡q /ù'l ?I
Date
April 7, 1993
MEMORANDUM
TO: Chairman Gingerich and Members of the Board of Appeals
and Advisors r
FROM: Kenneth G. Larsen, ~,~~
Director of Buildin 'd Housing
Secretary to the Boa d of Appeals and Advisors
SUBJECT: REQUEST FOR APPEAL TO UNIFORM FIRE CODE- ARTICLE 81:
CURTAIN BOARDS
Please find enclosed the related Agenda materials for the Monday,
April 12, 1993 Board Meeting. As you may observe, the background
materials transmitted by the applicant, Tomes, Van Rickley and
Associates to support their request is quite extensive. A
representative from their organization is anticipated to attend the
Meeting to respond to any questions the Board may have regarding
their application. Fire Marshal Gove is also anticipated to
attend.
As you will note by the Fire Marshal's transmittal via myself to
the Board, the Staff recommendation is to deny the request based on
the evidence submitted to date. At the time of prepdration of this
transmittal, I am currently unaware of whether addition information
will be provided at the Meeting by the applicant to support their
request.
As always, please do ,not hesitate to contact either myself, Brad
Remp, Assistant Director or Carol Gove, Fire Marshal in the event
further information or clarification of the support material or
staff recommendation should be neccessary.
Att: Agenda Package
276 FOURTH AVENUE/CHULA VISTA, CALIFORNIA 919101(619) 691-5280
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CllY OF
CHUlA VISTA
FIRE DEPARTMENT
April 7, 1993
TO: The Board of Appeals and Advisors IJI'Y
VIA: Kenneth G. Larsen, Director of Building and ~
FROM: Carol Gove, Fire Marshal ~
SUBJECf: REQUEST THAT CURTAIN BOARD REQUIREMENT IN UNIFORM
FIRE CODE, ARTICLE 81, BE WAIVED - THE PRICE CLUB COMPANY
BACKGROUND:
Tomes, Van Rickley & Associates, A Fire Design Group is requesting a waiver of the curtain
board requirements pursuant to the 1991 Edition Uniform Fire Code, Article 81, as adopted
by this Agency. The issue of the curtain board requirements has been discussed at length with
both the Applicant and Applicant's client, The Price Club Company, at several meetings,
Based on these discussions and the support documentation provided, the Fire Department
concludes that elimination of the curtain board requirement pursuant to Article 81 is not
substantia]]y justified.
RECOMMENDATION:
The recommended action to the Board of Appeals and Advisors is to deny the Applicant's
request.
DISCUSSION:
Article 81, Section 81.1 07 (b & B3 & cl) requires that smoke and heat vents and curtain boards
be installed. Table 81,1 07-A states that for designated storage height not to exceed 20 feet,
curtain board depth of 4 to 6 feet is required, Maximum area formed by curtain boards is
either 3,000 or 10,000 square feet, depending on the option selected (Attachment A), No
exceptions are noted within this section or table,
447 F STREET'CHULA VISTA, CALIFORNIA 91910,(619) 691-5055
. .
The Board of Appeals and Advisers -2- April 7, 1993
The purpose of curtain boards is to compartmentali7f~ a fire, enabling the fire sprinkler system
to activate and control, and in many cases, extinguish a fire. The heat is collected within the
curtain board area, thus localizing instead of spreading to involve other areas.
The 1991 Uniform Fire Code Section 2.301 (a & B), (Attachment B), states in part: "(a).
Practical Difficulties The Chiefis authorized to modify any of the provisions of this code upon
application in writing by the owner, lessee or a duly authorized representative where there are
practical difficulties in the way of carrying out the provisions of the code, provided that the
spirit of the code shall be complied with, public safety secured and substantial justice done,"
RESPONSE:
The Fire Department cannot substantiate any practical difficulties the applicant would
encounter with the installation of curtain boards.
Alternate Materials, The Chief, on notice to the building official, is authorized to approve
alternate materials or methods, provided that the Chief finds that the proposed design, use or
operation satisfactorily complies with the intent of this code and that the material, method of
work performed or operation is, for the purpose intended, at least equivalent to that prescribed
in this code in quality, strength, effectiveness, fire resistance, durability and safety."
RESPONSE:
The Applicant has not offered any alternate materials. With respect to methods, the applicant
is proposing an increase in the minimmn venting ratio from the required 1:100 to 1:75. Staff
has reviewed this proposal and believes that the twenty-five percent (25%) increase in venting
ratio does not warrant the reduction of the mandated curtain boards pursuant to Article 81.
Contained for your reference is a portion of the National Fire Protection Association (NFP A)
publication No, 204m, "Guide for Smoke and Heat Venting," The Board is advised to review
Chapter 3, Curtain Boards, as researched by NFP A for purpose and practability of curtain
boards as a passive non-mechanical fire protection system (Attachment C).
In the event further information or clarification ofstafT'srecommendation should be necessary,
please do not hesitate to contact me at 691-5055,
KL:kw
(040693,MEM)
CITY OF CHULA VISTA
-
ATTACHMENT A
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ATTACHMENT A
TABLE NO, 81,105·A-REQUIREMENTS FOR FIRE PROTECTION ·
:g
SMAll HOSE ·
SMOKE REMOVAL CONNECTION c:
AUTOMATIC MAXIMUM MAXIMUM MAXIMUM Z
DESIGNATED ;;
COM· STORAGE FIRE· SMOKE BUILDING MINIMUM PILE USABLE PILE 0
MDDITY AREA' EXTINGUISHING DETECTION ACCESS AISLE DIMENSION) STORAGE' ~ I VOLUME 1'/1" Adclilional "
CLASS (slI·It·1 SYSTEM SYSTEW (S.c. 81.109) WIDTH (It.) (It.J (tu,tI.) Mtct!anic¡1 Vtnts V.lves Equipment? I:
I-IV 0-500 NIR NIR NIR" N!R NIR NIR NIR NIR NIR NIR NIR "
:¡;
501-2,500 NIR Yes NIR' 8 fl. 100 40 100,000 NIR NIR NIR NIR m
Yes NIR NIR' 9 100 40 400,000 NIR NIR NIR NIR C')
2.501- 0
12,000 0
m
Option]
2.501- NIR Yes Yes 8 II. 100 40 200,000 NO! Yes Yes Yes
12,000 aJJowed
Option 2
12,001- Yes NIR Yes " 100 40 400,000 10 NIR NIR
20,000
20,001- Yes NIR Yes , 100 40 400,000 10 Yes Yes
300,000
Greater Yes 12 Yes 9 100 Un- Un- 10 12 Yes
than limited limited
300,00011
V 0-500 NIR NIR NIR" NIR NIR NIR NIR NIR NIR NIR NIR
\01- NIR Yes NIR' 8 II. 50 20 50,000 NIR NIR Yes Yes
2.50013
2,50]· Yes 12 Yes 8 fl.7 50 30 75,000 10 Yes Yes ...
·
50,00013 :..
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TABLE NO, 81,107·A-REQUIREMENTS FOR SMOKE VENTING AND CURTAIN BOARDS' I:
"
MAXIMUM DISTANCE :¡;
DESIGNATED MAXIMUM AREA MAXIMUM TO VENTS FROM m
STORAGE CURTAIN BOARD FORMED BY VENT AREA SPACING OF WALL OR C')
COMMODITY HEIGHT DEPTH CURTAIN BOARDS TO FLOOR VENT CENTERS CURTAIN BOARDS 0
CLASSIFICATION (leel) (Ieel) (sq, ".) AREA RATIO (Ieel) (leel) C
]O,OIX) m
I-IV lOOf less " 1:100 ](X) 60
(Option I) over 20 to 40 Ó 8,000 1:75 100 55
(·IV 20 or Jess 4 3,000 ];75 100 55
(Option 2) over 20 10 40 4 3.000 1:50 100 50
200r Jess Ó 6,000 LSD 100 50
V over 20 10 30 6 6,000 1:40 90 45
30 or Jess 4 2,000 1:30 75 40
I For storage heights in excess of those indicated, an approved engineered design shall used.
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ATTACHMENT B
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5'"2 rt ;:2 =- £. 5- ~ :7 .:;.., :: :; ~' :: ~ .., (";, n "2. =. Q. .... < 0. ::ri'J':¡ ... ::I ... =- ~ :;. :r ë: r:
~ to: -§ rt 0 <. n -< =. ~ ~ .., .... a. :;::. ~ 0 ~ ;::;. t'Þ en "';:" . ñ' ¡;;. C" c.. "'0' :: !"'J C =- 5' ::i-
0"" . ....,n~ -=" ~....o.:¡;> ...." ::r....nc C,...,::! - E;
5- ::.; 7 J"J:;;:' :r ~ 5 ::¡ ~ :;;: ~ g ,..., 0 to: ~ 5- r=. ;I oN _. c.: ~ ('¡ :: ::. ...., c: ~ ¡;rQ'Q, to:
(t ,.; 5" ~ to: ~ ~ c..). ~~. ~ :: .g ;:j È.::! ~ õ' 0 0 ~ 2. =. 5- 9... ~"E 2.. r;.> ~ ~
~ 0 'T'; ::r: ~ <: "" Q ~ S c.. g '-<. £. '" 0 ", :. 0. O::J 1"10 c rJ 0. 'J; Q a 0 "'0 t.: ~
~. ;:: c.: õ ?" ~ =- ~, _. :J., ~ ,'" ;:;. ¡g.. ;. §. :;:, ~ ::I g. m :;;.... ¡;; ~ g. =. 0 :: ::! ~ 0
(J'Q ('¡ "'0 '" '"' II: ""' ... ¡if 0 _. 0. Co: 0. '" c.. "" :E _. _ "' n 0. 0. r;.> C ... no 0 _,_,
?J ;. ~ (7 ~. ~ =---, ';< .=: 3 -<"S¡ ë = n ;J 2. "'0 :I. ~ C ::I g C ª S!:? g ~ ~ ~ 5
c ;:j ~ :r 0 (J'Q 5- >- ;:j 0 n ~ .... ¡;r::r a .... ~ .... ¡;;. c: ~ _. ....., ~. n ~ ::r ::; Q.. ", ...
~ £. =-[=- ~"':g ê-Q..~ 5..?f -,!i;E[g.~ ~::c a-~~.."':, ~ 3. r:; ~ U)
~ ~ c - 0 =. g-... ",,' ~ "1;J 0 0- c: :r. '-. .... no-'" r=.. Q.. c.. 0- n 0 ¡;¡ C" ~ 9-: 2 ~
:= ñ' ;::'X~ a.~~ p c ~==. 3,~~ ~~'< Š m ,<3~'< ~ £5;ì.'< ::r:;:,"1;J c:
Q "" ;r ..,..c::: ,.... c.. t.: Õ. "'0 '" ::r c: ¡;; - :=. '" c...... :I. en '" c¡ n c¡ 2 - 0 ;. 0 '" Co: Z
... . ,. ... c: '"' -, - n t.: -, ::r - ,..., "0 -.::r . _. 3 -,.... '" _. 0- _ ::I
C "'0 to: ~ _. '< :: '" 0. t:J :E - = n ~ ri -- -.", ~ g- - :='I c..'" ::I :r. c: g n :;;
... a ~ !t ~ :r ~ § 5 ::;, 5- =- ~ =- c.. a· ~ 0 = = õ ~. ~. r;;' 3. ~ 8 :. 0 ';: 0
!=!"¡ "" ...(t....,c...c......"~cnool:~ o-...",,::Inr."'c. !;_,.::; 2J
"'~ ::5:::rfD C:::='Ioc:::I::rr.-' a::l.....,::;:O::l° (\¡::rc¡/JO...n't:l0. ::I.... I:
(\¡ '" ,. '< '" "".., ~ -..... - -, ... .... n _. .... 3 n to: n. 0 .-- __ _
"" - - c: '. '" " -' r: ::r". .... 0. '. n ::I ... :: '" V'-' ... ::r
9.., ~ r. Co: '" :.:~. 5- ~..' ::; r. ~' "" ~ ....¡ if "" .'" 0 0 "R c.. r') õ' ~ "'_ ::r 0 ~ " 'TI
C¡' 3~~e--n':<õ':;-':-c¡c..::rn-·C¡e.: ::I§o-.g::lc..&~ .....,t-ic: $
"'0 . - ~:E c¡ :r. .., 0. -, _ 't:I n ::I - ....., ~ '< (t _ :='I"
0- .., ¡;:. "'0 "0 ~ ::r c: ..;. ... ; 5' ",' "1;J -§ "'0 8. .... ", '< ~ 3 ~.§ =: n 0- ~. 3 ~ m
c8. r'I",:!"" ","'~::r C;..t.>-:CC1(þC"VlC1 ::1::1 ::ro<-'t'iI c¡I"Ð.... (")
~ C :I 0 g ():: 5"::1 0. £, :r c: ñ :: :1 "" ", ~ ~ ('I VI" =. 0 :: ~ Q 1"10. :- ~ ::; 0
_. n ==- <. -, 8. ~ "" /JQ "'0 .... .... ;. to: .... ¡=¡ ::r :E ('I '< c.. _ =: ~ .... :! ... :;; r. c.:
::I (7 0 ", 0 ~ n :;' 5- E¡ ::. ~ 0 a ::r c: r=.. r;.> 0 0 0- e; :: 0 ::r::l C" 0. ¿ :I m"
1"10. ..,c.......,...,'<. ''''''''.~'_'<..,-. '<...(J'Q-,~rn<I"Ð::I ,,<
ATTACHMENT C
(;E\'I·:K\l. 1:o..:¡:() {\1Xll()~ 204M-7
NFPA 204M dlll-ing whICh (tt) the eflects of the fire will be confined to
the ctJl'falned area, and (b) visibility up to a dcsig-n-
Guide for ('k\'ation ano,,{' the HOOf of the curtained arc¡.¡ will he
1l1;lintaiued. This minil11um dcar·\'isihilily dcsiRt1 timc will
Smoke and Heat Venting ;¡('ilit¡¡te ~Ilch élClivifjes as locali~1g ¡he fir~, ~rprélising the
lilT s{'\'t'n!)' and l"x!et11, ('V;-Hllatmg tilt' hili III 111 I-{, and mak-
ing all informed decision OJ] deploy men I of pnmnl1l'1 ill1d
1991 Edition e< llipmC1!1 10 he used I()f fire fìghting. The minimum
dear-visibility dt'sign lime is measured from the time the
lirst \'cnls flCli\,;¡[('.
Chapter I General Information
1-1.4 Vents arc nOl a substitutc for sprinklers Of other
1-] Importance. extinguishing facilities.
1-1.1 Sincc !he end of World Wal II 1hen' has hec1\ ,I 1-2 Application and Scope.
gCIH:ral trend toward th(' l()[ls1runiol\ 01 LJrge indllstli;d
and storage buildings widl t':\!t'llSi\'c 11I1dl\'ided Ho()]' ;1¡l',I~ 1-2.1 I'¡()\i~iom 01 Scnio¡¡s I':~ through -t.,1.:~ an'
In mam cases. largc ILIHli\'ickd IIlHJI .!n,-'d~ ¡tiT tlnl'~~,!l\ ¡nll'IHkd IlJ ofIeI guicLnlcl' in the design oftarititic.s f()f the
tÙr rhe lunni(lIlal operd! I( f] oj ! he huilding. ()nc I ('sill I, L'n!\,-'rgellc~ \e[][ing ,)1 proùllcls (If cOlJlbu.sti(Jn frclll1 , l!nCOIl-
from a hrl' pfotection \"1l'\\'P0illl. h;¡~ been the !nnt'~I~t'd 1t.:1'!Il'd {¡ITS III n{)n~prlnklelT(J, SllIgk-"lOl) huddll1gs.
pOlential Ii) " large loss hITS in\'oking l':\temi\'c indi\ldlLd 11¡ ()I'lllatio[l regarding \'l'llting in sprillkk'l'cc! hllildings is ,J
hn.' areas. To a great c:\!eJ11. thl~ telldl'IH\ hits hCt'l1 l¡fl~l'l ¡winded 1t1 Chaptn () 111l' pro\,i.,lon" df) no! allcmp! to <~.
Ihrough !he IIHTeased IIse oj ,\\Iloll\al\( spllnkk! ¡Hott'( - sjll'cdy limier what condilions venting mtl"t be provided
tlon. as this is dependent upon an analysis of the individual
situatIon.
1.1.2 Furthermore, large undi\'ided !loor areas presellt
extremely difJlcult hre fìl4luing problem". since !hc ,111(' 1-2.2 Th(, provisions of this guide may be applied to the
department nUl"t enter these arca" II) oldcl' to comb;!t III n IO > slon of multiple·st()!", buildings. J"here ¡Ire many £Ca-
in (('Illral porllo!1\ of the buildl11g. It tht' lire de]>dr!!1lt'lll lmL'~ !]¡,¡t would be difliui!! 01 ill1prauic...al [0 IIHorpOl:¡¡!t.'
15 ullable 10 enter because of the accul1\lIldl1()11 01 (¡Cd 1 ;lnd into the lower stories o slleh build1l1g.s.
sllloke, hre hghling dJorls I11d\ he reduled to ;1 lut de
application of hose SUTdl1lS (0 pni11lctn ílred~ while hre ."., . .
consumes the intenor. \\ïll<!()\\ Ie~~ li\ldding~ ab() prt'Scllt 1.-2.3, 11us glllCk òot's not applY to other \·(·ntllalH).n (or
similar hn.' hghtlng problems, Ont.' tire I)]'()tt'l ! 1011 to()1 !]¡;-j! hgh.!l11g, ,., ma\ he ~~H case with rn{)n {o~s and sky.hg~ls)
may be a \'alllable asset for fire hghllng o ler<1!Jo!1\ HI slIch [!o]glled :' ,J regulal!ol1 of (emper~lUre WI.thlO a hulld~ng.
buildings is smoke and heat \Tllting, (;uidancc is pnJ\ickd for personnel c()m~()rt 01 prod.llcfl~>n equlpmen! ((.)otmg,
herein rclali\'c to the use of smoke and heat \'cnting OJ .!O \Tnlll1g prm·]d.cd for explosllm pressure relief (.~N
S¡'¡--'A 68, G/lIde fur Explo.\/oll Venlmg).
1.2.4 Building construction of all types is included.
Curtain 1./' ,~\ F,re b¡¡rrier
r'd'"" ';~~~t~.
.. ~,\'\vh"'ß '
....- - -
+ Small ·:;e
Fire sPec la' '\azard,;ial
°"9'" deep curtain 'ard
boards
figure- J·I Be-havior of Combustion Products Under Vented
and Curtain{'d ROIJL
1-1.3 rhO eli/krl'llt !ypn of .~ln(LIIHt' ;Irc p¡()\idcd I ht' --~ Ai _
hrsl ha" !o d() \\îlh ¡]w \t'111I1\g of 11J1II1t"d-~r()lIlh II!\,' _,a - ....-a - - ~~""'~.-:7.---=-~--
rhcs(' dlT I¡rt"~ II1;II;t1t !1o!c'pn!cr! (I' gIIJ\\ 11('\"lld.l __..::: -:..... -,~ -
predilLlhk hl';¡!·rl'1cd~{" 1,11t' H\ hdIIJ\\III:": tlw It'(I)II\IIWI)' _ --
d;I!IlJI1~ 111 Ihe (;¡~t' of liI1111('c!-"I ',\\lh 111(". ¡ l'IILIII1III\I]I ,,¡ _~
Ihl' dl('i h 1>1 (hI' lilt, !I) 1\1( !q~H'I \,ilIIIJ\(' ,01 (hl' (1111,IIII\d -.. - ----:- .-'
,II(,~I (II t'l(' {l I~II\ (,111 In .!llIl(lli.ll\'d .1' ¡"ill..:. ,I' 1Ii\ Idl!ìli .,'
]I).L:" ((I11~IIIj(I\ql\ It'11].II)¡, 1111.1(( 11]( '("llld 1\IH "I ~III'¡- ...
dlHt" I" Iclt'\dI1l1IJ !hc \('111111" ,)j Jil(' III.I! ]f !111111\Lk'll .--,
\\ill [0111111\1(' 1(1 grol\ !(I '()11H·'·"(lnkl1lll\11 ..Ill I-¡H II)I~ II! ( :..;>~j."d:"~~~"':'t~1-,_'~;-- ..'
()fcon!lIll](.\l~-g!"o\\-¡h !lle. th(' "'p('nll( glllet.lllle PII)\'IClctl
"llows onl' to establish d 11l!1l1lJ1l1111 pl('dit[dhk d(,Slgl\ lJlm Figure 1·2 Plant With Roof Vents.
1991 Edition
· -
204M-8 S\ Ol\E :\"1) HEAl \'E~TI~'(~
1-2.5 The concepts set 10n11 in this ¡.{lIidc W('IT dC\Tloped 1-4,3 II is [0 be reco~niz<:d thaI many plants will }¡;¡\T
for venting nres in large undivided fioor areas with ceiling buildings or areas with different ftlT hazards. Accordin,l.{h,
heights sufficient 10 allow the design fìrc plume and snlOke \TJ11ing !;¡ciluil's IJI<1Y he designed Ii)!" Ill{' appropriôllt' hn-
layer to dcvelop [normally, 15 n (4..~7 Ill) OJ' greater]. Such growth chal'anclislics as discussed in this gllidl'.
conditions arc frequently encountcred 111 induslri;d and
storage buildings. The in c,fmalion in Chapin 4 rclélli\'l' 10
fire growth was specihcally dcveloped fÙr these occupall- Chapter 2 Vents
(ies. The application of these concepts to buildings of other
occupancies or lower ceiling heights requires careful engi- 2·1 Types of Vents,
neering judgment.
Principles of Venting. 2-1.1 Experience has shown that any opening in a roof.
1·3 o\'er a fire, will relie\'e some heal and smoke. Howe\'Cr,
1-3,1 The follO\\ing is a descriptioll ofthl' significallt phe- huilding designers and fìrc pnJtection enginecrs CHnno(
rely on casual inclusion of skylights, windows, or monitors
nomena thai occllr duril¡g a hre \\hen ¡¡ lire \'{'Il(ing s\],II- itS ilde< udle \'l'l1tillg Illl'ans. Standards now exist (Lndcr-
egy is implemented; writers Lahor;¡tories, Factory \ll1lual) that include design
(a) Dut' 10 huoyancy, hot gasc... rise \'n!i(all~ Irol1! the nilcrid and t('sl proccdures lor llllit vcnts Ihat call ff) ' SIII1-
('()fnhustion zOl\e and thel1 /low hOrJ/()IIt,d!\' hd()h- (hl" rHo 1 lddled fill' (esLs a.... well as l'tlgilll"lTillg an;tlrsis_
until blocked by a vertical barrier (a wall o'r draft cllrldi1J),
thus initiating a layer of hot gases helow the roof. 2-1.2 111(' guide... and table.'> in this documellt are based
(b) The vo!llme' and tcmpníltun' of g;lses to !H' \Tllted Oil aU!()II\;ttic opera(ing \'l'II!S as Ihe "('sult of<l("(i\,ati()1! Of;l
arc;¡ fUIl((IO[J urlbc rate olhcal n·!cd....e (¡flhc ¡In' and (hc hedt-rc-" )()n~i\T <In'ill' rdled al 100"F C{ï.H"(:) to :!~wor
amount olair Cl1lr,lIl1ec! il1lt) Ihe blll)\';tnl phllllC pl'odlHTd (10-1,-1"(:) ,tI'O\T ;ullhil"ln h<l\'ing <I I imc {( I!~I;II!1 01 1101
In() "(' th,J!I~:):\ ....n dl :) II (I..~):) Inj H'I sl'(()nd g;¡.... \'e¡o(Lt~
(c) Thl' depth Oflhc Id\l'I" (Jfho¡ gasn i!1ne;J'il'~. the fire \\'jlll slHh ;1 dnin' ¡lrtccllO each \el1!.
continues to grow, and the byer lemperature C()I1(lI1lleS to
rise until vents operate, 2-1.3 :\11 ;l!ternale mode of operation, whelher hy he;l1,
(d) Operatìon of vents h'ilhill a curtained ;tICiI \I'ill sllloke, or othn ]llelhod, Olav he tailored (ollie b;u,nd so
enable some of the upper layer of hot gases to c....cdpe and IOl1g as the acccptcd syslcm ~\-illl)pcratl' al least as LIS! iI'i
slow [he rate of deepening of the ];l\'C!' or hot gases. \\ïth the ahOH' noted hcat-rcsponsi\'{' de\'icl' ;md i'i eith(' " lisled
sufficient \'enting area, the raIl' oj deepcning or ¡hc la\,(T or prO\c'l1 to he equi\'alent h\' sati~f;¡(Ï{)ry data or bv CllgI-
can be arrested and en:n re\'ersed, n (· ratc' of dl~r!l<lrg(' neering anah'sis.
through a vcnt of gi\'cn ¡¡rca is prim¡¡rih- dctt'lll!incd b~
the depth of the la\'cl of hOI gases and its tc'mperattn-e, 2-2 Vent Design Constraints.
Adequate quantities of replacclllel1l inlet air from low k\'cI
air inlets arc required if the products of comhustion-Iaden 2-2,1 Méll('rial.s of cons!flHlion ;\Tld metllOds of iml;¡llfl-
upper gases are [() escape according to design. lion Illust be u.sed appropriately 10 resi.st expelll'd
exllTllles of temperature, wind, huilding 111 (}\'L'1ll ell 1. rain,
1-3,2 The heal-release rate of Ihe fire is the hasis In hail. snO\\-, icc, sunli14ht, corrosi\(' environment. inrernal
which ;111111e plle!IOI1H'!]d of 1-:~, I {,tI1 !)(' (o!11 JlJlnl 111 (his dlHI l'x!nndl dml, din, dnd debris. COlT1jJdlihili(\ hel\\{Tn
regard, Ihi,s glluk is h¡I~l'd on ,Ill apprOprrd((' rl!dr,[( ({'i/a- illl' \('III II (HIIHiHg clCI1H"J1h ;Hld Ihc hllildlng ~tl'l ((un' t()
lion or Ihe fire's glowlh pO(('lIlial pCI Tallks -I-! dlHI 'I_~, \\httJ¡ tllt"\ <l1'l' ,1I1¡Hltn! I1!IIS( IH' ¡¡SSllred (llO!dil!g powel,
Onc(' such a dldl,KtelJ/,llioJ\ " made and ~ubseqll{'l1t ('lcllrodH"lni('al interaction, wind lilt, hllilding t11()\'ell)('IJI,
design guicks ¡\I(' implemented, (he desired hel1cfil~ ell ¡.
described in 1-1.3 can be anticipated.
2·2,2 Vl'n1S designed 10 h¡.-¡\'(' multiple functions (cla~'-
1-4 Classification of Occupancies, lighting, rIHif accC'ss, cOll1fÙr! \,(,lltilali()l1, Cle.) require
I11dil1t('I];II1('(' of thc fire protectioll function Ih;1I might he
1·4,1 Tests and studil's prmidl' ;r bilsl.... lor di\i~I()11 of l1l\pairt'd 11\ the other ust's. (ht'st' m¡IY irH ]ude I(J~.~ of
occupancies into ddsses dl'p('nding IIp()n ¡he fuel ;I\';lilabk 'ipring lel1~ion, rackìng or we<lr of mo\'ing pans, adH'rSl'
for comribution to fire. There is ;\ widc \'ari<t!II)(l in tht' eXlerim {ooling dt"ccts on Ihe fire prole{"(iol1 re!case 1I1t'{'h-
quantities of combuslible material'i in Ihe ll1an~ kinds of al1isl11, ildH'ISl' d1<111,L;l'S in perfiJrl11al]cc seqlH'IHc SIH h <IS
industrial plants and also between various buildings and prematlln: heal anuation leading to \'('nt opening, or
areas of mOSI individual plalHs. Classification should take reduce'd scnsiti\'it)' to heat.
into account the a\"erage or amicipated fuel loading and
the rate of heat release anticipated from the combustible 2-2,3 To ,I\'oid inadvertcnt opel"dtion, it is important that
materials or flammable liquids conr;lined thercin. Ihe attu<lling e1cn1<.'nl be selcctl'ci wilh rl'g~lrd to the
ex petted full range of ambient conditions.
1-4,2 To assisl in quantifying the type of fire ìn occupan-
cies of interest, Table 4-) presents charactnistie heèlt- 2-2,4 \'ellts may be single unit (entire lInit 0Pl'llS full~
release rates for limited-growth fires, and Table 4-2 pre- with.. single sen....o¡-) or Illultiple ¡¡nits in r()ws, clu....len,
senls characteristic growth times for continuolls-growth groups, or 'Other ;nrays Iha[ will satisf\ the H°]J1Îng re< uirl'-
fires, in a variety of different Iypn of fuel array.~. n1<.'l1ts for tTlt' specdie hazard.
1991 Edition
ATTACHMENT C
en: 1.\1 ,- IH>:\RD~ 204M-9
2-2,5 II the ha/drd is ]o(',di/cd (dip Link, so I \'l'1lI SI01,ig't', «I) 'I"he I()tal vent arca pt.'r Cllrr¡,in (,(Impartml'nt under
elc ). il is prdcl',d)1c IC)r Ihe \TJJh to he I(){dlcd dinT!h the ceiling (It'pends on [h<-' severity or [he expcctcd lire.
aho\'e such IliIl<lrd. \\'hich is discussed in Ch,Lplt_'r 4.
(c) \\'hcrc Illl'chanic¡¡! vents ,I1T considered, the IOla]
2-2,6 It ¡.. essential thaI the ,,]weill{ \'l'Il! 1IJtThanisIIJ ,l1le! sllg¡.{l'slcd vcnt area may be replaccd hy "Iowl exhaust
slruclurt.: (01 " n:prcscnt,ll¡\(' llIoduLlr scellon) he flow "
arranged to be casih inspected
2-2.7 Rcmote or p'rogT¡¡mmcd ()PC(ïI!101J of \'l'¡Hs may be Chapter 3 Curtain Boards
used to rOmpll'IlH..'IH, but !lot to n:plact' or impair, individ·
ual awoll1atit sensor actuation. 3-1 General.
2-3 Methods of Operation, 3·1.1 Curtain boards an: imp0lÏant IÙr prompt and pos-
2-3,1 .-\11 ,llllol1latl( .. llll'chdJìJSIll ¡()]' o )l'ning the root il in' activation of Ihe vents because they bank up heat in
vents is desiJ"<lb!e for dh..Tli\\: release of heal. sllloke, and the curtained area.
gaseous by..produns. if excessive smoke is likely to be gell-
cr;ìted prior 10 the H:lease of sut'liÙel)\ hedt 10 open \Tllls,
smoke detectors with appropriale linbges to open vents ~~1
Illay be prCfcrtTd.
2-3,2 .\IH<)lI1dll( ;L("Illatio)l ;we! opl'l'dliol1 need to h;I\T ;]
H
11111l111lllt11 "I ..Lti1uJ'l: J¡1I11IS .. (;In\ Olll' 01 which (ould 'l"////////////////////////////////l/////////////////////.
impair 111(" \1..'111), II "bihll c" ot d (0I11])() 1I..'11I onlln. it \\'111
prL'ft:Llbh kad 10 an "open \'('[11" (ol1ditio1\ as a less hM-
arc!ous Illode ,han ;1 "J1() lOpcnjngP condition if ,] lire
occurs, (,!"<lvit\' ;1.., (t source of "I()]TC to opcn" is prckrrcd, (8) Flat rool
widl assurancc thaI such a llIechanism is [lot easil\' hl,)(ked
by snow 01" roo ' dehris or in[('rnal projcnions. ·.-\1Innat('
opl'1Iing l1H'dnnisllls !leed 10 Iw ;q)pro\'{'d ;IS 10 l"el:,dJÌlit\ ¡-
o! perlo!'llIdlHe and cstill1;lIed lIsdu! lite.
2·3,3 ..-\]1 automatic \'ems should also h.... designed 10 open
H
by lllanLlal means.
2-3.4 !"o he clkeli\'e, LlIcbing nH.'{]¡;llìi"I11" need 10 \)1..'
<lIl1- H()ol. {orrOSiOIl-I"I'Slst;\IlI, <I[HI I"CSlsLlnl 10 pressun /
ddkn'l1li,¡]" ¡¡rising I¡om wind"torms, pr(){TS" 0Pl'LlllI)!]", (b) Gabled roof
()\'erhl.';HI doors, or Iral/It \-ihr;lli()!ls.
2-3,5 1101 or cold {"..I enol" wind" pl..'nl'lrallng and
ad\'crsel\' aflecting the heat-actuated sensors may ha\'c an
achersl..' cllce! Oil Ill(' "automatic" response of the \'Cllt \0
<Ill intnior lilT. This bC! nlTessilalcs a nitieal <lIl<lI\'sis of
'ipudic iJl'iI,¡\L!!iolls offì\.ed or ()perd[jng 10\l\,(:l"s, sh~l1lers,
or d<LJlIpl'r'i info lill' ()\TI,dl \TJ\[illg sYS!l'lI1.
/
2-4 Dimensioning and Spacing of Vents, !lIe dil1lell- (c) Sloped roof
~i()ning and spacing of \Tllts ,liT (tJllsidel"l'd 10 be dlcrti\'t
when the following criteria are met:
(a) The area of a unit vent or clusler does not exceed ~ ~
2cf, where d is the depth of the curtain board OJ" the
design depth of the smoke layer. The'ie dt.'pths are mea-
sured from the center lin(' of ¡he vent. (Srr Figllri' 3-1.)
(OJ The wIdth of the 1I1onilor docs nol cx«;,ed Ihe depth
H
of the (lJrlain b()ard d OJ the design d....pth of the smoke 'l"////////////////////J/////////////////////////////////.
layn \\'hen curtains are not pro\'ided.
(c) The \'l'nt spacing does \lot exceed an arrangcllH.·m
sllch tJ¡;lt on plan the dislanrc bt.,twl'l'J) any poinl on the
Bonr and IIH' ncarest \Tnl, all \\,¡Ihin Ihe curtained arca, ~d) Sawtootn roof
does not exceed :!.HH ((he di'Lgonal (If <I square whose side Figure 3-1 Measurement of Ceiling Height (H) and Curtain Depth (d).
IS 2H). where H is the ceiling height. (.-1110 If'/' Fi¡pll"/' ,-I,)
1991 Edition
-
204M-IO S\I() ;'F.\\J) F:\1 \'1-,:\11:\(,
3-1.2 CUrI¡¡;n hoards '>C!\T 10 I¡mil the sprc;Ld otht'ilI ;n](1 4·1.1.3 t"uk..." the (\tTlIP;IIlCY or ha/arc! is SHth III;l! rIll'
smoke helical ¡ [he (ciling during dt',ign dur;lrioH oj rhl' t'x H'('Icd lilT will IH'dk or !en' of! ;11 a prn[¡( Llhl(, III<lxi-
\TI1[ ng SYSll'Ill. tlUIII] ..,i/l', rhl' illS1dllcd \-('n1 ;In'a (or n,]¡;I1IS1 LIP;Hity) wjJI
;¡I..,!) depend on [hc IlJinill1l11l1 clc<lr-\-Îsibilll) design rime
3-2 Construction. II i:-. dcslr;d)lc dId! {Urldin hOdrds be (1/'1' I-I.J) <IS Jncasllrcd frolll the ,ime the first Yents
madL' of <In\' SlIhSI;¡llli;¡1. I!OIHOJ1lhl¡S¡íhlc 111;1[('11;¡] IIl'l! I\"ill ;t([]\,;¡lc.
resist the P¡~SSdgL' o!" sn]()).;,L'.
4·1.2 RC()IlIIl1l'ndcd \'('nl <trcas pn curtained comp;¡r!-
3·3 Location and Depth. mCI1[ ha\'l' been ('slahlishcd f()r two general classes of fircs:
. " , ' 0'" \\' T 'm." I '{ ." 4·1.2.1 Umilf'd-r;rrm'lh Fin>s ,include tIH,)SC whi~'h arc not
33.1 CUlt,un b :I,Ieb" hI.' C ¡~1 HI((: sll add c\t(,l1d expected to grow past a pre(ilnablc maximum SIze, such as
ciown from Tl1(' ceiling for a, sU.~l(iellt (!is,lance. [0 cnsure special hazard fìres,
that the \',d\le of d as sh()\\n 111 tlgure :~-] IS a mltlIHWm of
~O Perccnl of ceiling hcighl (H) \,'here HIs: '. " h .
, , 4-1.2.2 (.rllltllllwlI.I-(,¡-ml'!/¡ FII'I'.\ mclude t ose whICh can
(a) For fJ;¡t roofs. 111l'<lSllred from cciling to floor. he expl'c[ed to g-ro\\' inrlcfini[cl) IIIHil inlCn'CIlI¡OIl by fire
, , , , figluers,
(b) tor sloped roots, 1lIl'<lSlIITd !rolll ('cnlcr oj \Tllt 10 '
Ihe floor. "
4-1.3 I1)C rl'colllllH.'ndcd \'cIlI areas (mslalled \Tnl areas)
"()·]T S'" t-', -, '\ ] \\'1, I'''.. I· "1) "" I I' are based on the <lssumption thai the acrod~'nalllic dis-
,," L .tlrlg¡¡ll,- 1(ll((:\((((S_f>ll(lI1l0, ,I fT" 1'1 ," ' ' If
il is d(',it,!hlt' 111:11 11 = II Iw 11111 It"s 111,1(1 III f( I:I.W, 111) ( largc coc ( lent 0 [1(' \Tllts IS (j,b, whit' 1 IS norma or
(()JJÍlI1l'ITi,d gl,H'lIy \Tnh, ¡fthe dischargc COL'flicit'lJl is dJ!~
3-3.2 Around spc(i,1I h,l/dlds, ¡he llll'(;1(11 should plcln> (crcI~1 from ().¡;, lhe .ll'COIllIl~Cn(kd vu1t are~s,nt'L'd to he
¡¡hly cx!clld down 10 \\'Ithll! ilpproXIIII;t[ch ]0 It \3,W) III) IJH,lIllp!led b~ [he lallO of (J,b [0 IhL' aclllal dJs(hcllgc {oet·
Irom lhe floor. (1{1{'IlI.
If, hO\\'l'\'er, the ]¡;¡¡,Ird IS located more !lUll 10 !i 4-1.4 For lllL'chanic,,1 \'c[lIillg syslcms capable offIlIlC[ìoll-
(:LO;·) Ill) abo\'c 11ll' !I ()() r. lhe deplh of the ClII-[;lin hoard Ing IIndcr Ihe expeclcd fire exposure. IT(OIllIlJt'IHlcd
lIIay Ilced 10 he d(TIT,I'icd to allow !()r t'!lnlin' ;¡ lpliLJliol1 exhausl capacilies per cun;¡illed ('omp;¡rlll1t'1l1 ¡¡[T
or lire hg]l!illg dppli,II]{t'\, plO\ldctl 111<11 111{' I);¡"il (rilnia obl;¡lllcd 1,,- simpi<' ('olJ\'l'l''iion rom ¡hc re(OIllIJH':lIdcd
for \'{'Illlug ilH hldc(ll!] ¡)Ii, gllidc dll' (Ih'tï\'l'd \l'n( arcas pCI' ('urI,lillcd (,lll1parI111eIlL The (:OI\\Tl'Si()1I
depends Ol! rhe deplh of lIJL' cur[din board. or rht' design
3·4 Spacing. depth of Ihe.smoke laycr, in lhc following manllcr:
. , " Mechanical Exhaust Capacity
3·4.1 I he drstancc bctwccIJ rurt;l!1l hO<lrds should not per Unit Area of Gravity Vent
excecd H timt's the ({'ilmg hl'ighl 10 e11SIIlT l!ldt \Tnts Curtain Depth (ft) (SCFM/ft2)
remote fro!l1 1hl' tire within [he rUI'[;lil1l'c! (OJllPdrll1l{'JH G :~:)4
will be dk(¡i\'e, ~ 40~¡
1 () 4;)Î
3·4.2 Sn.1;tllcr nlJ'(;LII\cd dlCd" m<l\ he desiLd)]{' where II I~ ~~~
, 1 ) :)/0
o{'{lIpa[J('[l's ¡¡n> Jdrl (uLlrh \'ulnnilble to (;LJJ1;q,.;e, II()\\- ')(1 ¡¡.1Î
l'\'cr, i[ is ¡'lIl >orld(][ [h;J[ lilt' distallce b{'[wcen {lIruill ~_I ÎOX
hoards he not less [h;(JJ ~ limes the ceiling heighl, unk,,,
I] I' I I I ! I 'I t' ] t ¡(j '(¡II 'i(F\1 'iLHHLnd (:lIhl< f'l'('II'<'1 \¡inult' 1'i!;UHI,lId I I'T!I H' ,1-
)e (ur <1111 )(Jar( s {'X(l'IH (own to d (CPI 1 () ;11 e;ls . IIII( ;111,1 1'\('''"1('1
per(,l'1H of the tl'lhng Iwigln, 1"1 'il {nil' I fl '\(11:-; It): ¡ fl' '- ,(1'1:">'111\-'
Chapler 4 Inslalled Vent Area or 4-2 Limited·Growth Fire.
Exhaust Capacity
4-2.1 Recommended Vent Area.
4-1 General. R ¡ ¡ . I
4·2.1.1 eU)Jl1JJJell( ('( \'elll are(ls pCI' curtalnc( ((Imparl·
4 11 C 'd C !1lell[ (in sq ft) arc plolled [11 Figure "1-1 .q,';<lillst Ihe
.. urtame ompartments. ¡ . I I ., t ,. 1
CX H'(' ('( IHdXIIlIUI11 1e;lt-rt' eilSl' r:l1l' (In B[(\fSelOIl( ) () 11l'
{omlJuslihl{'s IJlHkrl1l'alh the cUr1;¡ill{'d (,Oll1pdrll1l{,lIt (11'1'
4.1.,.l.ll(i"nsl't1.li<lllhd(ulÏ;¡ilwd«(J1l1p,IIIIJlcll(sl)rthe /.// '/1 '·1 I· . . , ¡ I . "I)
.. , .. II J 1''''- , H: Iglll'e >l'rlillllS to a lllrlam ( cpl 1 I 1at IS _
cc¡]rng <ttTd of h(J¡ dll.lgs '('( lIlnng 1111 (\11'1;1111 hn;lrds he , 1 'I. ,. , I" , .,. I· I 1
" " ptTtel11 0 (It' {l'l Il1g Il'lg H, '01' {'<lC 1 C<-'llJ1g lelg 11. I It'
furnrshed wJlh ,I (O(;I! !Ihtdlkd \l.'111 ~Jr(';¡ (or exhaust ('<11,.,1{- .. ," h I 1
. , -..' ,'...' " .. _ rt'''Pl'ct1\l'tUnC )cgllls at a ('¡-¡I·r(' ease rate: \\' 1('IT \TIlIS
J{\, III LI"l' ()ll1lcchdl1l(,¡] \l'nldatlon) sllf!HIClll 10 \l'nt Ilrcs 1 . C¡. , ",. .1 b " I " ,
. \\' lose Opc:ral1llg (l'\'ICe 15 (Ie lJll'( \' _- ,_ are Irs!
of the experted seHTlt\', ,
expected to he useful.
4-1.1.2 In addition to the expence! fire se,-ni[\', the 4-2.1.2 FUr!hnmore, for each ceiling height. Ihe rL'spn-
ins[alled \'(.'111 are<l (or eXhatL"[ cap,Hit\) \\¡]] depend Oil (hl' II\'(' cunc [crmina[cs near a heat-release: rate bc\'olld
depth of the ('UrT,JlIl b( ;¡rd" or the doign depth of the "hieh llie kasibilir\' of the \'enlillg approach rc(otl1-
sllloke Idyer. mCllded in tillS gllidc Illi¡.{ht be: que,slrolled ((2jl'fl'¡¡'¡')'
1991 Edition
ATTACHMENT C
J\ST:\LI.EIJ \T',!' AREA OK EXIIAl'ST CAPACITY 204M- J J
Table 4·1 Limited-Growth Fires 4-2,1.3 Along Ihl' c!;\SIH'd segmellt of the rllr\'l'S, gas lel11-
Jkal-l't'k.j~l I;LI(' pcr lJl)il 110111' <lrea 01 tlllh ilj\'oln'd nl1l1hllsli- pt:r¡¡lllrCS ill ('Hess ()f (HHIOF (!):~7.7°(;) ,..viii 1)(· rc¡¡dll'¡I;
hln. <!sslIllling- !DO pl.'lTl'rH comhustion dlHil'nn un Jroll'C{ed structural stl'clma)' begllllo lose strenglb, and
(I'E =: pnl\'l'tll\Il'Ill'; I'S = 11)1\'SI\Tt'IW: P\"(: = polninyl chloride; Hasho\'cr mav occur within the curtained area The lowest
1'1' ~ p()I\pt'r)p\It'IH'; Pl ~ pohllrt'(hêll1e; FRI' ~ FíhergLtss- r<ile of heal Tt.'leasl' at which this O(:lllrs is referred '0
kl'iI1!in'('l,(1 I(¡I\'l'SllT.J as Q (HIO'
4·2,1.4 For curtain depths greater than 20 perccIH of [he
BIUiSt'C per ft2 of Floor Area ceiling height, the vent areas read from, Figure 4-1 may he
· multiplied by the following factors:
. ~ ·
, · Curtain Depth in Percent Multiplication
. ·
1 Woocipalle1$, slac~ed .--- of Ceiling Heighl Factor
1 (thignI612', ----.-,-.--r---
-. ~=:.::-T: 0
mois!I<rel --.- ;-, :HJ 0_;1
".... 40 O.:·J:I
2, Wood D~lle!$, slaçked --j ,
,rthlghI612'.... -=----1=-:-·-:.,'. :)0 0,40
mOI$ture) ~ ~~'~-~~~P:~~~ -- --T ~. GO O,~q
] Wood palle¡~, slacked 70 O,~()
10 flllOgl1 (6-12% HO 0,1:1
mO;$turel 0
- --. -'.
4 Wond r?~llel$, stac~ed .-.- For S] lnil~ ] Ii '" .3041'\ In
16fl"'ghI612"(
mo'ste"e)
.,.. 4-2,1.4,1 For curtain depths grl'é-IILT than 20 percent 01
'5 Ma,:bagl, filled '--." --- Ihe (eiling- heig-ht, Q¡OIlfI' which i~ Ihe hl'{l!-rele;¡~t' ralt'
$1Orer!5f¡hlyh - -. :.~o: :':::.
-f ...-,- -- - -" wherc ga~ temp('ratur('~ in excc."~ of I OOO°F (:,:1ï. ¡O(;) III<I~
6, Cartons. comrJa'1 ..... --, {¡(cur, carl be estimaled from the following equation
menl~d, sl~cked 15 ---, -.----.-. ...~- . -,
(th'gh -- .-., ".'.-. - ¢--. (where H is the ceiling height in II and d is the curtain
7, PEl e~ t er 1r a ,- 5 .---. hoard depth in ft):
_.- :=::::3·:,..- -
f, 1\'1 ~, I~ac k ed 5 ..4.. <.2I1HHI (Rtu/see) = 69 (H - d)"~
fllng'loncarl
~--,'
8PEtr¡¡,>-,C,o"'(';' -- .. - For curtain depths greater than 20 perccllt - of
incðnon$S1açkec 4-2,1.4,2
1511/1,gl- ...- _:0': --,-.-- the ceiling height, the heat-release rate beyond which \'t'nl-
--, .--. -- -.-_.--_.
9 FRP showe' St~ils _w_ .-.-_. ing may not be feasible according to the \'ellling approach
in cartons, stacked
15fth,gh _..- 0.. in this guide, Qf",,,,M~' can be estimated from:
10.PEboltlespacKed Q¡mllMr (Btu/sec) = JI30(H-d¡"'"
,nite....,6 0
11 PEnonle,,- 4-2,2 \'ertl a reèl~ per curtained romparl ment, del(' '-
ca' tons, ~t¡¡C:Ked 1,
flh,ql' 0 I mined ¡-¡(cording to 4-2.1.1 and 4-2.1.4, arc to bc' sized and
12, PU insulation board. ---.- I I distributed within the constraints of 2-4.1.
,igid foam. $tacked 15 I !
(¡high
13. P~ Jars packed 4·2,3 Consult Table 4· J for examples of heat-release rale
,nltem6 dala. MosI of these dala pertain 10 f.tirly high "'Iolflgt'. FOI
14,PStUt)lnelleC Im·\'er storage heights. il IlldY be asslIlllullhat heal-release
cartons, st~c"erl 14 I,..re i!'. proportional to storag-e height. Larger storage
1111,<;1 0 heighI.'> should be extrapolated wilh (';llIliOIl.
15 PS lay r:>ans·n
cartons, stacked 15 4·3 Continuous·Growth Fire.
/thlgh 0
16_PSin$ulat¡onboard, .- .- 4·3,1 Recommended Vent Area.
,ig'dfQ:lm. !tacked 14 ---.
!1high 4·3,1.1 Starting after an incuhation period, the heat-
17, pvc bon Ie. packed i release rate of these fires grows continuously proportional
inltem6
18 PP tubS packed to thc square of time. The growth time of a given fire is
'nllerr>6 0 ddineu as the interval of time hetween the cfT<:uive igni-
Ig PPand PE film tion time and the time when the fire reaches an intcrmcdi-
¡nrollS,Slacked14 ate energy release rate of 1000 Btu/sec. (See Figure 4-2 lJnd
hhigh '/(¡hle 4-2,)
20_Melhylalcohol "
21 Gasoline 0 4·3.1.2 Recommended \'ent areas per curtained campart·
1-- ment depend on the ceiling height (H) and the growth
22lterosene
time (.~ft' 4-3.1.1). They also depend on the spacing of cur·
23 Diesel 011 0 tain boards (Sr), the vent spacing and means of vent activa-
tion, as well as the desired minimum clear·visibility design
FOIl'S] ¡nib Ih ,\()-t¡.\ Ill; I h-' '" ( 9~q m' time from the time the first vents activate,
1991 Edition
204M-12 S\HHi.E :\~ ) lib\T \'f)\'TINC
107
For SI Lnils: I in. = 25.-1 nun; 1ft'> = .093 m:; I BIlI'"St·( == \.054 kw,
Figure 4·} Limited Fire Growth: Rel:ommended Vent Areas per Curtained Compartment for Various Maximum Heat-Release Rates (Blwsecond).
4-3.1.3 Recommcnded vent areas per curtained compart- 4-3,1.6 ',\-'here values are not given in Table 4-3, heal-
ment art' listed in Table 4<~ for the minimum rC(OIll- release rates afC g-rcalcr than (J,¡m"blr (Set' 4-2.1.1 and
mended curtain dl' Hh or:zo PtTCl'111 of ('eiling height (\N ~-2J4.)
3~3./) (In(1 i)r vents SP;¡U'(! at no !11()n: than one halfl)ftllc 4·3,1.7 Entries in parentheses correspond lo levels of
curtain board spacing. For olhcr ,han square curtains. [hc
Sp.H:ÎlIg S, is interpretcd as ¡he largest sparing ddi )ul by heat n'lcase grciltt'l" than QIOOO' (.'·ff 4-2././ (Juri 4-2./.4.)
ItH' (IIrtail1t'd area. 4·3,1.8 To illuslI,ltt' IIse of 111t' 1,lhk, ronsì(kr all installa-
tion wilh heal-responsive devices rated approximately
4·3,1.4 The t<tolllatcd arcas arc <JpprOXlIlJélte, pertaining IOooF (3ï.H"C) above ambient, a ceiling height of 20 ft
to vents that are operated by he;\t-responsin' de\'ices of (G.1 Ill), a growth time of 1;>0 see, a curtain spacing of RO ft
avcrage therm,¡ inertia and rated h('t\\'('l't1 loo"r (:~ï.H"C) (24.4 01) (\ = .~ x H), and a minimum clear-visibilitv
and 220"F (HH.rC) ¡¡hUH' the ambJl'nI (:mpC],tI\l!T. Lteh dcsig-n time of 10 min: the lower [imil 100"F en.H"C) ()fth~'
entry in Table 4-;; gi\'es Ihe range ()f"\CIJ¡ ¡¡rcas [in I()()() Iì:' appmprj¡¡!e entry in Table 4-1 indicates a \'CIlI area per
(90. m:!)] a~sociatcd with the select cd rangt' of temperature curtained ('ompartment orO.64 x 1000 = 640 rt:' (59.3 m:!)
ratings. for this case.
4·3,1.9 The recommended vent area per cunained com-
4·3,1.5 Enrries boxed in arc not possible (since the \'em panmenl is reduced if larger curtain depths than mini-
areas exceed Iht, largest possible curtained area of S,- x Sf); mum (20 percent of ceiling height) are installed. The
however, thest' entries Ill;!\ be IH'('(lcd lor curtain depths r('(hlCcd ar('as arc calculated by multipl\"ing the \"alues
greater than 20 I_H'1"(el1t of ceiling height d~ t¡-eated in listed in Table 4-3 by the appropriale multiplication faclor
4-3,1.9 list<-'d in 4-2.1.4, depending on curtain depth.
1991 Edition
ATTACHMENT C
-- ~ ~100)
IS' ~~IS')
" ~ C1§ ú)
-
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úì J:P ) (j)
& (0) -::J en
1<
'''"' ~
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I
I
=:J ~ )1 n
C
~
"
UJ } ~
:::r ~ z
(1J
, p 0 IX>
I ./' r1 "- 0
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,- ~
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.-
- - -
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--
I
APPLICATION FOR A CODE MODIFICATION OR USE OF
AN ALTERNATE MATERIAL OR METHOD OF CONSTRUCTION
Tomes, Van Rickley & Associates is presently co-chairing a committee with the California
Fire Prevention Officers to rewrite Article 81 of the Uniform Fire Code, A rewrite of Article
81 has been submitted by the Southern California Fire Prevention Officer's with the
elimination of curtain boards, The experts on this committee have obvious concerns
about the installation of curtain boards, This is based on the following:
(1 ) Curtain Board in Sorinklered Buildinas. Fire testing has shown within sprinklered
buildin,gs curtain boards provided little or no benefit and are sometimes detrimental
to fire sprinkler system operation.
Roof vents and curtain boards were originally used as an aid to fire fighting in
unsprinklered buildings, In unsprinklered buildings. roof vents. augmented by
curtain boards, can sometimes relieve smoke accumulation by containing radial
movement along the ceiling and by permitting the smoke to escape. Vents and
curtain boards are of much less value for fires in sprinklered buildings. In fact,
curtain boards can have a detrimental effect by actually increasing burning
intensity and spread,
CeDing 'A'
S Inld ,. \ I \ I \ I \ ^ ^
pr 81"" ''-, :' '\, (, ''., :'~, ~ Draft Cur1aln
,. ''', , " I', ,
,. , ,/" '"" ~v "
Smoke & He,-, ' ,'~", ,.'...,1, ,.'...,1, "
, ' V \ \ , . y , \ , . , \ \ " ,
Layer' , . , , ,
Heat Advance
Commodities
In Racks FIre Orig In Commodiløs
n Racks
I
(2) Prevent pre-wettina of commodities by the sprinkler svstem, This would occur as I
a fire advances down a rack towards the curtain boards and could possibly keep I
the sprinkler heads from opening up in front of the fire (see illustration). This could ¡
I
cause 'the commodity that the fire is burning towards not to be pre-wetted, All of I
us that have been involved in the testing of high piled combustible stock storage I
fires over the years all understand the importance of pre-wetting in controlling high
piled stock fires,
(3) Thickness of the Upper Smoke Laver, A major concern has developed with the
thickness of the upper smoke layer at the ceiling over the fire, Tests have shown
that smoke logging in the designated storage area can be caused by pulling the
smoke layer down when the operating ceiling sprinklers go through the layer. This
issue was brought to the attention of the Article 81 Rewrite Committee by the The
National Institute of Standards and Technology Building and Fire Research I
Laboratory (NIST) Test Program called LAVENTS (Link Activated Vents and
Sprinklers), It simply demonstrated that if the ceiling smoke layer above the fire
gets to a certain depth or thickness, it can actually cause the smoke and heat to
be drawn down by a venturi type action created by the water from operating
sprinkler heads going through the layer (see illustration). Thought the actual
critical depth of that smoke layer is not specifically known, it is thought to be three
feet or less, By adding 6 foot or 4 foot curtain boards, the thickness of the smoke
layer is increased where the sprinklers are operating. This thickened smoke layer
will encourage smoke logging throughout the building, This phenomena was
recently observed at a full scale fire test at Underwriters Laboratories, It is very
important to keep this phenomenon from happening because it will hinder fire
fighters from getting to the seat of the fire which is important in a high piled stock
fires, Often the complete extinguishment of these types of fires is dependant upon
fire fighters with hand hose lines,
(4) Skippina Sprinkler Heads. The activation of sprinklers are affected by many
factors, including the ceiling temperature and ceiling jetstream or heat velocity,
Computer modeling has shown that installing draft curtains will cause turbulence
as the ceiling jetstream makes contact with the draft curtain, This turbulence could
effect the response of the sprinklers and cause skipping of adjacent sprinkler
heads, As fire advances on a curtain board, there is a concern that a downward
draft of the heat column would be created by the curtain board which would
prevent the operation of the sprinkler heads on the non-fire side.
The results of present testing and analysis of past data clearly indicate that curtain boards
provide no benefit in a sprinklered building but could clearly cause problems. This
conclusion has become widely accepted within the fire industry.
We believe the elimination of the curtain board requirements will provide superior fire
protection for this facility, In lieu of curtain boards, the vent area to floor area ratio will
be increased from 1:100 to 1:75.
Based on the above reasons, we support the installation of the smoke and heat vents,
but request that the curtain boards be eliminated based on the above fire protection
concerns. The basis for this request is the design of the automatic sprinkler system, and
the potential risk posed by the curtain boards,
¡' ~
I
Reasons for
Proposed Revisions
To
Uniform Fire Code Article 81
I
Division IV
Ventilation; ..
,
Summarv
The ventilation topic was the portion of existing article which the committee
felt needed the most work. The basis for and documentation to support the
use of smoke and heat vents and curtain boards in sprinklered buildings is an
age old question which has generated more disagreements among fire protection
professionals than any other area in high-piled fire protection.
The reasons for this problem are the lack of full scale fire testing using
smoke and heat vents and curtain boards. None of the current National Fire
Protection Association or Factory Mutual Engineering tests, which are the
basis for all current fire protection standards, incorporated smoke and heat
vents and draft curtains In the testing process. Thus, one's position on
this issue is probably based upon insight gained from real life fire
experience or speculation.
The main questions which need to be addressed are as follows:
1) Do smoke and heat vents affect automatic fire sprinkler activation?
Are smoke and heat vents beneficial for manual fire fighting and
when is the optimum time for the smoke and heat vents to activate
in relation to fire sprinkler activation?
To answer these questions and hopefully put this issue to rest once and for
all, a two-part program was established. First, all existing testing in this
area was compiled and analyzed. Next, the new testing and research presently
underway was examined. The committee's hope was that by looking at research
in an analytical manner, the myths and misconceptions could be separated from
the science and engineering and thus a logical conclusion reached.
The conclusions reached by the committee are as follows:
1) All research done indicates that smoke and heat vents do not have a
detrimental effect an automatic sprinkler operations. Smoke and heat
vents do reduce ceiling temperatures and improve visibility for manual
fire fighting.
2) The smoke and heat vents should probably activate prior to activation of
the fire sprinklers to reduce the thickness of the upper layer and thus
the potential for smoke-logging of the building.
Revised 6-12-92 39
--.._---"-- ...- -,_._- .,_. ----------- ------
· ..
3) curtain boards provide no benefit in a sprinklered building and could
adversely affect sprinkler activation and increase the likelihood of
smoke-logging.
Division IV of Article 81 was written with this in mind. Venting ratios have
::'5en increased and curtain boards have been eliminated in sprinklered
~,.1Ìldings. Due to the apparent lack of performance of mechanical smoke
~emoval systems, smoke and heat vents were made the primary requirement, with
an exception to allow mechanical smoke removal if smoke and heat vents are
deemed not practical (i. e. in cold storage buildings or where weather
conditions restrict the use of vents) by the chief. In addition, an appendix
was created which gives guidelines for the design of the smoke removal
system. The exhaust quantities used in this section were taken from the
atrium 'smoke removal section of the Uniform Building Code. The committee
felt that the mechanical smoke removal design criteria presently in the code
was' arbitrary and inadequate.
Backqround
The history of smoke and heat vents and curtain boards in buildings used for
high-piled stock is somewhat of a mystery. The first use of these devices,
although not documented, was reported to be in 1966 by the Los Angeles County
F !-re Department. This application was based upon judgement by the fire
marshal. This was no fire testing to confirm this decision.
In the 1971 Edition of the Uniform Fire Code, Article 35, B:igh-Piled
( illustible stock was introduced. Requirements for smoke and heat vents and
c~rtain boards were introduced in this edition. smoke and heat vents and
curtain boards were required in all buildings used for high-piled stock
regardless of automatic fire protection. section 35.107 states "Draft
curtains shall be provided to limit the area of sprinkler operation and to
aid the operation of roof. vents," No fire testing or research was done at
that time to justify this position. Article 35 remained unchanged in the
1973 and 1976 Editions.
A major rewrite of Article 36, which was later changes to 81, was undertaken
for the 1979 Edition of the Uniform Fire Code, Research conducted during
this rewrite indicated that a mechanical smoke removal system was preferred
and that smoke and heat vents and curtain boards were not required in
buildings protected by an approved fire-extinguishing system [Section
81.107(a)]. Smoke and heat vents and curtain boards were also not required
in fully sprinklered buildings in the 1982 Edition of the Uniform Fire Code.
The 1985, 1988, and 1991 Editions of the Uniform Fire Code have again changed
the smoke and heat vent and draft curtain requirements. These codes require
either smoke and heat vents and draft curtains or mechanical smoke removal in
buildings used for high-piled stock storage regardless if the building is
sprinklered or not. No new research or fire testing was done to support this
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change in position.
The most well known and widely distributed testing on smoke and heat vents is
we done by Factory Mutual Research corporation in their Rhode Island
tes1:ing facility in' 1974. Factory Mutual's conclusion was that smoke and ~
heat vents were detrimental to automatic fire sprinkler operation and thus
should not be installed in sprinklered buildings. Unfortunately, what is not
commonly known is that due to the constraints of the Factory Mutual testing
facility, these tests have no similarity with real world applications or use
of smoke and heat vents. The most striking problem, for example, is that the
testing used vents placed on vertical wall sections, not the horizontal
ceiling, as found in real world application. This and other problems, in the
committee's,opinio~, completely invalidate Factory Mutual's testing. !
In 1982, the Illinois Institute of Technology Research (IITRI) began IITRI
Project JO 8385 - Fire venting of Sprinklered Buildings. This project
consists of experiments and testing designed to assess the influence of
automatic fire venting on the interaction of automatic fire sprinklers.
Eleven full-scale fire tests were conducted with automatic sprinklers and
smoke and heat vents to determine the behavior of each. The IITRI testing
concluded that "the ability of 165°F-rated automatic sprinklers to control,
or nearly control, a fire otherwise capable of growth, in a large one story
structure, is not impaired by the presence of automatic fire vents of typical
spacing and area." Furthermore, "venting appears to playa stronger positive
role on 286°F sprinkler controlled fires, based sQlely on tests with propane
fires." In other words, the smoke and heat vents had no detrimental affect
or the automatic fire sprinkler system activation.
The National Institute of standards and Technology Building and Fire Research
Laboratory (MIST) is nearing the conclusion of a two year study designed to
investigate fire sprinkler and smoke and heat interaction. The key
objectives of the project were to complete a collaborative research effort
between NIST and Factory Mutual Research, develop a computer model, LAVENTS
(Link Activated Vents and sprinklers) to simulate the interaction of fire
sprinklers and smoke and heat vents, and finally to conduct full-scale fire
tests to validate the LAVENTS model. All but the full-scale fire testing has
been completed. One result from this study indicated that ceiling vents can
have a significant effect on controlling the thickness and temperature of
smoke layers to avoid the deleterious effect of "smoke-logging" that is
typically brought about by sprinkler operation.
other research projects are underway in Europe. The Swedish Fire Research
Board has established an ad hoc committee to study this topic. This
committee consists of an international collection of experts on smoke and
heat venting. From this committee, a recent research project conducted by
COLT International in Ghent, Belgium, was made public. This project
consisted of full-scale fire testing to explore the fire sprinkler smoke vent
phenomenon. Preliminary results show that the ventilation system had little
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effect on the opening times of the first sprinklers. other testing done in
portsmouth, England, also by COLT International, indicated that temperature
rise in the buildings without fire ventilation was over three times the
~mperature rise in the buildings with fire ventilation. In addition,
uperation of the ventilation system did not hamper the operation of fusible
link devices which were set to simulate the operation of fire sprinklers.
From the NIST research, another important discovery' was made. Due to
interaction with the various gas layers which appear in a fire located in a
sprinklered building, the role of curtain boards became somewhat
questionable. The likelihood of "smokelogging" a building increases as a
depth of the upper layer (smoke layer along the ceiling) increases. The
deeper the . upper layer, the greater the amount of smoke which will be
entrained by the water droplets of the sprinkler system and thus'· be
"downdragged" into the ;Lower layer. This lower layer is typically clean air
and infiltration of smoke into this layer will greatly increase the
likelihood of smoke-logging the building.
standard automatic sprinklers control fire by cooling the fire itself, and
prewetting the area around the fire thus impeding fire growth, Installation
of curtain boards could prevent this prewetting of adjacent areas and
adversely affect sprinkler effectiveness.
The activation of the sprinkler head is affected by many factors including
the ceiling temperature and ceiling jet or heat velocity. The LAVENTS model
shows that installing curtain boards will causetubulance as the ceiling jet
makes contact with curtain board. The tubulance could affect the response of
.he sprinklers and cause skipping of adjacent sprinklers.
This concept is confirmed in NFPA13, which requires smaller sprinkler head
placement' (130 square feet maximum) for sprinklers located below panalized
roof systems than sprinklers located below a smooth ceiling (200 square feet
:aaximum) . It is thought that due to the irregularities in the surface below
the panalized roof system pocketing of heat and the prementioned tubulance
can cause skipping of adjacent sprinklers. Thus sprinklers are placed within
these pocket areas.
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