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Natlonal Research Consell natlonal1 5 4 8)*Iouncil Cmatia de recherches Canada2 Institute for lnstitut de- / Research in recherche enConstruction construction

Experimental Fire Tower Studies of ElevatorPressurization Systems for Smoke Controlby G.T. Tamura and J.H. Klote

ANALYZEDReprinted fromASHRAETransactions 1987Vol. 93, Pt. 2p. 2235-2256(IRC Paper No. 1548)

NRCC 291 21

I R C - 'Q=. EI L I B R A R Y & * (/1 B I B L I O T H ~ Q U E 'I I R C ICNPC - l r Y 1 5 T 4I_I.---

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On a effectuC des essais dans la tour experimentale d'incendie du Conseil national derecherches du Canada afin d'ktudier le mouvement de la furnee dans les puits d'ascenseurssous I'effet d'un gros incendie, et de determiner la capacitk des installations mkaniques demise en pression B maintenir les puits et entrees d'ascenseurs aptes B 1'Cvacuation despersonnes handicapkes et B l'intervention des pompiers. Les essais ont rev616 qu'il fallaitcontrbler la pression pour parer h la perte de pression due h l'ouverture des portes. On aformule des equations facilitant la conception de systkmes de contr6le de la pressioncomportant soit un debit variable d'alimentation d'air avec contrble en retour, soit desregistres dktendeurs placCs dans lesmurs des puits ou des entrCes d'ascenseurs. Les essaisrealis6 dans la tour ont montre que dans le cas de ces deux mkthodes de contrble de lapression, les valeurs mesurCes et calculCes des debits d'alimentation d'air et des Ccarts depression concordaient gCnCralement.

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EXPERIMENTAL FIRE TOWER STUDIESOF ELEVATOR PRESSURIZATIONSYSTEMS FOR SMOKE CONTROLG.T. Tamura, P.E. J.H. Klote, P.E., D.Sc.ASHRAE kl low ASHRAE Member

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EXPERIMENTAL FIRE TOWER STUDIESOF ELEVATOR PRESSURIZATIONSYSTEMS FOR SMOKE CONTROLG.T. Tarnura, P.E. J.H. Klote, P.E., D.Sc.ASHRAE Fellow ASHRAE Member

ABSTRACT

Tes ts were conducted in t he ex per imenta l f i r e tower a t th e Nat ional Research Counci l of Canadat o s tudy smoke movement through e lev ato r sh af t s caused by a la rg e f i r e and to determine thee f f e c t i v e n e s s of mechan ica l p r es s ur i za t i on i n keep ing t he e l ev a to r sha f t and l obb i es t enab l efo r evacua t i on of t he handi capped and fo r use by f i r e f i g h t e r s . The t e s t s i nd i ca t ed t h a tp r e s s u r e c o n t r o l i s requ i red to cope wi th los s of p res sur iza t io n due t o open doors. Equationsw ere d e ve lo pe d t o a s s i s t i n d e s ig n i ng p r e s s u r e c o n t r o l s ys te m s i n v ol v in g e i t h e r a v a r i a b l esupp ly a i r r a t e w i th f eedback con t ro l o r r e l i e f dampers i n t he wa l l s of t h e e l e v a t o r s h a f t o rlobb ies . Tes t s conducted in the tower indic ated th at fo r both methods of pressu re cont ro l ,compar ison of measured and calcula ted va lues of supply a i r ra te s and pressur e di f f ere nce s a rei n good agreement.

INTRODUCTION

I t i s a gen era l p r ac t i ce t o d i scourage occupan ts f rom us ing e l eva to r s a s means of e scapedur ing a f i r e by warn ing s i gn s p l aced ad j acen t t o t he door s and by au tomat ic e l eva to r r e ca l lt o t he ground f l o or upon f i r e s i gna l s . I f , however, one o r more e l e va to r s can be made safefro m t h e e f f e c t s of f i r e , t h e y c a n be used t o s e r v e a v i t a l f u n c ti o n i n a i d i n g f i r e f i g h t e r sand i n evac uat in g handicapped people. Such an el ev at or must have con tr ol s and power supp liesth a t a r e r e l i ab l e , and t h e i r l obb i es and sh a f t mus t be p ro t ec t ed a ga i ns t f i r e and smoke.

To de ve lop smoke c o n tr os a f e e l e v a t o r , a j o i n t p r o j e c t(NRCC) and t h e Na ti on al Bureau

1 t echno logy f o r e l e va to r s as one of the requirements of a f i r e -was undertaken by t h e Na tio na l Research Council of Canadaof S tandards (NBS) i n t h e Unit ed S t a t e s . I n i t i a l s t u d i e s

involved a computer an al ys is of se ve ra l pos si bl e smoke co nt ro l systems (Klote and Tamura1986). The re su l t s of th e an al ys is conducted fo r both summer and winte r and f o r ce rt ai n open-door condi t ions ind i ca t ed t h a t a l l sys tems cons ide red , excep t f o r t he one wi th f eedbackc o n t r o l of s up p ly a i r f o r e l e v a t o r s h a f t p r e s s u r i z a t i o n , f a i l e d t o m a in t a in t h e r eq u i re dpr es su ri za ti on when some combination of do ors was open. I t was a l so no t ed t ha t t he re a r eprobably ot he r systems capable of p rovi ding adequ ate smoke con tro l .

T h i s paper dea l s w i th t he fo ll ow-up s tu d i e s i n t he exper imenta l f i r e tower of t h eNa tio na l Fi re Lab or at or ie s (NRCC). The t e s t s invo lved examining th e smoke movement pa tt er ncaused by the temperature ef fe ct of f i r e and the ef f ect ive nes s of th e mechanicalp r e s s u r i z a t i o n e i t h e r of t h e e l e v a t o r s h a f t o r e l e v a t o r l o b b i es i n t h e e l e v a t o r s h a f t l l o b b yusable . Equat ions were developed fo r des igning pre ssu r iz a t io n sys tems wi th pressure con t ro lt o cope with press ure lo ss due t o some open door con f igura t ions . The types of press urecon t ro l sys tem examined were feedback con t ro l of supply a i r r a t e f o r p r e s s u r i z a t i o n a nd r e l i e f

G.T. Tamura, I n s t i t u t e fo r Research i n Construct io n, Natio nal Research Council of Canada,Ottawa, and J.H. Klote , Center fo r Fi r e Research, N at ional Bureau of Standards , Gai thersburg,MD .

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dampers i n t h e w a l l s of e i t h e r t h e e l e v a t o r s h a f t o r e l e v a t o r fobby i n t h e ca se of l obbyp r e s s u r i z a t i o n . T he se e q u a t i o n s w er e v a l i d a t e d w i t h t e s t s i n t h e e x p e r i m e n t a l f i r e t ow er .They w i l l probably be use fu l t o des ign e r s ; t h i s pape r , however , does no t deve lop a coyp l e t edes ign methodology f o r e le va to r smoke con t ro l .

DESCRIPTION OF THE EXPERIMENTAL FIRE TOWER

The f i r e to we r ( F i g u r e 1 ) i s p a r t of t h e e x pe r im e nt a l f a c i l i t i e s of t h e N a ti o n a l F i r eLabora tory loc a te d be tween C ar le ton Pla ce and Almonte , On tar io , a bout 40 mi les (60 km) west ofOttawa. The 10-story tower compr ises an exp er im enta l tower and an a t t ach ed obse rva t io n tower .The t y p i c a l f l o o r h e i g h t i s 8 .5 f t ( 2 .6 m) e x ce p t f o r t h e f i r s t and se co nd f l o o r s , w hich a r e12 f t (3 .6 m). Both t ower s $ re cons t ruc t ed o f mono l i t h i c r e in fo rc ed con c re t e ( t h i ckn es s of8 i n [ 2 0 0 mm]). The p l an v i ew o f a t yp i c a l f l o o r i s shown i n Fi gur e 2.

The o b s e r v a t i o n t ow er c o n t a i n s a f r e i g h t e l e v a t o r , s t a i r w a y , a workspace fo ri n s tr u m e n ts , and d a t a a c q u i s i t i o n u n i t s f o r mo n it o ri n g f i r e e x p er i me n ts . I t i s pro t ec t ed by af i r e w a l l a nd f i r e d o o r s w i t h s m a l l f i x e d w i re d -g l as s o b s e r v a t i o n windows. An i n de p en d en t a i rsys t em ma in t a in s a comfor t ab l e t empera tu re i n win t e r and p re s su r i ze s t he obse rv a t ion tower t op reven t i ng re s s of combust ion p roduc t s f rom the f i r e tower.

The e x p er i m e nt a l to we r c o n t a i n s a l l t h e s h a f t s a nd o t h e r f e a t u r e s n e ce s sa r y t o s i m u l a t ea i r and smoke movement pa t t e rns o f a t y p i ca l mu l t i s t o ry bu i ld in g , i nc l ud in g the e l ev a to r ,s t a i r , smoke e x h a us t , s e r v i c e , s u p p l y , and r e t u r n a i r s h a f t s . The e l e v a t o r a nd s t a i r s h a f t sa r e f u l l - s i z ed , b u t t h e e l e v a t o r s h a f t , a t p r e s e n t, h a s no c a r o r h o i s t i n g a p p a r a t u s , wh il et h e s t a i r s h a f t is e qu ip pe d w i th a s t a n d a r d s t a i r c a s e . A s u rr o un d in g c o r r i d o r i s o l a t e s t h eg ro up of s h a f t s f ro m t h e e x t e r i o r w a l l s , c r e a t i n g a t y p i c a l c e n t e r c o r e. A l l j o i n t s of t h ec o n c re t e s t r u c t u r e a r e s e a l e d t o m in im iz e u n c o n t r o l l e d a i r l e a k ag e s. The e x t e r i o r w a l ls a ndw a l l s of v e r t i c a l s h a f t s a r e p r ov i de d w i t h v a r i a b l e o p en i ng s t h a t c a n be set t o p r o v i d ed e s i r e d l e ak a ge a r e a s of t y p i c a l b u i l d i n s. Two propane ga s burn er s e t s , each cap able off,roducin g he at a t an outp ut of 8.56 x 10 Btu/h (2.5 MW ) , a r e l o c a t e d on t h e s e co nd f l o o r b ur na r ea wi th t he gas t r a i n r i g s l oca t e d immedia t ely below on the g round f loo r . The s econd f l oo ri s c o m pl e te l y p r o t e c t e d w i t h h i g h t e m p e ra t u re i n s u l a t i o n t o p r e v en t t h e c o n c r e t e f ro m t h e r m aldamage of t he co nc ret e.

A s e p a r a t e s t r u c t u r e a d j ac e n t t o t h e to we r ( F i g u re 3 ) ho us es t h e a i r moving and hea t ingp l a n t o f t h e e x p e r im e n t a l t ow e r; t h e a i r d u c t s b ei n g c a r r i e d u nd er gr ou n d t h r ou g h a s h o r tt u n n e l t o t h e bo tt om of t h e ex p e r i m e n t a l f i r e t ow er . T he re a r e two a i r s ys te m s. The f i r s th a n d le s t h e ma in a i r s u p p l y an d h e a t i n g l o a d . I t n o rm a l ly o p e r a t e s i n t h e r e c i r c u l a t i o n mode,but i t can be o p e r at e d on 100% o u t s i d e a i r and us e d t o p r e s s u r i z e t h e e n t i r e b u i l d i n g. T hi ssys t em can a l so be run in an exhaus t mode by us ing a s ep a ra t e va r l ab l e - f low exhaus t f anmounted a t t h e t o p of t h e r e t u r n a i r s h a f t . The s ec on d a i r sy s te m s u p p l i e s o u t s i d e a i r ,e i t h e r t o t h e e xp er im e nt al s t a i r and e l e v a t o r s h a f t s o r t o v e s t i b u l e s in t e rpos ed between th ee n t r a n c e s t o t h e s e s h a f t s a n d t h e b ur n a r e a . The a i r sy st em s a r e o p e r a t e d fr om t h e f a nc o n t r o l room i n t h e a t t a c h e d s e r v i c e u n i t ( F i g ur e 3 ) . The a i r f l o w r a t e s i n t h e a i r d u c ts a r em ea su re d w i t h e i t h e r m u l t i- p o in t s e l f - a v e r a g i n g t o t a l p r e s s u r e t u b e s a nd t h e i r a s s o c i a t e ds t a t i c p re s s u re t a p s o r w i th an o r i f i c e p l a t e . They w ere c a l i b r a t e d u s in g t h e p i t o t t r a v e r s emethod.

Temperatu re s a r e measured i n t en d i f f e r e n t l oc a t i ons on each f l oo r u s in g chrome-alumelthermocouples . Add i t io nal temper a ture measurements a re made i n th e burn area of t he f i r ef l o o r . P r e s su r e d i f f e r e n c e s a c r o s s t h e v a r i o u s w a l l s a r e measu red us in g 18 s t a t i c p re ss ur eta ps (0.25 i n [6.3 mm] O.D. c o pp e r t u b i n g ) m ounted f l u s h t o t h e w a l l s o n ea c h f l o o r . A l lp re s su re l i ne s a r e connec t ed to a 24-po rt p r e s su re swi t ch equ ipped wi th a d iaph ragm- typem a gn e ti c r e l u c t a n c e p r e s s u r e t r a n s d u c e r and l o c a t e d o n t h e same f l o o r i n t h e o b s e r v a t i o n a r e a .C arbon d i o x i de c o n c e n t r a t i o n s a r e m e as ur ed a t s i x l o c a t i o n s on ea ch f l o o r i n t h e s h a f t s ,lob bie s , co r r id or s , and burn ar ea by copper sampl ing tub es (0 .25 i n [6 .3 mm] O.D. coppertub ing ) connect ed t o a 12 -por t s ampling swi t ch un i t w i th a non d i sp e r s i ve i n f r a r e d g a sana lyze r . A l l dev ices of th e th re e sys tems are co nt r o l l ed and moni tored by a computer basedd a t a a c q u i s i t i o n a nd c o n t r o l s ys te m.

The c r o s s - s e c ti o n a l a r e a of t h e e l e v a t o r s h a f t , w hich r e p r e s e n t s a s i n g l e c a r s h a f t , i s84 f t 2 (7.84 m2). Openings i n t h e wa l l s fo r t h e e l e va to r door s a r e covered wi th a movab leplywood pat le l t o pe rmit a va r i ab l e s i ze open ing up t o 6 .0 f t 2 (0.56 m2) t o s imu l a t e a l eakagea rea due to an open e l e va t o r door wi th t he ca r a t t he open ing . The re i s a removable ha tch a t

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t h e t o p of t h e e l e v a t o r s h a f t a nd a n o u t s i d e v e n t c on ne c te d t o t h e b o tt om of t h e s h a f t a t t h es ub gr ad e l e v e l , t o pe r mi t n a t u r a l v e n t i n g e i t h e r a t t h e t o p o r b ot to m of t h e s h a f t . A l so a tt h e s u b gr a de l e v e l t h e r e i s a n op eni ng f o r a i r s u pp ly t o t h e s h a f t . The elevator lobby, whosea r e a i s 70 i t 2 (6.44 m2), i s p ro vi de d w it h a s t a n d a r d f i r e d oo r on a l l f l o o r s e xc e pt f o r t h esecond f lo or where t he door i s of p l a s t e r bo a r d w i th a v e r t i c a l l e a ka ge s l o t i n t h e c e n t e r t orep resen t th e l eakag e a re a of a ty p i ca l d oo r. T here i s an o p en ing i n th e w a l l of each lo bb yt o s up pl y a i r f o r l o bb y p r e s s u r i z a t i o n . A more d e t a i l e d d e s c r i p t i o n o f t h e e x pe r i me n t al f i r etower may be found i n Achakji (1987).

DESIGN APPROACH

The i n t e n t of a n e l e v a t o r p r e s s u r i z a t i o n s y s te m i s t o p r e ve n t smoke m i g r a t i on i n t o e l e v a t o rs h a f t s and lo b b i e s d u r i n g a f i r e . T h is is d on e by d ev e lo p in g p ress u res i n th e lo b b ies th a ta re s u f f i c i en t t o ov erco me th e a d v er se p ressu re d i f f e ren ces caused by v a r io u s mech an isms , sucha s w e at h er , t e m pe r a tu r e e f f e c t o f f i r e , v e n t i l a t i o n sy s t em s , and t h e p i s t o n e f f e c t c a u se d byan e l e v a t o r i n m ot io n. L ob bies se r v e as t em po ra ry r e fu g e a r ea s fo r th e h an d icap ped w a i t in g t obe evacuated by an e l ev at o r ; t h e y a l s o p r o t e c t t h e e l e v a t o r d oo r and i t s control mechanismf ro m th e f i r e t em pera tu re . The h i g h e s t a d v e r s e p r e s s u r e d i f f e r e n c e f o r a g i v e n b u i l d i n g d uet o a combination of th es e va ri ou s mechanisms is t h e d es i g n pr e s s u r e d i f f e r e n c e t h a t ane l e v a t o r s h a f t p r e s s u r i z a t i o n s ys t em must be cap ab le of m a in ta in in g ac r o ss th e lo bb y d o ord u ri n g a f i r e . The determination of t h e de s i g n p r e s s u r e d i f f e r e n c e i s beyond t he s cop e oft h i s p aper and is t h e s u b j e c t of a n o t he r i n v e s t i g a t i o n . T h i s p ap er d ea l s o n ly w i th th ecomponent of t h e d e s i g n p r e s s u r e d i f f e r e n c e ca us ed by t h e t e m p e r at u r e e f f e c t o f f i r e .

A c a l c u l a t i o n p r oc e d ur e was d e ve l op ed t o a s s i s t i n d e s i g n in g p r e s s u r e c o n t r o l s y st e msi n vo l vi n g e i t h e r v a r i a b l e s u pp ly a i r o r r e l i e f dam pe rs i n t h e w a l l s of t h e e l e v a t o r s h a f t o rlo b b ies . F ig u re 4 shows t h e sch em at i c drawing s of b oth t h e e l ev a t o r s h a f t an d th e e l ev a to rlobby p re ssu r iz at i on sys tems. The l e a ka g e a r e a s i n t h e w a l l s of t h e a i r f l o w s ys t em s a r ei n d i c at e d i n t h es e f i g u r e s . By c o n s i d e r i n g e q u a t i on s f o r p a r a l l e l a nd ser ies f lowc o mb in a ti on s d e s c r i b ed i n K lo t e and F o t h e r g i l l ( 1 98 3 ), t h e r e q u i r e d s u p pl y a i r r a t e s f o r ag i ve n d e s ig n p r e s s u r e d i f f e r e n c e , t h e r e s u l t a n t p r e s s u r e d i f f e r e n c e s when d oo r s a r e o p en ed ,and th e r eq u i red r e l i e f damper s i ze s can be c a l c u l a t e d . T he se e q u at i o n s f o r b ot h t h e e l e v a t o rs h a f t a nd l ob by p r e s s u r i z a t i o n s ys te ms a r e l i s t e d i n Appe ndix A. The ba s i c equat ion i s

whereQ = s up pl y a i r r a t eC = c o ns t a nt f o r a s t a n d a r d a i r c o n d i t i o n

Ae = o v e r a l l e q u i v a l e n t l e a k a g e area f ro m t h e p r e s s u r i z e d s p a c e t o o u t s i d e p e r f l o o rAP = p r e s s u r e d i f f e r e n c e f ro m t h e p r e s s u r i z e d s p a c e t o o u t s i d e

The values of Ae f o r t h e e l e v a t o r s h a f t a n d t h e e l e v a t o r l ob by c an be c a l c u l a t e d f r o mequat ions i n Appendix A, s t e p 1. F or a g i v e n d e s i g n pr e s s u r e d i f f e r e n c e a c r o s s t h e e l e v a t o rlobby door (AP3) , t he requ i red AP can be c al cu la te d f rom equat ions i n Append ix A, s t e p 2 ,which show t h a t AP,/AP i s c o n s t a nt f o r a g i ve n set of l eak ag e a rea s . The r eq u i red su p p ly a i rr a t e s c an be ca lzu ia t ed f rom eq u a t io n s i n A pp en dix A, s t e p 3. For th e open-door con f ig ura t io nw i t h t h e e l e v a t o r , e l e v a t o r l o bb y , a nd e x i t d oo rs on t h e g r ou nd f l o o r o pe n s o t h a t t h ee l e v a t or s h a f t i s d i r e c t l y exp os ed t o o u t s i de p r e s s u re , th e f lo w r a t e on th e g ro un d f lo o r f romt h e e l e v a t o r s h a f t t o o u t s i d e c an be ca l cu l a t e d w i th eq u a t io n s i n Ap pendix A, s t e p 4. Thet o t a l o u t s id e s up pl y a i r r a t e s r e q u i r e d t o p r e s s u r i z e t h e e l e v a t o r lobby t o a s p e c i f i e d d e si g nl e v e l (AP $ can be c a l c u l a t e d using eq u a t i o n s i n A pp en dix A, s t e p 5 an d s t ep 7 , f o r t h e c a sewirh all ioors c l o s e d , QT, an d with Lhe ground f l oo r doors open, QT1, res pec t iv ely . Thec a l c u l a t i o n of QT ' can in c lu d e o p en lo bb y d o ors o n o th e r f lo o r s to con fo rm t o a g iv en d es ig nc r i t e r i a by us i ng a s u i t a b l e va lue of Ae on t h o s e f l o o r s , as i n d i c a te d i n t h e n o te i n s t e p 1.For a v a r i a b l e s up pl y a i r f a n g y s t e m w i t h f e e db a c k c o n t r o l , t h e r a n ge of s u pp l y a i r r a t ereq u i red is then given by QT an d QT1.

With supp ly a i r , QT , se t f o r th e a l l-d o o r s -c lo sed s i tu a t io n , t h e lo wered v a lu e o f AP 'caused by opening doors on the ground fl o o r i s given by equ ati ons i n Appendix A, s t e p 6 , aria,

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co r resp on d in gly , w i t h su pp ly a i r , QT1 , se t fo r th e open-door co n d i t io n , t h e in c reased v a lu e ofAP3caused by c l os in g a l l doors i s g i v e n by e q u a t i o ns i n s t e p 8. The values of APjl and AP3should be checked, f o r i n the former ca se, AP3' may be t o o low t o p r e v e n t smoke i n f i l t r a t i o n ,whereas f o r th e l a t t e r ca se , AP3 may be g re at enough to cause d i f f i c u l t y i n open ing lobbydoors. The problem of ove rp re ss ur iz at io n can be overcome by providing r e l i e f dampers i n th ew a l l s of e i t h e r t h e s h a f t o r l o b by on e ac h f l o o r . The e q u a t io n f o r t h e r e q u i r e d s i z e ofre l i e f d am p er i s give n i n Appendix A, s t e p 9 , and t h e c o r re s p on d in g r e q u i r e d s u pp l y a i r r a t ei n s t e p 10. A f a c t o r , L , t o a c co un t f o r t h e s p e c i f i e d i n c r e a s e i n AP3 is i n c o r po r a t e d i n t h ee q ua t i on i n s t e p 9 f o r s i z i n g t h e d amper s o t h a t t h e r ise i n AP3 when t he el ev at or door i sc l o s e d i s l i m i t e d t o p re v en t d i f f i c u l t y i n d oor o p e r at i on . The r e l i e f dampers a re c l osed whenth e e le va to r and lobby doors a re open and they a r e f u l l y open when a l l d o o rs a re c lo sed .

When an e le va to r sh af t i s p r e s s u r iz e d t o a c h i e ve t h e r e q u i r ed p r e s s u r e d i f f e r e n c eac r o ss a lob by do o r on th e f i r e f l o o r and an e l ev a to r o r lob by d oo r on some o th e r f l o o r o p en s,the amount of p r es su r i za t i on i s d ec r ea s ed due t o t h e i n c r e a s e i n t h e t o t a l l ea k ag e a r e a of t h es h a f t . Assuming t h e t o t a l q u a n t i t y of p r e s s u r i z a t i o n a i r s u p pl i e d t o t h e smoke c o n t r o l s ys t emi s c o n s t a n t , t h e r e l a t i o n s h i p be twe en t h e p r e s s u r e d i f f e r e n c e a nd t h e l e a ka g e a r e a b e f or e a nda f t e r t h e do or i s opened can be expressed as

( = (3)K ( 2

N = number of floorsA = e f f e c t i v e l ea ka ge a r e a f rom e l e v a t o r s h a f t t o o u t s i d e p e r f l o o reA = leakage are a of an open e l ev at o r door

Combining Equations 2 , 3, and 4 g iv e s(5 )

For a s e l e c t e d va lu e of AP2/AP1, AP2 i s above a minimum acc ep t ab l e va lu e when th e e le va to rdoor is opened i f A+--- (N-1) >9

Ae ( 6 )

For example, i f AP /AP > 113 and t he minimum acc ep ta bl e va lue of AP = 0.05 i n of water (12.5aa ), Ae = 0.318 f t (0.0295 m2), and A = 6.00 i t2 0.557 m2), then AP2 is above t h e minimuma c c e p t a b l e va l u e f o r a t ow er h ig h er th an 24 s t o r i e s . Th is is a l s o t h e c a s e f o r t h e l o -s t or yto wer , i f t h e v a l u e of A i s l e s s than 2.65 i t2 0.246 m2). The leakage area , A, can bed ecreased by t ig h t en i n g up th e c a r en c lo s u re and d ec reas in g t h e c l ea ran ce b etween th e ca r andt h e do or s i d e of t h e s h a f t . F or t h e s e c a s e s , no s p e c i a l p r o v i s i o n i s r e q u i r ed f o r p r e s s u r eco n t ro l t o acco un t fo r an op en e l ev a to r d o or . Equation 6 i s , h e nc e , u s e f u l i n t h e d e s i g n ofa n e l e v a t o r p r e s s u r i z a t i o n s ys t em t o c h ec k w he t he r p r e s s u r e c o n t r o l i s needed. If some lobby

2238

where-= t o t a l l e ak ag e a r e a of t h e s h a f t

S u b sc r ip t1 = b e f o r e t h e e l e v a t o r d oo r i s open2 = a f t e r t h e e l e v a t o r do or i s open

The value of AP2 should be e q u a l t o t h e d e s i g n p r e s s u r e d i f f e r e n c e t o p r e ve n t s mokei n f i l t r a t i o n i n t o t h e e le v at o r s h a ft . The leakage areas A! and A2 ca n be de fi ne d as

A1 = NAe ( a l l d o or s c l o se d )an d as an example of an open door condition

A2 = (N-l)Ae + A (e le v a to r , l o b b y , an d e x i t d oo r s on th e g ro un d f l o o r o pen) ( 4 )where-

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doors are assumed to be open, then th e average valu e of Ae for the tower should be used i nEquation 6.

The re su lt s of the example c al cu la ti on fo r the tower following th e procedure i n AppendixA are given in Appendix B.

TEST PROCEDURE

The leakage are as of th e tower were se t t o simulat e those of a buil ding with averag ea i r t ig htn ess es and a f l oo r a rea of 9 ,730 f t 2 (904 m2) or seven t i m e s t ha t of the f lo o r a rea ofthe experim ental tower. The values of leakage are as f o r the tower given i n Table 1 wereestimated from measurements of other buildings conducted by Tamura and Shaw (1976, and 1978).

The i n i t i a l se r i es of t e s t s were coaducted wi th low and h igh f i r e tempera turecon dit ion s, both foll owin g approximately th e ASTM-El19 st and ard time-temperature curve up tothe maximum t e s t temperatures and held cons tant the re af te r. For the low temperature fi r e ,intended t o repr esen t a spr ink ler ed f i r e , th e maximum temperature was s e t a t 840 F (400C).This temperature, which is probably much h igher than expec ted i n a s pr in kle r ed f i r e , wasdi ct at ed by th e minimum temperatu re a t which th e t e s t gas burners could be operated. For thehigh temperature f i r e , th e maximum f i r e temperature was s e t a t 1380 F (750C); f i v e minutesa f t e r i ni t i on , th e eas t and west wal l vents on the second f l oo r , each wi th an a rea of 5 f t 250.46 m ), were opened t o si mu la te broken windows. I t i s rea l iz ed th a t a much h igh ertempera ture can occur i n an ac t ua l f i r e , bu t th e se lec te d tempera ture le ve l was considered t obe adequate fo r the purpose of the te s t s . The cont ro l tempera ture fo r the burners wasmeasured 1.0 f t (0.3 m) below th e cei l i ng dir ec tl y above th e gas burners. The heat ou tput swere 0.92 and 2.8 x l o6 Btu/h (0.27 and 0.82 MW fo r the low and high temperature fi r e s ,res pec tiv ely ; th e corresponding out sid e combustion a i r supp lies were 385 cfm (0.18 m3/s) and740 cfm (0.35 m3/s). The tes t schedule was s e t t o monitor smoke migration duri ng the burnperi ods and th e performance of both th e eleva tor sh af t and lobby pres su riz ati on systems withthe e leva to r door c losed and open. The supply a i r for pressu r iza t ion was in j ec t ed a t thebot tom of the e l eva to r s ha f t o r the bottom of the a i r d i s t r i bu t ion s ha f t fo r lobbypre ssu r i za t ion . For the low and h igh t empera tu re f i r e t e s t s , t he e l eva to r lobb ie s w e r epres suri zed t o 0.05 i n. of water (12.5 Pa) and 0.10 i n of water (25.0 Pa), res pect ively . Forthes e te s t s two ext r a pressure t ap s were p laced 1.33 f t (0.40 m) and 6.33 f t (1.93 m) abovethe second f loo r lev e l i n the in sula ted p las te rboard lobby door and connec ted t o a pressuretran sduc er whose out put w a s recorded on a continuous pen recorder. They complemented theex i s t i ng p re ssu re t ap loca ted 10.12 i t (3.08 m) above f l oo r leve l . An ex tr a gas sampling tubewas placed ins id e th e second fl oo r lobby and connected to an in fr ar ed gas ana lyze r, whoseoutp ut was a ls o recorded on a continuous pen reco rder ..

The f i r e t e s t s were conducted ' of both an e lev a to r sha f t pre ss ur i za t ion system and anel ev at or lobby pres sur iza tio n system. Both systems were te st ed ag ai ns t low and hightemperature fi r es . The pr es su ri za ti on system was act iva ted f o r 15 minutes, shutdown, and the nreac t iva ted 40 minutes a f t e r ign i t i on of the f i r e to de termine the p re ssu re d i f f e rences ac rossthe lobby door due t o pre ssu r iz a t i on a lone , f i r e a lone , and both ac t i ng toge ther . The lowtempera ture f i r e te s t wi th lobby pres sur i za t i on system was conducted wi th t he press ur iz a t ionsys tem ac t iv a ted p r io r t o ig n i t ing th e bu rner s t o more c lo se ly s imu la te expec ted f i r es i t u a t i o n s . A t about 70 minutes a f t e r ign i t ion , t he f i r s t f l oo r e l ev a to r door , l obby door,and an ex t e r i o r doo r w ere opened t o s tudy the e f fe c t of the r e s u l t ing d rop in p re ssu r i z a t ion .

A se r i e s of non - fi r e t e s t s were conduc ted to ve r i fy t he ca lcu la t ion p rocedure s given i nAppendix A. The methods of pressure cont ro l tes ted were f or a var i ab l e supply a i r system andth e use of re l i e f dampers i n the wal ls of the e lev a to r sh af t on each f loor. - With the e lev a to rdoor c losed and open, th e pressu re d i f fe r ence across the e leva tor lobby wal l was contr o l le d t oa minimum of 0.05 i n of wa ter (12.5 Pa) t o prevent smoke i n f i l t r a t i o n due t o a low temperatu ref i r e and a maximum of 0.15 i n of w ate r (37.5 Pa ), which i s well be low the a l lowable l i m i t of0.36 i n of water (90 Pa) f or door operation. This l a t t e r l i m i t was based on the requirementof th e Nationa l F ir e Pr ot ec ti on As so cia tio n F i r e Saf ety Code (NFPA 1985) on th e maximumallowable door opening forc e of 30 l b (133 N ) and assuming a door s i z e of 7 f t (2.13 m) by3.33 f t (1.02 m) and a fo rc e of 11 l b (40 N) t o overcome th e door clos ur e.

The te s t s were conducted with temperature di ffe ren ces between th e ins id e and outs ide ofl e ss than 10 F (6OC) and wind speed of l e s s th an 10 mph (16 kmlh). Te st s unde r non -fir e

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co n d i t io n s t o v a l i d a te th e eq u a t io n s i n Appendix A were conducted wi th the ou ts i de wal ll eakag e a rea s fo r th e f i r s t and secon d f lo o r s h av ing th e same v a lues a s th o se of th e r em ain in gf l o o r s t o s i m p li f y v a l i d a t i o n .

RESULTS AND DISCUSSIONS

Smoke MigrationA d e t a i l e d h a z ar d a n a l y s i s c o n s i de r i n g t h e e f f e c t of h e a t f l u x , t o x i c g a se s a nd smokeo b scu ra t io n i s beyond th e scope of t h i s paper. However, a sim pl if ie d approach t o th e smokeobscurat ion p rob lem i s t a ke n a ss um in g t h a t p a r t i c u l a t e c o n c e nt r a t i o ns f ro m a s o l i d f u e l f i r ewould be p ro p o r t io n a l t o th e'm easu red C02 co n cen t ra t i o n s f rom th e se t e s t s . This assumption i sp r ob a bl y c o n s e r v a ti v e i n t h a t smoke d e p o s i t i o n r e d uc e s p a r t i c u l a t e c o n c e n tr a t i o n .

The C02 c o n c e n t ra t i o n s i n t h e t ow er f o r t h e h i g h t e m p e r a tu r e f i r e t e s t s 45 m in ut es a f t e ri g n i t i o n and 1 5 m i nu te s a f t e r e l e v a t o r s h a f t p r e s s u r i z a t i o n a t 0 .10 i n of wa ter (25 Pa) ar eg iv en i n Ta bl e 2 an d s i m i l a r l y a f t e r lobby p r e s s u r i z a t i o n i n T ab le 3. The C02 co nc en tr at ion sa r e ex pressed as p e rcen tag e of th e co n cen t ra t io n i n th e secon d f lo o r m easu red 1 f t (0 .3 m)below t h e c e i l i n g i n t h e b ur n a r e a . From a c on si de ra ti on of smoke ob sc ur at io n, i t can beassumed that an area i s r e a so n ab l y s a f e i f i t i s n o t c on ta m in at e d t o a n e x t e n t g r e a t e r t h a n 1%of t h a t i n t h e v i c i n i t y of a f i r e a r e a (McGuire et a1 1970) . I t i s s e e n t h a t w i t h o utm ec ha ni ca l p r e s s u r i z a t i o n , t h e C02 c o n c e n t r a t i o n s a r e w e l l a bo ve t h e 1% l e v e l i n a l m os t a l ls p a ce s i n c l u d i n g t h e e l e v a t o r s h a f t a nd l o b b i e s . The h igh est con cen tra t io n , 70X, occurred i nth e secon d f l o o r e l e v a t o r lob by . The h i g h e s t C02 c o n c e n t r a t i o n s i n t h e v e r t i c a l s h a f t so c c u r r e d i n t h e s e r v i c e s h a f t . E xa mi na ti on of t h e t e m pe r a tu r e r i s e i n t h e t ow e r , g i ve n i nT a bl e 4, shows t h a t among v e r t i c a l s h a f t s , t h e s e r v i c e s h a f t had by f a r t h e g r e a t e s tt em p era ture i n c r eas e w i th an av e rage r ise of 100 F (38OC). P r e ss u r e d i f f e r e n c e s i n t h e t ow erg i v e n i n Ta bl e 5 show t h a t , a s e x p e c te d , t h e g r e a t e s t p r e s s u r e d i f f e r e n c e s o c c u rr e d a c r o s s t h ew a l l s of t h e s e r v i c e s h a f t w i t h fl ow f ro m t h e f l o o r s p a c es i n t o t h e s e r v i c e s h a f t below t h ef i f t h f l o o r a nd t h e r e v e r s e f l ow d i r e c t i o n a bove i t . A s i m i l a r f l o w p a t t e r n c an be s e e n f o rt h e r e t u r n a i r s h a f t , b u t t h e p r e s s u r e d i f f e r e n c e s a r e munch l ow er t h a n t ho s e of t h e s e r v i c es h a f t . I t would appear th at the s er v ic e s ha f t ac ted a s a f l ue and was the main passageway f o rC02 t o mi g ra t e t o u pp e r f l o o r s , c a u si n g a t e n de nc y f o r C02 on t h e s e f l o o r s t o e n t e r t h e s t a i ran d e l ev a to r lo b b ies .

A f t e r 1 5 m in ut e s of e l e v a t o r s h a f t p r e s s u r i z a t i o n , as shown i n T ab le 2 , t h e e l ev a to rs h a f t w a s c lea red o f C02 b u t th e l ev e l s of C 02 i n th e e l e v a t o r lo b b ies were s t i l l above thec r i t i c a l l e ve l . S i mi l a rl y , as shown i n Tabl e 3, when th e lo bb y p r es su r i za t i o n was ac t i v a te d ,th e lo b b ies w ere c l ea red of C02 b u t co n cen t r a t io n s of C 02 i n th e e l e v a t o r s h a f t w ere ab ov e th ec r i t i c a l l ev el . A low t em p era ture f i r e t e s t w i t h t h e l o bb y p r e s s u r i z a t i o n s ys t em a c t i v a t e dp r i o r t o i g n i t i o n was s u c c e s s f u l i n k e ep in g t h e e l e v a t o r s h a f t a nd l o b b i e s smoke f r e e a s l o n ga s a l l d o or s w er e k e pt c lo s e d. Thes e r e s u l t s i n d i c a t e t h a t it i s i m po rt a nt t o a c t i v a t e t h ep r e s s u r i z a t i o n s ys t em b e f o r e t h e e l e v a t o r s h a f t a nd l o b b i e s a r e h e a v i l y c o nt am i na t ed w i t hsmoke. T ab les 2 an d 3 a l s o show t h a t , as e x p e c t e d, C02 c o n c e n t r a t i o n s i n t h e u n p r e s s u r iz e ds t a i r w e l l i n c r e a s e d when t h e e l e v a t o r p r e s s u r i z a t i o n s ys t em s were a c t i v a t e d .

Temperature , P r essur e Dif fe rence , and CO , Concen tra t i on o f th e Second F lo or Lobby Due t o F i reT ab les 6 and 7 g iv e th e t em p era tu res in s i d e and o u t s i d e t h e secon d f lo o r e l ev a to r lo bb y , t h ep ress u re d i f f e re n ce s ac ro ss t h e lo b by w a l l , and th e C02 co n ce n t ra t io n s i n s i d e th e lob by . Theyshow th a t when th e b u rn e r s a r e o p era t in g , t h e e l ev a to r lob by t em p era tu res a re w e l l abo ve th edanger le ve l fo r human exposure . The two wa l l s o f th e lobby t h a t a re exposed t o the burn areaa re co n s t ru c ted o f a l a y e r of 518 i n ( 1 6 mm) t h i c k gypsum w al lb o ard on e i t h e r s id e o f m e ta ls tu d s . With th e p ress u r i za t io n sy s tem o n , th e lo bb y t em p era tu res were lowered t o abou t90-100 F (33-37OC) f o r th e low te mp er at ur e f i r e and t o abo ut 125-145 F (52-63OC) f o r th e hi ghtem p era ture f i r e . F or th e case when th e sh a f t p re s su r i z a t i o n was ac t iv a ted b e fo re th e b urnp er io d , t h e lob by t em p eratu re f o r a low t em p era tu re f i r e was 9 8 F (37OC).

E xamina tion of t h e r e su l t an t p res su re d i f f e r en c es ac r o ss th e e l e v a t o r lo bb y w a l lind ica ted th at they were abou t 20% and 40% gr ea te r th an t he a lg eb ra ic sum of the p r ess ured i f f e r e n c e due t o p r e s s u r i z a t i o n a nd t e m pe r a tu r e e f f e c t of f i r e f o r t h e low and hight e mp er a tl ir e f i r e s , r e s p e c t i v e l y . The g r e a t e r v a l u e f o r t h e h ig h t e mp e r at u r e t ha n f o r t h e lowt em p er a tu re f i r e may be a t t r i b u t e d t o t h e f i r e f l o o r b ei ng v e nt e d t o t h e o u t s i d e f o r t h e

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former case, re su l t in g i n somewhat h igher press ure d i f fe rence s on f lo or s above and below th ef i r e f lo or . I t would appear tha t an amount of p res sur iza tio n equa l to t he advers e pres sur ed i f f e r e n c e due t o f i r e w i l l l i ke ly be more than adequate to prevent smoke migration in to t heelevator lobby.

Figure 5 shows the pressure d i f f e re nce pro f i le acr oss the lobby wal l for both the lowand high temperature fires. For th e low tempera ture f i r e , t he neu tra l pressure lev e l (NPL) i sloca ted a t about the 5.5 f t (1.6 m) le ve l and for the h igh tempera ture f i r e a t the 3.2 f t(0.9 m) leve l . The loc at io n of NPL depends on both th e d i s t r i b u t i o n of leak age openings onthe f i r e f l oo r and the gas t empera tu res . The lower NPL fo r th e high tem pera ture f i r e i s duet o the lower gas densi ty outs ide the e le va to r lobby than f or t he low tempera ture f i re . Themaximum adv ers e pr ess ur e di ff er en ce s of 0.026 i n of water (6.5 Pa) and 0.030 i n of wat er (7.5Pa) fo r the low and h igh tempera ture f i r e s , r espe c t ive ly , occurred near the ce i l i ng lev e l ofth e lobby wall. When th e mechanical pr es su ri za ti on was a c t i v a t ed , t h e p r es s u r e p r o f i l es h i f t e d t o t h e r i g h t to show pos i t ive p r e ssu r i za t ion fo r the f u l l he igh t of th e lobby, butwhen the el ev at or , lobby, and e x i t doors on the ground f lo or were opened, i t s h i f t e d t o t h el e f t t o underpressur ize th e upper wal l s of the lobby.

The va ri at io n of lobby temperature, pres sure di ff er en ce , and C02 conc entr atio n duringthe bum, p re ssu r i za t io n , and open door per iods a re g rap h ica l ly i l l u s t r a t ed i n Figu re 6. Thetime-lobby pres sure d if fe re nc e curve shows t h a t soon a f t e r i g n i t i o n of t h e b ur n e rs , t h e r e i s asudden momentary inc rea se i n adverse pres sure d if fe re nc e, probably caused by th e rapid thermalexpansion of gases t o 0.05 i n of wat er (12.5 Pa) with a sp ike of 0.085 i n of wat er (21 Pa) anda dec rea se t o a s t e ady va lue a s the burn a rea r eached th e con t r o l f i r e t empe ratu re . For thelow temperatu re f i r e , thermal expansion caused a maximum pr ess ure di ff er en ce of 0.06 i n ofwate r (15 Pa) with a spik e of 0.10 i n of w ater (25 Pa). A higher thermal expansion e f fe c toccurred with the low as compared t o the h igh tempera ture f i r e , probably because fo r th eformer, only one burner s t r i p was used, whereas f or th e la t t e r , t h r ee burner s t r i p s wereig ni te d i n sequence. Pressur e dif fer enc es due t o thermal expansion, which were of s ho rtdu ra t ion , d id no t c ause s ig n i f i c a n t concen t ra t ion of C02 i n th e e l eva to r lobby i n the ca se ofthe low tempera ture f i r e wi th the lobby d i re c t ly p ress ur iz ed t o 0.05 i n of water (12 .5 Pa)p r i o r t o i g n i t i n g t h e b u rn er . The supply a i r fo r pre ssu r iza t ion probably d i lu ted smoke th a tmight have in f i l t r a t ed th e lobby.

Examina tion of C02 concentra t ion s i n the e le va t or lobby, a s g iven i n Tables 6 and 7 ,shows tha t t he C02 concentra t io ns were reduced s i gn i f ic an t l y wi th s ha f t pre ssur iza t i on (seea l so Figure 6) and reduced t o the background l eve l wi th lobby pre ss ur i za t ion , but C02 lev e lsi n the lobby and e leva tor sh af t increased fo r both th e sh af t and lobby press ur iz a t io n when thedoors on th e ground fl o o r were opened.

Comparison of Calcul.ated and Experimental ResultsThe re su l t s of the t e s t s conducted to check the equa t ions i n Appendix A, developed for thedesign of pre ss ur iza tio n systems with press ure con tro l , ar e summarized in Table 8. For boththe var ia b le supply a i r and re l i e f dampers f o r pressure con tro l , th e measured and ca lcula t edva lues of supply a i r r a t es and press ure d i f fe ren ces agreed wel l wi t h in 10% of each o ther . Tofa c i l i t a t e compar ison of the c a lcu la t ed and the measured v a lue s , t he supp ly a i r r a t e f o re le va t or pressu r iza t ion was kept cons tant with cl os ing o r opening of the doors on the groundf loo r . In p rac t i c e , t he supp ly a i r r a t e , a cco rding to the f an cha rac te r i s t i c , would dec reasew i th the c lo s ing of doors due to the inc rea se i n th e sys tem 's f low res is t anc e , and theoppo site would occur with the opening of doors; hence, assuming a cons tant supply a i r r a t ewould g ive conservat ive va lues of pressure d i f fe renc e acros s the e le va t or lobby wal l .

The leakage openings a t t he top of the e l eva tor s ha f t were not considered i n thecal cul ati on . Measurements by Tamura and Shaw (1976), i n sev er al bui ldi ngs indi cated th at theyvari ed from 4 t o 10 f t 2 (0.37 t o 0.93 m2), except fo r one case of 0.50 f t 2 (0.046 m2) i n whichopenings i n the co ncre te flo or sl ab of the machine room were pa rt ly covered with sheet metal .The leakage openings a t t he top of a pressu rized el ev at or s ha ft should be minimized o r takenin to account in the ca lcu la t io n of supply a i r ra te s and s i ze of r e l ie f dampers . Using theequa tion i n Appendix A, s t e p 4 , fo r an open ele vat or door with A replaced by the leakage ar eaa t t he top of an e l eva ted sha f t w i l l give conserva t ive va lues .

Elevator, Lobby, and Exit DoorsThe examples. shown i n Tab le 8 a r e fo r the ca se s w ith a l l doors c lo sed and w ith e l eva to r ,

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lobby, and ex it doors open on the ground floo r. For the case of a va ri ab le a i r supplypres sur i za t io n system, the pressur e d i f fe r ence across the e lev a tor lobby was in tended to becon tro lle d to 0.05 in. of water (12.5 Pa) fo r a low temperature fi re . The required supply a i rra te f o r ele vat or s ha ft p res su riz ati on ranged from 2000 t o 5590 cfm (0.944 t o 2.64 m3/ s); ifthe lobby doors on a l l f l oor s except the f i r e f lo or were a l so assumed t o be open, th e requiredmaximum supp ly a i r r a t e would have been 5950 cfm (2.82 m3/ s). For the case of apres sur i za t io n system wi th re l i e f dampers t o main ta in the same pressure d i f fe r enc e as i n thecase with the ground flo or doors open, but t o 0.15 i n of water (37.5 Pa) with a l l doorsclo sed , t he req uire d s iz es of dampers were 0.21 f t 2 (0.020 m2) and 0.11 f t 2 (0.011 m2) f o r th ee le va t or shaf t and lobby pres sur i za t io n systems, respec t ive l y . To mainta in th e pressuredi f f e ren ce a t 0.05 i n of water (12.5 Pa) wi th a l l doors c losed , l a r ge r s iz e re l ie f damperswould be required, and they can be ca lcu la ted using equa t ions i n Appendix A, s t ep 9, w i thL = 1.0. For th i s cas e, t he required s iz es of damper in th e sh af t wal ls would be 0.62 f t 2(0.057 m2) and 0.67 f t 2 (0.063 m2) fo r th e sh af t and lobby pre ss ur iz at io n systems,re spec t ive ly. Fu rthermore , i f t he lobby doors on a l l f loo r s excep t the f i r e f lo o r w ereassumed al so t o be open, the required damper si z e s would be 0.68 f t 2 (0.063 m2) i n th e sh af tw a l l fo r the sha f t p re ss u r i za t ion sys tem.

CONCLUSIONS

1. F i re t e s t s conduc ted i n the exper imenta l f i r e tower ind ic a ted tha t t he tow er wascomplete ly contaminated wi th smoke (C02 as ind ica tor ) due to e f f ec t of the f i r etemperature alone. The e l eva to r s ha f t p re ssu r i za t ion sys tem was e f fe c t iv e in c l ea r ingsmoke i n the s ha f t in a s hor t t ime , but r es id ua l smoke wi th conce ntra t ions above thec r i t i c a l l e v e l r em ai ned i n t h e l o b b i e s , a nd , s i m i l a r l y , t h e e l e v a t o r l obb y p r e s s u r i z a t i o nsystem was e ff ec t i ve i n c le ar in g smoke i n th e lobbies in a sh or t t ime , but res i dua l smokeremained i n th e sh af t f o r some t ime. I t i s i mp or ta nt t o a c t i v a t e t h e p r e s s u r i z a t i o nsystems before th e e leva t or sh af t , and lobbies a re heavi ly contaminated wi th smoke.

2. Examination of t he pres sure di ff er en ce s due t o mechanical pr es su ri za ti on and those due t othe f i r e ind ica ted th a t an amount of p re ssu r i za t i on equa l to th e adverse p re ssu red i f fe rence caused by th e f i r e w i l l l i k e l y be more than adequate t o prevent smokem i gr a ti o n i n t o e l e v a t o r l o bb i es . T e st r e s u l t s i n d ic a t ed t h a t a t s t e a dy f i r e te m pe r at u re ,maximum adverse pressure d i f fe r enc es due to th e thermal e f fe c t of f i r e occurred acro ssth e e leva tor lobby wal l a t the ce i l in g le ve l of about 0.026 i n of water (6 .2 Pa) f or th elow temperature f i r e and 0.03 i n of water (7.5 Pa) fo r th e high temperature f i r e . Thosedue to thermal expansion soon af te r ig ni t i on were much highe r but of sh or t duration . I ti s l i ke ly tha t a pres sur i za t io n acr oss the e leva t or lobby wal l of 0.05 i n of water (12.5Pa) and 0.10 i n of w at er ( 25 Pa) would be su f f i c i en t f o r low and h igh t empe ratu re f i r e sresp ectiv ely. Adverse pres sure di ff ere nce s caused by ot he r mechanisms, however, shoulda l s o be considered i n th e design .

3 . Opening e le va t or , lobby, and ex i t doors on the ground f lo or caused a reduc t ion i np re ssu r i za t i on r e su l t i ng i n the con tamina tion of the e l eva to r sha f t and lobby on the f i r eflo or. To cope with open door s i t ua ti o ns , equati ons were developed t o permit the desig nof p re ssu r i z a t ion sys tems w i th va r i a b le supp ly a i r w i th f eedback con t ro l and a l so w i threlief dampers. These equa t ions gave r es u l ts th a t were w e l l wi th in 10% of th e measuredva lue s in the expe r imen ta l f i r e tow er. It should be emphasized, however, th at t o designan e f fe c t iv e pres sur iza t i on system requ ires a knowledge and contr o l of the a i r leakagec h a r a c t e r i s t i c s of t h e b ui l d in g an d, i n p a r t i c u l a r , t h o s e of t h e e l e v a t o r s h a f t andlobbies .

REFERENCES

Achakji, G.Y. 1987. "NRCC experimen tal f i r e tower f or st ud ie s on smoke movement andc o n t r o l i n t a l l b u i l d i n g s . " In s t i tu te fo r Research in Const ruc t ion , Nat iona l Research Councilof Canada, I n t e r n a l Report No. 512.

ASHRAE. 1985. ASHRAE handbook - 1985 fund amen tals , p. 22.4 At lan ta: American So ci et y ofHeating, Ref rig era tin g, and Air-Conditioning Engineers, Inc.

2242

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Klote, J.H. 1983. "Elevators as a means of f i r e escape." V.89,Pt. 1.

Klote , J.H. , and Tamura, G.T. 1986. "Smoke c on tro l and f i r e evacuation by eleva tors ."ASHRAE Transac tions V.92, Pt .1.

Klote , J.H., and Fo the rg i l l , J .W. Jr. 1983. "Design of smoke co nt ro l systems f o rbuilding s." Atlanta: American Society of Heating, Refr ige rat in g, and Air-Condit ioningEngineers, Inc.

McGuire, J.H., Tamura, G.T., and Wi lson , A.G. 1970. "Fac to r s i n con t ro l l ing smoke in .high buildings. '? Pr oc eed ing s, Symposium on Fi r e Hazards i n Bui ld in gs , ASHRAE, pp. 8-13.Tamura, G.T., and Shaw, C.Y. 1976. "Air leakage da ta fo r the design of e le va t or and

s t a i r sh a f t p re ssu r i za t ion systems-." ASHRAE Tra nsact io n , Vol. 82 , p a r t 2, pp. 179-190.Tamura, G.T., and Shaw, C.Y. 1978. "Exper imenta l s tudies of mechanica l vent ing for

smoke con t ro l i n t a l l o f f i c e bu i ldings . " ASHRAE T ran sac ti ons , Vol. 84, p a r t 1 , pp. 54-71.

ACKNOWLEDGEMENT

The auth ors gr a t e f u l ly acknowledge th e c ontr ibu t ion of R.A. MacDonald i n s e tt i ng up andconduct ing the t e s t s in t he expe r imen ta l f i r e tow er and p rocess ing the t e s t r e s u l t s ; o fJ.E. Berndt i n running the da ta acq uis i t i on and c on tro l system and the gas burner system, andfo r prepar ing sof tware fo r da ta reduc t ion; and of o th er s t a f f members of the Nat ional Fi reLaboratory i n a ss i s t i ng du r ing the p repa ra t ion and conduc t of the t e s t s .

APPENDIX ACal cula tion of Pr ess ures , Flow Rates, and Vent Si zes

The fo l lowing equa t ions were der ive d fo r the e l eva tor s ha f t and lobby pressu r iza t ionsystems, which a re i l lu s t r a t ed i n Figures 4a and 4b , res pec t ive l y , by apply ing the equa t ionsf o r pa ra l l e l / s e r ie s f low and a i r f low through leakage openings, which a r e g iven i n (Klote andFotherg i l l 1983) .

P re ssu r i zedEleva to r Sha f t

1. Ae, o v e r a l l e q u i va l e n t ( A1+ '23e "4leakage a rea f rom the [(*I+ A23epre ssu r i zed space t oo u t s i d e -here

Pre ssu r i zedLobbies

where

note : wit h lobby door open- note: with lobby door-A3 >> A2) openA3 = leakage a r ea due t o

door opening.V e r t i c a l f lo w i n s h a f tassumed to be neg li gi bl e.

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2. AP, ov e ra ll pre ssu red i f f e r ence f r om t hepr es su r i zed space t oo u t s i d e

3. Q , p r e s s u r i z a t i o n f l o wfr a t e p er f l o o r

4 - Qo, f l ow r a t e a t g roundf loor through openelevator door wi th lobby

and entrance doorsa l so open

5. QT, t o t a l r eq u ir e dp r e s s u r i z a t i o n f l o w r a t ef o r a given AP w it h a l l3doors on ground f l o or ofStep 4 closed

where

AP = p r e s s u r e d i f f e r e n c e a c r o s s t h e e l e v a t o r3lobby door

where-= AP3/AF' (See Step 2)

For a i r a t s t a n d a r d c o n d it i o nC = 2400 with Q (cfm) , Ae ( f t 2 ) , U 3 ( i n of w at e r)c = 7 7 2 with Q ( g / s ) , Ae (m2), @ 3 ( Pa )

where

A = l eakage area of0

an open e levator doorN = t o t a l number of f lo or s

6 . AP31; QT with ground f loor

e l eva t o r , l obby , andent rance doors open

7. Q T t , t o t a l requi red (N-l )Qf + Qof lo w r a t e f o r a g iv e nAP w ith ground f l o o r3ele va tor , lobby andent rance doors open

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28. AP3 ; QT1 w ith a l l doo rs

c losedSha f t wall Sha f t wall

9. Ad , required s i ze of *23e [A1' =- T' QT 'C N ( L A P ~ )J - A23e = CN(LAP J f - A3re li ef damper fo r eachf loo r in the w a ll of thee lev a tor shaf t / lobby fo ra f a c t o r L

whereL = a l lo w ab l e f a c t o r f o r

i n c r e a s e i n AP when3open doors on groundf l o o r a r e c l o s e d

10. QdT, r e q u i r e d t o t a l QT'supply a i r r a t e w ithre l ie f dampers

Ad = A l t - A1Lobby wall

APPENDIX BPres sure s, Flow Rates, and Vent Sizes f o r th e

10-Story Experim ental F ir e Tower

Leakage AreasA1 = 0.07 ft2(0.006 m2);A2 (e leva tor door c losed) = 0.75 ft2(0.070 m2);A2 (elevator door open) = 6.00 f t2( 0.5 57 m) ;A3 = 0.30 ft2(0.028 m2);A4 = 0.79 f t2( 0.0 73 m2)

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Pressu r i zedEleva to r Sha f t1. Ae ( p e r s t o r y ) 0.318 f t 2 (0.0295 m2)

1.39 AP3900 (AP3) cfm26.4 (dp3)+ 11s

+16980 (AP3) cfm507 ( A P ~ ) +/ s

+9000 (AP3) cfm264 (AP3)+ i / s0.13 AP3

25000 (A P ~) ' fo745 (AP3)+ 11.

7.7 APg

0.335 f t 2 , (0.0311 m2)1.22 AP3888 (AP3) cfm

26.0 (AP3)' 11s11900 (AP3)+ cfm

355 ( A P ~ ) + l s8880 (AP3)+ cfm

265 ( AP3)+ Y s0.20 AP3

19900 (AP3)' cfm590 ( AP3)' V s

5.0 AP3

Shaf t wal l Lobby wa ll0.21 f t 2 (0.020 m2) 0.11 f t 2 (0.010 m2)

same as 7

Sha f t w a l l0.11 f t 2 (0.010 m2)same a s 7

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TABLE 1Leakage Flow Areas per F loo r of t h e Experimental F i r e Tower

Location Area-Outside wal ls1 s t f l o o r e a s t w a ll1 s t f loo r west w a l l2nd f l oo r e a s t w a l l (w a l l2nd f l oo r e a s t w a l l (w a l l2nd f lo or west wall (w all2nd fl oo r west wall (w allT y pi ca l f l o o r e a s t w a l lTypical f lo or west wal l

vent c losed)vent open)vent c losed)vent open)

Eleva to rF l oo r s pa ce t o e l e v a t o r s h a f t 0.07 0.006Floor space t o el ev at or lobby (lobby door closed) 0.30 0.028Flo or space t o el ev at or lobby (lob by door open) 21.00 1.951Eleva tor lobby t o e le va t or sh af t (e le va to r doors c losed) 0.75 0.070Elevato r lobby t o el ev at or sh af t (e lev ato r doors open) 6.00 0.557S t a i r sF lo or s p ac e t o s t a i r s h a f tFloor space to s t a i r lobby ( lobby door c losed)Floor space to s t a i r lobby ( lobby door open)S t a i r l obby t o s t a i r s h a f t ( s t a i r door c l os ed )S t a i r l obb y t o s t a i r s h a f t ( s t a i r door open)V e r t i c a l S h a f t sF l oo r s pa ce t o s e r v i c e s h a f tF loo r space to supp ly a i r sha f t*F l oo r s pa ce t o r e t u r n a i r s h a f t *C e i l i n g* Supply and re t ur n a i r openings sealed on the second floor

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TABLE 2C0 Concent ra t i on s with High Temperature F ir e- E l e v a t o r S h a f t P r e s s u r i z a t i o n

Unbracketed numbers - 45 min. a f t e r i gn i t i o n and w it hou t p r e s su r i za t i onBracketed numbers - 1 5 min. a f t e r p r e s s u r i z a t i o n s ys te m i s a c t i v a t e d

Cog c o n c e n t r a t i o n , X of c o n c e n t r a t io n i n t h e f i r e r e g io nBurn E l eva t o r E l eva t o r S t a i r S t a i r Se r v i ce

F l oor a r ea l obby Sha f t l obby sh a f t sh a f t

TABLE 3C02 Concentrat ions with High Temperature Fire- Elev ator Lobby Pre ssu r iz a t i on

Unbracketed numbers - 30 min. a f t e r ig ni t i on and without pres . sur iza t io nBracketed numbers - 15 min. a f t e r p r e s su r i z a t i on sys tem i s a c t i v a t e d

C02 c o n c e n t r a t i o n , X of c o n c en t r at i o n i n t h e f i r e r e g io n

Floor10987

654

321

Burna r e a

El eva t o rlobby

E l e v a t o r S t a i rShaft lobby

S t a i r S e r v i c es h a f t s h a f t

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TABLE 4Temperature R i s e i n t he Tower 30 Minutes A f t e r

I g n i t i o n During a High Temperature F i r e Tes tOu t s ide t empe ra tu r e 45 F (7OC)

Burn E l e v at o r E l e v at o r S t a i r S t a i r S e r v i c eF l o o r a r e a l ob by S h a f t l ob by s h a f t s h a f t

F (OC) F (OC) F (OC) F (OC) F (OC) F (OC)

TABLE 5Pres su re D i f f e r enc es i n t h e Tower 30 Minu tes Af t e r

Ig n i t i on Dur ing a H igh Tempera tur e F i r e Tes tP r e s s u r e d i f f e r e n c e - i n o f w a t e r ( P a)

Re fe r ence p r e s su re - burn a r eaFloor

1098765432

1

-- -S t a i rlobby

--Return Airs h a f t

S e r v i c es h a f t

E l e v a t o rlobby

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TABLE 6R e s u l t s of F i r e T e s t s wi t h E l e v a t o r S h a f t P r e s s u r i z a t i o n

E l ev a to r l ob by on f i r e f l o o r (2nd f l o o r )

Temperature AP lobby wal l C02o u t s i d e i n s i d e in . o f wa te r (Pa)lobby lobby 1.33 f t 6.33 f t 10.12 f t % a b s o l u t eF( OC) F( OC) (0.40 m) (1.93 m) (3.08 m)r e f e r e n c e p r e s s u r e - b u rn a re a

Low Temp. F i r e

P r e s s u r i z a t i o n - - 0.046 (11.5) 0.046 (11.5) 0.048 (11.9)Burn - 30 min. 760 (405) 153 (67) 0.026 (6.5) -0.004 (-1) -0.026 (-6.5) 2.20Burn + Press . 673 (356) 91 (33) 0.081 (20.2) 0.051 (12.7) 0.017 (4.2) 0.12- 15 min.Burn + Press . 716 (380) 116 (47) 0.055 (13.7) 0.010 (2.5) -0.019(-4.7) 0.20& open doors onground f loor- 15 min.High Temp. F i r e1380 F (750C)P r e s s u r i z a t i o n - - 0.102 (25.4) 0.100 (24.9) 0.098 (24.4) -Burn - 30 min. 1243 (673) 460 (238) 0.006 (1.5) -0.018 (-4.5) -0.030 (-7.5) 2.94Bum + Press . 1070 (576) 145 (63) 0.140 (34.9) 0.100 (24.9) 0.094 (23.4) 0.25- 15 min.Bum + Press . 1217 (630) 159 (87) 0.030 (7.5) 0.101 (2.5) -0.010 (-2.5) 0.75& open doors onground f loor- 15 min.

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TABLE 7Resul ts of Fl r e Tes ts wi th Elevator Lobby Pressu r iza t ion

Elevato r lobby on f i r e f lo o r (2nd f l o o r )

Temperature AP lobby wal l (3'2outs i de ins ide in . of water (Pa)lobby lobby 1.33 f t 6.33 f t 10.12 f t X absoluteF('c) F( OC) (0.40 m) (1.93 m) (3.08 m)

re fe rence p re s su re - b u m a r e a

Low Temp. F i r e

Pres su r iza t ion - 0.053 (13.2) 0.051 (12.7) 0.050 (12.5) -Burn + Press. 656 (347) 98 (37) 0.087 (21.7) 0.053 (13.2) 0.020 (5.0) 0.04- 15 min. 664 (351) 100 (38) 0.052 (12.9) 0.013 (3.2) -0.018 (-4.48) 1.4

Burn + Press.6 open doors onground floor- 15 min.

High Temp. F i r e1380 F (750C)Pres su r iza t ion - - 0.097 (24.1) 0.100 (24.9) 0.100 (24.9) -Burn - 30 min. 1230 (667) 390 (199) 0.013 (3.2) -0.033 (-8.2) -0.040 (-10.0) 0.90Burn + Press. 945 (496) 125 (52) 0.158 (39.3) 0.120 (29.9) 0.075 (18.7) 0.04- 15 min.

Burn + Press. 1106 (597) 140 (60) 0.069 (17.2) 0.023 (5.7) -0.018 (-4.5) 0.106 open doors onground floor- 15 min.

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TABLE 8Comparison of th e Ca lcu lat ed and t he Measured Values

of Supply A i r Rates and Pressure Di f ferences across theElevato r Lobby fo r Pressure Con t rol of Elevato r Pr es sur iza t io n Sys tems

Note: comparison in di ca te d by und erlin ed numbers

Method ofp r e s su r e con t r o l

Variable Supply A i ra l l d oo rs c l o s ed

1 s t f l o o r e l e v a t o r,lobby and exi tdoors open

Relief Dampers*1 s t f l o o r e l e v a t o r ,lobby, and exi tdoors openA l l doors closed

* Si ze of r e l i e f dampers f o r e l ev a t o r s ha f t p r e s su r i za t i on , 0.21 f t 2 , ( 0.019 m2)f o r e l ev a t o r l obby p r e s s u r i z a t i o n , 0.11 f t 2 ( 0. 011 m2)

2252

El eva t o r l obby Pr es su r i z a t i onl e v a to r s h a f t P r e s s u r i z a t i o nQT , cfm (m3/s) AP3, i n of

Calc.

1980(0.934)4440(2.09)

4440(2.09)

4440(2.09)

QT, cfm (m3/s) waLerCalc.

0.050(12.5)0.050(12.5)

0.050(12.5)

0.150(37.5)

Meas.

2050(0.968)

4670(2.20)

4670(2.20)

4670(2.20)

AP3, i n ofCalc.

2000(0.944)5590(2.64)

5590(2.64)

5590(2.64)

(Pa)Meas.

0.050(12.5)0.050(12.5)

0.050(12.5)

0.142(35.4)

waterCalc.

0.050(12.5)0.050(12.5)

0.050(12.5)

0.150(37.5)

Meas.

2030(0.958)5620(2.65)

5620(2.65)

5620(2.65)

(Pa)Meas.

0.050(12.5)0.050(12.5)

0.050(12.5)

0.156(36.1)

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Figure I . Fxperimental fire tower

14.6m 6 . 5 m I

! S M O K E S H 4 F 14 E L E V I T 0 9 S T AI R V E S T IB U L C SUPPLY5 s i n t n S UD PL Yi S T I l H E x l < d ~ j TI S f R V l C t S + 4 1 F 7? L L t Y A ' O * j + & ' T

Figure 2 . Plan of the experirne,ztal fi re touer

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B U R N H A L L

T O W E R 4C O M P U T E R

F A N C O N T R O L

S E R VI CE U N I T

D A TA R O O MR O O M

\M E C H A N I C A L

Figure 3. Luy-out of t he national fi re taboratory

E L E V A T I O N V l E W P L A N V l E W

a ) P R E S S U R I Z E D E L E V A T O R S H A F T

b ) P R E S S U R I Z E D L O B B I E S

Figure 4 . Elevator pressurization system2254

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L O W T E M P E R A T U R E F I R E , 8 4 0 F ( 4 50 C )1 2 - - 3.5

- 3 . 08 - WATER, 1 2.5 Pa - 2.5

- 2 .06 - - 1. 5

O PEN D O O R S O N - 1 . 02 - - 0. 5

I- 0 E- 715 -10 .05 0 -05 -10 -15 +I I I 1 I I I I I I-+

I - 40 20 0 20 40 + 5-Z H I G H T E M P E R A T U R E F I R E , 1 3 8 0 F ( 7 5 0 C )

N= 1 2 -

N- 3. 5

Cnn - 3.0- 2.5- 2 .0- 1. 5

4 - PEN DOORS ON1st FLOOR - 1 . 02 - 0 - 0. 5

0- -15 -10 -05 0 .05 -10 a15 +P R E S S U R E D I F F E R E N C E , I N C H E S O F W A T E RI I 1 I I 1 I I I- 40 20 0 20 40 +P R E S S U R E D I F F E R E N C E , P a

Figure 5. Pressure differences across the walls ofthe second floor elevator lobby duringf ire te s t s wi th elevator shaf t pressurizat ion'

20OOF B U R N P RY 1

O U T S I D E

> -0.08mm crO W2 -0. 04ag 3+ LL

-- E R N . RI+..,,, 1'\:-?-. - -. - < 6

g o2 m_1 WY I 0.040m zm -o 0.08cd -0 5

s 4 - B U R N P R1"

ELEVATO R LO BBY

I I0 20 40

T IMFigure 6 . Resu lts o f mfloor elevattemperatureshaft press

II

0"- ---- --- >'-REFERENCE PRESSURE

- B U R N A R E A ,L\,1.33ft(0.

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DiscussionC. ROUSSEAU, Nevcomb ti Boyd, Atlanta, GA: Have you run into the problem of leaky elevatorshaft construction vs. tight exterior building construction and the inability of the shaftpressurization to maintain pressure difference between the shaft and the occupied space?KLOTE: When considering the possible use of elevators for fire evacuation, the pressuredifference of interest is not between the shaft and the building but between the elevator lobbyand the building. For an elevator system to be considered for fire evacuation, the elevatorlobbies must be protected from smoke during evacuation. The leakage areas around a number ofelevator doors were measured by Tamura and Shaw and reported in a paper published in ASHRAETransactions 1976 entitled "Air Leakage Data for Design of Elevator and Stair ShaftPressurization Systems." For these few tests the leakage area around a closed elevator doorwas in the range of 112 to 314 square feet. This was for double opening elevator doors whichare the most common. It is easy to observe that the gaps around most elevator doors are large.For the elevator smoke control systems envisioned in buildings, the leakage area from the shaftto the lobby is much greater than that from the lobby to the building. This means that thepressure difference between the lobby and the shaft is very small while the pressure differencebetween the lobby and the building is much larger. Thus we can maintain a large pressuredifference across the elevator lobby doors even if the gaps around the elevator doors are verylarge. The advantage of this is that the most commonly used elevator doors that have largegaps can be used without modification. Further, leakage areas between the elevator door frameand the walls are not a concern. The high leakage areas from the shaft to the lobby areespecially useful when the elevator lobby is indirectly pressurized by air supplied to theshaft. For the systems we are talking about, tight fitting elevator doors should be avoided.ROUSSEAU: Where is the preferable location to inject air into shaft?G. JOLETTE, AMCA, Arlington Heights, IL: Where should fan be placed due to smoke on roof?TAMURA: To minimize the possibility of smoke ingestion, the preferred location of the fan isnear ground level. Also, during cold weather, the operation of the fan at this location willbe assisted by stack action, whereas, on the roof, the reverse is the case.JOLETTE: Was the example airflow rate for elevator and for the lobby intended to be a singieflow?TAMJRA: The supply air for pressurization given in the paper were injected entirely either inthe elevator shaft or in the elevator lobbies.

Reprinted from ASHRAE TRANSACTIONS by permission of the American Society ofHeating, Refrigerating and Air-Conditioning Engineers, Inc.

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This paper is b ein g d i s t r i b u t e d i n r e p r i n tf or m by t h e I n s t i t u t e f o r Re se ar ch i n .Const ruc t ion. A l i s t of bu i ld ing pr ac t i c ea nd r e s e ar c h p u b l i c a t i o n s a v a i l a b l e f ro mt h e I n s t i t u t e may be ob ta ined by wr i t i n g t ot h e P u b li c at i on s S e ct io n , I n s t i t u t e f o rResearch i n Const ruc t ion, Nat iona l ResearchC o u n c i l o f C an a d a, O t t a w a , O n t a r i o ,KIA 0R6.

Ce document e s d i s ri bu G sous forme det i r8-a-par t par 1' I n s t i t u t de r e ch er ch e e ncons t ruc t ion . On peut obteni r une l i s t ed e s p u b l i ca t i o n s d e 1 ' I n s t i t u t p o r t a n t s u rles techniques ou le s recherches en matisrede ba t iment en Gcrivant a l a S e c t i o n d e sp u b l i ca t i o n s, I n s t i t u t d e r ec he r ch e e nc o n s t r u c t i o n , C o n s e i l n a t i o n a l d erec her che s du Canada, Ottawa (O nta rio ),KIA OR6.