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The performance of a vestibule pressurization system for the
protection of escape routes of a 17-story hotel
Ser
TH1N21d
0.954
N a t i o n a l R e s e a r c h Council of Canada
c. 2C o n s e i l n a t i o n a l d e r e c h e r c h e s d u Canada
BLDG
- --T H E P E R F O R M A N C E
O F A VESTLBULE PRESSURIZATION
I
SYSTEM F O R T H E P R O T E C T I O N O F E S C A P E ROUTES
I
O F A 17-STORY H O T E L
I
by G. T . T a m u r a
R e p r i n t e d f r o m
ASHRAE T r a n s a c t i o n s
Vol. 86, P a r t 1 , 1980
p. 593
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OTTAWA
RESUME
-.
On a effectu6 des essais en hiver sur le systsme de protection mscanique
du vestibule d'un h8tel 2 appartements de 17 6tages situ6
5 Ottawa et
construit en 1974. Le systeme a 6te conqu pour prot6ger contre la conta-
mination par la fum6e un ensemble comprenant une cage d'escalier et une
cage pour deux ascenseurs situ6es 2 une extr6mit6 d'un couloir. On a
6valu6 la performance du systzme de protection en effectuant des mesures
des courants d'air et des pressions pour r6aliser un sch6ma de la circu-
lation et de la pression dans l'immeuble; cel3 a permis de deviner le
comportement probable de la fum6e pendant un incendie. Les essais ont
d6montr6 que le systsme de pressurisation du vestibule devrait assurer
une protection efficace contre la contamination par la fum6e des cages
des ascenseurs et de l'escalier.
THE PERFORMANCE OF A VESTIBULE
PRESSURIZATION SYSTEM FOR THE
PROTECTION OF ESCAPE ROUTES-OF
A 17-STORY HOTEL
G.T. TAMURA, P.Eng.
Member ASHRAE
INTRODUCTION
The migration of smoke into elevator and stair shafts as a result of a fire in a building can pose a threat to the lives of occupants, particularly in high-rise buildings where rapid evacuation may not be possible. Several measures to provide protection against this hazard were developed by the Division of Building Research, National Research Council of Canada, and were first published in 1970~; the most recent information on these measures was published in 1977.2 One of the smoke control measures in the original document is identified as the
"Protected Vestibule Access to Stairs and Elevators." This measure is intended to restrict the movement of smoke through the escape routes by providing vestibules that are either naturally vented to the exterior by means of an opening in the outside wall, or mechanically pressurized with outdoor air. With this method, a single vestibule on each floor can be used to protect a group of stair and elevator shafts in contrast to shaft pressurization where each shaft is treated separately. The vestibule also provides an additional door, which can assist in preventing adverse flow of smoke when an elevator or a stair door is opened, and serves as a staging area on the fire floor for fire fighters. The results of tests on a vestibule-type protection system with an outside-air mechanical supply to the vestibule and the associated stair shaft have been reported by Cottle et a1.,3 and by ~ a ~ e n k o l b ~ for a system with supply and exhaust of air in both the vestibule and the protected stair shaft.
Tests were conducted in December of 1976 on the vestibule pressurization system of a 17-story apartment hotel tower (Fig. 1) situated in Ottawa and built in 1974. It was designed to protect from smoke contamination both the one stair shaft and 2-car elevator shaft, located at one end of the corridor. Although the stair shaft was provided with a pressurization system, the test results reported in this paper were obtained with this system shut down. To evaluate the performance of the vestibule protection system alone, tests were also conducted with the building ventilation systems in operation and shut down and, also, with various
combinations of vestibule, room and balcony doors open to assess the probable movement of smoke in the event of a fire in a room.
DESCRIPTION OF THE VESTIBULE PROTECTION SYSTEM
The pressurization fan is located in the exterior wall of the 2nd floor and supplies air to the vertical duct that distributes the supply of outside air to the vestibules on the various floors (Fig. 2). A branch duct located in the linen room on each floor connects the vertical distribution duct to the supply grille in the wall of the vestibule (Fig. 3). The protected vestibule, which is located at one end of the corridor, gives access to the stairs, the 2-car elevator, and the corridor. The two vestibule doors to the corridor are held open during normal occupancy with electrically activated magnetic door holders, which are deactivated upon receipt of a fire alarm. The enclosed floor area of the vestibule is 25.36 m2 (273 ft2).
A second stair shaft without a vestibule is located at the opposite end of the corridor. Each room is provided with a swing-type glass door that gives access to a balcony. The
corridors are supplied with make-up air, and air is exhausted from the rooms via the washrooms
G.T.
Tamura, Research Officer, Energy and Services Section, Division of Building Research, National Research Council of Canada, Ottawa, K1A OR6 Canadaand discharged to the exterior above the roof of the building. The fans for make-up and exhaust, which are located in the top mechanical room, are shut down during a fire emergency.
The required supply air rate calculated from Eq A1 of Appendix A, obtained from Ref 1, was
0.65 m3/s (1,380 cfm) per vestibule for a total flow rate of 10.4 m3/s (22,000 cfm). The
capacity of the supply air fan that was installed for vestibule pressurization was 15.8 m3/s (33,450 cfm) at about 50 Pa (0.20 in. of water) static pressure. Eq A1 is intended to account for leakage flow from the vestibule to the corridor, floor space, and elevator and stair shafts, with the vestibule pressurized by 25 Pa (0.10 in. of water) greater than its
surroundings. The value of factor E of Eq Al, which is given in Fig. Al, depends on building height. It is intended to take into account the adverse pressure difference caused by stack action during cold weather.
TEST PROCEDURE
Tests were conducted under the following situations: Test No.
1) Building ventilation systems in normal operation; 2) Building ventilation systems shut down;
3) Vestibule pressurization system in operation;
4) Vestibule pressurization system, and make-up and washroom exhaust systems in operation.
Tests No. 1 and 2 were conducted to compare the pressure and air flow patterns with those
of Test No. 3 (vestibule pressurization system in operation). Test No. 4 was conducted to
determine the effect of the operation of the make-up and washroom exhaust systems with the vestibule pressurization system in operation. For each test configuration, measurements were made firstly with all doors closed and secondly with various doors of the 5th floor open. This
floor was chosen as the hypothetical fire floor with Room 505 as the hypothetical fire room. One of the two vestibule doors on this floor was either intentionally open or closed, as well as the entrance door of Room 505 and the balcony door, which was open to give a free area of 0.37 m2 (4.0 ft2) to simulate an opening created by glass breakage caused by a fire.
During each test, pressure differences were measured across the doors of the vestibule, stair, elevator, and entrance and balcony of a room on each side of the corridor. These measurements were made on floors 1,3,5,8,11,14 and 17, with a diaphragm-type pressure
transducer calibrated with a micromanometer and corrected for zero shift before each reading. The supply air rates to the vestibules were calculated from the air velocity measurements made with a hot wire anemometer traverse at the supply air grilles. This technique was also used to measure the flow rates at the open doors where the flow was uni-directional. Where it was not, only the flow direction was recorded by running a smoke pencil from the top to the bottom of the door opening.
RESULTS AND DISCUSSION
The pressure and flow measurements were made to determine the probable pattern of the movement of smoke from a fire in a room on a lower floor of a high-rise building. These tests were conducted primarily to help assess the performance of the vestibule pressurization system and to compare its performance with the building air-handling systems operating and also with them shut down.
The results of the tests are presented, firstly to give an overall picture of the pressure and air flow patterns for the 4 test configurations and, secondly, to determine .the smoke movement on the 5th floor, which was designated as the fire floor, with various combinations of open and closed doors on this floor. At the time of the test, the outside temperature was -ll°C (12OF) and the wind was from the northwest at 19 km/h (11.8 mph) recorded at the airport. A. General Air Flow and Pressure Patterns
Test A1
-
Building Ventilation Systems in Normal Operation. Fig. 4 gives the air flowand pressure patterns for all typical floors, with the make-up air and the washroom exhaust
systems in operation and the two-vestibule doors open. The directions of flow were into stair
No. 1 and into the elevators at the lower floors and out from them at the upper floors, which is the characteristic flow pattern caused by stack action. The direction of air flow across
t h e d o o r s of s t a i r No. 2 was from t h e s t a i r t o t h e c o r r i d o r . When t h i s s t a i r s h a f t was checked a f t e r w a r d s , i t was found t h a t a s t a i r door l e a d i n g d i r e c t l y t o a lunchroom i n t h e basement had been l e f t open, which a p p a r e n t l y allowed a s u b s t a n t i a l flow o f a i r from t h i s room i n t o t h e s t a i r s h a f t .
The combination of make-up a i r s u p p l y t o t h e c o r r i d o r and washroom exhaust from t h e room r e s u l t e d i n p r e s s u r e d i f f e r e n c e s o f 2 t o 20 Pa (0.008 t o 0.080 i n . o f w a t e r ) a c r o s s t h e room e n t r a n c e door w i t h a i r f l o w i n g from t h e c o r r i d o r i n t o t h e rooms. T h i s flow p a t t e r n i s f a v o r a b l e i n terms of p r e v e n t i n g t h e t r a n s f e r o f smoke from t h e room t o t h e r e s t o f t h e b u i l d i n g d u r i n g a f i r e , a s w e l l a s odor d u r i n g normal occupancy. The room p r e s s u r e s were a l l n e g a t i v e w i t h r e s p e c t t o t h e o u t s i d e p r e s s u r e s , which r e s u l t e d i n a i r i n f i l t r a t i o n through t h e e x t e r i o r w a l l s of a l l t y p i c a l f l o o r s .
T e s t A2
-
B u i l d i n g V e n t i l a t i o n Systems Shut Down. With t h e make-up a i r and washroom e x h a u s t f a n s t u r n e d o f f , t h e flow p a t t e r n s a c r o s s t h e s t a i r and e l e v a t o r d o o r s were about t h e same a s when t h e f a n s were on ( F i g . 5 ) . The d i r e c t i o n s o f flow a c r o s s some o f t h e room e n t r a n c e d o o r s were from t h e c o r r i d o r i n t o t h e room, w i t h t h e measured p r e s s u r e d i f f e r e n c e s r a n g i n g from 0 t o 2 Pa (0 t o 0.008 i n . of w a t e r ) . The p r e s s u r e d i f f e r e n c e s measured a c r o s s t h e balcony d o o r s i n d i c a t e d t h a t t h e n e u t r a l p r e s s u r e l e v e l was l o c a t e d a t about t h e 1 3 t h f l o o rl e v e l , w i t h a i r i n f i l t r a t i o n through t h e e x t e r i o r w a l l s below t h i s l e v e l and a i r e x f i l t r a t i o n above i t .
In t h e e v e n t o f a window breakage i n t h e f i r e room, t h e 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 x t e r i o r w a l l would be t r a n s f e r r e d t o t h e c o r r i d o r w a l l and, hence, a f i r e l o c a t e d on a lower f l o o r i s much more s e r i o u s i n terms o f smoke c o n t a m i n a t i o n t h a n one l o c a t e d on an upper floow.
T e s t A3 - V e s t i b u l e P r e s s u r i z a t i o n System i n O p e r a t i o n . F i g . 6 g i v e s t h e p r e s s u r e and flow p a t t e r n s w i t h t h e v e s t i b u l e p r e s s u r i z a t i o n system o p e r a t i n g w i t h t h e two v e s t i b u l e d o o r s c l o s e d and w i t h t h e make-up a i r and t h e washroom exhaust f a n s s h u t down. The v e s t i b u l e s were p r e s s u r i z e d from 34 t o 47 Pa (0.14 t o 0.19 i n . o f w a t e r ) above t h e c o r r i d o r p r e s s u r e s . From t h e measurements o f p r e s s u r e d i f f e r e n c e s a c r o s s t h e room e n t r a n c e and balcony d o o r , t h e
v e s t i b u l e p r e s s u r e s were h i g h e r t h a n t h e o u t s i d e p r e s s u r e s by 23 Pa (0.092 i n . o f w a t e r ) on t h e 2nd f l o o r , and ranged up t o 67 Pa (0.27 i n . o f w a t e r ) on t h e t o p f l o o r . F i g . 6 i n d i c a t e s t h a t a i r flowed from t h e c o r r i d o r t o t h e rooms and, a l s o , t h a t t h e n e u t r a l p r e s s u r e l e v e l was lowered from t h e 1 3 t h f l o o r , a s o b t a i n e d from t h e p r e v i o u s c a s e ( T e s t A2), t o t h e 1 0 t h f l o o r l e v e l i n d i c a t i n g t h a t t h e rooms were i n d i r e c t l y p r e s s u r i z e d when t h e v e s t i b u l e s were
p r e s s u r i z e d .
The r a t e s o f o u t s i d e s u p p l y a i r measured a t t h e s u p p l y a i r g r i l l e s o f t h e v e s t i b u l e were a s f o l l o w s :
Flow Rate, A i r Change F l o o r m 3 / S (cfm) p e r Hour 17 0.315 (667) 18 14 0.304 (644) 17 11 0.326 (690) 19 8 0.364 (771) 2 1 5 0.532 (1127) 3 1 3 0.555 (1173) 32 3
These s u p p l y a i r r a t e s were l e s s t h a n 0.65 m / s (1380 cfm), which was c a l c u l a t e d according t o E q A l . The p r e s s u r e d i f f e r e n c e s a c r o s s t h e v e s t i b u l e d o o r s , however, were g r e a t e r t h a n 25 Pa
(0.10 i n . o f w a t e r ) , and t h e p r e s s u r e s o f t h e lower v e s t i b u l e s were g r e a t e r t h a n t h e o u t s i d e p r e s s u r e s . Allowing f o r an i n c r e a s e i n t h e 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 due t o s t a c k a c t i o n , t h e y would s t i l l be g r e a t e r t h a n t h e o u t s i d e p r e s s u r e s a t t h e w i n t e r d e s i g n t e m p e r a t u r e of -2S°C (-13OF) f o r Ottawa. T h i s e n s u r e s t h a t t h e flow d i r e c t i o n d u r i n g c o l d weather would be from t h e v e s t i b u l e t o t h e c o r r i d o r even i f t h e c o r r i d o r p r e s s u r e s approached t h e o u t s i d e p r e s s u r e s w i t h t h e e n t r a n c e door o f t h e f i r e room open and t h e g l a s s o f t h e e x t e r i o r w a l l broken i n t h a t room. The r e l a t i v e l y h i g h a i r change r a t e s i n t h e v e s t i b u l e s would a s s i s t i n d i l u t i n g and d i s p e r s i n g any smoke t h a t might have migrated i n t o t h e v e s t i b u l e . I t would a p p e a r t h a t E q A1 g i v e s a good e s t i m a t e o f t h e r e q u i r e d s u p p l y a i r r a t e t o t h e v e s t i b u l e s . I t i s
b e t t e r t o e r r on t h e h i g h s i d e because t h e s u p p l y a i r r a t e s can be e a s i l y a d j u s t e d t o lower v a l u e s , whereas i t i s d i f f i c u l t t o a d j u s t t o h i g h e r v a l u e s . I t should be c a u t i o n e d t h a t E q A 1
does n o t t a k e i n t o account a i r l e a k a g e s o t h e r t h a n t h o s e o f t h e d o o r s i n t h e v e s t i b u l e e n c l o s u r e .
I t i s seen t h a t t h e s u p p l y a i r r a t e s d e c r e a s e d w i t h h e i g h t , w i t h t h e s u p p l y a i r r a t e a t t h e t o p e q u a l t o about o n e - h a l f o f t h a t a t t h e 3rd f l o o r . D e s p i t e t h e imbalance o f t h e s u p p l y a i r flow t o t h e v e s t i b u l e s , t h e amount o f p r e s s u r i z a t i o n t o t h e v e s t i b u l e was e s s e n t i a l l y uniform, probably owing t o t h e r e d i s t r i b u t i o n o f s u p p l y a i r through t h e e l e v a t o r s h a f t .
L o c a t i n g t h e s u p p l y a i r f a n n e a r t h e bottom of t h e b u i l d i n g , a s i n t h i s c a s e , i s more d e s i r a b l e t h a n a t t h e t o p o f t h e b u i l d i n g because t h e s u p p l y a i r r a t e s a r e l i k e l y t o be g r e a t e r n e a r t h e bottom where t h e a d v e r s e s t a c k e f f e c t i s g r e a t e s t and where s t a c k a c t i o n can a s s i s t t h e f a n d u r i n g c o l d weather. Also, t h e r e i s l e s s l i k e l i h o o d o f i n g e s t i o n o f smoke a t t h e f a n i n t a k e .
T e s t A4 - V e s t i b u l e P r e s s u r i z a t i o n Make-up and Washroom Exhaust Systems i n O p e r a t i o n . F i g . 7 shows t h e p r e s s u r e and flow p a t t e r n s w i t h t h e make-up a i r and washroom e x h a u s t systems t o g e t h e r w i t h t h e v e s t i b u l e p r e s s u r i z a t i o n system i n o p e r a t i o n . The p r e s s u r e d i f f e r e n c e s a c r o s s t h e v e s t i b u l e and room e n t r a n c e d o o r s were g r e a t e r f o r t h i s c a s e t h a n t h o s e w i t h o n l y t h e v e s t i b u l e p r e s s u r i z a t i o n system i n o p e r a t i o n ( F i g . 6 ) . I t would a p p e a r t h a t o p e r a t i n g t h e make-up a i r and washroom e x h a u s t systems can improve t h e performance o f a v e s t i b u l e
p r e s s u r i z a t i o n system.
B . R e s u l t s of Door-Opening T e s t s on t h e 5 t h F l o o r
T e s t B1
-
B u i l d i n g V e n t i l a t i o n Systems i n Normal O p e r a t i o n . The r e s u l t s of t h e door- opening t e s t s conducted i n Room 505 of t h e 5 t h f l o o r w i t h t h e make-up a i r and washroom exhaust systems i n o p e r a t i o n a r e given i n F i g . 8 , which shows t h e p a t t e r n of smoke flow on t h i s f l o o r assuming t h a t c o l d smoke was g e n e r a t e d i n Room 505. With t h e room e n t r a n c e and t h e balcony d o o r s c l o s e d ( F i g . 8A), a i r flowed i n t o t h e room through b o t h t h e c o r r i d o r and e x t e r i o r w a l l s w i t h t h e smoke exhausted through t h e washroom e x h a u s t s y s t e m s .The p r e s s u r e d i f f e r e n c e o f 39 Pa (0.15 i n . o f w a t e r ) a c r o s s t h e e x t e r i o r w a l l and t h a t o f 4 Pa (0.02 i n . o f w a t e r ) a c r o s s t h e c o r r i d o r w a l l i n d i c a t e d t h a t t h e o u t s i d e p r e s s u r e was 35 Pa
( 0 . 1 3 i n . of w a t e r ) h i g h e r t h a n t h e c o r r i d o r p r e s s u r e because o f t h e combination o f s t a c k a c t i o n o f 22 Pa ( 0 . 0 9 i n . o f water) a s g i v e n i n F i g . 5 and t h e o p e r a t i o n o f t h e b u i l d i n g v e n t i l a t i o n systems. Thus, when t h e balcony door was open t o s i m u l a t e window breakage caused by a f i r e ( F i g . 8B), a i r flowed i n t o t h e room from t h e e x t e r i o r , r a i s e d t h e room p r e s s u r e s , and r e v e r s e d t h e d i r e c t i o n o f flow a t t h e room e n t r a n c e door. A s a r e s u l t , smoke from t h e room flowed i n t o t h e c o r r i d o r and s p r e a d t o o t h e r u n i t s and i n t o t h e e l e v a t o r and s t a i r s h a f t s . Opening o n l y t h e room e n t r a n c e door ( F i g . 8C) r e s u l t e d i n an i n t e r c h a n g e o f room and c o r r i d o r a i r w i t h a consequent c o n t a m i n a t i o n o f o t h e r u n i t s and t h e e l e v a t o r and s t a i r s h a f t s . When t h e balcony door was a l s o open ( F i g . 8D) t h e p o t e n t i a l f o r t h e s p r e a d of smoke i n t o t h e s e a r e a s was g r e a t l y i n c r e a s e d a s i n d i c a t e d by t h e i n c r e a s e i n t h e u n f a v o r a b l e p r e s s u r e d i f f e r e n c e s a c r o s s t h e d o o r s o f o t h e r u n i t s and t h e d o o r s o f t h e e l e v a t o r and s t a i r s h a f t s . The flow through t h e open door of Room 505 f o r t h i s c a s e was 1 . 3 9 m3/s (2,945 cfm)
.
I t i s seen t h a t t h e o p e r a t i o n of t h e make-up a i r and washroom e x h a u s t system i s e f f e c t i v e a s a smoke c o n t r o l measure a s long a s t h e i n t e g r i t y of t h e e x t e r i o r w a l l o f t h e room on f i r e i s i n t a c t and i t s door t o t h e c o r r i d o r i s c l o s e d . Otherwise, smoke c o n t a m i n a t i o n of t h e c o r r i d o r , o t h e r u n i t s on t h e f i r e f l o o r , and t h e e l e v a t o r and s t a i r s h a f t s can be e x p e c t e d .
T e s t B2 - V e s t i b u l e P r e s s u r i z a t i o n System i n O p e r a t i o n . The r e s u l t s o f t h e t e s t s conducted w i t h t h e v e s t i b u l e p r e s s u r i z a t i o n system i n o p e r a t i o n w i t h b o t h v e s t i b u l e d o o r s c l o s e d a r e shown i n F i g . 9 . F i g . 9A i n d i c a t e s t h a t t h e c o r r i d o r p r e s s u r e was lower t h a n t h e o u t s i d e p r e s s u r e by 6 Pa (0.025 i n , o f w a t e r ) and t h a t t h e v e s t i b u l e p r e s s u r e was h i g h e r t h a n t h e o u t s i d e p r e s s u r e by 41 Pa (0.16 i n . of w a t e r ) . Opening e i t h e r t h e balcony o r room e n t r a n c e d o o r s o r b o t h f o r Room 505 r e s u l t e d i n c o n t a m i n a t i o n o f t h e c o r r i d o r and o t h e r u n i t s , but t h e v e s t i b u l e , e l e v a t o r and s t a i r s h a f t s were k e p t f r e e o f smoke a s shown i n F i g . 9B, 9C and 9D.
t h e ( 1 ,
The t e s t s w i t h t h e v e s t i b u l e p r e s s u r i z a t i o n system i n o p e r a t i o n were r e p e a t e d w i t h one of v e s t i b u l e doors open. The r a t e of a i r flow through t h e open v e s t i b u l e door was 0.83 m 3 / s 760 cfm), which r a i s e d t h e c o r r i d o r p r e s s u r e s by 9 Pa (0.036 i n . of w a t e r ) above o u t s i d e p r e s s u r e s . As a r e s u l t , t h e c o r r i d o r and o t h e r u n i t s on t h e 5 t h f l o o r were k e p t f r e e o f smoke except f o r t h e c a s e with o n l y t h e room e n t r a n c e door open, a s shown i n F i g . 10. In a l l c a s e s , t h e v e s t i b u l e , e l e v a t o r and s t a i r s h a f t s were p r o t e c t e d from smoke c o n t a m i n a t i o n .
As seen i n F i g . 10A and 10B, t h e flow d i r e c t i o n s a c r o s s t h e e l e v a t o r and s t a i r d o o r s r e v e r s e d when t h e v e s t i b u l e door was opened. The r e s u l t a n t leakage flow from t h e s e s h a f t s i n t o t h e v e s t i b u l e t o g e t h e r with a p r o b a b l e i n c r e a s e i n t h e flow a t t h e s u p p l y a i r g r i l l e
contributed to the flow of air at the open vestibule door, which was significantly greater than the supply air rate to the vestibule with its doors closed.
The tests with the building ventilation systems (make-up air and washroom exhaust systems) operating with the vestibule pressurization system indicated that the air flow patterns were similar to those with only the vestibule pressurization system operating, except for the case where one of the vestibule doors and both the balcony and room doors were open. For this case, there was an interchange of outdoor and room air at the balcony door opening, and also of the corridor and room air at the open entrance door, which resulted in smoke contamination of the corridor and other units on the 5th floor. Because of the various conditions that may occur during a fire, it is not clear whether it would be better to operate the make-up air and exhaust systems together with the vestibule pressurization system.
The tests have indicated that the vestibule pressurization system was effective in protecting the elevator and stair shafts from smoke contamination. Under certain situations, however, the corridor and rooms on the fire floor can be contaminated with smoke, particularly when the entrance door of the room on fire is left open. Providing closures for room entrance doors, therefore, can significantly reduce the amount of smoke contamination. In addition to vestibule pressurization, mechanical pressurization of the stair shaft and elevator shaft or bottom venting the shafts to the exterior in winter provides added protection to these escape routes.
C. Vestibule Air Temperature
During the tests, the air temperature of the vestibule was taken near the stair shaft. As shown in Fig. 11, the air temperature of the vestibule on the 5th floor dropped rapidly during the first hour to reach a quasi-steady state temperature of 1.6OC (35'~). Soon after the end of the series of tests, which lasted for about 3 h, the hot water pipe of the radiator unit beneath the windor burst on several floors, probably because of freezing. As can be seen in Fig. 2, the supply air grille was located near and above the radiator unit which was cooled by the downwash to below the measured air temperature. Tempering of the supply air during cold weather should be considered to avoid freezing of water lines as well as to provide comfort to the occupants who are leaving the building by this route.
D.
Fire ExperiencesThere is evidence to indicate that air pressures can contribute to the control of smoke during a fire. A fire in a room on the 12th floor of a 13-story apartment building reported by ~ a l b r e a t h , ~ which involved the kitchen and living room area, resulted in the breakage of a large picture window. The occupant took refuge on the balcony. The fire fighters reached the 12th floor corridor to find it was free of smoke. When the door to the apartment was opened the corridor filled with smoke, but this dispersed rapidly as the fire fighters brought the fire under control. The outside temperature at the time of the fire was 24OC (7S°F). The pressure difference across the door measured at a later date indicated that the corridor pressure was 7.5 Pa (0.030 in. of water) above the room pressure.
Another fire incident reported by ~ a ~ l o r ~ involved a room on the 20th floor of a 21-story apartment building. The occupant left the room closing the door behind him. The corridor on this floor was smoke free when the fire fighters arrived despite the fact that the door was burned off. The make-up air system was designed for corridor pressurization of 25 Pa (0.10 in. of water). Because the fire occurred in March, and at a high level of the building, stack action together with the make-up air supply prevented the smoke from flowing into-the corridor. Stack action would have been detrimental if a fire had occurred in a room located on one of the lower floors.
CONCLUSIONS
The tests conducted in winter have indicated that the vestibule pressurization system of.the test building likely would provide effective protection against smoke contamination of the elevator and stair shafts in the event of a fire even with glass breakage in the fire room or with the door to that room open. The vestibules were pressurized from 34 to 47 Pa (0.14 to 0.19 in. of water) above the corridor pressures and sufficiently above outside pressures to counteract stack action at the winter design temperature. Eq A1 of Ref 1 gives a good estimate of the required supply air rate for vestibule pressurization.
The vestibule pressurization system or other smoke control systems are unlikely to prevent the contamination of the corridor and other units of the fire floor when the door to the fire room is left open and the exterior wall of the fire room remains intact. Providing automatic closures to the doors at the room entrance can greatly reduce the possibility of an intolerable level of smoke in the corridor.
. With only the make-up air and the room exhaust systems operating, which is the normal mode
of operation, the amount of corridor pressurization, which inhibits the flow of smoke from the fire room to the corridor, varied from 2 to 20 Pa (0.008 to 0.080 in. of water) above room pressures. Tests have indicated, however, that in winter, with the fire room located on one of the lower floors and with an opening in the exterior wall of that room, this amount of
pressurization is insufficient to prevent the contamination of the elevator and stair shafts, as well as other units on the fire floor.
It was uncertain from the test results whether it would be better to operate the make-up air and exhaust systems with the vestibule pressurization system in operation. Although not validated during the test, from examination of the pressure and flow patterns, it is likely that the possibility of flow of smoke from the washroom exhaust stack into the upper rooms from a fire in a room on a lower floor is reduced.
ACKNOWLEDGEMENTS
The author gratefully acknowledges Urbanetics Ltd. for the arrangement made to conduct the tests and the cooperation received during the tests; Clemann Large Patterson and Assoc. Ltd. for the discussion of the protection system during the design stage and their assistance during the tests; and Morguard Properties Ltd., the owner representative, and Pension Fund Realty Limited, the owner of the building, for permission to publish this paper. He also wishes to thank C.Y. Shaw and R.G. Evans for their assistance in the field tests.
REFERENCES
1. "Explanatory Paper on Control of Smoke Movement in High Buildings," Associate Committee on the National Building Code, National Research Council of Canada, Ottawa, Canada,
NRCC No. 11413, 1970.
2 . 'IMeasures for Fire Safety in High Buildings," Associate Committee on the National Building Code, National Research Council of Canada, Ottawa, Canada, NRCC No. 15764, 1977.
3. Cottle, T.H., Bailey, T.A., Butcher, E.G., and C. Shore, "Smoke Tests in the Pressurized
Stairs and Lobbies in a 26-storey Office Building,I1 Fire Research Note No. 850, Joint Fire Research Organization, November, 1970.
4. Degenkolb, J.G., 'Smoke Proof Enclosures," ASHRAE Journal, Vol. 13, No. 4, pp. 33-38, 1971.
5. Galbreath, M., and G.W. Shorter, "Air Pressures Contribute to a Smoke-Free Corridor," Fire Research Note No. 3, Division of Building Research, National Research Council of Canada, April, 1966.
6. Taylor, R.E., "The Carlyle Apartment Fire: Study of a Pressurized Corridor," ASHRAE
F i g . 1 T e s t b u i l d i n g F i g . 2 P R E S S U R I Z E D V E S T I B U L E V e s t i b u l e p r e s s u r i z a t i o n s y s t e m 1 . V E S T I B U L E P R E S S U R I Z A T I O N F A N - 2 N D F L O O R 2 . M A G N E T I C V E S T I B U L E D O O R H O L D E R 3 . V E R T I C A L S H A F T F O R D I S T R I B U T I N G S U P P L Y A I R F O R P R E S S U R I Z A T I O N F i g . 3 P l a n o f t y p i c a l f l o o r
H O O M K O O M
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VESTIBULE C O R R I D O R I-R O O M R O O M O U T S I D E TEMP - - l l ° C N O T E . PRESSURE D I F F E R E N T I A L IS I N P A S C A L S W I N D 19 k m / h O U T S I D E TEMP - 1 1 ° C N O T E : PRESSURE D I F F E R E N T I A L I S I N P A S C A L S W I N D 1 9 k m / hFig. 4 Pressure differential and air flow pattern with building ventilation systems in normal opera tion
Fig. 6 Pressure differential and air flow
pattern with vestibule pressurization system in operation VESTIBULE C O R R I D O R I R O O M R O O M . K O O M K O O M I / l t 4 D / , A R L J D W A R D O U T S I D E TEMP -11'C N O T E : PRESSURE D I F F E R E N T I A L I S I N P A S C A L S W I N D 19 k m / h
Fig. 5 Pressure differential and air flow pattern with building ventilation systems shut down
O U T S I D E TEMP - 1 1 ° C N O T E : PRESSURE D I F F E R E N T I A L I S I N P A S C A L S W I N D 19 k m / h
Fig. 7 Pressure differential and air flow pattern with vestibule pressurization, make-up air and washroom exhaust systems in operation
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, , . . . . . 0 . 2 4 " s 3 / : N O T E PRESSURE D I F F E R E N T I A L I S I N P A S C A L S F i g . 9 R e s u l t s o f d o o r - o p e n i n g t e s t s o n 5 t h f l o o r-
v e s t i b u l e p r e s s u r i z a t i o n s y s t e m i n o p e r a t i o n ( v e s t i b u l e d o o r s c l o s e d ) T I M E , h F i g . 1 1 V e s t i b u l e a i r t e m p e r a t u r e o n t h e 5 t h f l o o rDISCUSSION
ROBERT
E.
TAYLOR, Coordinator, Codes & Standards, Republic Steel Corp., Cleveland,OH: Is there any reason why elevators should not be used for evacuation when vestibules are pressurized in high-rise apartment structures or office buildings? G.T. TAMURA: Elevators can be used for evacuation, provided that the door open- ing mechanisms are protected from heat and smoke; the elevator shaft is main- tained free of smoke; electrical conductors for the operation of elevators are protected against exposure to fire; there is an emergency power supply for the operation of elevators; and elevators are operated manually by responsFble per- sons.
PAT SCHUROTT, Dir. of Eng., Oxford-Anschutz Devel. Co., Denver, CO: ("general" question) With the number of various structures and systems, is there a formula or series of formulas that will satisfy design intent and actual operation dur- ing a fire mode?
G.T. TAMURA: There are data and formulas in various publications which can
assist in the design of a smoke control system. ASHRAE T.C. 5.6, Fire and Smoke
C o n t r o l , is currently undertaking a research project to produce a designer's manual for smoke control systems.
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