Structural fire protection in Japan

STRUCTURAL FIRE PROTECTION I N JAPAN

K . Kawagoel, H . S a i t o 2 , H . Sa to3 , T. Ouchi 3

'Center f o r F i r e S c i e n c e and Technology, S c i e n c e U n i v e r s i t y o f Tokyo, 2641 Yamasaki, Noda-shi, Chiba 278 Japan 2Department o f A r c h i t e c t u r a l E n g i n e e r i n g F a c u l t y o f Engi- n e e r i n g , Chiba U n i v e r s i t y , 1-33 Yayoicho Chiba 260 J a p a n 3Kajima I n s t i t u t e of C o n s t r u c t i o n Technology, 19-1 Tob i t akyu 2-Chome, Chofu-shi , Tokyo 182 J a p a n

1. I n t r o d u c t i o n

A s b u i l d i n g s become l a r g e r , t a l l e r and more c o m p l i c a t e d , well-grounded p r i n c i p l e s f o r a d e s i g n sys t em f o r b u i l d i n g f i r e safety are r e q u i r e d , i n which v a r i o u s coun te rmeasu res a g a i n s t f i r e s are combined e f f e c t i v e l y . I n J a p a n , however, e x i s t i n g f i r e r e g u l a - t i o n s are t h e s p e c i f i c a t i o n t y p e , s o t h e r e are many problems, s u c h as t h e g r e a t expense n e c e s s a r y f o r i n s t a l l i n g many coun te rmeasu res a g a i n s t f i r e s . Even i f f i r e p r e v e n t i o n i n s t a l l a t i o n are equ ipped s u f f i c i e n t l y , r e q u i r e d f i r e r e s i s t a n c e is n o t r educed .

With t h e above i n mind, a r e s e a r c h p r o j e c t , "Development of Design System f o r B u i l d i n g F i r e S a f e t y " , was i n i t i a t e d i n A p r i l , 1982 a s a f i v e y e a r p r o j e c t sponsored by t h e M i n i s t r y of Cons t ruc - t i o n . T h i s p r o j e c t had t h e c o o p e r a t i o n of p e o p l e from many d i f f e r - e n t areas, and was concluded i n 1987.

A s a r e s u l t of t h i s p r o j e c t , new d e s i g n r e g u l a t i o n s f o r s t r u c t u r a l f i r e p r o t e c t i o n were p roposed , based on wel l -grounded p r i n c i p l e s e s t a b l i s h e d by a n a l y t i c a l method.

p rocedure f o r f i r e r e s i s t a n c e o f b u i l d i n g s i n Japan, and g i v e a n o u t l i n e of t h e new d e s i g n r e g u l a t i o n s f o r s t r u c t u r a l f i r e p r o t e c t i o n and an example of d e s i g n based on t h e s e r e g u l a t i o n s .

2. T r a d i t i o n a l d e s i g n p r o c e d u r e

I n t h i s p a p e r , w e w i l l e x p l a i n t h e t r a d i t i o n a l d e s i g n

A t p r e s e n t , t h e f i r e r e s i s t a n c e of a b u i l d i n g i s es- t a b l i s h e d by c e r t i f i c a t i o n of t h e r e q u i r e d performance a c c o r d i n g t o t h e number of s t o r i e s o f t h e b u i l d i n g and b u i l d i n g e l e m e n t s by s t a n d a r d f i r e r e s i s t a n c e tes ts , similar t o many o t h e r c o u n t r i e s .

S p e c i f i c a l l y , Article 27 of t h e B u i l d i n g S t a n d a r d Law s p e c i f i e s c e r t a i n b u i l d i n g s which s h o u l d be f i r e p r o o f o r q u a s i - f i r e p r o o f . f i r e p r o o f o r q u a s i - f i r e p r o o f i n f i r e p r o t e c t i o n d i s t r i c t s and q u a s i - f i r e p r o t e c t i o n d i s t r i c t s , r e s p e c t i v e l y . Art ic le 107 of t h e Bu i ld - i n g S t a n d a r d Law Enforcement Orde r s p e c i f i e s t h e r e q u i r e d f i r e re- s i s t a n c e a c c o r d i n g t o t h e number o f s t o r i e s of a b u i l d i n g s and b u i l d i n g e l e m e n t s . t i o n , s p e c i f i c a t i o n of s t a n d a r d f i r e p r o o f c o n s t r u c t i o n and t h e

INTERFLAM '88 PAGE 179

Articles 61 and 6 2 s p e c i f y b u i l d i n g s which ough t t o b e

I n t h e N o t i f i c a t i o n of t h e M i n i s t r y of Construc-

d e s i g n a t e d method o f new f i r e p r o o f c o n s t r u c t i o n are p r e s c r i b e d .

proved s p e c i f i c a t i o n s f o r t h e r e q u i r e d f i r e r e s i s t a n c e time w i t h o u t s p e c i a l knowledge o f s t r u c t u r a l f i r e p r o t e c t i o n d e s i g n . c e d u r e h a s t h e advan tage o f f a c i l i t a t i n g d e s i g n , b u t l a c k s r a t i o - n a l i t y and s a f e t y .

f o r s teel s t r u c t u r e s i n J a p a n is by s p r a y i n g on rockwool cement m o r t a r . case by case. s u c h a s s i l i c a - a l u m i n a m i x t u r e s .

3 . A new d e s i g n method f o r s t r u c t u r a l f i r e p r o t e c t i o n

I n t h i s way, d e s i g n e r s c a n proceed by s e l e c t i n g t h e ap-

T h i s pro-

I n t h i s c o n n e c t i o n , t h e main f i r e p r o o f c o n s t r u c t i o n method

C ladd ing w i t h s i l i c e o u s c a l c i u m boa rd e tc . is a p p l i e d on a N e w developments i n c l u d e f i r e p r o t e c t i o n materials

The development g roup f o r f i r e p r o t e c t i o n of b u i l d i n g s t r u c t u r e s w i t h t h i s p r o j e c t a c t i v e l y developed a l o g i c a l method o f d e s i g n f o r s t r u c t u r a l f i r e p r o t e c t i o n based on t h e p r e d i c t i o n o f r e a l f i r e b e h a v i o r , t h e r m a l and s t r u c t u r a l behav io r .

t h i s method: (1) O u t l i n e o f d e s i g n p rocedure

p r o t e c t i o n is c a l c u l a t e d p r e d i c t i o n o f t h e b e h a v i o r of f i r e s , t h e r - mal b e h a v i o r and s t r u c t u r a l b e h a v i o r , f o r d i f f e r e n t b u i l d i n g s . The g e n e r a l p rocedure i s a s f o l l o w s (see F ig .1 ) :

The f o l l o w i n g i s a n o u t l i n e o f t h e d e s i g n p rocedure u s i n g

The p r i n c i p l e of t h i s d e s i g n method f o r s t r u c t u r a l f i r e

Set- t h e g o a l f o r f i r e r e s i s t a n c e . S e t t h e f i r e compartment. S e t s a f e t y f a c t o r s and d e s i g n c o n s t a n t s r e l a t i n g t o b e h a v i o r p r e d i c t i o n . Propose d e s i g n o f b u i l d i n g e l e m e n t s which s u p p o r t and c o n s t i t u t e t h e f i r e compartment, and se t c r i t e r i a f o r e v a l u a t i o n o f f i r e r e s i s t a n c e c o r r e s p o n d i n g t o t h e g o a l . C a l c u l a t e t h e f o l l o w i n g : a. F i r e t empera tu re - t ime r e l a t i o n i n a compartment. b . Temperature- t ime r e l a t i o n f o r b u i l d i n g e l e m e n t s w i t h t h e

p r e d i c t e d f i re b e h a v i o r . c . Deformation and s t r e n g t h of b u i l d i n g e l e m e n t s w i t h t h e above

t empera tu re - t ime r e l a t i o n s . I f i t is d i f f i c u l t t o c a l c u l a t e t h e above , make p r e d i c t i o n s by s t a n d a r d t e s t methods. Confirm t h a t t h e r e s u l t s of b e h a v i o r p r e d i c t i o n s a t i s f y t h e c r i te r ia f o r f i r e r e s i s t a n c e . Repeat s t e p s 3 t o 7 f o r e a c h f i r e compartment.

The p rocedure of t h i s d e s i g n method is t o p r e d i c t t h e I

above b e h a v i o r and e v a l u a t e s t r u c t u r a l s a f e t y up t o a f i r e p r o c e s s as t h e g o a l . E v a l u a t i o n o f d e s i g n performance of s t r u c t u r a l f i r e p r o t e c t i o n i s t o c e r t i f y t h a t t h e p r e d i c t e d b e h a v i o r (unexposed s u r - f a c e t e m p e r a t u r e , de fo rma t ion and s t r e n g t h o f b u i l d i n g e l e m e n t s o r f r a m e s , e t c . ) s a t i s f i e s t h e c o r r e s p o n d i n g c r i te r ia f o r e v a l u a t i o n .

methods of a n a l y s i s , app rox ima te c a l c u l a t i o n programs and d e s i g n d i a - grams are p r e p a r e d . F o r b u i l d i n g s n o t r e q u i r i n g e x a c t p r e d i c t i o n of b e h a v i o r , d e s i g n s based on a n e q u i v a l e n t f i r e d u r a t i o n time may b e

For behav io r p r e d i c t i o n i n t h i s d e s i g n method, v a r i o u s

INTERFLAM '88 PAGE 180

p e r m i t t e d .

i t can be a p p l i e d t o r e i n f o r c e d c o n c r e t e s t r u c t u r e s . For t h i s t y p e of s t r u c t u r e , it i s a l l o w a b l e f o r p r e d i c t i o n c a l c u l a t i o n s t o be conducted f o r d e s i g n f i r e behav io r and t e m p e r a t u r e r i se of b u i l d - i n g e l emen t s . r e s i s t a n c e tests, t h a t is a l l o w a b l e steel t e m p e r a t u r e , e tc . ( 2 ) Example of d e s i g n

o f f i c e b u i l d i n g w i t h a s tee l s t r u c t u r e of 30 f l o o r s as shown i n F ig .2 . 1) C a l c u l a t i o n of f i re temperature- t ime c u r v e

t h e f i r e temperature- t ime r e l a t i o n w a s c a l c u l a t e d .

Though t h i s d e s i g n method mainly c o n c e r n s steel s t r u c t u r e ,

F i r e r e s i s t a n c e e v a l u a t i o n i s based on s t a n d a r d f i r e

S t r u c t u r a l f i r e p r o t e c t i o n d e s i g n w a s c a r r i e d o u t on a n

Based on t h e b a s i c t h e o r y developed by Kawagoe and Sek ine ,

C o n d i t i o n s of a n a l y s i s The f i r e was assumed t o o c c u r on t h e 3 r d f l o o r , w i t h t h e

f i r e compartment be ing t h e whole a p a r t from t h e c o r e . F i r e l o a d d e n s i t y : 49.17 Kg/m' (x + 0 based on observed r e s u l t s

under similar c o n d i t i o n s ) Opening: 1 . 7 m h i g h , 1 4 . 4 m wide a t c e n t e r and 11.2 m wide

Surroundings: Ou te r wall - normal c o n c r e t e 70 mm t h i c k a t t h e edges.

F l o o r s l a b - normal c o n c r e t e 120 mm t h i c k P a r t i t i o n - gypsum board

F l o o r h e i g h t : 3.5 m C a l c u l a t e d r e s u l t s

r e l a t i o n are shown i n Fig.3. 2 ) C a l c u l a t i o n of temperature- t ime r e l a t i o n f o r b u i l d i n g e l e m e n t s

r a t u r e - t i m e r e l a t i o n shown i n F i g . 3 was c a l c u l a t e d by t h e one- d imens iona l d i f f e r e n t i a l method. C o n d i t i o n s of a n a l y s i s

p r o t e c t i o n material, and t h e s tee l temperature- t ime r e l a t i o n was c a l c u l a t e d f o r s e v e r a l t h i c k n e s s e s . f o r t h e t h e r m a l p r o p e r t i e s :

a . S p e c i f i c g r a v i t y : 300 Kg/m' b. Mois tu re c o n t e n t : 1% c. S p e c i f i c h e a t : 0 .22 Kcal/Kg"C 3. Thermal c o n d u c t i v i t y : Depending on t e m p e r a t u r e ,

The c a l c u l a t e d r e s u l t s of t h e f i r e temperature- t ime

S t e e l t empera tu re r i se when exposed t o a f i r e w i t h tempe-

Sprayed rockwool cement mor t a r was assumed t o be t h e f i r e

The f o l l o w i n g v a l u e s were used

0.054(O°C) - 0.2375(900°C) Kcal/mh"C

INTERFLAM '88 PAGE 182

Fig .2 Plan F i g . 3 F i r e temperature- t ime curve

C a l c u l a t e d r e s u l t s The c a l c u l a t e d r e s u l t s of s t e e l t empera ture are shown i n

F i g . 4 and 5. is l a r g e and s tee l tempera ture rise i s s m a l l w i t h a r e l a t i v e t h i n l a r g e r of f i r e p r o t e c t i o n material.

A s column walls are 60-100 mm t h i c k , thermal c a p a c i t y

F i g . 4 C a l c u l a t i o n r e s u l t s (Column C1)

TIW(MINWE1

F i g . 5 C a l c u l a t i o n r e s u l t s (Beam G 2 )

INTERFL AM '88 PAGE 183

3 ) C a l c u l a t i o n o f deformat ion and s t r e n g t h - t i m e r e l a t i o n f o r b u i l d i n g e lements

C a l c u l a t i o n of deformation and s t rength- t ime r e l a t i o n f o r b u i l d i n g e lements was c a r r i e d o u t w i t h a @ - @ f rame and a @ - a f rame, as shown i n Fig.6. S i x f l o o r s were ana lysed .

I c3 CI a3 1 cz 1

c4 c3 I cz I a3 a3

0-

cz L L cz

c4 I ---.- br*co

0 c , l 3 , ~ 0 0 x 1 2 0 0 x 1 0 0 C I , C < D 7 0 0 x 700X SO

GI B H - 9 5 O x 4 0 0 x 1 9 X 3 6 GZ B H - 8 0 0 X 3 0 0 X I 6 X Z 8

F i g . 6 Analys is o b j e c t

1 iw

F i g . 7 Thermal stress development F i g . 8 Thermal stress development (Column) (Beam)

INTERFLAM '88 PAGE 184

C a l c u l a t e d r e s u l t s

F i g s . 7 - 9. t e m p e r a t u r e a t t h e t o p of a column is 520 - 570"C, and t h a t a t t h e c e n t e r o f beam i t is 150 - 190°C. ( t he t e m p e r a t u r e a t which t h e c u r v a t u r e e x c e e d s 10 times y i e l d c u r v a t u r e a t room t e m e p r a t u r e ) of a column i s o v e r 600"C, and t h a t of beam is 420°C.

R e s u l t s of a n a l y s i s f o r t h e @ - @' f r ame are shown i n From these r e s u l t s , it c a n b e s e e n t h a t t h e y i e l d

The p l a s t i c h i n g e t e m p e r a t u r e

D e f l e c t i o n c r i te r ia used h e r e are L2/800H f o r beams and h/30 f o r columns, where L , H and h are beam l e n g t h , beam h e i g h t and column h e i g h t , r e s p e c t i v e l y . From F i g . 9 , it c a n b e s e e n t h a t columns and o u t e r beams do n o t r e a c h t h e d e f l e c t i o n c r i t e r i o n a t 600°C, b u t i n n e r beam r e a c h a t 590°C.

~

c z 2""

B

T*mn'rr,"r* L

F i g . 9 Defo rma t ion

4 ) D e t e r m i n a t i o n of f i r e p r o t e c t i o n t h i c k n e s s

impor t ance o f t h e b u i l d i n g , s o e v a l u a t i o n c r i te r ia a l s o va ry . F i r e p r o t e c t i o n t h i c k n e s s depending on e a c h c r i t e r i o n are as f o l l o w s .

The g o a l f o r f i r e r e s i s t a n c e v a r i e s a c c o r d i n g t o t h e

column beam Based on p l a s t i c h i n g e t e m p e r a t u r e 5mm 50mm Based on d e f l e c t i o n c r i te r ia 5mm 3 5mm Based on t r a d i t i o n a l r e g u l a t i o n s

Uppermost t o 4 t h s t o r i e s f rom t h e uppermost s t o r y 3 0 m m 2 5mm 5 t h t o 1 4 t h s tor ies from t h e

15th o r more s t o r i e s from t h e uppermost s t o r y 40mm 3 5mm

uppermost s t o r y 50mm 4 5mm

INTERFLAM '88 PAGE 185

4 . Conclusion

s t r u c t u r a l f i r e p r o t e c t i o n i n Japan . I n t h e example of d e s i g n , w e on ly inc luded c a l c u l a t i o n of p r e d i c t e d behav io r . For p r a c t i c a l d e s i g n , it i s n e c e s s a r y t o se t t h e a p p r o p r i a t e g o a l f o r f i r e re- s i s t a n c e f o r e a c h b u i l d i n g , t a k i n g i n t o accoun t t h e a p p r o p r i a t e s a fe ty f a c t o r s .

We have mainly i n t r o d u c e d new d e s i g n r e g u l a t i o n s f o r

Acknowledgements

T h i s paper is p a r t l y e x t r a c t e d from t h e r e s u l t s o f t h e development group f o r f i re p r o t e c t i o n of b u i l d i n g s t r u c t u r e s (Chairman P r o f . H. S a i t o ) and development group o f systematic des ign method f o r o v e r a l l f i r e s a f e t y (Chairman P r o f . K . Kawagoe) i n t h e r e s e a r c h p r o j e c t , "Development of Design System f o r Bu i ld ign F i r e S a f e t y , " sponsored by t h e M i n i s t r y o f C o n s t r u c t i o n . wish t o thank t h e members concerned.

The a u t h o r s

Refe rences

1. "Development of d e s i g n method f o r f i r e r e s i s t a n c e of b u i l d i n g s t r u c t u r e s " , Bu i ld ing Research I n s t i t u t e , 1987.3 ( I n Japanese )

"Development of s y s t e m a t i c d e s i g n method f o r o v e r a l l f i r e s a f e t y " , B u i l d i n g Research I n s t i t u t e , 1987.3 ( I n Japanese )

2.

INTERFLAM '88 PAGE 186