Fire tests on protected steel columns under different fire severities

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Fire tests on protected steel columns under different fire severities

Konicek, L.; Lie, T. T.

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NATIONAL RESEARCH COUNCIL OF CANADA DIVISION OF BUILDING RESEARCH

FIRE TESTS ON PROTECTED STEEL COLUMNS UNDER DIFFERENT FIRE SEVERITIES

L . Konicek and T . T . Lie

F i r e Study No. 34 of the

Division of Building Re s e a r c h

Ottawa August 19 74

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FIRE TESTS ON PROTECTED STEEL COLUMNS UNDER DIFFERENT FIRE SEVERITIES

L. Konicek and T. T. Lie

Six f i r e t e s t s were conducted t o provide experimental data which would verify computer calculations of temperature course in f i r e protected s t e e l columns exposed t o different s e v e r i t i e s of f i r e .

DES ESSAIS D'INCENDIE DE

S~VE/RITE/

VARIABLE SUR DES POTEAUX DIACIER P R O T I ~ G I ~

L. Konicek et T. T. Lie

On a fait six e s s a i s dlincendie en vue d'obtenir de s donnCe s expgrirnentale s servant

'a

vCrifier d e s calculs p a r ordina- t e u r de l a courbe de tempkrature dans d e s poteaux d ' a c i e r protCgCs contre le feu e t exposCs

'a

d e s incendies de SCVC- ritC diffCrsnte.

(4)

F I R E TESTS ON PROTECTED S T E E L COLUMNS UNDER DIFFERENT F I R E SEVERITIES

by

L. Konicek'g and T. T . Lie**

M a t h e m a t i c a l e x p r e s s i o n s d e s c r i b i n g the t e m p e r a t u r e c o u r s e f o r different f i r e s e v e r i t i e s have been developed (1). Taking into consideration s e v e r a l significant p a r a m e t e r s i. e . the opening f a c t o r , the t h e r m a l p r o p e r t i e s of the wall m a t e r i a l s of a c o m p a r t m e n t and the f i r e load, it i s possible t o define a t i m e - t e m p e r a t u r e c u r v e which

r e p r e s e n t s the t e m p e r a t u r e c o u r s e of a ventilation controlled f i r e i n a p a r t i c u l a r c o m p a r t m e n t . Assuming t h e f i r e load is known, the f i r e t e m p e r a t u r e -time r e l a t i o n can be extended even t o the d e c a y p e r i o d of the f i r e , which s t i l l b r i n g s a potential d a n g e r of f a i l u r e t o load- b e a r i n g construction.

Knowledge of f i r e conditions r e p r e s e n t e d by the s e t of newly developed t i m e - t e m p e r a t u r e c u r v e s c a n be d i r e c t l y applied to f i r e

protection design. A s a f i r s t s t e p in t h i s d i r e c t i o n , a c o m p u t e r p r o g r a m w a s developed t o calculate a t e m p e r a t u r e distribution i n s t e e l columns with box type f i r e protection f o r t h e growth and d e c a y p e r i o d s of a f i r e .

A s a verification of t h i s t h e o r e t i c a l work, a s e r i e s of s i x t e s t s w a s c a r r i e d out. F u r n a c e t e m p e r a t u r e w a s r u n according t o a

s e l e c t e d t i m e - t e m p e r a t u r e curve d e s c r i b i n g growth and d e c a y p e r i o d s of a f i r e . T e m p e r a t u r e s developed in the s t e e l e l e m e n t s w e r e o b s e r v e d and c o m p a r e d t o calculated values. The r e s u l t s of t h e s e t e s t s and t h e i r c o m p a r i s o n t o t h e o r e t i c a l values a r e p r e s e n t e d in t h i s r e p o r t .

DESCRIPTION O F F I R E PROTECTIVE MATERIAL ( 2 )

All s p e c i m e n s w e r e protected by 1 -in. thick Vicuclad b o a r d s cemented t o g e t h e r and t o the s t e e l with a n adhesive m o r t a r . The b o a r d s a r e produced f r o m specially s e l e c t e d v e r m i c u l i t e which, a f t e r

*

S t e e l I n d u s t r i e s Fellow, F i r e R e s e a r c h Section, Division of Building

Re s e a r c h , National R e s e a r c h Council of Canada.

*:g R e s e a r c h Officer, F i r e R e s e a r c h Section, Division of Building Re s e a r c h , National R e s e a r c h Council of Canada.

(5)

p r e - t r e a t m e n t , i s bonded with an inorganic binder t o produce a non- combustible board. The technical d a t a concerning Vicuclad have been provided by William Kenyon and Sons (Vicuclad) Ltd., C h e s h i r e , England. T h e r m a l conductivity of protective m a t e r i a l a t elevated t e m p e r a t u r e s w a s d e t e r m i n e d a t the National R e s e a r c h Council of Canada, Division of Buil.ding R e s e a r c h , F i r e R e s e a r c h Section. The data used f o r computation of s t e e l t e m p e r a t u r e c o u r s e s a r e p r e s e n t e d in Table I of t h i s r e p o r t .

DESCRIPTION OF S T E E L ELEMENTS

The wide flange s t e e l columns with welded s t e e l end p l a t e s w e r e used f o r e x p e r i m e n t a l work. The p a r a m e t e r s of t h e i r c r o s s -

sections specified in Table11 w e r e applied during t h e computer c a l c u l a - tions of p a r t i c u l a r t e m p e r a t u r e c o u r s e s in s t e e l under the f i r e conditions.

DESCRIPTION O F TEST SPECIMENS

The wide flange columns w e r e fitted with nogging p i e c e s of 1 -in. thick Vicuclad, fixed between the flanges and t o the web with

adhesive m o r t a r . The noggings w e r e spaced at 2-ft c e n t r e s on e a c h side of the column. The Vicuclad panels w e r e fixed t o the outer f a c e s of the f l a n g e s with the s a m e adhesive m o r t a r . To complete the e n c a s e m e n t , additional panels w e r e fixed t o the noggings and t o Vicuclad panels a l r e a d y in place. The d e t a i l s of the column e n c a s e m e n t a r e shown in F i g u r e s 1 , and 2 -

TEST PROCEDURE

The t e s t s w e r e c a r r i e d out according t o t h e p r o g r a m which is p r e s e n t e d in Table 111. The columns w e r e t e s t e d v e r t i c a l l y i n a g a s - f i r e d f u r n a c e . The furnace t e m p e r a t u r e w a s m e a s u r e d by nine t h e r m o -

couples positioned s y m m e t r i c a l l y about the column a s shown in F i g u r e s 3 , and 4.

The thermocouples w e r e enclosed i n 1/2-in. black i r o n pipe with a c a r b o n s t e e l c a p a t the tip. The hot junction of the thermocouples w a s placed 12 in. away f r o m t h e s u r f a c e of the specimen. The individual t e m p e r a t u r e s a t the nine points w e r e r e c o r d e d during the t e s t .

Since the p r e s c r i b e d t i m e - t e m p e r a t u r e c u r v e s differ f r o m the Standard T i m e - T e m p e r a t u r e c u r v e ( 3 ) , the fuel input t o the f u r n a c e was controlled manually.

The t e m p e r a t u r e of the s t e e l columns was m e a s u r e d by t h e r m o - couples peened into the s t e e l a t five levels. The location of t h e s e

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OBSERVATIONS

The cladding r e m a i n e d intact throughout the t e s t without excep- tion. Towards the end of the longer t e s t s , c r a c k s developed in the v e r t i c a l joints of the Vicuclad panels. The s t r u c t u r a l s t r e n g t h of the e n c a s e m e n t was noticeably affected by the t e s t and in s e v e r a l i n s t a n c e s p i e c e s of the Vicuclad panels f e l l away f r o m the column a s it w a s

being removed f r o m the f u r n a c e .

F i g u r e s

6

and 7 show a column before and a f t e r the f i r e t e s t . The d e t e r i o r a t i o n a t the joints, evident in F i g u r e 8 , i s typical of the longer t e s t s .

RESULTS

The s t e e l t e m p e r a t u r e s w e r e m e a s u r e d on five l e v e l s in the v e r t i c a l direction ( F i g u r e 5). T h r e e of t h e m , l e v e l s 1 , 3 , and 5, w e r e plotted in p a r t i c u l a r f i g u r e s ( F i g u r e s

9

t o 15). T e m p e r a t u r e differences between level 1 and level 5 a r e in the range of 1 5 0 ° F .

The m a x i m u m m e a s u r e d s t e e l t e m p e r a t u r e in e a c h t e s t was

compared to the calculated t e m p e r a t u r e . R e s u l t s of a l l t e s t s a r e in v e r y good a g r e e m e n t . Differences a r e in the range of 5 0 ° F (approximately 570 difference). The calculated t e m p e r a t u r e was always higher than the experimental, in the above -mentioned t e m p e r a t u r e range.

C ONC LUSION

The r e s u l t s of the t e s t s w e r e found t o be in c l o s e a g r e e m e n t

with computed values. T h i s v e r i f i e s the validity of the r e c e n t l y developed computer p r o g r a m .

Assuming that the s e t of t e m p e r a t u r e - t i m e c u r v e s u s e d i n t h i s study c h a r a c t e r i z e s with sufficient a c c u r a c y the s e v e r i t y of actual f i r e s , i t i s possible, given the t h e r m a l p r o p e r t i e s of the f i r e -protective

m a t e r i a l , t o u s e a cornputor p r o g r a m f o r the evaluation of the f i r e protection of s t e e l columns under any f i r e conditions found i n p r a c t i c e .

Application of t h i s method t o the engineering of f i r e -protection design can significantly reduce the n u m b e r of full s c a l e column t e s t s and improve the economy of building production.

REFERENCES

1. T. T. Lie: C h a r a c t e r i s t i c T e m p e r a t u r e C u r v e s f o r Various F i r e S e v e r i t i e s , f o r submission t o F i r e Technology, Ottawa, 1973.

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2. W . W . Stanzak, T . T. Lie: F i r e T e s t s on P r o t e c t e d Steel Columns with Different C r o s s - S e c t i o n s , F i r e Study No. 30 of the Division of Building Re s e a r c h , National Re s e a r c h Council of Canada, Ottawa, F e b r u a r y 1973.

3 . Standard f o r F i r e T e s t s of Building Construction and M a t e r i a l s , U n d e r w r i t e r s ' L a b o r a t o r i e s of Canada, 1971.

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TABLE I. THERMAL PROPERTIES OF FIRE PROTECTIVE MATERIAL

TABLE

II.

TECHNICAL PARAMETERS OF TESTED S T E E L COLUMNS

Legend: W = weight of steel section per unit height.

D

=

heated perimeter, i. e . development of

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TABLE

LII.

TEST PROGRAM

Surrounding Figure Table

3 10W 0 . 0 5 4 . 5 heavy 7

8 , 9

I

1 5

6

14W I 12W 12W 0 . 0 2 0 . 1 I 0 . 1 4 . 0 7 1 0 . 1 5

6 . 7 6

heavy heavy heavy 8 10 11 1 0 , l l 1 2 , 1 3 1 4 , 1 5 -

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TABLE IV. FURNACE TEMPERATURES Opening F a c t o r F = 0.05 F i r e Load Q

=

3.38 lb/ft2

Heavy Mate r i a l Surrounding

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TABLE V. MEASURED AND CALCULATED STEEL TEMPERATURES Column "low" Opening F a c t o r F = 0.05

F i r e Load Q = 3.38 lb/ft2 Heavy M a t e r i a l Surrounding

Caleulated Steel T e m p e r a t u r e , O F 105.2 229.8 366.9 496.8 618.3 732.4 832.5 904.1 948.0 967.5 966.1 947.2 Time

=

0.05 _{F i r e Load}

_{Q =}

_{4.1 lb/ft 2} Heavy M a t e r i a l Surrounding F l a m e T e m p e r a t u r e Decay T e m p e r a t u r e 1 -P r e s c r i b e d , "F 1400 147 5 1520 1540 1570 1700 E x p e r i m e n t a l ,

"F

I

i

I ! I I

1 I

i

7 5 t 80 I

1

1675 ' 8 5 90 9 5 100 1 0 5 110 11 5 120 125 I 1651 i I I 130 135 1502 1 540 906

j

935 1353 1204 140 145 150 4 1400 I i 1205 I 7 57 607 1055

I

1055 770 57 0

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TABLE VII. MEASURED AND CALCULATED S T E E L TEMPERATURES Column "10W" F i r e Load Q

=

4.1 lb/ft 2 Opening F a c t o r

F

=

0.05 Heavy M a t e r i a l Surrounding Calculated S t e e l T e m p e r a t u r e ,

OF

I 70 105.2 229.8 366.9 496.8 61 8 . 3 732.4 839.9 938.4 1014.0 1065.0 1094.0 1103.7 1096.7 1075.5 1042. 5 T i m e

I

Opening Factor F

=

0.05 F i r e Load

Q

=

4. 5 lb/ft 2

Heavy Material Surrounding

Time Flame Temperature

i

min. Decay Temperature Prescribed, OF Prescribed,

1

Expe:kmental,

OF

i

Experimental, OF I

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T A B L E IX. MEASURED

AND

CALCULATED S T E E L TEMPERATURES Column "1 OW" Opening F a c t o r F

=

0 . 0 5

L

F i r e Load

Q =

4. 5 lb/ft Heavy M a t e r i a l Surrounding

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T A B L E X. FURNACE T E M P E R A T U R E S Opening F a c t o r F = 0 . 0 2 F i r e Load Q = 4.07 lb/ft 2 Heavy M a t e r i a l S u r r o u n d i n g I T i m e L r n l r l . 0 5 10 1 5 20 2 5 30 3 5 40 4 5 50 55 60 6 5 7 0 7 5 80 8 5 9 0 9 5 100 1 0 5 110 1 1 5 120 1 2 5 130 1 3 5 140 1 4 5 150 1 5 5 160 1 6 5 170 175 1 XU 1x5 190 1 0 5 200 L O 5 210 Decay P r t . a r r i b n d . ' k' 7 0 1472 1442 1412 1382

1

1353 1323 215 220 225 L 30 235 240 24 5 2 50 255 2 60 265 270 275 2 HO 285 2YO 29 5 I 300 T e m p e r a t u r e Il;xpt!rinic-ntitl. "F 70 F l a m e T e m p e r a t u r e lJt.c:nc:ribt~d, EXPI-rimc.nti11. " F " k- - 70 688 9 2 8 1019 1058 1081 1099 1116 1134 1 1 5 3 1171 1190 1209 1293

I

1263 1233 1204 1174 1144 11 14 1084 1055 1025 9 9 5 9 6 5 9 3 5 906 876 84 6 7 0 500 9 20 1010 1040 1075 1030 1160 1 1 60 1 1 80 1180 1 200 1240

I

816

1

786 1228 1246 1263 1280 1297 131 3 1328 1342 1356 1370 1382 1394 1406 1417 1 4 2 8 I 1438 1447 1456 1 4 6 5 1 4 7 3 1481 1488 1495 1 SO2 1250 1260 1270 1290 1300 1320 1350 1360 1370 13x0 1410 1420 1420 1430 1430 1450 1 4 6 5 1470 1470 1 4 8 5 1500 1500 1510 1520

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T A B L E XI MEASURED AND CALCULATED S T E E L TEMPERATURES

Column " 1 4 W" Opening Factor F

=

0. 02

L

Fire Load Q

=

4. 07 lb/ft Heavy Material Surrounding

!

I Time

j

! Measure Steel Temperature

L !

!

rnin.

1

~ e v e i 5, Level 3,

I

T A B L E XI1 FURNACE TEMPERATURES L Opening F a c t o r F = 0. 1 F i r e Load Q = 10. 1 5 lb/ft Heavy M a t e r i a l Surrounding F l a m e T e m p e r a t u r e Decay T e m p e r a t u r e m i n .

,t

10

1

1 5 2 0 25 30 3 5 40 4 5 5 0 5 5 60 6 5 70 75 8 0 8 5 9 0 9 5 100 105 110 11 5 120 125 130 135 1 40 145 150 155 160 165 170 175 180 185 190 195 200 205 210 P r e s c r i b e d , O F E x p e r i m e n t a l , E x p e r i m e n t a l , O F

1

_E

_OF

I

I " F I I _I ₁ I

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TABLE XIV FURNACE TEMPERATURES

L

Opening Factor F

=

0. 1 Fire Load

Q

=

0 70

_I

₇₀ _I 5

1

1010 980

!

1539

I

1260 15 l o 1675 1754

t:

1

1800 30 1 1820 1500

i

1650

i

I

I 35 40 4 5 5 0 65 70 1720 1830 1870 18 50 1876 1900 1935 1965 1995 I I

1452 I 1470

I

r

I I 1362 1360 1271 1275 105 110 115 120 125 130

1

100

i

1181 1190 I 1 I 1090 I 1100 1000 960 910

)

870 820 810 730

i

7 00

-

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TABLE X V MEASURED AND CALCULATED STEEL TEMPERATURES

Column "12 W" Opening Factor F

=

0 . 1

2

Fire Load Q

= 6 .

76 lb/ft Heavy Material Surrounding

I

Measured Steel Temperature

t T i e

I

I Calculated Steel I I

1

_{Level 3,} Temperature,

,

min. Level 5,

!

" F

"

F

I O F

!

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F I G U R E 1

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I:'

-

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T O T A L O F 9 T H E R M O C O U P L E S C E N T R A L TC O N O N E S I D E O N L Y

/

3 / 4 " PlPE U N I N S U L A T E D B L A C K I R O N C O L U M N

u

3 " BLACK I R O N PlPE I N S U L A T E D

F I G U R E 3

L O C A T I O N O F F U R N A C E T H E R M O C O U P L E S

I N R E L A T I O N T O C O L U M N

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V E R T I C A L S E C T I O N

H O R I Z O N T A L S E C T I O N

F I G U R E

4 D B R F L O O R F U R N A C E I M P R O V E D

B Y R E F L E C T I V E

(26)

5 L O C A T I O N O F T H E R M O C O U P L E S

O N W I D E F L A N G E C O L U M N S

(27)

(28)

(29)

I '-

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T I M E , M I N .

F I G U R E 9

C O U R S E O F F U R N A C E A N D S T E E L T E M P E R A T U R E S , C O L U M N " l O W 1 ' , O P E N I N G F A C T O R

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T I M E , M I N .

F I G U R E 1 0

C O U R S E O F F U R N A C E A N D S T E E L T E M P E R A T U R E S , C O L U M N " 1 O W " . O P E N I N G F A C T O R F = O . 05, F I R E L O A D Q = 4 . 1 L B I F T ~ , H E A V Y S U R R O U N D I N G M A T E R I A L S

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1. S T E E L T E M P , L E V E L I 3 . S T E E L T E M P , L E V E L 3 5. S T E E L T E M P , L F V E L 5 2 . S T E E L T E M P , C A L C U L A T E D 4. F U R N A C E T E M P , E X PE

H

l M E N T A L 6. F U R N A C E T E M P , C A L C U L A T E D

l

I

1 I

l

I

l

I

1

1 I

₁

0

₁₀ 2 0 3 0 4 0 5 0 6 0 70 80 90 100 I 2 0 130 1110 150 160 T I M E , M I N . F I G U R E 1 1 C O U R S E O F F U R N A C E A N D S T E E L T E M P E R A T U R E S , C O L U M N " l O W " , O P E N I N G F A C T O R F = 0 . 0 5 , F I R E L O A D Q = 4 . 5 L B I F T ~ , H E A V Y S U R R O U N D I N G M A T E R I A L S

(33)

T I M E , M I N .

F I G U R E 1 2

C O U R S E O F F U R N A C E A N D S T E E L T E M P E R A T U R E , C O L U M N " 1 4 W " , O P E N l N G F A C T O R F = 0 . 0 2 , F l R E

(34)

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s

3 3 0 -' e 0 E v 3 w-

*

=

>

z,'

a w

E5

=

P.

-

s

:

W LL I-- d m w - '

(36)

1. S T E E L T E M P , L E V L L t 3. S T E E L T E M P , L E V E L 3 5 . S T E E L T E M P , L E V E L 5 2. S T E E L T E M P , C A L C U L A T E D 4. F U R N A C E T E M P , E X P E R I M E N T A L 6. F U R N A C E T E M P , C A L C U L A T E D

I

T I M E , M I N . F I G U R E 1 5 C O U R S E O F F U R N A C E A N D S T E E L T E M P E R A T U R E S , C O L U M N ' 1 1 2 W " . O P E N I N G F A C T O R F = 0 . 1 , F I R E L O A D Q = 6 . 7 6 L B I F T ~ , H E A V Y S U R R O U N D I N G M A T E R I A L S