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FIRE RESISTANT ROOFS MADE OF SANDWICH PANELS

Bogdan Wróblewski M.Sc. Civil Eng.

Andrzej Borowy Ph.D.

Building Research Institute (ITB)Fire Research Department

Warsaw, Poland

CONGRESS PAN and PRO EUROPE , EPAQPORTO 16-17 September 2010

2THERMAL ACTIONS

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STANDARD CURVES

1) Standard curve (N):

Θ = 345 log (8t+1) + 20

2) External fire curve (E):

Θ = 660[(1 - 0,687exp(-0,32t) - 0,313exp(-3, 8t)] + 20

3) Hydrocarbon curve (H):

Θ = 1080[1 – 0,325exp(-0,167t) – 0,675exp(-2,5t)] + 20

4) Slow heating (smouldering) curve (S):

Θ = 159 t 0,25 + 20 for 0 < t ≤ 21Θ = 345 log10[8(t – 20) +1] + 20 for t > 21

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EN 1365-2:1999 Fire resistance tests for loadbearing elements – Part 2: Floors and roofs

EN 1363-1:1999Fire resistance tests – Part 1: General

requirements

size of testing element - 300x400 cm

fire resistance classification - REI, RE

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Fire resistance classification of roofs for tested inclination angle:

≤ 100 – roofs of inclination angle from 00 to 250;250 – roofs of inclination angle from 150 to 450;300 – roofs of inclination angle from 200 to 500.

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Influence factors on fire resistance of roofs made of sandwich panels:- shape and dimensions of joints,- core material- thickness of sandwich panels- sealants in the joints- types of fixing, spacing of screws- type and thickness of facing- type and quantity of glue- profile geometry of bottom and top facing of roof sandwich panels

EN 14509:2006+AC2008 Self-supporting double skinmetal faced insulating panels – Factory made products –SpecificationsAppendix C (normative) C.2 Fire resistance, Table C.2 direct application of tests results

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Rules for determining of load in fire resistance tests of roofs in Poland:

load of snow - Ψ1 x Sk = 0,2 x snow load according to table 1 and Fig.1 (map of snow load in Poland according to

Eurocode 1-3 ) for example:for zone 1 Ψ1 x Sk = 0,2 x 0,7 kN/m2

for zone 2 Ψ1 x Sk = 0,2 x 0,9 kN/m2

for zone 3 Ψ1 x Sk = 0,2 x 1,2 kN/m2

for zone 4 Ψ1 x Sk = 0,2 x 1,6 kN/m2

for zone 5 Ψ1 x Sk = 0,2 x 2,0 kN/m2

load of suspended ceilings, ventilation ducts, etc. – real load, without any factors

Dead load on the roof – real load, without any factorsno wind load

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Zone Sk, kN/m2

1 0,007·A – 1,4 Sk ≥ 0,72 0,93 0,006·A – 0,6 Sk ≥ 1,24 1,6

5 0,93·exp(0,00134 · A) Sk ≥ 2,0

A = height above the see level (m)

Map of Poland – snow load on the ground zones according to

PN-EN 1991-1-3: 2005

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Achieved fire resistance classification of roofs made of sandwich panels:

- roofs made of sandwich panels with mineral wool core from REI 30 to REI 120,

- roofs made of sandwich panels with polyurethane core from REI 15 to RE 120,

- roofs made of sandwich panels with polystyrene core from RE 20 to RE 60.

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Fire resistance classes of roofs according to PN-EN 13501-2+A1:2010

R 30

REI 15 20 30 45 60 90 120 180 240

RE 20 30 60 90 120 180 240

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Requirements according to building regulationsin Poland

180 240

Building category Roof loadbearing structure

Roof

A R 30 RE 30

B R 30 RE 30

C R 15 RE 15

D - -

E - -

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Czech Republic: Snow load at sea level

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The fire resistance classifications of roofs made of sandwich panels are valid under the following

conditions:

- roof loadbearing structure fire resistance class R minimum the same as roof fire resistance class

RE or REI

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- bending moment in the span from uniformly load(including snow load) not bigger than Md [Nm/m](per 1 meter of width of the panel); bending moment onthe support from uniformly load (including snow load) notbigger than Md [Nm/m] (per 1 meter of width of the panel).In calculations the value of snow load 0,2 x Sk shall betaken, where Sk – characteristic snow load value on theground in Poland according to PN-EN 1991-1-3:2005in chosen zone (according to location of the building);

- roofs of angle inclination from 00 to 250;

- sandwich panels can not be loaded by forces fromsuspended ceilings, ventilation ducts, etc.

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Photo Bogdan Wróblewski 2010

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CONCLUSIONS

Achieved fire resistance classes of roofs made of sandwich panels give wide range possible applications fulfilling fire resistance requirementsof building regulations.

Influence factors on fire resistance of roofs made ofsandwich panels :- shape and dimensions of joints,- core material,- thickness of sandwich panels,- sealants in the joints,- types of fixing, spacing of screws,- type and thickness of facing.

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CONCLUSIONS

Modern buildings with roofs made of sandwich panels are nice and can be safe in case of fire.

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THANK YOU FOR YOUR ATTENTION