Page 181 - ICC IEBC 2018

RESOURCE A

the supporting elements, can be subjected to a fire test. table is at least the fire endurance of the slab. There
Therefore, a fire endurance classification cannot be would have to be an adjustment for the weight of the
issued for the slabs separately. roof cover in the allowable load if the test specimen
did not contain a cover.
(3) The designer and contractor believe this slab will
yield a 2-hour fire endurance even without the cover, (4) The supporting structure or element would have to
and any beam of at least 2-hour fire endurance will have at least a 2-hour fire endurance when tested sepa-
provide satisfactory support. Is it possible to obtain a rately.
classification for the slab separately? Discussion
Solution If the tables did not include tests on assemblies which con-
(1) The answer to the question is yes. tained the slab, one procedure would be to assemble the roof
slabs on any convenient supporting system (not regarded as
(2) According to Rule 10 it is not contrary to common
sense to test and classify roofs and supporting ele- part of the specimen) and to subject them to a load which,
ments separately. Furthermore, according to Rule 2, if besides the usually required superimposed load, includes
the roof slabs actually yield a 2-hour fire endurance, some allowances for the weight of the cover.
the endurance of an assembly, including the slabs, Example 3
cannot be less than 2 hours.
Problem
(3) The recommended procedure would be to review the A steel-joisted floor and ceiling assembly is known to have
tables to see if the slab appears as part of any tested yielded a fire endurance of 1 hour and 35 minutes. At a cer-
roof or floor/ceiling assembly. The supporting system tain location, a 2-hour endurance is required. What is the
can be regarded as separate from the slab specimen,
and the fire endurance of the assembly listed in the

FIRE FIRE

t 1 t 2 t 12 t 1 t 2 t 1 t 2 t 1 t 2
12
2
1
2
2
t> t + t 2 t> t 1 t> t 1 t> t 1
RULE 1 RULE 2 RULE 3 RULE 4
LOW CONDUCTIVITY HIGH CONDUCTIVITY LOW CONDUCTIVITY HIGH CONDUCTIVITY MOIST DRY
FIRE FIRE FIRE FIRE

t 1 t 2 t 1 t 2 t 1 t 2 t 1 t 2
1 t ≈ τ 2 1 t> t t2 t 1 ≠ t 2 t> t 2
1
RULE 5 RULE 6 RULE 7 RULE 8

BEAM TESTED AS BEAM TESTED FOR THE FLOOR FOR A BEAM WHEN
PART OF FLOOR SEPARATELY ASSEMBLY TESTED SEPARATELY
t 1 t 2

A B
t 1 t 2
1
t> t 2 BEAM A CAN BE REPLACED BY BEAM B IF t 2 > t
RULE 9 RULE 10 1
Diagrammatic illustration of ten rules.
t = fire endurance

162 2018 INTERNATIONAL EXISTING BUILDING CODE ®
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