Introduction to Health and Safety at Work

13.12.5 Insulating 
materials
Building materials used for thermal or sound insulation 
could contribute to the spread of fi re. Only approved fi re 
resisting materials should be used.
13.12.6 Fire 
compartmentation
A compartment is a part of a building that is separated 
from all other parts by walls and fl oors, and is designed 
to contain a fi re for a specifi ed time.
The principal object is to limit the effect of both 
direct fi re damage and consequential business interrup-
tion caused by not only fi re spread but also smoke and 
water damage in the same fl oor and other storeys.
Buildings are classifi ed in purpose groups, accord-
ing to their size. To control the spread of fi re, any 
building whose size exceeds that specifi 
ed for its 
purpose group must be divided into compartments that 
do not exceed the prescribed limits of volume and fl oor 
area. Otherwise, they must be provided with special 
fi re protection. In the UK, the normal limit for the size 
of a compartment is 7000 m
3
. Compartments must be 
separated by walls and fl oors of suffi cient fi re resistance. 
Any openings needed in these walls or fl oors must be 
protected by fi re-resisting doors to ensure proper fi re-
tight separation.
Ventilation and heating ducts must be fi tted with 
fi re dampers where they pass through compartment 
walls and fl oors. Firebreak walls must extend completely 
across a building from outside wall to outside wall. 
They must be stable; they must be able to stand even 
when the part of the building on one side or the other is 
destroyed.
No portion of the wall should be supported on 
unprotected steelwork nor should it have the ends of 
unprotected steel members embedded in it. The wall 
must extend up to the underside of a non-combustible 
roof surface, and sometimes above it. Any openings 

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