Section 5 Cover for Fire Resistance

During the course of a fire, temperatures in excess of about 200ºC reduce the strength of both steel and concrete. Fortunately the insulation properties of concrete are greater than those of steel, and the concrete cover is the best and cheapest method of increasing the fire resistance of structures.

The cover for fire resistance depends on:

(a) the type of member;

(b) how that member carries the loads imposed on it;

(c) whether or not it is continuous (flexurally or structurally) with other members; and

(d) the fire resistance period it provides.

Concrete strength is not taken into account when selecting cover for fire resistance. Similarly, the effects of fire need only be considered for members which are required, by Building Regulations or through other Authorities, to attain a specified fire resistance level. In certain structures which have a high exposure classification, due to proximity with hazardous materials for example, resistance to fire may take precedence over all other factors.