It may be seen that fire load determines the duration of the fire, whereas the openings influence both intensity and duration. From this it is possible to determine the fire temperature course for a given building. Influence of fire load on fire temperature course. Influence of opening factor on fire temperature course. Temperature in Members .
Methods exist for calculating the temperatures in fire-exposed structural members.
In these, the dependence of material properties on temperature can be taken into account and a high accuracy obtained if the material properties are known. In practice, an accuracy of 15 to 20 per cent is obtainable, and in the field of fire this may be regarded as fairly accurate. Strength of Members . When temperature rises in fire-exposed members, their strength is reduced. If the fire load is sufficient and the duration of the fire long enough, a stage will be reached at which the strength of the member will no longer be adequate to support the structural load.