16.3.1
The calculation of PSA involves:
- a) Calculation of the strength of the element as a function of temperature of the element and the determination of limiting temperature;
- b) Calculation of the thermal response of the element, that is calculation of the variation of the temperature of the element or the parts of the element with time, when exposed to fire; and
- c) Determination of PSA at which the temperature of the element or parts of the element reaches the limiting temperature.
16.3.2 Determination of Period of Structural Adequacy
The period of structural adequacy (PSA) shall be determined using one of the following methods:
- a) By calculation:
- determining the limiting temperature of the steel (Tl) in accordance with 16.5 ; and
- determining the PSA as the time (in min) from the start of the test to the time at which the limiting steel temperature (t) is attained, in accordance with 16.6 for protected members and 16.7 for unprotected members.
- b) By direct application of a single test in accordance with 16.8; or
- c) By calculation of the temperature of the steel member by using a rational method of analysis confirmed by test data or by methods available in specialist literature.