Prescriptive or Performance Design for Fire

Prescriptive fire design is based on protective cover derived from simply supported members conditioned to a standard moisture content and loaded with design loads in a furnace heated under a standard rate. Where building have indeterminate members in the structure the prescriptive design would be uneconomical and in certain cases may be unsafe and performance design described in this paper should be undertaken. Three approaches to fire design that are currently available are: The direct application of data from full size furnace tests using the standards ISO 834 Time Temperature curve , the values of which are tabulated in Building Codes; conventional ultimate limit state design in bending for fire, taking into account idealized material losses in strength; and a complete analysis of structural members using iterative solutions of finite differences or finite elements to estimate temperature gradients and finite elements to estimate temperature gradients and finite elements to determine the resulting stress and strain resultants.