A new T-equivalent method for fire rated wall constructions using cumulative radiation energy

Recent tests have shown that some wall and door constructions, when exposed to temperature conditions greater than those used for the standard ISO 834 test, fail in lesser time than their standard time rating. The premature failures that occur have been known for some time but specific tests have been conducted only recently to demonstrate the facts. It has been widely-accepted since the late 1970s that the predominant mode of heat transfer in a fire compartment is by radiation rather than convection. Analysis of the specific tests mentioned above demonstrates the benefit of using cumulative radiation energy (CRE) as a prediction method for wooden doors and drywall construction. This article demonstrates how the CRE prediction method can also be applied to other values of thermal inertia such as those that occur in constructions using concrete or steel.