Heat transfer model for unprotected steel members in a standard compartment fire with participating medium

A heat transfer model accounting for the radiative properties of combustion products in a compartment standard fire is presented. The model used is based on a conceptual scheme of a grey gas mixture exchanging radiative energy with a black enclosure. The proposed model, with a radiation heat transfer that accounts for the effect of combustion products on the rate of heat transfer from the fire to the structural elements, is simple to use and the predictions of the temperature response of unprotected I-columns heated from all sides are superior to those predicted by the classical method using the Stefan-Boltzmann radiation equation with constant emissivity.