Concrete Insulation for Fire Resistance: An Analytical Investigation

In any design of steel structures to resist fire, it is essential to know the temperature of the steel. A simple step-by-step calculation technique is illustrated to determine the temperature of non-insulated and insulated AISC rolled steel sections exposed to a standard fire. The time-temperature responses of the insulated rolled steel sections has been determined for varying thicknesses of two insulating materials viz. concrete and cement plaster. The rolled steel section has been idealized as a lumped mass of steel having a uniform temperature. The ISO 834 specified time-temperature curve has been used as an input in the analysis. The proposed procedure is a useful tool for predicting temperatures of non-insulated and insulated simple rolled steel sections in standard fire-resistance tests and also helps to illustrate the efficacy of the type and the thickness of the insulating material on the elevation of temperature in the steel sections. The results of this investigation can be used to determine the fire-resistance ratings in the temperature domain for simple steel members.