Simple approach for calculating maximum temperature of insulated steel members in natural-fires

The maximum steel temperature of key elements to natural fires should be considered in evaluating the fire resistance of steel structures by rational approach. Natural fires are complex that advanced analytical simulations are always required to obtain the temperature distribution of steel members in natural fires. Simple calculation approaches which can give acceptable predictions are needed for the daily design work. This paper proposes a simple approach for calculating the maximum steel temperature of insulated steel members subjected to natural fires. The approach adopts time equivalent to relate natural fires with the standard fire, and use a simple quadratic equation for calculating the maximum steel temperatures. By comparing with numerical results and test data, the proposed approach can give satisfactory prediction of maximum steel temperatures in the range from 300 to 600 °C. The approach only need hand calculations which is easy and convenient for practical usage.

► Approach to get maximum steel temperature of insulated member to real fire is proposed.
► The approach is simple which only needs hand calculation.
► The approach gives acceptable results in the range from 300 °C to 600 °C.