SPREADSHEET METHOD FOR TEMPERATURE CALCULATION OF UNPROTECTED STEELWORK SUBJECT TO FIRE

摘要

The determination of fire resistance level of a structural member in a building requires an efficient and accurate assessment of its limiting temperature in an enclosure fire environment. A significant discrepancy in the results of calculation of the limiting temperature could lead to an increase in the size of the structural member or an increase in the thickness of the fire protection materials. In either case, the cost of construction may increase. This paper introduces an efficient and accurate method for temperature prediction of steel members under four-sided fire exposure conditions. The method is based on the heat transfer principles commonly adopted in current codes of practice. However, the proposed method emphasizes the effect of gaseous composition of the combustion products on the evaluation of heat transfer coefficients that most codes of practice ignore. In addition, the complex forms of heat transfer coefficients have been simplified for practical use while the accuracy is still maintained. This method is well suited for practising engineers performing structural design for fire as the calculation procedure can be carried out entirely on a spreadsheet.