It is shown that a special fire insulation with a thickness of 20 mm is effective against explosive spalling of high strength concrete（HSC） at high temperature.Based on test results

mean thermal conductivity coefficients of the fire insulation are determined in different thermal ranges.Then

fire resistance performance of HSC columns with the fire insulation is analyzed by using the computer program SAFIR

and the influences of axial load ratio

cross - sectional dimensions

load eccentricity ratio and reinforcement ratio are discussed.Finally

a regressive formula is proposed for calculation of fire resistance rating of HSC columns with the fire insulation.Simulation results show that:（a） the thermal conductivity coefficient of the fire insulation decreases slightly with increase of temperature;and（b） the fire resistance of HSC columns with 20 mm thick fire insulation can be 40%～350%larger than those without the fire insulation.