Objectives  With the development of aluminum alloy and composite material structure on surface ships, fireproof materials nowadays are not able to meet the new requirements. Appropriate thermal conductivity coefficient is necessary in the design process of new fireproof materials aiming at such situation.

  Methods  The algorithm of thermal conductivity coefficient is established according to the overall design method and the background of standard fire resistance test. First, the heat-transfer calculation process is realized on the base of the theory resolution of unsteady heat-transfer calculation on infinite plate by using discrete method. Then the fire ground calculation model is established. The low sensitivity of surface coefficient of heat-transfer and surface emissivity to the calculation result is tested and proved in order to do approximate process on these parameters. After the analysis of mechanical behavior under high temperature of aluminum alloy and composite material, the temperature on the back side of fireproof materials is obtained. The qualified thermal conductivity coefficient can be found by iterative computations and comparison. Taking ceramic wool as example, its temperature on back side is calculated and compared to the public experiment data.

  Results  It is proved that the proposed algorithm is credible by comparing the example of ceramic wool with public experiment data. The results show that the thermal conductivity coefficient of the fireproof materials which is used on aluminum alloy and composite material structure should be lower than 0.032 and 0.020 W·m^-1·K^-1.

  Conclusions  The obtained thermal conductivity coefficient and the algorithm can provide reference for the development of new fireproof materials.