Abstract: In order to investigate the effect of thermal radiation intensity on the performance of wood fire retardant coatings after fire retardant treatment by the surface coating method for the amnioblast coatings of the P?N?C fire retardant system, experiments were carried out using cone calorimetry (CONE) and simultaneous thermal analyzer (STA). The carbon layer secondary heating method was proposed to effectively test the flame retardant performance of fire?resistant coatings under different fire conditions, and the reliability of the conclusions was verified using thermogravimetric analysis technology. Through the thermogravimetric analysis of the coatings and the analysis of the secondary radiation heating data of the coated specimens, it was concluded that the coatings were completely charred in the temperature range of 575~750 ℃ and entered into a relatively stable stage. Meanwhile, the ignition time, heat release rate, total smoke production and fire growth index of the secondary heating of the coated specimens were analyzed in comparison with those of the radiation intensity of 35 kW/m2 in this temperature range, and it was concluded that the fire retardancy of the expanded charcoal layer was the best in this condition.

Key words: intumescent fireproof coating, fire coating for wood, thermal radiation intensity, repeated heating, thermogravimetric analysis, cone calorimeter