Abstract: The combustion characteristics of spray paint on thin metal surfaces were studied by cone calorimeter. Four heat radiation intensities of 35, 50, 65 and 80 kW/m2 were selected, and parameters such as ignition time, heat release rate and CO release rate were obtained. It was found that the paint on the thin metal surface is a typical hot thin solid, and the reciprocal of the ignition time has a linear relationship with the thermal radiation intensity. The more the number of spray layers, the smaller the heat radiation intensity required for ignition, and the higher the fire hazard. The experimental results show that the critical heat flux intensity of 1-layer spraying, 2-layer spraying and 3-layer spraying is about 30.8, 10.0 and 5.0 kW/m2, respectively. The heat release rate showed a bimodal characteristic, the first peak and the second peak increased linearly with the thermal radiation intensity, and the peak increased with the increase of the number of sprayed layers. The CO release rate showed three peaks. With the increase of thermal radiation intensity, the fire performance index of each sample continued to decrease, the fire spread index continued to increase, and the fire risk increased.

Key words: spray paint, thin metal, combustion characteristics, cone calorimeter, fire performance index, fire spread index