Effects of low atmospheric pressure on combustion characteristics of polyethylene and polymethyl methacrylate

Combustion characteristics of polymers are affected significantly by low atmospheric pressure and oxygen concentration at high altitude. In this study, vertical downward experiments aimed at investigating these characteristics, including mass loss rate (burning rate), flame temperature, flame spread rate, and flame height for polyethylene and polymethyl methacrylate having different thicknesses were conducted at elevations of 2295 m (77.4 kPa) in Xining and 29.5 m (101.8 kPa) in Hefei, China. Experimental results showed that mass loss rate and flame temperature are proportional to the ambient pressure. Power-law progressions of flame height and flame spread rate to pressure were produced, and linear relationships between the exponents and thickness of samples were obtained. The influence of ambient pressure and thickness on flame height is similar to that on flame spread rate for polymethyl methacrylate.