Experimental Study on the Combustion of Flexible Polyurethane Foam Under Marine Environment Conditions

The common upholstered furniture filler flexible polyurethane foam (FPUF) is a synthetic polymer whose wide range of application environments include not only land but also sea, especially in ship cabins, where FUPF is used extensively to improve the comfort and aesthetics of passenger cabins. In marine air, halogen ions in marine air can act as quenchers of gas-phase radicals, blocking the conversion of CO to CO2 in the combustion of polyurethane foam, which causes different combustion characteristics of FPUF. Therefore, the combustion characteristics of FPUF and the content of asphyxiating gas components in the combustion flue gas were studied by using a conical calorimeter and a steady-state tube furnace (SSTF) to simulate a marine air environment with high salinity and humidity, as well as the fractional effective dose (FED) model to evaluate the flue gas toxicity. The results show that the heat release rate (HRR) curves of FPUF combustion are similar for pilot ignition and non-pilot ignition modes in air with different salinity and humidity, and the ignition time of FPUF will increase about 1% with the salinity of air droplets increase 1% in both non-pilot and pilot ignition modes. The variation of flue gas components from FPUF combustion in air with different salinity and humidity has a similar pattern: the generation of CO and HCN increases with increasing phi values (the ratio of actual fuel-air ratio to the ratio of stoichiometric fuel-air ratio), while the generation of CO2 and NO decreases with increasing phi values. When the phi value is is close to 0.9 or 2.33, the ventilation conditions play a dominant role in the generation of each component in the flue gas. And the air with high salinity and humidity has a greater effect on the generation of each flue gas component when the equivalent ratio phi is in the range of 0.9 to 1.8. As the salinity in air increases, the threshold for FED to reach danger shifts from phi = 1.61 to phi = 1.36. The presence of NaCl in the air with high salinity and humidity increases the generation of asphyxiating gas components in FPUF combustion, the study has practical implications for evacuation, toxicity prediction, and safety evaluation.