Fire Safety Science Digital Archive

The production of free TDI from the thermal and thermal oxidative decomposition of polyester and polyether flexible polyurethane foams has been monitored at temperatures between 200 and 800C. The decompositions were undertaken in an all-glass system and the TDI collected in dry toluene and analysed by gas chromatography and mass spectrometry. The polyester foam releases a maximum of 1.1 and 1.15 weight per cent of TDI in nitrogen and air atmospheres respectively whereas the polyether foam generates respectively 0.9 and 0.7 weight per cent. These maximum yields are recorded at the relatively low temperatures of 250 to 300C. At temperatures above about 800C in nitrogen and 700C in air, TDI is completely destroyed in the decomposition apparatus. Realistic fire tests involving TDI based flexible foams are required in order to evaluate the hazard of free TDI in real fire situations. Additional information on the toxic effects of TDI may be required for this appraisal.