Assessment of the Fire Hazard Presented by a Burning Pool of Toluene Diisocyanate (TDI)

Fire tests have been conducted with TDI under conditions simulating a pool fire originating, e.g. from a leakage of stored TDI. The facilities of Cerchar ^* provide conditions of a free-burning, well-ventilated fire. Burning rate, heat and smoke development and toxic gas emission were determined as a function of the pool diameter up to 1 m². Results are compared with small scale test results.

Burning rate increases with increasing pool diameter reaching 2 kg/m2-min at 1 m² area. Yields of permanent gases do not differ significantly with increasing pool area, with HCN amounting to 5 mg/g. Free TDI is found in fire gas up to 15 ppm corresponding to a yield of 7 mg/g.