Investigation on the self-decomposition and explosion hazard of azo compounds

Azo compounds are self-reactive chemicals that violently produce flammable gases with heat release (i.e., an exothermic reaction). However, the explosion mechanism and ignition probability of azo compounds have not been clearly defined for storage or transportation. In this study, explosion scene analyses and various pyrolysis tests were performed to evaluate the thermal decomposition characteristics and explosion phenomena of azo compounds in a storage facility. The chemical debris collected from a fire scene was determined to be similar to the pyrolyzate of one of the tested azo compounds used by Py-GCMS. The minimum amounts of azo compounds, which could be ignited by self-decomposition heat, were calculated from the results of differential scanning calorimetrys and the heat transfer equation. The results were used to discuss a safety and response strategy for preventing the propagation of an explosion accident, namely a chemical backdraft.