Assessing the Burning Rate of Solid Oxidizers

A method for assigning solid oxidizers and products containing oxidizers to an NFPA Class was developed. The method consists of two reaction-to-fire tests: a bench-scale screening test with thirty gram piles and an intermediate-scale fire exposure test with twenty four pounds of material in combustible test packaging. Using data collected from oxidizers with a range in composition and burning behavior, burning rate was defined using fire test response characteristics namely the peak heat release rate, maximum mass loss rate and duration of active burning. A similar screening test is being developed by an IGUS oxidizer working group to improve the UN Test O.1 for solid oxidizers for transportation. The significance of a new method to classify oxidizers, differences between the proposed NFPA and current DOT screening tests and their criteria, what it means for the fire codes and safe handling, storing, using and transporting solid oxidizers will be discussed.