BURNING OF POLYMERS AT THE LIMITING OXYGEN INDEX

摘要

The limiting oxygen index (LOI) is widely used as a measure of flammability because, in its standardized form , the test is precise and produces quantitative results as opposed to the qualitative (pass/fail) results obtained in other small flame tests . The LOI is the minimum oxygen concentration in a flowing atmosphere that will sustain downward burning of a plastic strip or fabric . As such, the LOI involves the coupling of condensed and gas phase processes of flaming combustion at or near extinction, and for this reason, has defied simple description because the combustion characteristics that are associated with low flammability in flame and fire tests are associated with high LOI values . In this paper we investigate how material and fire properties contribute to the outcome of the LOI test by measuring the heat release rate in the test and applying steady burning and flame spread criteria to explain the results.