Limiting Oxygen Index
A relative measure of flammability that is determined as follows. A sample is ignited in an oxygen/nitrogen atmosphere. The oxygen content is adjusted until the minimum required to sustain steady burning is found. The higher the value, the lower the flammability. (Troitzsch J (2004) Plastics flammability handbook: Principle, regulations, testing and approval. Hanser-Gardner, New York; Tests for comparative flammability of liquids, UI 340. Laboratories Incorporated Underwriters, New York, 1997).