The Bottom Ignition Oxygen Index Test

Abstract

A variant of the oxygen index flammability test has been developed which, used in conjunction with the candlelike determination, contributes to a truer understanding of the flammability of materials. This test is entitled the Bottom Ignition Oxygen Index (B.I.O. I.) and is run by igniting the bottommost surface of the test sample rather than the upper most surface as in the normal, candlelike determination. It is shown that the high, e.g., 27 or more, candlelike Oxygen Index (O.I.) of certain materials is not an adequate indi cation of flame retardance. These materials can be completely consumed in an alternative flammability test and afford much lower O.I. when tested in the bottom ignition manner. A useful criterion for flame retardance appears to be a candlelike O.I. of at least 27 in addition to a B.I.O.I. of at least 22.