Alcance
This document specifies a test method for determining the minimum volume fraction of oxygen, in admixture with nitrogen, at ambient temperature, that supports combustion of small vertical sheet test specimen under a specified gas velocity that is higher than that specified in ISO 4589-2.NOTE The result is expressed as a high gas velocity oxygen index (HOI).In addition, this document specifies the testing apparatus for determining the HOI.The test method is applicable to materials in the form of sheets up to 2 mm thick. It is also applicable to flexible sheet materials that are supported vertically by a specified specimen holder.