BS ISO 4589-4:2021

This standard BS ISO 4589-4:2021 Plastics. Determination of burning behaviour by oxygen index is classified in these ICS categories:

• 83.080.01 Plastics in general
• 13.220.40 Ignitability and burning behaviour of materials and products

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.

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.