ISO 7231:2023

This document specifies two methods for determining the air flow value of flexible cellular polymeric materials: —     method A, for conventional types of flexible cellular polymeric material; —     method B, for all types of flexible cellular polymeric material, but especially for materials with a low permeability to air. For method B, two methods are specified in this document: —     method B1: with manual measurement; —     method B2: with automatic measurement. NOTE 1       Air flow values can be used to give an indication of the effects of formulation and production variables on the cellular structure. NOTE 2       In this document, the expression “conventional type of flexible cellular polymeric material” means types which are unsuitable for sealing purposes.