本标准提供了气体和蒸汽分类指南。它描述了一种测试方法，用于测量正常温度和压力条件下气体或蒸汽-空气混合物的最大实验安全间隙（MESG），以便选择合适的设备组。本标准还描述了一种用于测定大气压力下空气中化学纯蒸汽或气体的自燃温度的试验方法。

This Standard provides guidance on classification of gases and vapours. It describes a test method intended for the measurement of the maximum experimental safe gaps (MESG) for gas- or vapour-air mixtures under normal conditions of temperature1 and pressure so as to permit the selection of an appropriate group of equipment. This standard describes also a test method intended for use in the determination of the auto-ignition temperature of a chemically pure vapour or gas in air at atmospheric pressure.