ISO/IEC 80079-20-1:2017作为双对数标准发布，并提供气体和蒸汽分类指南。它描述了一种试验方法，用于在正常温度和压力（20°C，101,3 kPa）条件下测量气体-空气混合物或蒸汽-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。本文件还描述了一种试验方法，用于在大气压力下测定蒸汽-空气混合物或气体-空气混合物的自燃温度（AIT），以便选择合适的设备温度等级。提供材料的化学性质值，以帮助选择用于危险区域的设备。当验证试验的结果可用时，可添加更多数据。表（见附录B）中所列材料和特性的选择特别参考了在危险区域使用设备的情况。 本文件中的数据取自参考书目中给出的大量参考文献。这些测定MESG或AIT的方法也可用于气体-空气惰性混合物或蒸汽-空气惰性混合物。然而，有关空气惰性混合物的数据并未制成表格。 关键词:气体和蒸汽的分类，最大实验安全间隙（MESG）的测量

ISO/IEC 80079-20-1:2017 is published as a dual log standard and 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-air mixtures or vapour-air mixtures under normal conditions of temperature and pressure (20 °C, 101,3 kPa) so as to permit the selection of an appropriate group of equipment. This document also describes a test method intended for use in the determination of the auto-ignition temperature (AIT) of a vapour-air mixture or gas-air mixture at atmospheric pressure, so as to permit the selection of an appropriate temperature class of equipment. Values of chemical properties of materials are provided to assist in the selection of equipment to be used in hazardous areas. Further data may be added as the results of validated tests become available. The materials and the characteristics included in a table (see Annex B) have been selected with particular reference to the use of equipment in hazardous areas. The data in this document have been taken from a number of references which are given in the bibliography. These methods for determining the MESG or the AIT may also be used for gas-air-inert mixtures or vapour-air-inert mixtures. However, data on air-inert mixtures are not tabulated. Keywords: classification of gases and vapours, measurement of the maximum experimental safe gaps (MESG)