This part of IEC 60079 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. The method does not take into
account the possible effects of obstacles on the safe gaps2. 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.
The tabulated values of chemical and engineering properties of substances are provided to
assist engineers in their selection of equipment to be used in hazardous areas. It is hoped to
publish further data from time to time, as the results of tests made in several countries
become available.
The scope of these data has been selected with particular reference to the use of equipment
in hazardous areas, and notice has been taken of standard measurement methods.
NOTE 1 The data in this standard have been taken from a number of references which are given in the
bibliography.
NOTE 2 Some variations in the data may appear when references are compared, but usually the discrepancy is
sufficiently small to be of no importance in the selection of equipment.
BS EN 60079-20-1:2010 history
0000 BS EN 60079-20-1:2010(2012)
2010BS EN 60079-20-1:2010 Explosive atmospheres. Part 20-1: Material characteristics for gas and vapour classification. Test methods and data