Gas pressure-regulating (GPR) stations are part of the nation-wide pipeline network which supplies customers with natural gas. GPR stations are equipped with gas vents to release small amounts of gas in rare instances for operational reasons. The operators of gas transport facilities are required to determine the size of the explosion-hazardous areas (EHAs) that may occasionally develop at the gas vents and to keep them free from ignition Sources. In order to facilitate the calculation of the EHAs, the German DVGW issued a guide to the efficient calculation of explosion-hazardous areas. The calculation method takes account of the particular properties of the venting systems in order to determine the rate at which gas is released. Based on this figure and on additional parameters, gas dispersion and size of the EHAs are assessed. The method of calculation and e.BEx (R), its software version, were developed by E.ON Ruhrgas AG.