GOST 31610.1.1-2012 Electrical apparatus for explosive gas atmospheres. Part 1-1. Flameproof enclosures ?D?. Method of test for ascertainment of maximum experimental safe gap
2012GOST 31610.1.1-2012 Electrical apparatus for explosive gas atmospheres. Part 1-1. Flameproof enclosures ?D?. Method of test for ascertainment of maximum experimental safe gap