VDE 0170-15-1-2014 "Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure ""t"" (IEC 60079-31:2013); German version EN 60079-31:2014"
VDE 0170-15-1-2016 "Explosive atmospheres - Part 31: Equipment dust ignition protection by enclosure ""t"" (IEC 31/1248/CD:2016)"