The common symbols of explosion-proof solenoid valves are "Ex D I/II BT3" and "Ex" as general symbols, which indicate explosive "d" as "explosion-proof type d". The "I" or "II" denotes the classification of electrical equipment, i. e. electrical equipment for coal mines and I I. equipment for explosive gas environment other than coal mines. Among them, type II explosion-proof "d" and intrinsically safe "i" electrical equipment. The equipment is also divided into category II A, II B and type II C. "T3" represents the temperature group.

China's explosion-proof grade standard is "GB3836.1-2000 electrical equipment for explosive gas environment", which will be supplemented or modified by the following special standards for explosion-proof types.

GB3836.2 electrical equipment for explosive gas atmospheres second part: Flameproof D

GB3836.3 electrical equipment for explosive gas environment third part: increased safety type "e".

GB3836.4 electrical equipment for explosive gas atmospheres fourth part: intrinsically safe "I"

GB3836.5 electrical equipment for explosive gas environment fifth part: positive pressure type "P".

GB3836.6 electrical equipment for explosive gas environment sixth part: oil filled "O"

GB3836.7 electrical equipment for explosive gas environment part seventh: sand filled "Q"

GB3836.9 electrical equipment for explosive gas environment part ninth: cast "m"

GB7957 Mine Safety Cap Lamp and above Standard and this Standard are not applicable to medical electrical equipment, explosive device, explosive device tester and ignition circuit tester.