Which Has the Highest Explosion-Proof Level

Explosion-proof classification: The IIC level is the highest, encompassing the applications of IIB and IIA; IIB exceeds IIA in ranking.

Class And Level	Ignition Temperature And Group
-	T1	T2	T3	T4	T5	T6
-	T＞450	450≥T＞300	300≥T＞200	200≥T＞135	135≥T＞100	100≥T＞85
I	Methane
IIA	Ethane, Propane, Acetone, Phenethyl, Ene, Aminobenzene, Toluene, Benzene, Ammonia, Carbon Monoxide, Ethyl Acetate, Acetic Acid	Butane, Ethanol, Propylene, Butanol, Acetic Acid, Butyl Ester, Amyl Acetate Acetic Anhydride	Pentane, Hexane, Heptane, Decane, Octane, Gasoline, Hydrogen Sulfide, Cyclohexane, Gasoline, Kerosene, Diesel, Petroleum	Ether, Acetaldehyde, Trimethylamine		Ethyl Nitrite
IIB	Propylene, Acetylene, Cyclopropane, Coke Oven Gas	Epoxy Z-Alkane, Epoxy Propane, Butadiene, Ethylene	Dimethyl Ether, Isoprene, Hydrogen Sulfide	Diethylether, Dibutyl Ether
IIC	Water Gas, Hydrogen	Acetylene			Carbon Disulfide	Ethyl Nitrate

Maximum surface temperature: This refers to the highest temperature that electrical devices can achieve under the worst specified operating conditions, potentially igniting the surrounding explosive atmosphere. The maximum surface temperature must be lower than the flammable temperature.

For instance: In environments where explosion-proof sensors are used, if the ignition temperature of the explosive gases is 100°C, then the maximum surface temperature of any component of the sensor must remain below 100°C.