These represent completely distinct concepts.
| Usage Area | Gas Classification | Representative Gas | Minimum Ignition Spark Energy |
|---|---|---|---|
| Under The Mine | I | Methane | 0.280mJ |
| Factories Outside The Mine | IIA | Propane | 0.180mJ |
| IIB | Ethylene | 0.060mJ | |
| IIC | Hydrogen | 0.019mJ |
IIC is typically associated with explosion-proof environments, characterized by substances such as hydrogen and ethyl nitrate. Conversely, IIIC, as defined by national standards, pertains to conductive dust explosions, designated as DIP A21. IIIA covers flammable fibers, and IIIB encompasses non-conductive dust.
IIC is not interchangeable with IIIC; therefore, products with dust explosion-proof ratings such as DIP A20/A21 should be chosen.
