Applicable for the factories having the explosive mixtures formed from class IIA,IIB and IIC T1-T6 group flammable gas, steam with air in area No.1 , No.2, and appearing the explosive hazardous area due to the mixture of flammable dust and air in area No.20,No.21 and No.22,such as oil field, chemical plant, port, oil storage, steamship, oil drilling platform, gas stations, coal mine, aviation, military, medicine, steel, firecrackers production, machinery, food processing and storage and so on.Espeically for tanker, dangerous good transport vehicles, tankers, small warehouses, chemical reagents labs, pharmaceutical plants, explosion-proof elevator and also high requirements on size and weight places.