There are indeed two types of explosion-proof fans: gas explosion-proof and dust explosion-proof. There are essential differences between the two in terms of explosion-proof principles and applicable scenarios:

Differences in explosion-proof types

Gas explosion-proof blowers are mainly designed for combustible gas or steam environments, and use explosion-proof and safety enhancement technologies to prevent the danger caused by explosive gases. Dust explosion-proof fans are suitable for combustible dust environments, and can block dust explosion conditions through shell protection, surface temperature control, and other methods.  ‌

Core design differences

Gas Explosion proof: Typically designed with explosion-proof or increased safety features, the enclosure has a lower level of protection and may allow gas infiltration.  ‌

Dust Explosion proof: The enclosure has a higher protection level (such as IP66) and is equipped with positive pressure, spark free and other technologies to prevent dust from entering or accumulating.  ‌

Applicable scenario limitations

Gas explosion-proof equipment cannot be used in dusty environments, and dust explosion-proof equipment is also not suitable for gas environments. For example, although the shell protection level of dust explosion-proof motors is high, they cannot prevent gas from entering, so the two cannot be used interchangeably.

Gas explosion-proof is divided into CT4 and BT4

CT4 and BT4 are two different explosion-proof standards in the gas explosion-proof level, with the main differences as follows:

Difference in explosion-proof grade

CT4: Explosion proof grade is ExdIICT4, suitable for environments with high-risk gases such as hydrogen and acetylene, with a maximum surface temperature not exceeding 135 ℃.  ‌

BT4: Explosion proof grade ExdIIBT4, suitable for conventional gases such as methane, petroleum gas, etc., with a maximum surface temperature not exceeding 135 ℃.  ‌

Applicable scenarios

CT4: Suitable for areas with extremely hazardous gases such as acetylene and hydrogen (such as petrochemical and industrial gas processing).  ‌

BT4: Suitable for conventional gas environments (such as methane, ethane, etc.), commonly found in ordinary industrial or commercial places.