Explosion proof grade

Explosion proof grade

Explosion proof rating is a classification standard used to identify the safety of explosion-proof electrical equipment in explosive environments. Its core elements include explosion-proof type, gas/dust category, temperature group, and protection level. Here is a specific analysis:

1、 Explosion proof level classification standard

Explosion proof type

Explosion proof type (d): It isolates internal explosions through a sturdy shell and is suitable for zones 0 to II.

Increased safety type (e): Normal operation does not produce sparks or high temperatures, suitable for zones 1 to II.

Intrinsic safety type (i): By limiting sparks or thermal effects through design, Class IA is suitable for Zone 0, and Class IB is suitable for Zone 1.

Other types: such as oil filled type (o), positive pressure type (p), etc.

Gas/dust category

Gas class: Class I (underground coal mine), Class II (non coal mine gas environment, including Class IIA, IIB, and IIC, with IIC compatible with IIA/IIB conditions).

Dust class: Class III (non coal mine dust environment, including Class IIIA, IIIB, and IIIC, with IIIC applicable to conductive dust).

Temperature group

According to the highest surface temperature of the equipment, there are a total of 6 groups:

T1 (450 ℃) to T6 (85 ℃), the lower the temperature, the higher the explosion-proof level.

For example, T4 represents ≤ 135 ℃, and T6 represents ≤ 85 ℃.

Protection level (IP)

Composed of two numbers, such as IP54 representing dustproof level 5 (particle diameter ≥ 2.5mm)+waterproof level 4 (water spray test). It is not related to the explosion-proof level.

2、 Precautions for choosing explosion-proof grade

Matching environmental requirements: Select the corresponding level based on the flammability, temperature, and hazardous area of explosive gases/dust (such as IA level for Zone 0 and IB level for Zone 1).

Avoid level escalation: For example, Class IIC equipment cannot be used in Class IIA environments.

Considering both cost and applicability: High level equipment has higher costs, and it is necessary to balance safety and economy according to actual scenarios.

3、 Example of Explosion proof Grade Identification

Exd Ⅱ CT4: Explosion proof type, suitable for non coal mine gas environment, temperature group T4 (≤ 135 ℃).

Exia Ⅱ CT6: Intrinsically safe type, suitable for gas environment underground in coal mines, temperature group T6 (≤ 85 ℃).

By meeting the above standards, it is possible to ensure the safe operation of explosion-proof equipment in explosive environments and reduce the risk of accidents.