Intrinsic Safety (“i”) Explosion-Proof Certification is a certification system for electrical equipment used in hazardous areas. It prevents the generation of electric sparks or high temperatures that are sufficient to ignite explosive mixtures by limiting energy (electrical and thermal energy). The core of this system is to restrict the energy of electrical equipment through design, ensuring that the electric sparks and thermal effects generated by the equipment under normal operation or fault conditions cannot ignite the surrounding explosive mixtures (including gases, vapors, dust, etc.).

The intrinsic safety explosion protection levels are classified as follows:

ia: Applicable to electrical equipment that cannot ignite explosive gas mixtures under normal operation, with 2 counted faults plus the most adverse uncounted faults. It is suitable for Zones 0, 1, 2 and Zones 20, 21, 22.

ib: Applicable to electrical equipment that cannot ignite explosive gas mixtures under normal operation with 1 counted fault plus the most adverse uncounted faults. It is suitable for Zones 1, 2 and Zones 21, 22.

ic: Applicable to electrical equipment that cannot ignite explosive gas mixtures only under normal operation. It is suitable for Zones 2 and 22.

Applicable National Standards in China

GB/T 3836.1-2021 Explosive atmospheres - Part 1: General requirements for equipment

GB/T 3836.4-2021 Explosive atmospheres - Part 4: Intrinsic safety "i"