Increased safety type, flameproof type, encapsulated type – how to choose? How should security be ranked?

GB∕T 3836.1-2021 Explosive atmospheres – Part 1 – It should be available for retrieval.

1 Flameproof type (standard number: GB3836.2)/Explosion protection mark: Ex d Flameproof type (standard number: GB3836.2)/Explosion protection mark: Ex d Principle of flameproof protection: The flameproof enclosure is capable of withstanding internal explosions of flammable mixtures that penetrate inside the enclosure through any joints or structural gaps in the enclosure, without being damaged; it also prevents ignition of an explosive atmosphere formed by one or more gases or vapors outside the enclosure. Common flameproof equipment includes motors, lighting fixtures, flameproof thermocouples, flameproof thermal resistors, flameproof pressure transmitters, and other flameproof instruments. 2 Increased safety type explosion protection (standard number: GB3836.3)/Explosion protection mark: Ex e. Principle of increased safety type explosion protection: For devices that do not generate arcs, sparks, or dangerous high temperatures during normal operation, additional protective measures can be incorporated into their design to prevent the occurrence of arcs, sparks, or overheating under normal operating conditions or under approved overload conditions; this enhances the safety of the device and achieves the purpose of explosion protection. Common intrinsically safe equipment: intrinsically safe motors, intrinsically safe electrical appliances, intrinsically safe lighting fixtures, etc. 3 Intrinsic safety explosion protection (standard number: GB3836.4) / Explosion protection mark: E*s. Principle of intrinsic safety explosion protection: The circuit used ensures that neither the electrical sparks nor the surface temperature generated under normal operating conditions or specified fault conditions can cause an explosion in the specified explosive mixture. Commonly used intrinsically safe devices: intrinsically safe temperature transmitters, pressure transmitters, level transmitters, etc. Note: Intrinsic safety is the highest level of explosion protection. It can be used in Zone 0, Zone 1, Zone 2, or non-hazardous areas; it is the only explosion-proof type permitted for installation in Zone 0. Its use is allowed only when it forms a proper intrinsically safe system together with associated equipment (such as safety barriers). Other explosion-proof types can only be used in Zones 1 and 2; the hazard levels decrease from Zone 0 to Zone 1 to Zone 2. 4 Positive pressure explosion protection (standard number: GB3836.5) / Explosion protection mark: Ex p. Principle of positive pressure explosion protection: A protective gas, such as fresh air, is continuously introduced into the interior of the equipment’s enclosure, thereby keeping the pressure inside the equipment higher than the external pressure. This prevents combustible gases from entering or reaching concentrations sufficient to cause an explosion. It is also equipped with gas pressure detection and flammable gas concentration alarm devices; in the event of low pressure or a flammable gas concentration that exceeds the safe level, it can automatically cut off the power supply. Common positive pressure equipment: Positive pressure analysis cabin. 5 Immersed-type explosion-proof (standard number: GB3836.6) / Explosion-proof mark: Ex o. Principle of immersed-type explosion-proofing: The components within the equipment that may generate sparks or arcs, or the entire equipment itself, is submerged in transformer oil to isolate it from flammable gas mixtures. Common oil-filled equipment: explosion-proof switches, terminals, etc. 6 Sand-filled explosion protection (standard number: GB3836.7) / Explosion protection mark: Ex q. Principle of sand-filled explosion protection: Sand is filled inside the equipment’s enclosure, so that under specified conditions, the flame generated by arcs within the enclosure, as well as the excessive temperatures on the enclosure walls or the surface of the sand, cannot ignite the explosive mixtures surrounding it. Common sand-filled component devices: capacitors, fuses, transformers, etc. 7 Spark-free explosion protection (standard number: GB3836.8) / Explosion protection mark: Ex n. Principle of spark-free explosion protection: It prevents the ignition of surrounding explosive mixtures during normal operation, and it also does not generate electrical equipment that could cause ignition failures. Common spark-free devices: motors, lighting fixtures, plug-in devices, low-power electrical appliances. 8 Encased explosion-proof (standard number: GB3836.9)/Explosion protection mark: Ex m. Principle of encased explosion-proof design: The ignition sources that could ignite explosive mixtures in electrical equipment—such as arcs, sparks, and dangerous high temperatures—are enclosed within a resin-based sealing material, thereby preventing them from igniting any explosive mixtures present in the surrounding area. 9 Airtight explosion-proof (standard number: GB3836.10)/Explosion protection mark: Ex h

Explosion-proof areas are classified into Zone 0, Zone 1, and Zone 2; different explosion-proof products must be selected for these three hazardous areas. For Zone 0, explosion-proof equipment can be used: electrical equipment and circuits that meet the requirements of IEC60079-11 for intrinsically safe design can be utilized in Zone 0. Therefore, the electrical equipment to be used in Zone 0 can only be intrinsically safe electrical devices or specially manufactured explosion-proof electrical devices. Equipment for Zone 1: Electrical equipment that meets the requirements for use in Zone 0, or one or more of the requirements for the following explosion-proof types, can be used in Zone 1. Flameproof enclosure “d” meets the requirements of IEC60079-1; increased safety type “e” meets the requirements of IEC60079-7; intrinsically safe type “i” meets the requirements of IEC60079-11. Positive pressure type p, sand-filled type q, oil-immersed type o, encapsulated type m. Equipment for Zone 2: The following electrical equipment can be installed in Zone 2: electrical equipment designed for Zone 0 or Zone 1, or “n” equipment, or special “s” equipment