Shenhai Explosion-Proof
Gb: Specifies protection levels for Category 1 and 2 devices. Importantly, the updated explosion-proof markings further divide the flameproof category into da, db, and dc.
| Equipment protection level EPL | Da | Db | Dc |
|---|---|---|---|
| The protection levels for equipment are prescribed based on the varying characteristics of explosive gas environments, explosive dust environments, and coal mine methane explosive environments, as well as the possibility of the equipment becoming an ignition source. | Equipment for use in explosive dust atmospheres with a “very high” degree of protection, which is not a source of ignition under normal operation, expected failures or rare failure conditions. | Equipment for use in explosive dust environments, with a “high” degree of protection, which is not a source of ignition under normal operation or under conditions of expected failure. | Equipment for use in explosive dust environments, with a “normal” level of protection, is not a source of ignition during normal operation, and additional protective measures can be taken to ensure that effective ignition does not occur in situations where a source of ignition is expected to occur frequently (e.g. malfunctioning of a luminaire). |
| Zone | Zone 20 | Zone 21 | Zone 22 |
da:
Designed exclusively for catalytic sensors in combustible gas detectors, and is approved for use in Zone 0.
db:
A prevalent standard, db denotes the conventional flameproof type.
dc:
Intended for use with switch contacts and EX components within electrical devices.