In the selection of electrical equipment for Oil & Gas industry application, particularly those inside classified hazardous areas, the equipment protection level is necessary as a criterion.
Equipment Protection Level (EPL) is a system to clearly indicate the inherent ignition risk of equipment, no matter what type of protection is used. EPL was introduced in IEC 60079-14 (2007). The idea is to expound the information about the inherent ignition risk of an equipment during normal operation and during fault conditions or malfunctions. It is logical that any equipment having very high level of protection during normal operation will have a lower probability of becoming an ignition source during the occurrence of a fault or malfunction. With this property, the equipment is definitely suitable for use in an area having a high probability of becoming hazardous, that is Zone 0, thus only the equipment with the highest EPL should be installed in Zone 0 classified locations.
| EPL | Application | Description | Zone |
|---|---|---|---|
| Ga | Gas | equipment for explosive gas atmospheres, having a "very high" level of protection, which is not a source of ignition in normal operation, during expected malfunctions or during rare malfunctions | 0, 1, 2 |
| Gb | Gas | equipment for explosive gas atmospheres, having a "high" level of protection, which is not a source of ignition in normal operation or during expected malfunctions, | 1, 2 |
| Gc | Gas | equipment for explosive gas atmospheres, having a "enhanced" level of protection, which is not a source of ignition in normal operation and which may have some additional protection to ensure that it remains inactive as an ignition source in the case of regular expected occurrences (for example failure of a lamp) | 2 |
| Da | Dust | equipment for explosive dust atmospheres, having a "very high" level of protection, which is not a source of ignition in normal operation, during expected malfunctions, or during rare malfunctions | 20, 21, 22 |
| Db | Dust | equipment for explosive dust atmospheres, having a "high" level of protection, which is not a source of ignition in normal operation or during expected malfunctions | 21, 22 |
| Dc | Dust | equipment for explosive dust atmospheres, having a "enhanced" level of protection, which is not a source of ignition in normal operation and which may have some additional protection to ensure that it remains inactive as an ignition source in the case of regular expected occurrences (for example failure of a lamp) | 22 |
| Source: IEC 60079 | |||
EPL marking on equipment is now common as indicated in this IECEx Certificate of Conformity IECEx SIR 09.0124X. This equipment is marked "Ex ia IIC Ga".