Types of Protection

We have learned about hazardous areas, gases, zones and EPL and now we should discuss what types of measures manufacturers apply to the electrical devices in order to achieve certification from the notified body. There are many protection types, and some more common than others and each type has a specific purpose and concept. Here are the most common protection types for hazardous areas.

Type of Protection Symbol Concept of protection Zones EN / IEC 
Increased safety e Enclosure (IP54) + no arcs, sparks, surface temp 1 & 2 60079-7
Flameproof d Contamination of explosion in enclosure 1 & 2 60079-1
Intrinsic Safety i Insufficient energy / sparks and surface temp 0, 1 & 2 60079-11
Pressurized enclosure p Keep flammable substance out with pressure 1 & 2 60079-2
Encapsulation m Keep flammable substance out with encased resin 0, 1 & 2 60079-18
Oil Immersion o Keep flammable substance out with submersion 1 & 2 60079-6
Optical Radiation Op Inherently safe, protected by shutdown 0, 1 & 2 60079-28
 Powder filled q Quenching of flames, sand/powder/quartz filled 1 & 2 60079-5


Many of the protection types have sub classes, such as “ia”, “ib” and “ic” referencing the EPL and Zone which the “i” equipment is certified for. An “ib” device is therefore Intrinsically Safe Zone 1. Multiple protection types can also be combined in one product or certification for increased safety. For example BARTEC PIXAVI mobile devices have both “i” intrinsically safe protection as well as “m” encapsulation. It is therefore Ex’im’. Addittionally you have in some cases “op is” which is Optical Radiation safety related to lasers and fiber optic signals. If a device is marked with “op is” it means that the laser, light or fiber optic signal sources are limited to below the threshould value. For BARTEC PIXAVI devices the “op is” is referring to the laser which is below 15 mW for Zone 1 T6.


Sources: BARTEC TECHNOR, Wikipedia and IECEx websites.