An Ex nR or restrictive breathing enclosure removes the fuel element of an explosion by stopping any flammable gasses entering the internal enclosure. In doing so, potentially explosive gases never come into contact with hot surfaces or an ignition source potentially present inside the enclosure. Restrictive breathing enclosures are only certified to Zone 2 hazardous areas, where the area is considered safe in normal operation with flammable gases only present in fault conditions. The technique ensures the cumulative concentration within the enclosure does not exceed the lower explosive limit for the gas or vapor concentration over short and long periods of time. A Ex nR enclosure typically has the following characteristics: Lightweight metallic or non-metallic construction Designed to prevent flammable gases entering High ingress protection levels Tightly sealed iWAPXN3 Zone 2/Division 2 Hazardous Area Enclosure […]

An Ex d enclosure is designed to contain an explosion and stop any flames, sparks, and hot gases from escaping into the surrounding atmosphere should an internal explosion occur. In addition, an Ex d enclosure protects the fitted equipment against external moisture, dirt, dust, or water. The enclosure may house equipment such as, contactors, relays, power supplies, transformers, radio devices and other electrical equipment with potentially hot surfaces. Sometimes referred to as ‘flameproof’ or “explosion-proof”, an Ex d enclosure includes what is known as a flame path. The flame path design can vary depending on the construction of the Ex d enclosure system. Flame Path Flame paths are gaps within the enclosure that, if an internal explosion occurs, ensure that by the time the flame has reached the end of the flame path it has […]

The main standards for hazardous area equipment globally are ATEX, IECEx and North American NEC 500/505. For ATEX and IECEx, covering most of the world, the IEC 60079 series of standards are typically used for the approval of equipment installed in hazardous areas. Most national or regional domains derive their own standards from the IECEx standards and issue a version, often identical, as their own national or regional standard. The most frequently used electrical equipment protection standards are: 60079-0 General requirements 60079-1 Explosion proof enclosures 60079-7 Increased safety 60079 -11 Intrinsic safety 60079 -15 Non sparking, hermetic sealing and restricted breathing 60079-18 Encapsulation Who Governs the Hazardous Area Standards? In Europe the ATEX directives ensure that every ATEX certificate must be recognised by a notified body. IEC standards are also already fully accepted in national […]