Materials used to manufacture explosion proof devices are non-sparking, such as copper-free aluminum, polyamide, polycarbonate and thermoplastics. Extended flame paths within the explosion proof enclosure ensure gases or ignitions are actively cooled down.
What is Explosion Proof Electrical Equipment?
Explosion proof electrical equipment are Class-rated devices and electronics used in combustible work areas. Explosion proof protection for this type of equipment is essential, as electricity can interact with flammable materials lurking around the facility and generate sparks, resulting in ignitions, fires or explosions. Furthermore, electrical devices are known to get hot under heavy loads or abnormal operating conditions. High temperatures can also ignite volatile substances, which must be controlled in hazardous locations.
Equipment with explosion proof features are designed to contain ignitions within the unit, where it cannot interact with external, combustible substances. Hence, this type of protection has a lot to do with the internal mechanisms of the unit. Materials used to manufacture explosion proof devices are non-sparking, such as copper-free aluminum, polyamide, polycarbonate and thermoplastics. Extended flame paths within the explosion proof enclosure ensure gases or ignitions are actively cooled down.
Explosion proof electrical equipment can be found in the following types of establishments: oil and gas sites, oil refineries, gasoline stations, battery storage facilities, food processing, chemical processing, grain storage, agricultural sites, construction, labs, extraction rooms, shipyards, confined spaces, hazardous locations and industrial sites.
Examples of explosion proof electrical equipment include the following: industrial lighting systems, portable lights, power distribution stations, switches, sensors, speakers, horns, dust collectors, fans and more.
Explosion Proof Classifications and Ratings
Explosion proof equipment is classified in the US, based on guidelines published by the National Electric Code (NEC). The Occupational Safety and Health Administration (OSHA) administers safety regulations concerning the use of explosion proof electrical equipment in combustible work locations. Classifications for explosion proof electrical equipment are Class I, II and III.
• Class I: Environments where flammable gas/vapors are present.
• Class II: Locations where combustible dust is present.
• Class III: Areas where flammable fibers/flyings are present.
In addition to classifications, explosion proof units are further categorized by Divisions and Groups. Division 1 refers to environments wherein flammable substances are always present, during everyday operations. Division 2 areas are sites wherein combustible compounds are only present during abnormal working conditions or emergencies. With this in mind, explosion proof equipment with a Division 1 rating take on more protective features than explosion proof equipment with a Division 2 rating.
When it comes to Groups, explosion proof units can be rated for protection against specific combustible substances. Ranging from Group A to Group G, the ratings are suitable for hazardous work locations that frequently deal with a particular flammable substance. For example, hydrogen plants may utilize Class I, Division 1 Group B electrical equipment, which directly addresses hydrogen particles. It is important to point out that explosion proof electrical equipment can be rated to address multiple Groups.
Outside of the US, the term “explosion proof” is referred to as “flameproof” which take on the same definition. However, the standards that govern flameproof electrical equipment are global safety organizations, such as ATEX/IECEx.