The safety categories, outlined by the National Electric Code (NEC), specify protective features of various equipment in regard to particular combustible chemicals or conditions.
What is classification that is explosion proof?
Equipment used at flammable work sites is categorised or grouped according to its explosion proofness. The safety categories, outlined by the National Electric Code (NEC), specify protective features of various equipment in regard to particular combustible chemicals or conditions.
Classifications for explosive resistance
• Class I: Combustible situations when there are enough flammable gases and/or vapours present to cause ignitions.
• Class II: Combustible areas with significant concentrations of conductive and/or flammable dust that can cause ignitions.
• Class III: Flammable conditions with enough flammable fibres or flyings to cause ignitions.
Divisions one and two
Division 1 and Division 2 are possible divisions for these classes. A Division 1 rated facility is one where combustible compounds may be constantly present in the air during routine activities (the term "explosion proof" is used).
Facilities that handle, process, or consume flammable liquids or gases where they may be present during operations are classified as Division 2 rated facilities (sometimes referred to as hazardous locations).
Groups
Explosion proof categories may include Groups in addition to Class I, II, and III ratings and Division 1 and Division 2 ratings.
- Acetylene is in Group A.
- Hydrogen is in Group B.
• Group C: Vapours of ethylene and ethyl ether
• Group D: Alcohol, Butane, Benzol, and Gasoline
• Group E: Magnesium and Metallic Dust
• Group F: Carbon Black and Coal
• Group G: Grains and Flour Starch
If the Class and Group are the same, a Division 1 rated item may be used in a Division 2 rated area, but not the other way around. The NEC and OSHA have authority over the United States, therefore explosion proof categories are valid here as well. Local safety regulations, such as ATEX/IECEx requirements, must be followed at overseas sites.
