There are lot of industrial locations that require explosion-proof rated housings and security cameras. Those locations might have hazardous gases, chemicals or vapors that regular standard housings would not be able to withstand. This might cause an explosion due to electrically charged components within the cameras. Cautions must be taken at plants, factories or locations that produce by-products of flammable gases, flammable liquid–produced vapors, combustible liquid–produced vapors, combustible dust, or ignitable fibers present in the air in quantities sufficient to produce explosive or ignitable mixtures. Electrical equipment, low or high voltage, that must be installed at such classified locations should be specially designed and tested to ensure it does not initiate an explosion or fire.
Engineers, along with policy regulators, defined technical specifications to identify features of electrically charged devices that need to be protected from surrounding environments to avoid initiation of an electric charge. For example, a simple house light bulb that emits a small electric arc might seem harmless for a house but would be quite explosively dangerous for irregular atmospheres that have flammable vapors.
Historically, the requirement for explosion-proof rated devices started when at least two explosion related coal mines were attributed to an electric bell signaling system. An electric arc by the bell system sparked the mine which caused a huge explosion killing many miners. High levels of methane gas and coal dust in coal mines make them incredibly dangerous to have any minute electric arcs.
Explosive gas area classifications
Hydrocarbons, hydrogen, and ammonia are common by-product gases produced by industrial factories. These gases are highly flammable and require explosion-proof equipment. Below are different explosion proof classifications which depend on environmental and specific safety hazard requirements.
- Class I, Division 1 area encompasses the combination of Zone 0 and Zone 1 areas.
- Zone 0 locations of high concentrations of combustible gases, vapors, dust or liquids always present for long periods of time during operations.
- Zone 1 locations might have combustible gases, vapors, dust or liquids present at any time during normal operations.
- Class I, Division 2 or Zone 2 are locations which normally do not have combustible by-products during normal operations and concentrations might be present under abnormal conditions, such as sudden leaks. As a general guide, those abnormal conditions should not exceed 10 hours a year.
- Non-hazardous or Unclassified locations are classified as neither Class I, Division 1 or Division 2, Zone 0, Zone 1 or Zone 2, or any combination. For example, the use of aerosol sprays in commercial or residential areas. Aerosol sprays might have flammable gases but they are still considered the very low risk of causing an explosion.
Explosive dust area classifications
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