Hazardous locations are areas where flammable liquids, gases or vapors or combustible dusts exist in sufficient quantities to produce an explosion or fire.
The National Electrical Code (NEC) defines hazardous locations as those areas “where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings.” Hazardous Location Types.
In hazardous locations, specially designed equipment and special installation techniques must be used to protect against the explosive and flammable potential of these substances.
An area where a potential hazard (e.g., a fire, an explosion, etc.) may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dust or ignitable fibers or flyings.
Hazardous locations can also be described as those locations where electrical equipment might be installed and which, by their nature, might present a condition which could
become explosive if the elements for ignition are present. Unfortunately, flammable substances are not always avoidable, e.g., methane and coal dust in mines. Therefore, it is of great importance that a user of electrical equipment, such as push buttons and explosion proof lighting , be aware of the environment in which these products will be installed. The user’s understanding of the hazard will help ensure that the electrical equipment is properly selected, installed and operated to provide a safe operating system.
There are a great variety of applications, especially in the chemical and petrochemical industries, that require explosion protected equipment. As a result, there have been principles and technologies developed to allow electrical instrumentation and control devices to be used even in environments where there is a danger of explosion.
However,focus on explosion protected electrical equipment is not limited to utilization and processing of oil and natural gas. It has expanded into new fields such as waste disposal,landfills and the utilization of bio-gas.