Components for Hazardous Environments

Components for Hazardous Environments

A major safety concern in industrial plants is the occurrence of fires and explosions. No other aspect of industrial safety receives more attention in the form of codes, standards, technical papers, and engineering design. Regulatory bodies like the Occupational Safety and Health Administration (OSHA) have established systems that classify locations which exhibit potentially dangerous conditions to the degree of hazard presented.

OSHA Publication 3073 defines a hazardous location as follows:

Hazardous locations are areas where flammable liquids, gases or vapors or combustible dusts exist in sufficient quantities to produce an explosion or fire. In hazardous locations,specially designed equipment and special installation techniques must be used to protect against the explosive and flammable potential of these substances.

About Class/Division Classification
In North America, the classification system that is most widely utilized is defined by the NFPA Publication 70, NEC, and CEC. They define the type of hazardous substances that is, or may be, present in the air in quantities sufficient to produce explosive or ignitable mixtures. The NFPA establishes area classifications based on Classes, Divisions, and Groups which are factors combined to define the hazardous conditions of a specific area.

About Zone Classification
The IEC classification system, used throughout much of the world outside of North America, varies from the traditional NEC Class/Division system in that it recognizes three levels of probability that a flammable concentration of material might be present. These levels of probability are known as Zone 0, Zone 1, and Zone 2. The Zone designations replace the Divisions found in the NEC system. No exact correlation can be made between the Zone and Division designations.

Hazardous Location Products Ratings and Certifications Chart
Rockwell Automation has developed a chart that provides a matrix of the ratings and certifications for their industrial control (IC) products.  Click the chart below for full-size version

Hazardous Location Products Ratings and Certifications Chart

Want to learn more?  Our New Orleans branch’s September User Group topic is scheduled to be on products for hazardous locations – click here to Register.

Other Resources

Addition Information:

Related Videos: