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.”
When operating equipment in these hazardous locations, it is important and required that the equipment has been held to a certain level of safety standards. OSHA, the NEC, CEC, and the National Fire Protection Association (NFPA) regulate hazardous locations into a Class/Division system. The classes define the type of explosive or ignitable substances that are present in the atmosphere. Each class is then subdivided into divisions, which define the likelihood of the hazardous material being present in a flammable concentration. In order to appoint a product to a certain class and division and approve it for production, a thorough study and completion of tests must be done. One of the most common hazardous location certifications is the Class I, Division 2 certification. So what exactly does that certification entail?
The NFPA Publication 70, NEC, and CEC define Class I locations as those in which flammable vapors and gases may be present. Class I, Division 2 locations are those in which flammable liquids or gases are handled or used, but are normally confined within closed containers or systems. This means that these vapors and gases can only escape if there was an accidental rupture, breakdown, or abnormal operation of the equipment. For example, the area outside of or beside a gas pump would be a Class I, Division 2 hazardous location because there are no ignitable concentrations of the gasoline in that area. The gas tank is below ground and has a very unlikely chance of escaping and causing an explosion. The actual tank underground or on the truck, however, would not be a division 2 location because the tank directly holds ignitable concentrations of flammable contents and an explosive atmosphere could happen in normal operating conditions. (see Figure 1)
It’s nearly impossible to eliminate electrical equipment from a hazardous location. When proper precautions aren’t taken, dangerous scenarios are more likely to happen. To prevent explosive and flammable situations, make sure all equipment is specifically tested and approved to work in environments where hazardous conditions exist.