When working in a Hazardous environment, you may have come across an enclosure or two without even noticing it. However, what is Class 1 or Division 2? Or better yet, what is a Class 1 Division 2 enclosure?
Class 1 Division 2
Let’s define Class 1 Division 2.
Class 1 defines locations where flammable gases or vapors may be present in the air. Additionally, sufficient quantities of flammable substances may produce explosive or ignitable mixtures. There are two Divisions and three Zones that subdivide Class I.
Class I, Division 1: Three different situations could exist to classify an area as a Class I, Division 1 location.
- Ignitable concentrations of flammable gases or vapors may exist under normal operating conditions.
- Ignitable concentrations of gases or vapors may frequently circulate the location because of repair, maintenance operations, or leakage.
- Faulty operation of equipment and processes might release ignitable concentrations of hazardous substances. Also, the concentration of gases and vapors may potentially cause simultaneous failure of electric equipment.
Class I, Division 2: Three situations exist for an area to consider a location as Class I, Division 2.
- Facilities handling, processing, or using volatile flammable liquids or flammable gases. However, the hazardous liquids or gases confine within closed containers or closed systems. Only in the event of accidental rupture, breakdown, or abnormal operation of containers or systems will the hazardous substance escape.
- Mechanical ventilation prevents ignitable concentrations of gases or vapors from becoming hazardous.
- Similar to Class I, Division 1 location, ignitable concentrations of gases or vapors might occasionally circulate. Yet, by utilizing positive-pressure ventilation from a source of clean air and safeguards against ventilation failure, the circulation of hazardous substances can be prevented.
To summarize
Class 1 Hazardous Locations refer to facilities that deal with flammable gases, vapors, and liquids.
Division 2 specifies that flammable materials are handled, processed, or used at a location. But, concentrations of hazardous substances are not high enough to be ignitable.
This applies to devices such as Flashlights, Meter readers, Enclosures, etc.
So a Class 1 Division 2 Enclosure is used in facilities that deal with flammable gases, vapors, and liquid materials. Additionally, the facility handling, processing, or using the materials in the defined hazardous location contain concentrations insufficient to be ignitable.