Documenting Risk Assessment : Using Equipment Protection Levels to Classify Zone Areas

The international electrotechnical commission (IEC)-based term equipment protection levels (EPLs) refers to a process for identifying and selecting equipment for installation in hazardous (classified) locations. The process involves special equipment markings, an optional comprehensive risk assessment after area classification, and selection criteria to identify the equipment that can be installed in hazardous locations.The optional comprehensive risk assessment involved with this process is subsequent to the classification of the area and may allow for the selection of equipment that would not normally be associated with the involved area classification designation. While the term EPLs may be relatively new and all aspects of the concept not fully implemented in the United States, the concept of assessing risks and consequences associated with a classified area andthe utilization of mitigation methodologies to address equipment selection for a given classified area are not new. For example, the use of combustible gas detection systems and pressurized enclosures are common mitigation methodologies in U.S. classified areas. In this article, a broad-based perspective on the adoption and implementation of all aspects of these EPL concepts in the United States will be provided by representatives from the U.S. codes and standards, product certification, area classification, and installation communities.