ISA12.29 - Equipment Protection Levels (EPL) Working Group
Scope
- Survey, monitor, and participate in the development of national and international standards, practices, and codes addressing EPLs in hazardous (classified) locations.
- Provide support to ISA in the area of EPLs regarding equipment, area classification, and installation standards for hazardous (classified) locations.
Purpose
- To develop, publish, and maintain standards and practices related to EPLs in hazardous (classified) locations.
- To enhance the concept of risk assessment encompassing EPLs as an alternative approach to the selection of Ex equipment, and ISA's continued leadership in this area.
- To promote current technology for the proper risk assessment and application of EPLs in the selection, installation, use, and maintenance of Ex equipment to enhance safety.
- To provide technical support to industry in the area of EPLs in hazardous (classified) locations.
Activity
The most recent ISA12.29 EPL working group meeting took place on 22 May 2012 by means of teleconference and web-based document sharing.
- Reviewed the use of EPLs in IEC equipment and installation standards. While the term “EPL” may be new to the US, the concept of assessing the risks associated with a classified area, and utilizing mitigation methodologies to allow selection of equipment to be installed in a given classified area that normally would not be allowed in the area based on the area’s classification, is not new. The use of combustible gas detection systems and pressurized enclosures are common mitigation methodologies in the US.
- While the concept of using EPLs for the selection of equipment is applicable to both the US Division and US Zone systems, it was decided to focus only on the US Zone system (for now).
- To effectively adopt and implement EPLs in the US Zone system, the concept and application of EPLs needs to be addressed in our type of protection standards, area classification standards, and installation standards.
- Regarding our type of protection standards, EPLs are already included in the same way they are included in the related IEC Ex standards, i.e. a “hard-coded” relationship.
- Regarding our installation standards, there needs to be more detailed installation information in the NEC that addresses similar “hard-coding” of equipment selection content.
- Regarding our area classification standards, this is the most critical stage, and the only stage where flexibility exists in the use and application of EPLs. Once an area is classified, then the specification of equipment by EPLs can be applied based on a risk assessment. This EPL risk assessment considers the consequences of any possible ignitions, and whether these consequences may require the use of equipment of a higher EPL, or may justify the use of equipment with a lower EPL than normally would be required.
- Development is needed of draft guidelines for the proposed inclusion of the EPL concept in US codes and standards. No intent to address how to perform an EPL risk assessment as part of any of these proposals, only to mention the need for such.
ISA Meetings
For information about all upcoming ISA12 meetings, please visit www.ISA12.org.
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