NEMA’s electroindustry May 2010 - 20

Code Actions/Standardization Trends
› NEMA, USNC Urge OSHA Acceptance of IECEx Scheme
It was August of 2003 when the U.S. National Committee of the IECEx Scheme (USNC/IECEx) declared a 15-year transition period for the U.S. to become fully compliant with the IECEx Scheme standards. We are approaching the halfway mark and there is much progress to show. USNC/IECEx, under Chairman Jeff Olson of Flowserve Corporation, has adopted 18 IECEx standards as American National Standards (ANS), with 24 remaining. There is progress at the National Electrical Code® (NEC) level as well. NEC has historically classified hazardous locations according to the “division method,” which looks at the properties of the flammable vapors, liquids, gases, or combustible dusts or fibers that may be present and the likelihood that a flammable or combustible concentration or quantity is present. A recent addition to the NEC is the IEC method for classifying hazardous locations, know as the “zone classification method.” Having alternative methods in the NEC allows the user to decide whether to use either NEMA- or IEC-type of explosive equipment. In the U.S., OSHA is the regulatory agency responsible for overseeing workplace safety, and it has referenced NEC in its regulations. USNC/IECEx has been working to get OSHA to recognize the IECEx Scheme under its nationally recognized testing laboratory program (NRTL), as it has for the IECEE CB Scheme. This would allow NRTLs to use test results from IECEx Scheme members to obtain national certification. OSHA currently prohibits NRTLs from using IECEx test reports in their decision process, regarding the issuance of national certification for explosive equipment intended for use in “division” applications. The policy was stated in a March 2004 NRTL Update and was recently reiterated by OSHA. NRTLs approved to use OSHA’s NRTL Programs 2 or 3 (Acceptance of Evaluation and Test data from independent organizations other than NRTLs) could accept hazardous location testing from independent laboratories, including those that participate in the IECEx scheme, provided that the NRTL drafting a policy document that would implement acceptance of the IECEx Scheme on an interim basis. To do so would require OSHA to overcome two hurdles. The first would require a determination that the U.S. zone-based standards are at least as safe as current NRTL division standards. This conflicts with OSHA’s mandate to adopt standards developed by standards bodies accredited as ANS developers. IECEx standards were developed by an international committee of technical experts. Adoption as ANSI standards requires approval by a committee operating in accordance with ANSI’s Essential Requirements, as well as its membership having a balance of interest and technical expertise. The essential requirements ensure the ANS development process is done in accordance with the principle of due process. U.S.-adopted IECEx standards were reviewed and modified to ensure consistency with NEC and OSHA regulations by two accredited standards developers—ISA and UL. The second hurdle is a need to review the IECEx Scheme rules to determine if they are consistent with the requirements and policies of the NRTL program. One area of focus is the use of manufacturers’ generated test data. OSHA’s review of U.S.-adopted IECEx standards and the IECEx Scheme rules has not yet started and is very likely to take several years to complete. NEMA is scheduled to meet with the incoming director of OSHA in order to move the acceptance of the IECEx Scheme along.

International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres (IECEx System)
NEC also allows some IEC hazardous location equipment to be used in division classified areas. Such flexibility has not been reciprocated by IEC-based countries, even though NEC is consistent with the important safety principles stated in IEC 60364, a collection of documents that provides broad performance requirements but is not usable as an installation document. follows procedures that comply with the corresponding OSHA criteria, and that testing falls within the NRTL’s scope. Such an approach, however, is cost prohibitive. OvercOming Hurdles The March 2004 NRTL Update also states that OSHA is considering a modification to permit NRTLs to make use of the IECEx Scheme. OSHA is in the process of

Joel Solis, NEMA Conformity Assessment Manager and USNC/IECEx Secretary | joel_solis@nema.org

NEMA electroindustry

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May 2010

NEMA’s electroindustry May 2010

Table of Contents for the Digital Edition of NEMA’s electroindustry May 2010