Here’s a safety riddle for you:
What do 1910.307(g)(4)(i), Hazardous Locations, Zones, and Professional Engineers have in common?
Answer: They are ALL required when your facility has Hazardous Locations using “zones” rather than divisions (e.g. Class I, II, and III areas) to classify an area.
In 2007 OSHA did a major revisions of their Electrical Standards and a couple of these revisions were to 1910.307 Hazardous (classified) locations, one of these was the addition of (g)…
All of section (g) is new to 1910.307 (well relatively new since 2007) and in (g)(4) OSHA states a Professional Engineer is REQUIRED:
1910.307(g)(4)(i) Classification of areas and selection of equipment and wiring methods shall be under the supervision of a qualified registered professional engineer.
SAFTENG members can read my “Hazardous Locations” and complying with the “new” 1910.307” where I breakdown the new HAZLOC requirements for most of us; however, for those wishing to make the move from “divisions” to “zones” in your electrical classifications, that move will REQUIRE the direction of a Professional Engineer. Now don’t ask me if you can get cited if everything was done right and no P.E. was involved; I am just pointing out the language and the requirement for a P.E. We have always suggested that electrical classifications be signed-off or approved by a P.E. even when we used the traditional “division” methods; but now this is required when making the shift from using “divisions” to “zones”.
Here is a taste of what I wrote back in 2012…
Paragraph (g)(4) sets special precautions that must be taken with respect to hazardous locations classified under the zone system. First, the CLASSIFICATIONS of AREAS and the SELECTION OF EQUIPMENT AND WIRING MUST BE UNDER THE SUPERVISION of a qualified registered professional engineer (P.E.). This provision is contained in NFPA 70E-2000 and in the 1999 NEC. Because the zone system has been permitted in the U.S. only since 1997, employers and installers in this country have had relatively little experience with installations made using the zone classification system. The technical committees that developed NFPA 70E and the NEC have determined that, for the zone system, it is ESSENTIAL FOR COMPETENT PERSONS to classify the hazardous locations and select equipment for those locations. OSHA agrees with the consensus determination by these committees, which are composed of members (such as NRTLs, electric equipment manufacturers, electrical contractors, and affected employee organizations) with expertise in electrical safety in hazardous locations. Paragraph (g)(4) requires the services of a qualified registered professional engineer to ensure that the person primarily responsible for the design of the installation is particularly suited to the task. A registered professional engineer who does NOT have an understanding of the construction and operation of the equipment and the hazards involved in zone-classified locations would NOT meet the criteria spelled out in 1910.307(g)(4) and in the definition of “qualified person…
Click Here to see 1910.307.