NFPA has updated its NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, with a few minor revisions. Probably the most significant revision is NFPA’s position on “intentional releases and maintenance venting.” The most beneficial revision was NFPA officially defining “Unpierced.” Let’s discuss the 2027 revisions…
The first revision is that now NFPA recognizes UL 121203, Recommended Practice for Portable/Personal Electronic Products Suitable for Use in Class I, Division 2, Class I, Zone 2, Class II, Division 2, Class III, Division 1, Class III, Division 2, Zone 21 and Zone 22 Hazardous (Classified) Locations.
SAFTENG Note: I have discussed this standard a few times. It is for use when a device is needed inside a HAZLOC, but it is NOT available in a rating suited for the HAZLOC. I have always ONLY applied this to personal medical devices in an attempt to meet ADA requirements. But I have seen clients use it for process-related equipment. Just PLEASE understand, there are LIMITATIONS on the use of this standard!
5.1.4.3 Portable electronic products (PEPs) meeting the requirements for PEP-1 or PEP-2 of UL 121203, Recommended Practice for Portable/Personal Electronic Products Suitable for Use in Class I, Division 2, Class I, Zone 2, Class II, Division 2, Class III, Division 1, Class III, Division 2, Zone 21 and Zone 22 Hazardous (Classified) Locations, are considered suitable for use in Division 2 and Zone 2 locations.
The standard also clarified the definition of “unpierced”:
3.3.13 Unpierced.
Having no penetrations or having penetrations that have all been sealed consistent with the design of the original barrier.