Protect electrical equipment in flammable atmospheres by following the latest protection techniques outlined in the 2013 NFPA 496.
NFPA 496: Standard for Purged and Pressurized Enclosures for Electrical Equipment contains requirements for the design and operation of purged and pressurized electrical equipment enclosures. This protection technique is used in Class I and Class II hazardous (classified) locations to reduce or prevent the presence of flammable materials within electrical equipment enclosures as specified by NFPA 70®: National Electrical Code®. NFPA 496 also includes chapters covering protection of analyzers and rooms housing analyzers as well as a chapter on pressurized control rooms.
Consistent with the 2011 NEC®, the 2013 NFPA 496 includes the following updates to help control fire hazards:
Revisions to the definitions for Type X Pressurizing, Type Y Pressurizing, and Type Z Pressurizing clarify that pressurizing keeps a flammable atmosphere around a protected enclosure from entering an enclosure, which enables the use of either ignition-capable equipment (in Type X Pressurizing or Type Z Pressurizing) or Division 2 or Zone 2 equipment (Type Y Pressurizing) inside an enclosure.
Added a new requirement affecting electrical alarm actuators in Type Y Pressurizing to require them to be identified for a Division 1 or Zone 1 location
Clarified requirements affecting cutoff switch actuators in Type X Pressurizing
Order today to make sure you have the specialized knowledge needed to head off electrical equipment fires and explosions. (Softbound, 21 pp., 2013)