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
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What is NFPA 497?
Official document scope
NFPA 497: Document Scope
1.1 Scope. 1.1.1 This recommended practice applies to those locations where flammable gases or vapors, flammable liquids, or combustible liquids are processed or handled; and where their release into the atmosphere could result in their ignition by electrical systems or equipment. 1.1.2 This recommended practice provides information on specific flammable gases and vapors, flammable liquids, and combustible liquids whose relevant combustion properties have been sufficiently identified to allow their classification into the groups established by NFPA 70, National Electrical Code (NEC), for proper selection of electrical equipment in hazardous (classified) locations. The tables of selected combustible materials contained in this document are not intended to be all-inclusive. 1.1.3 This recommended practice applies to chemical process areas. As used in this document, a chemical process area could be a large, integrated chemical process plant or it could be a part of such a plant. It could be a part of a manufacturing facility where flammable gases or vapors, flammable liquids, or combustible liquids are produced or used in chemical reactions, or are handled or used in certain unit operations such as mixing, filtration, coating, spraying, and distillation. 1.1.4 This recommended practice does not apply to situations that could involve catastrophic failure of or catastrophic discharge from process vessels, pipelines, tanks, or systems. 1.1.5 This recommended practice does not address the unique hazards associated with explosives, pyrotechnics, blasting agents, pyrophoric materials, or oxygen-enriched atmospheres that might be present.
What does NFPA 497 address?
Table Of Contents.
Archived revision information
NFPA 497, 2012 Edition: Archived Revision Information
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NFPA 497, 2012 Edition: Archived Revision Information
Report on Proposals (ROP)
Report on Proposals (ROP)
Proposals can be submitted for text to be amended or included in NFPA Codes and Standards. Following the Call for Proposals period, the responsible Technical Committee or Panel holds a meeting to consider and act on all submitted proposals. The committee or panel may also develop its own proposals. A document known as the Report on Proposals (ROP) is prepared containing all the Public Proposals, Technical Committees' action on each Proposal, as well as all Committee-generated proposals. The ROP for the document in question is submitted for the approval of the responsible TC or Panel by a formal written ballot. If the ROP does not receive approval via written ballot in accordance with NFPA rules, the Report is returned to the committee for further consideration and is not published. If the necessary approval is received, the ROP is published in a compilation of Reports on Proposals issued by NFPA twice yearly for public review and comment, and the process continues to the next step. The ROP is published and widely distributed and anyone may download or request a copy.
ROP Meeting Notice
ROP Meeting Notice
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Regulations Governing Committee Projects (Section 3.3.3.3) for further information.
August 24-26, 2010, Norwood, MA, FM Global
ROP Meeting Agenda
ROP Meeting Minutes
ROP Ballot
Report on Comments (ROC)
Report on Comments (ROC)
Once the ROP becomes available, there is a 60-day comment period during which time anyone may submit a public comment on the proposed changes documented in the ROP. The committee or panel reconvenes at the end of the comment period and acts on all public comments. This committee or panel may also develop its own comments. As before, approval obtained via written ballot in accordance with NFPA's Regulations is required on all committee and panel actions. All of this information is compiled into a second Report, called the Report on Comments (ROC), which like the ROP, is published and made available for public review for a seven-week period.
ROC Meeting Notice
ROC Meeting Notice
Note: Please contact the appropriate staff liaison (listed on the Technical Committee tab) for information on attending an NFPA Technical Committee meeting as a guest. Read NFPA"s
Regulations Governing Committee Projects (Section 3.3.3.3) for further information.
ROC Meeting Agenda
ROC Meeting Minutes
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Motions Committee Report (NITMAM)
Motions Committee Report (NITMAM)
Proposed NFPA documents will be presented for action at the applicable Annual (June) Association Technical Meeting only when proper Amending Motions (Notice of Intent to Make a Motion - NITMAM) have been certified by the Motions Committee of the Standards Council as a proper amending motion. Documents that receive no motions will not be presented at the meeting and instead will be forwarded directly to the NFPA Standards Council for action on issuance.
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No NITMAMs
Association Technical Meeting
Consent document not presented at Association Technical Meeting. Document issuance by Standards Council: 12/13/2011
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