NFPA 499: Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
Current Edition: 2013 Next Edition: 2017

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NFPA 499:
2013 Edition
Item #: 49913
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What is NFPA 499?
NFPA 499: Document Scope
1.1 Scope. 1.1.1 This recommended practice applies to those locations where combustible dusts are produced, processed, or handled, and where dust released into the atmosphere or accumulated on surfaces could be ignited by electrical systems or equipment. 1.1.2 This recommended practice provides information on specific combustible dusts 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 also applies to chemical process areas. As used in this document, a chemical process area could be a chemical process plant, or it could be a part of such a plant. A chemical process area could be a part of a manufacturing facility where combustible dusts are produced or used in chemical reactions, or are handled or used in operations such as mixing, coating, extrusion, conveying, drying, and/or grinding. 1.1.4 This recommended practice does not apply to agricultural grain-handling facilities except where powdered grain is used in a chemical reaction or mixture. 1.1.5 This recommended practice does not apply to situations that could involve catastrophic failure of, or catastrophic discharge from, silos, process vessels, pipelines, tanks, hoppers, or conveying or elevating systems. 1.1.6 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.
Official document scope
What does NFPA 499 address?
Table Of Contents.
NFPA 499, 2013 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.
The ROP Draft is appended to the ROP listed above.
ROP Meeting Notice
ROP 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.
August 24-26, 2010, Norwood, MA, FM Global
ROP Meeting Agenda
ROP Meeting Minutes
ROP Ballot
ROP Ballot
The ballots posted on this page are for public information only. Voting on ballots is permitted by committee members only. See NFPA Regulations Governing Committee Projects, Section 3.3.4.
Ballot (PDF, 4 MB)
Ballot Circulation (PDF, 46 KB)
Ballot Final (PDF, 57 KB)
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.
Report on Comments (ROC) (PDF, 761 KB)
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
ROC Ballot
ROC Ballot
The ballots posted on this page are for public information only. Voting on ballots is permitted by committee members only. See NFPA Regulations Governing Committee Projects, Section 3.3.4.
Ballot (PDF, 269 KB)
Ballot Form (PDF, 83 KB)
Ballot Circulation (PDF, 47 KB)
Ballot Final (PDF, 47 KB)
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. More about the codes and standards making process including NITMAM.
Motions Committee Report (PDF, 599 KB)
Amendment Ballot
Association Technical Meeting
Final Results (PDF, 99 KB)
Transcript (PDF, 15 KB)
Standards Council Decisions
Archived revision information
NFPA 499, 2013 Edition: Archived Revision Information
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