2017 NFPA 497 Recommended Practice - Current Edition
In purchasing digital access through a PDF or subscription service, you are purchasing a single-user license to access content only by the named account holder. Certain restrictions apply.

NFPA Members save an additional 10%.

Item #: NFPA_497
Price: $0.00
Formats Available:

Spanish Formats Available:

  • Description

    Use NFPA 497 hand-in-hand with the new NEC® to determine ignitability hazards and select electrical systems and equipment for safe use in Class I hazardous (classified) locations.

    In places where flammable gases or vapors, flammable liquids, or combustible liquids are processed or handled, their release into the atmosphere could result in their ignition by electrical systems or equipment. Work with today's best practices to address potentially deadly and destructive hazards with the 2017 edition of NFPA 497: Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas.

    This important Recommended Practice also 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® for proper selection of electrical equipment in hazardous locations.

    NFPA 497 keeps pace with new knowledge. Updated references and definitions extracted from other NFPA® codes include:

    • The 2017 edition of the National Electrical Code
    • The 2016 edition of NFPA 59A: Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG)
    • The 2015 edition of NFPA 30: Flammable and Combustible Liquids Code

    Other changes and edits improve usability and provide consistency with related codes and standards.

    NFPA 497 is an essential on-the-job tool for installers and maintainers of industrial equipment using electrical power that is to be located in or near areas where flammable or combustible liquids, or flammable gases or vapors are stored, handled, or used; equipment manufacturers providing equipment suitable for use in such electrically classified areas; design engineers/consultants; loss prevention or safety engineers; insurance professionals; enforcing officials; and owners/operators of industrial facilities. (Print, 76 pp., 2017)


    Interested in other editions of NFPA 497? Use the drop down menu above to select the edition year you need.

  • Table of Contents (2017 Current Edition)

    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, 2017 Edition

    Chapter 1 Administration
    1.1 Scope.
    1.2 Purpose.
    1.3 Relationship to NFPA Codes and Standards.
    Chapter 2 Referenced Publications
    2.1 General.
    2.2 NFPA Publications.
    2.3 Other Publications.
    2.4 References for Extracts in Recommendations Sections.
    Chapter 3 Definitions
    3.1 General.
    3.2 NFPA Official Definitions.
    3.3 General Definitions.
    Chapter 4 Classification of Combustible Materials
    4.1 National Electrical Code Criteria.
    4.2 Behavior of Class I (Combustible Material) Gases, Vapors, and Liquids.
    4.3 Conditions Necessary for Ignition.
    4.4 Classification of Class I Combustible Materials.
    Chapter 5 Classification of Class I (Combustible Material) Areas
    5.1 National Electrical Code (NEC).
    5.2 General.
    5.3 Class, Division, Classified Locations.
    5.4 Class I, Zone Classified Locations.
    5.5 Unclassified Locations.
    5.6 Extent of Classified Locations.
    5.7 Discussion of Diagrams and Recommendations.
    5.8 Basis for Recommendations.
    5.9 Procedure for Classifying Locations.
    5.10 Classification Diagrams for Class I, Divisions.
    5.11 Classification Diagrams for Class I, Zones.
    Annex A Explanatory Material
    Annex B Example of a Method for Determining NEC Group Classification for Mixtures
    Annex C Informational References

    Annex C Informational References

  • NFPA PDF Products

    Licensed PDFs can be accessed immediately. Instructions can be found in your order confirmation.