NFPA 497 PDF

Highlights

The 2024 edition features changes that include:
Adding the definition for hazardous (classified) location from NFPA 70®, National Electrical Code®
Adding two new figures to establish classification areas around pressure relief valve vents
Removing the classification areas of the sources in several figures in Section 5.11 to eliminate confusion

Table of Contents

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 2024 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 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 Zones.
Annex A Explanatory Material
Annex B Example of a Method for Determining NEC Group Classification for Mixtures
Annex C Informational References