NFPA® 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment 2013 Edition

Chapter 1 Administration
1.1 Scope
1.2 Purpose
1.3 Application
1.4 Equivalency
1.5 Units of Measurement
1.6 Mandatory Rules, Permissive Rules, and Explanatory Material
Chapter 2 Referenced Publications
2.1 General
2.2 NFPA Publications
2.3 Other Publications
2.4 References for Extracts in Mandatory Sections
Chapter 3 Definitions
3.1 General
3.2 NFPA Official Definitions
3.3 General Definitions
3.4 NEC Extracted Definitions
Chapter 4 General Requirements for Pressurized Enclosures
4.1 Applicability
4.2 Suitability of Identified Equipment
4.3 Enclosure
4.4 Pressurizing System
4.5 Protective Gas System
4.6 Determination of Temperature Marking
4.7 Ventilated Equipment
4.8 Power Equipment
4.9 Type Z Pressurizing
4.10 Type Y Pressurizing
4.11 Type X Pressurizing
4.12 Markings
Chapter 5 Pressurized Enclosures for Class I
5.1 Applicability
5.2 General Requirements
5.3 Markings
5.4 Additional Requirements for Type Y or Type Z Pressurizing
5.5 Additional Requirements for Type X Pressurizing
Chapter 6 Pressurized Enclosures for Class II
6.1 Applicability
6.2 General Requirements
6.3 Markings
6.4 Marking Information
6.5 Additional Requirements for Type X Pressurizing
6.6 Additional Requirements for Ventilated Equipment
Chapter 7 Pressurized Control Rooms
7.1 Applicability
7.2 Protective Gas
7.3 Considerations Relating to Positive Pressure Ventilation
7.4 Requirements for Positive Pressure Air Systems
Chapter 8 Pressurized Enclosures Having an Internal Source of Flammable Gas or Vapor
8.1 Applicability
8.2 General Requirements
8.3 Specific Requirements
Chapter 9 Pressurized Analyzer Rooms Containing a Source of Flammable Gas, Vapor, or Liquid
9.1 Applicability
9.2 General
9.3 Specific Requirements
Annex A Explanatory Material
Annex B Informational References
Index