ISA 12.04.01 : 2003

1 Scope
2 References
3 Terms and definitions
4 Protection types
5 Constructional requirements for pressurized enclosures
6 Temperature limits
7 Safety provisions and safety devices (except for static
   pressurization)
8 Safety provisions and safety devices for static
   pressurization
9 Supply of protective gas
10 Pressurized apparatus with an internal source of release
11 Release conditions
12 Design requirements for the containment system
13 Protective gas and pressurizing techniques
14 Ignition-capable apparatus
15 Internal hot surfaces
16 Type verification and tests
17 Routine tests
18 Marking
19 Instructions
Annex A (normative) - Purging and dilution tests
Annex B (informative) - Examples of functional sequence
        diagram
Annex C (informative) - Examples of the changes in pressure
        in ducts and enclosures
Annex D (informative) - Information to be provided to the
        user
Annex E (normative) - Classification of the type of release
        within enclosures
Annex F (informative) - Examples for the use of the dilution
        area concept
Annex G (normative) - Infallibility test for containment
        system
Annex H (Informative) - Introduction of an alternative risk
        assessment method encompassing "equipment protection
        levels" for Ex equipment
Annex I (Informative) - US conversion factors
Annex J (Informative) - United States major deviations

Specifies the specific requirements for the construction and testing of electrical apparatus with pressurized enclosures, of type of protection "p", intended for use in hazardous (classified) locations defined as Class I, Zone 1 or Zone 2 by the National Electrical Code (NEC[R]), ANSI/NFPA 70. Also describes requirements for pressurized enclosures containing a limited release of a flammable substance.