or Zone 2.
FPN No. 5: For further information on electrical systems for hazardous (classified) locations on offshore oil and gas producing platforms, see ANSI/API RP 14FZ-
2000, Recommended Practice for Design and
Installation of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations.
FPN No. 6: For further information on the installation of electrical equipment in hazardous (classified) locations in general, see IEC 60079-14-1996, Electrical apparatus for explosive gas atmospheres — Part 14: Electrical installations in explosive gas atmospheres (other than mines), and IEC 60079-16-1990, Electrical apparatus for explosive gas atmospheres — Part 16: Artificial ventilation for the protection of analyzer(s) houses.
FPN No. 7: For further information on application of electrical equipment in hazardous (classified) locations in general, see ANSI/ISA-60079-0 (12.00.01)-2005, Electrical Apparatus for Use in Class I, Zones 0 and 1, Hazardous (Classified) Locations: General Requirements; ANS1/ISA-12.01.01-1999, Definitions and Information Pertaining to Electrical Apparatus in Hazardous (Classified) Locations; and ANSI/UL 60079-0, Electrical Apparatus for Explosive Gas Atmospheres — Part 0: General Requirements.
505.5 Classifications of Locations.
(A) Classification of Locations. Locations shall be classi fied depending on the properties of the flammable vapors, liquids, or gases that may be present and the likelihood that a flammable or combustible concentration or quantity is present. Where pyrophoric materials are the only materials used or handled, these locations shall not be classified. Each room, section, or area shall be considered individually in determining its classification.
FPN No. 1: See 505.7 for restrictions on area classification.
FPN No. 2: Through the exercise of ingenuity in the layout of electrical installations for hazardous (classified) locations, it is frequently possible to locate much of the equipment in reduced level of classification or in an unclassified location and, thus, to reduce the amount of special equipment required.
Rooms and areas containing ammonia refrigeration systems that are equipped with adequate mechanical ventilation may be classified as "unclassified" locations.
FPN: For further information regarding classification and ventilation of areas involving ammonia, see ANSI/ ASHRAE 15-1994, Safety Code for Mechanical Refrigera- tion; and ANSI/CGA G2.1-1989 (14-39), Safety Require-
ments for the Storage and Handling of Anhydrous
Ammonia.
(B) Class I, Zone 0,1, and 2 Locations. Class I, Zone 0,
1, and 2 locations are those in which flammable gases
orvapors are or may be present in the air in quantities
sufficient to produce explosive or ignitible mixtures.
Class I, Zone 0, 1, and 2 locations shall include those
specified in 505(B)(1), (B)(2), and (B)(3).
(1) Class I, Zone 0. A Class I, Zone 0 location is a location in which
(1) Ignitible concentrations of flammable gases or vapors are present continuously, or
(2) Ignitible concentrations of flammable gases or vapors are present for long periods of time.
FPN No. 1: As a guide in determining when flammable gases or vapors are present continuously or for long periods of time, refer to ANSI/API RP 505-1997, Recommended Practice for Classification of Locations for Electrical Installations of Petroleum Facilities Classified as Class I, Zone 0, Zone I or