and Tanks; NFPA 58-2008, Liquefied Petroleum Gas Code; NFPA 59-2004, Utility LP- Gas Plant Code; NFPA 497-2004, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas; NFPA

499-2004, Recommended Practice for the Classification of

Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas; NFPA 820-2008, Standard for Fire Protection in Wastewater Treatment and Collection Facilities;

ANSI/API RP500-1997, Recommended Practice for Clas- sification of Locations of Electrical Installations at Petro- leum Facilities Classified as Class I, Division I and Division

2; ISA-12.10-1988, Area Classification in Hazardous

(Classified) Dust Locations.

FPN No. 3: For further information on protection against static electricity and lightning hazards in hazardous (classified) locations, see NFPA 77-2007, Recommended Practice on Static Electricity; NFPA 780-
2008, Standard for the Installation of Lightning Protection Systems; and API RP 2003-1998, Protection Against Ignitions Arising Out of Static Lightning and Stray Currents.
FPN No. 4: For further information on ventilation, see NFPA 30-2008, Flammable and Combustible Liquids Code; and API RP 500-1997, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division I and Division 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 14F-
1999, Recommended Practice for Design and

Installation of Electrical Systems for Fixed and Floating

Offshore Petroleum Facilities for Unclassified and Class I,

Division I and Division 2 Locations.

500.5 Classifications of Locations.

(A) Classifications of Locations. Locations shall be clas- sified depending on the properties of the flammable

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 Refrigeration, and
ANSI/CGA G2.1-1989, Safety Requirements for the

Storage and Handling of Anhydrous Ammonia.

(B) Class I Locations. Class I locations are those in which flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors are or may be present in the air in quantities sufficient to produce explosive or ignitible mixtures. Class I locations shall include those specified in 500.5(B)(1) and (B)(2).

(1) Class I, Division 1. A Class I, Division 1 location is a location

(1) In which ignitible concentrations of flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors can exist under normal operating conditions, or
(2) In which ignitible concentrations of such flammable gases, flammable liquid-produced vapors, or combus- tible liquids above their flash points may exist fre- quently because of repair or maintenance operations or because of leakage, or
(3) In which breakdown or faulty operation of equipment or processes might release ignitible concentrations of flammable gases, flammable liquid-produced vapors, or combustible liquid- produced vapors and might also cause simultaneous failure of electrical equipment in such a way as to directly cause the electrical equipment to become a source of ignition.
FPN No. 1: This classification