AIRCRAFT HANGARS

513-1. Definition. An aircraft hangar is a location used for storage or servicing of aircraft in which gasoline, jet fuels, or other volatile flammable liquids or flammable gases are used. It shall not include locations used exclusively for aircraft that have never contained such liquids or gases, or that have been drained and properly purged. 513-2. Classification of Locations. (a) Below Floor Level. Any pit or depression below the level of the hangar floor shall be classified as a Class I, Division 1 location that shall extend up to said floor level. (b) Areas Not Cut Off or Ventilated. The entire area of the hangar, including any adjacent and communicating areas not suitably cut off from the hangar, shall be classified as a Class I, Division 2 location up to a level 18 inches (457 mm) above the floor. (c) Vicinity of Aircraft. The area within 5 feet (1.52 m) horizontally from aircraft power plants or aircraft fuel tanks shall be classified as a Class I, Division 2 location that shall extend upward from the floor to a level 5 feet (1.52 m) above the upper surface of wings and of engine enclosures. (d) Areas Suitably Cut Off and Ventilated. Adjacent areas in which flammable liquids or vapors are not likely to be released, such as stock rooms, electrical control rooms, and other similar locations, shall not be classified where adequately ventilated and where effectively cut off from the hangar itself by walls or partitions. 513-3. Wiring and Equipment in Class I Locations. All wiring and equipment that is or may be installed or operated within any of the Class I locations defined in Section 513-2 shall comply with the applicable provisions of Article 501. All wiring installed in or under the hangar floor shall comply with the requirements for Class I, Division 1 locations. Where such wiring is located in vaults, pits, or ducts, adequate drainage shall be provided; and the wiring shall not be placed within the same compartment with any service other than piped compressed air. Attachment plugs and receptacles in Class I locations shall be approved for Class I locations or shall be so designed that they cannot be energized while the connections are being made or broken. 513-4. Wiring Not Within Class I Locations. (a) Fixed Wiring. All fixed wiring in a hangar, but not within a Class I location as defined in Section 513-2, shall be installed in metal raceways or shall be Type MI, TC, SNM, or Type MC cable. Exception: Wiring in unclassified locations as defined in Section 513-2(d) shall be of a type recognized in Chapter 3. (b) Pendants. For pendants, flexible cord suitable for the type of service and approved for hard usage shall be used. Each such cord shall include a separate equipment grounding conductor.