ARTICLE 513. AIRCRAFT HANGARSARTICLE 513. AIRCRAFT HANGARS513.3. Classification of Locations. Figure 513-1 shows the details of hangar classifications. The entire floor area up to 18 in. (450 mm) above the floor, and adjacent areas not suitably cut off from the hazardous area or not elevated at least 18 in. (450 mm) above it, are classified as Class I, Division 2 locations. Pits below the hangar floor are classified as Class I, Division 1. Within 5 ft (1.5 m) horizontally from aircraft power plants, fuel tanks, or structures containing fuel, the Class I, Division 2 location extends to a level that is 5 ft (1.5 m) above the upper surface of wings and engine enclosures.
Frederic P. Hartwell; Joseph F. McPartland; Brian J. McPartland: McGraw-Hill's National Electrical Code 2017 Handbook, 29th Edition. ARTICLE 513. AIRCRAFT HANGARS, Chapter (McGraw-Hill Professional, 2017), AccessEngineering