Ensure design is in accordance with the requirements
designated in NFPA 70 for the specific division and class.
Class I, Division 1.
Class I, Division 1 locations
a) Outdoor locations and those indoor locations
having positive mechanical ventilation that are within 3 feet
(0.9 m) of the fill openings or vents on individual containers
to which flammable liquids are being transferred. Provide
alarm devices on all ventilation systems.
b) Outdoor locations within 5 feet (1.5 m) of open
end of vents and openings on flammable liquid storage tanks.
c) Entire pit, sump, open trench, or other
depression, any part of which is within a Division 1 or 2
location and is without mechanical ventilation.
d) Locations within and on exterior walls of API
e) Locations at fuel dispensers.
f) Locations within 3 feet (0.9 m) of vent,
extending in all directions, when loading a truck through the
g) All pump houses handling aviation turbine fuels.
h) Any area containing electrical equipment that is
or may be exposed to atomized fuel and where the ambient
temperature can at any time be above the flash point of the
Class I, Division 2.
Class I, Division 2 locations
a) Adequately ventilated indoor locations within 5
withdrawal fittings, meters, valves, screwed fittings,
flanges, and similar devices that are located in pipelines
except as modified by the above paragraph on pump houses