MIL-HDBK-1022A
8.3.4.3
Aboveground Concrete-Encased Tanks. Provided the
concrete encasement meets or exceeds the definition of fire-
resistant or vaulted tanks as stated in NFPA 30A, use the
spacing criteria for aboveground horizontal tanks and reduce
by 50 percent.
8.3.5
Distance From Buildings and Property Lines. Locate
tanks a sufficient distance from buildings and property lines
to prevent the ignition of vapors from the tank and to protect
buildings and their occupants or contents from damage by a
tank fire. Assume that the maximum internal pressure in a
fire exposure will not exceed 2.5 psig (17 kPa). As a
minimum, comply with requirements of the following paragraphs.
8.3.5.1
Underground Tanks. Locate underground tanks with
respect to buildings or similar structures so that the soil
pressure created by the building foundations will not be
transmitted to the tank. Pumping facilities which are often
located directly above underground tanks are excepted. Locate
horizontal cylindrical tanks not over 12 feet (3.7 m) in
diameter and not less than 10 feet (3 m) from the nearest
point of an adjacent building or property line except pumping
facilities. Locate vertical underground tanks at least 25
feet (7.6 m) from the nearest point of an adjacent building
and 50 feet (15 m) from the nearest property line except
pumping facilities.
8.3.5.2
Aboveground Tanks. Locate aboveground tanks with
consideration of fire safety. The first consideration is to
prevent the ignition of vapors from the tank, and the second
consideration is to protect the building and its occupants or
contents from damage by a tank fire. As a protective measure,
provide all aboveground tanks with some form of emergency
relief venting for fire exposure in accordance with NFPA 30.
In the following, it is assumed that all tanks are constructed
or equipped so that the maximum internal pressure in a fire
exposure will not exceed 2.5 psi (17 kPa). Recommended
minimum distances for aboveground tanks from buildings and
property lines are as follows:
a) Tanks, all sizes and types, containing petroleum
fuels with a flash point less than 100 F (38 C) - 100 feet
(30 m) or one tank diameter, whichever is greater.
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