MIL-HDBK-1022A
the differential pressure across the vessel reaches a preset
limit. Require a warning signal to alert the operator that
the switching operation has occurred. In cases of emergency,
include the capability to bypass the inlet filter separator
bank. For other types of fuels, the selection of filtration
depends on anticipated impurities, the source of the fuel, and
the shipping method. Consider the use of micronic filters,
cyclonic filters, and haypack filters as possible filtration
devices.
3.3.2.2
Off-Loading Drop Tanks. The introduction of air
into a fuel receiving system poses extreme hazards which can
result in fire and/or explosion. Hazards are compounded when
an air/fuel mixture is passed through receipt
filter/separators where static electricity is generated and
ignition can occur. For facilities with the capability to off-
load several tank trucks at once or where newer tank trucks
with multiple hoses are connected to multiple isolated
compartments, consider providing an underground, gravity-type,
receiving tank with submersible transfer pumps and level
controls. For smaller systems of one or two tank trucks,
consider a low profile, aboveground, receiving tank with a
centrifugal transfer pump. For either case, provide level
sensors to control the flow. See Facility Plate No. 005.
3.3.2.3
Equipment Required
a) Where tank trucks or tank cars are off-loaded
into aboveground tanks, provide centrifugal pumps configured
to provide automatic air elimination as shown on Facility
Plate No. 003. Provide one pump for each tank truck or tank
car that is to be off-loaded simultaneously, at an average
capacity of 300 gpm (19 L/s). Centerline height of suction
line from manifold to pump should not exceed 23.25 inches
(591 mm) above truck unloading, parked position. Where pumps
are required, provide at least two pumps to allow continued
operations if one is out of service. Where tank trucks or
tank cars are off-loaded into underground tanks, pumps will
not normally be required. When direct pump off-load of trucks
is provided, the preferred pump location is at the off-load
point, as opposed to a remote location.
b) Provide 4-inch (100 mm) diameter by 10-foot (3 m)
long lightweight reinforced vacuum rated off-loading hoses and
covered hose storage racks for each off-loading position.
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