MIL-HDBK-1022
c) Capital cost of pumping stations and attendant
facilities.
d) Operating cost of the system.
e) Harmful effects of excessive velocity of flow
including hydraulic shock and static generation.
f) Fatigue failure caused by cyclic loading.
9.1.2
Piping Arrangement. Wherever possible, arrange
piping in parallel groups to facilitate multiple use of
supports, to minimize the amount of trenching for underground
piping, and to minimize the number of steps or stiles needed
across pipe runs. For underground applications, consider
constructability when determining amount of spacing between
pipes. Use the following criteria:
a) Provide looped piping systems whenever practical.
Loops add to the flexibility and reliability of the system,
contribute to product cleanliness by making circulation
possible, and can be used to reduce the magnitude of hydraulic
shock. Sectionalize loops by double block and bleed valves to
provide verifiable isolation and to facilitate pressure
testing.
b) Between mains, install cross connections for
flexibility of operation and as an auxiliary means of
continuous operation in emergency situations. In addition,
permit the use of line blinds where space limitations preclude
the use of removable pipe sections or fittings. Provide a
separate piping system for each grade of fuel to be handled.
Do not provide cross connections between grades.
c) For short runs, provide a line slope of at least
0.2 percent. For long runs, make line slope sufficient to
establish positive drainage by gravity, but without excessive
bury depth. Make gradients uniform between high and low
points. Traps are undesirable because they provide a place
for water and sediment to accumulate. Install drains at low
points to allow removal of any water from condensation. These
low point drains also provide the capability to remove fuel
for line maintenance. If slope is not possible, design the
system to accommodate pigging by providing flange connections
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