MIL-HDBK-1005/7A
Anchorages should be provided for buried or exposed pipe at all
bends, as required to resist vertical or horizontal thrust.
Refer to AWWA C600, Installation of Ductile-Iron Water Mains and
Their Appurtenances; and AWWA C605, Underground Installation of
Polyvinyl Chloride (PVC) Pressure Pipe Fittings for Water for
standard blocking.
7.1.7
Railroad Crossings. Mains to be laid near railroads
should be designed to withstand the dynamic loads and vibrations
caused by trains. Place the mains in a larger sized conduit, to
reduce the vibration effects of moving trains. Refer to
American Railway Engineering Association (AREA), Manual for
Railway Engineering, Volumes I and II.
7.1.8
Stream Crossings. Wherever possible, underwater mains
should be buried in the stream beds for protection against
freezing and disturbance by currents, ice, floating debris, ship
anchors, and dredging. Consider multiple crossings when a high
degree of reliability is required. The following conditions are
recommended:
a) All joints should be watertight. Use flexible
ball joints with rigid pipe materials or flexible plastic pipe.
b) Provide shutoff valves at each end, so that the
mains may be isolated during testing and repairing.
c)
Provide flushing facilities.
d) Because of inaccessibility, make special provision
for corrosion control.
7.1.9
Valves. Refer to pars. 7.2 and 7.4 which recommend
air, vacuum, and blowoff valves to be used. Make any necessary
provision to release trapped air, break vacuums, and permit main
flushing.
7.1.10
Testing . Refer to AWWA Standards C600 series, for
testing requirements for each type of pipe material. For
disinfection testing requirements refer to AWWA C651,
Disinfecting Water Mains.
7.2
Transmission
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