MIL-HDBK-1164
(4)
Thawing Procedures
a.
DC Generator. To thaw pipe with a welding
generator or similar DC source, set the generator to the correct amperage for the pipe
to be thawed and connect leads to the pipe.
b.
AC Circuit. Transformers are required to adjust the
amperage of an AC circuit to the pipe being thawed. Consult the installation electrical
engineer for the best transformer arrangement. This arrangement depends on line
voltage, available transformers, and required amperage. To keep hazards to a
minimum, a competent electrician generally sets and connects transformers, makes the
connections, and assist in the thawing procedure. Where frequent thawing is
necessary at different points, the transformers may be mounted on a trailer for ready
use.
b)
Steam Thawing. Steam thawing is slower than electrical thawing
and is used only when insulating material in pipe joints or couplings makes the use of
electricity impractical. In steam thawing, a hose connected to a boiler is inserted
through a disconnected fitting and gradually advanced as the steam melts the ice.
Steam thawing is commonly used on fire hydrants.
Additional methods for thawing frozen pipes can be found in par. 2.1.4.
7.3.3
Water Main Tapping Procedures. Water main connections may be made
when the pipe is empty or filled with flow (wet tapping). Use wet tapping to make a
connection without turning off the water or interrupting service to existing customers.
More detailed information on tapping procedures may be obtained from the pipe
manufacturer or from the publication listed in par. 2.1.4.
7.3.4
Instrumentation, Control, and Information Management. Information on
these topics can be found in the publication listed in pars. 2.1.4 and 2.2.1.
7.4
Storage. Water storage serves to equalize supply and demand, increase
operating convenience, level out pumping requirements, decrease power costs, provide
water during power source or pump failures, provide large quantities of water to meet
fire demands, provide surge relief, increase detention times, and blend water sources.
General information describing water storage requirements, types of storage structures,
and associated equipment can be found in par. 2.1.4.
7.4.1
Operation of Water Storage Facilities. General information on O&M of
water storage facilities can be found in par. 2.1.4.
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