TM 5-852-5/AFR 88-19, Volume 5
CHAPTER 6
WATER DISTRIBUTION
6-1. General.
eliminate dead ends and related freezing problems
and requires the minimum amount of piping as
The basic criteria for design and construction of
compared to other circulation methods. A simple,
water distribution systems can be found in TM 5-
positive control of distribution is possible with flow
813-5/AFM 88-10, Vol. 5. This section presents
and temperature indicators on the return lines at the
information that is unique to the Arctic or Subarctic.
recirculation facility. Normally water is pumped out
Pressurized, pipe distribution systems are used for
at between 39 and 45 degrees F and returns at 33 to
exterior utilities and interior plumbing in most
39 degrees F. Pipe network design uses the same
military facilities in the cold regions. An exception
procedures used for standard water systems. The
might be small facilities at locations remote from the
return line does not have to be of the same size as
main distribution network. If individual wells are not
the delivery pipe because of withdrawals in the
feasible then vehicle delivery of water would be
network. Expansion of the system is provided by
necessary. Truck delivery systems are common at
construction of temporary links to close the loops at
remote civilian communities in Alaska, Canada and
the end of the present system when the system is
Greenland. Vehicle specifications for this special
expanded, the link is valved off and the pipe link left
purpose can be obtained from the U.S. Public
empty. If possible, the mains will be located at the
Health Service-Indian Health Service, 701 C St.,
rear of buildings, rather than in the streets, as shown
Box 65, Anchorage, Alaska 99513. The location of
in figure 6-1. This will provide greater thermal
pipe distribution systems and whether they should
protection (since snow is not typically removed),
be buried or above ground are discussed in chapters
result in less risk of damage to manholes and other
2 and 12 of this manual.
appurtenances, and will allow shorter, less costly
service connections to the buildings. There are
6-2. Single pipe recirculation system.
special advantages to this approach for barracks and
The single pipe recirculation system is recom-
family housing areas where large numbers of similar
mended for arctic conditions. As shown in figure 6-
structures tend to be laid out in a regular pattern.
1 it consists of one or more uninterrupted loops
originating at a recirculation facility and returning to
6-3. Alternative systems.
that point without any branch loops. This layout will
Conventional water pipe mains with no recirculation
are possible in very special situations, but require
careful planning in the initial site layout for military
installations. In these cases, there may be enough
flow in the system so that return loops are not
needed if a high volume consumer is placed at the
ends of the main line. Sizing of the pipe network
and other design details follow conventional prac-
tice. A dual pipe system relies on a large diameter
supply line and a small diameter return line placed
side by side in a utilidor or a preinsulated conduit as
shown in figure 6-2. The return line is sized to main-
tain the desired flow in the system. Figure 6-3 is a
schematic illustration of typical service connections
from a dual system. The service lines are taken off
the main and returned to the smaller diameter return
line. The pressure differential between the delivery
and the return line must be sufficient to induce
circulation in the service loop. The system is
complex and control mechanisms tend to be elabo-
rate. For example, varying consumption in different
6-1
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