Figure 7-3.Typical building water supply system.
Figure 7-4.Corporation stop.
provides for circulation of the hot water at all
times. The circulation is created because warm
water tends to rise and cold water tends to fall.
The circulating system shown in figure 7-2 is
known as an overhead feed and gravity-return
system because of its construction. This type of
system tends to become airbound, preventing cir-
culation of the hot water. Since air collects at the
highest point of the distribution piping, the most
practical way to relieve the air lock is to connect
an uncirculated riser to the line at that point. Any
air lock that develops is relieved when a fixture
on the uncirculated riser is used.
Piping and Fitting General
A typical building water-service line is
shown in figure 7-3. This line is composed of a
corporation stop, a flexible connector, a curb
stop, a stop and waste valve, and a meter stop
or gate valve.
Figure 7-5.Flexible gooseneck connector.
The corporation stop is installed at the loca-
tion (fig. 7-4) on the water main where a tap is
made. Its function is to make the removal of
the taping machine and the installation of the
remaining fittings easier by securing the water
flow from the tap. A corporation stop may not
be needed if you are installing building service
lines from a newly installed, unpressurized water
When you install the line between the corpora-
tion stop and the curb stop, use some type of
flexible connection for joining the pipe to the cor-
poration stop. This flexible connection protects
the corporation stop from strain or damage that
can result from any movement of the water main
or service pipe because of settling, earth move-
ment, or expansion and contraction.
Several types of flexible connectors are used.
The type you choose will depend on the type of
material used for the supply line. A gooseneck
(fig. 7-5) is used when galvanized iron or steel