describes how this is done. Also, since
tub/shower valve installation is completed
during second-rough, this process is described.
Figure 20-8 shows how to offset the hot
water piping so it can be installed around the
cold water pipe. It is not important which of
the pipes is offset, but it is essential that the
offset be made in either the hot or cold water
pipe and that enough clearance be provided so
that the pipes never touch. Expansion, contrac-
tion, and water hammer produce enough
movement in the pipes to cause wear, and ulti-
mately failure, if the pipes touch.
It is somewhat easier to install the offset pipe
first, so that it is not necessary to work around
the other pipe. Knowing the approximate
Chapter 20 Installing Water Supply Piping
357
Figure 20-8. It is necessary to create an offset in either the hot or cold water piping so the pipes can cross
each other.
B
To 2nd
bathroom
Tee
Horizontal
pipe runs
attached
to underside
of floor joists.
Offset
(Hot water pipe turned
up to permit it to pass
above cold water pipe)
Riser
A
90° ell