Figure 3-8.Typical stack and vent installation.
figure 3-9. These are normally referred to as
combination Y and 1/8 bends.
The STRAIGHT type of 90-degree Y-branch has
one section that is straight through and a takeoff on one
side. The side takeoff starts out as a 45-degree takeoff
and bends into a 90-degree takeoff. This type of branch
is used in sanitary sewer systems where a branch feeds
into the main, and it is desirable for the incoming
branch to feed into the main as nearly as possible in a
line parallel to the main flow.
The REDUCING 90-degree Y-branch is similar to
the straight type; however, as shown in view A, figure
3-9, the branch takeoff of the 90-degree Y-branch is
smaller than the main straight-through portion. It is
generally used the same as the straight type, except the
branch coming into the main is a smaller pipe than the
The DOUBLE 90-degree Y-branch (or DOUBLE
COMBINATION Y and 1/8 BEND) is easy to
recognize since there is a 45-degree takeoff bending
Figure 3-9.Types of cast-iron soil pipe, 90- and 45-degree
into a 90-degree takeoff on both sides of the fitting, as
shown in view A. It is very useful as an individual vent.
The BOX type of 90-degree Y-branch has two
takeoffs. It is designed for each takeoff to form a 90-
degree angle with the main pipe. The two takeoffs are
spaced 90 degrees apart.
There are two types of cast-iron soil pipe 45-
degree Y-branches. These are the reducing and the
straight types; both are shown in view B, figure 3-9.
The REDUCING type is a straight section of pipe
with a smaller size 45-degree takeoff branching to one
side. There are different sizes of this fitting. As an
example, a 4 by 4 by 3 reducing 45-degree Y-branch
has a 4-inch-straight portion with a 3-inch 45-degree
takeoff on one side.
The STRAIGHT type of 45-degree Y-branch, or
true Y, is the same as the reducing type, except that
both bells are the same size. It is used to join two
sanitary sewer branches at a 45-degree angle.
Cleanout plugs are installed to permit removal of
stoppages from waste lines. View A, figure 3-10,
shows one type of cleanout plug. It consists of an iron
ferrule caulked with the hub of a pipe or fitting. The top
opening is taped and threaded, so a pipe plug can be
screwed into it. Cleanouts should not be more than 50