After the pipe is taken from the casting, it is
glazed and fired in large kilns to create a
moistureproof baked finish. It is used for house
sewer lines, sanitary sewer mains, and storm drains.
The types of fittings for clay pipe are primarily
bends, tees, and Y-branches.
You may have to use plain precast concrete pipe
for sewers in the smaller sizes-less than 24 inches.
This pipe is not reinforced with steel. This concrete
pipe is similar to vitrified clay pipe in measuring,
cutting, joining, and handling.
HANDLING AND STORAGE OF CLAY
PIPE.Be careful when you store and handle clay
pipe because it is very fragile and cracks easily. Never
drop clay pipe or roll it down an embankment without
control. Do not drop heavy objects on clay pipe. When
backfilling a trench, do not use fill with rocks or other
heavy debris in it. Tamp by hand or by pneumatic
tampers, bearing in mind the density of the backfill.
Clay pipe should be laid in a trench and bedded evenly
and firmly. The more perfect the bedding, the greater
the load the pipe can sustain. Common sense can save
a lot of time by eliminating rework.
Figure 3-24.Gross section of clay or concrete fittings.
CUTTING.Vitrified clay and concrete pipe,
both available in such short lengths, seldom need
cutting except for manholes and inlets. If, after
measurement, you have to cut vitrified clay or concrete
pipe, score it with a chisel, deepening the cut gradually
until the pipe breaks cleanly at the desired point.
Vitrified clay and concrete pipes may be cut with CISP
snap-off or chain cutters.
Mix grout, using 1 part portland cement, 2 parts
clean, sharp, washed sand, and sufficient water to
Fill the joint with grout, using a packing iron.
Recaulk the joint after 30 minutes with a
packing iron. You have to close shrinkage cracks that
occur after the initial set of the grout.
Smooth and bevel the grout off with a trowel. In
hot weather, cover the joint with a wet burlap sack.
FITTINGS. Figure 3-24 shows some common
fittings used with vitrified clay and concrete pipes.
Note that these types of pipes are used outside the
building. This greatly reduces the number of different
types of fittings required.
Remove excess mortar with either a swab or a
JOINING.Joints on vitrified clay and
concrete pipe may be made of cement or bituminous
compounds. Cement joints may be made of grout,
which is a mixture of cement, sand, and water. The
following procedure may be used as a guide in joining
pipe with grout. This procedure is very similar for
joining pipe with bituminous compounds.
Note that a regular swab, with some additional
rags tied to the end to compensate for larger size pipe,
is ideal for dragging through each length to remove the
Insert the spigot of one length of pipe into the
bell of the other and align the two pieces to the desired
The use of speed seal joints (rubber rings) in
joining vitrified clay pipe has become widespread.
Speed seal joints eliminate the use of oakum and
mortar joints for sewer mains. This speed seal is made
a part of the vitrified pipe joint when manufactured. It
is made of permanent polyvinyl chloride and called a
plastisol joint connection. This type of joint helps to
ensure tight joints that are rootproof, flexible, and so
Caulk a gasket of oakum about 3/4-inch thick
into the bell to prevent the grout from running into the
The speed seal, or mechanical seal, joint can be
installed quickly and easily by one person. To make the
joint, first insert the spigot end into the bell or hub.