materials and the equipment used are presented
Cast-Iron Pressure Pipe
(For Water Mains)
The cast-iron pipe used for a water distribution
system is somewhat different from that used for waste
systems. Some of the major differences are in the
length of the pipe, the joints, and the lining. Cast-iron
soil pipe for waste, as you know, comes in 5-foot and
10-foot lengths. Cast-iron pressure pipe for water
mains comes in 20-foot lengths with either bell-and-
spigot or mechanical (gland-type) joints. This pipe
may be coated with coal-tar pitch or be cement-lined;
however, uncoated pipe is available if needed for other
MEASURING AND CUTTING.Cast-iron
pressure pipe is measured by the inside diameter; a
ruler or tape is frequently used for measuring. With a
cement lining, the lining goes beyond the inside
diameter of the pipe, so you have to allow for this
reduced inside dimensioning.
To cut cast-iron water pipe to the desired length,
use either a hand-operated chain cutter or a power
hacksaw. Because of the construction of this pipe, it
does not need reaming after cutting; but, you can use a
file to dress down the cut when necessary.
FITTINGS. Three major types of fittings for
joining cast-iron pipes in water service are tees,
elbows, and couplings. Since these fittings look like
those used for sewer lines, a detailed description need
not be provided here.
JOINING.In water service lines, bell-and-
spigot cast-iron pipe is joined with lead, lead wool, or
sometimes a sulfur compound. Specially prepared
treated paper may also be used.
Before making a joint, you should first check each
length of pipe for cracks or splits. After eyeing the pipe
for defects, rap it with a hammer. With a little
experience, you will know the difference between a
good pipe and a bad pipe (cracked or split).
Next, wrap the yarn around the spigot end, place it
in the bell of the previously laid length, then straighten
and adjust it with a yarning iron. Use enough yam to
fill the joint within approximately 2 inches of the face
of the bell. Then clamp a joint runner in place around
the joint, so it fits tightly against the outer edge of the
bell. The lead should then be poured into the V-shaped
opening left at the top by the clamped joint runner. This
lead fills the space between the yam and the runner.
This joint must be made in one pouring for best results.
After the lead has hardened (about 10 seconds), the
runner is removed, and the lead, which shrinks while
cooling, is expanded by caulking until it makes a tight
fit. Caulking requires skill; hammer blows that are too
heavy could split the bell, or blows that are too light
could leave a loose joint.
Lead wool is lead in shredded form that does not
require melting. Lead wool is sometimes used when
water is encountered in a trench. In this process, more
yarn is used; the joint is filled to about 1 inch of the face
of the bell. Lead wool requires more time in caulking
than poured lead.
A sulfur compound is melted on the job, like lead,
but at a lower temperature. It is then poured into a joint
prepared for a cast-lead joint. The fact that it is light in
weight is its primary advantage. It requires no caulking
and provides a strong joint that is unlikely to blow out.
Initially, joints of sulfur compounds leak or sweat
slightly, but they tighten up in a short time. Since the
joints are rigid, they should not be used to connect a
newly laid line to an old one, as the settlement of a new
line can cause a crack. A lead joint should be used at the
Mechanical joints are made with rubber sealing
rings held in place by metal follower rings bolted to the
pipe. This type of joint is designed to permit expansion
and contraction of the pipe without injury to the joints.
Copper pipe and tubing with soldered joints or
flared-tube connectors are used for water service.
Copper is highly regarded because of its corrosion-
resistant properties, flexibility, ease of installation,
and low resistance to flow throughout its useful life.
Three types of copper, designated as Types K, L,
and M, are commonly used. Type K is used for
underground service and general plumbing; Type L for
general plumbing; and Type M with soldered fittings
only. Types K and L copper come in either straight 20-
foot lengths of hard temper or in coils of 50 to 100 feet,
soft temper. Type M comes in straight 20-foot lengths,
hard drawn only.
Another type of copper, Type DWV (drain, waste,
and vent), is used only in aboveground soil, waste, and
vent lines. It is furnished in hard temper only and in
sizes from 1 1/4 to 8 inches. It is available in 12-foot
lengths as well as the standard 20-foot lengths.