Q13. For an air test to be satisfactory, the system
should hold 5 psi for what period of time?
Q14. What type of oil should be used for an odor test?
Ql5. A manhole should be what diameter at the sewer
Ql6. Earth fill should be placed in the trench over the
pipe in layers of what thickness?
ABOVEGROUND SANITARY PIPING
LEARNING OBJECTIVE: Identify pipe,
traps, vents, and installation methods for
aboveground sanitary drainage.
After the underground piping is installed for a
sewer system, the next phase is to install the
aboveground piping. Information on materials
applicable to the installation of aboveground sewage
piping is provided in the following sections.
Installation procedures are the same for aboveground
and underground sewer pipe.
TYPES OF PIPE
A number of different types of pipes are used in the
aboveground and interior parts of a plumbing system.
Some of the common types of pipes are discussed
While GALVANIZED WROUGHT-IRON PIPE
is an excellent material for aboveground plumbing, it
is costly. It is available in lengths from 18 to 22 feet.
Galvanized wrought-iron pipe is constructed of
wrought iron dipped in molten zinc to protect it from
corrosion and provide high resistance to acid waste.
ACID-RESISTANT CAST-IRON PIPE is
composed of an alloy of cast iron and silicon. It is used
to serve chemical laboratories and other installations
through which acid waste flows. In handling acid-
resistant pipe, such as Durion, be careful because it
is very brittle and cracks easily. It is cast in 5-foot
lengths and comes in single and double hubs.
BRASS PIPE consists of an alloy of zinc and
copper. Brass pipe has a smooth interior and can resist
most acids; however, it is expensive. It is available in
20-foot lengths; because it tends to bend, it must be
supported at intervals of 8 to 10 feet.
LEAD or LEAD-LINED STEEL PIPE is
sometimes used to carry distilled water for batteries;
however, tin-lined, block tin, glass, or some types of
plastic pipe must be used where no impurities are
acceptable. Because it bends easily, lead pipe must be
well-supported. It is available in three weights: (1)
standard, (2) common, and (3) extra heavy. The
standard weight is most commonly used.
COPPER PIPE. is suitable for use in waste, vent,
and water installations. Remember that ammonia and
water corrode copper and bronze lines. Also, when
copper is used for waste pipe installations, always
make sure it is rigid to overcome sagging. You can
obtain the pipe in convenient lengths, then cut it to size
for the job at hand.
PLASTIC PIPE is also suitable for use above-
ground for sewage, venting, and water.
A number of different types of traps are available;
however, the trap most commonly used with plumbing
fixtures is the P-trap (fig. 3-34). Traps are required
because they prevent sewer gases from entering a
building and causing serious illness or death.
The term trap seal refers to the water being held in
the bent portion of a fixture trap (fig. 3-34). True to its
name, the trap seal forms a seal against the passage of
sewer gases through the trap and into the building. The
most frequently used seal trap has a depth of 2 inches
between the overflow and the dip. The deep seal trap
has a depth of 4 inches.
The P-trap gets its name because of its general
shape-that of the letter P. It comes in sizes from 1 1/4
to 6 inches in diameter. Various types of P-traps are
available, so designs may differ from one
manufacturer to another. The P-trap is usually made