pipe: heavy grades of piping have smaller inside
galvanized steel, wrought iron, copper, plastic, or
diameters because of their greater wall thickness.
brass. Nickel-silver or chrome-plated piping is used
Piping over 12 inches in diameter is classified and
in locations where pipes are exposed to view.
referred to by its actual outside diameter.
Galvanized wrought iron is the material most
frequently used in theater of operations construction.
b. Fittings. Figure 3-6 illustrates the symbols
Fittings normally are of the same material as the
used for the most frequently encountered pipe
piping and are made with screw or flange
fittings. A more complete list is contained in
connections; screw connections are normally used
appendix A. Note that the basic line symbol for a
only for pipe up to 4 inches in diameter. Valves
section of pipe shown at the top of figure 3-6 will
usually are made of brass and may or may not be
actually be combined with the line symbology shown
plated. The material types to be used for the
in figure 3-5. In this way, you are able to determine
distribution system are designated in the
not only the size of pipe and method of branching
specifications; sizes and special instructions are noted
and coupling, but also the use to which the pipe will
in the drawings.
be put. This is important, in that the type of material
from which the pipe is made determines how the pipe
f. Waste System Materials. Waste systems
should be used. This subject will be discussed in
include all piping from sinks, water closets, urinals,
detail in later paragraphs.
showers, baths, and other fixtures that carry liquids
and sewage outside of the building. A waste system
c. Valves. Figure 3-7 illustrates the symbols
consists of a main building drain, branch mains, and
used for the most frequently encountered valves. A
soil and vent stacks. Water, soil, and vent piping
more complete list is contained in appendix A.
specifications include the materials of manufacture
Material and sizes for valves are normally not noted
for each type of piping: cast iron, galvanized steel,
on drawings, but must be assumed from the size and
wrought iron, copper, brass, lead, or acid-resistant
material of the connected pipe. However, when
cast-iron pipe.
Fittings or traps normally are
specified on a bill of materials or plumbing takeoff,
specified to be of the same material as the pipe.
valves are called out by size, material, and working
pressure. For example: 2-inch check valve, brass,
(1) Galvanized steel and iron piping.
175 pounds working pressure.
Galvanized steel and iron pipes and fittings are the
materials most commonly specified for waste system
d. Fixtures. General appurtenances such as
plumbing installations. Pipe ends have standard pipe
drains and sumps, plus fixtures such as sinks, water
threads and all pipes and fittings of this type are
closets, and shower stalls are indicated on the plans
joined by standard pipe threads. Such piping is
by pictorial or block symbols. The symbols for those
manufactured in three different weights and in
most frequently encountered are illustrated in figure
diameters from 1/8 inch to 12 inches to any one of
3-8. The extent to which the symbols are used
several specifications. The fittings are manufactured
depends on the nature of the drawing. In many cases,
in all the shapes required to change or intersect flow.
the fixtures will be specified on a bill of materials or
other schedule keyed to the plumbing plan. When
(2) Vitrified clay piping and fittings.
the fixtures are described on the schedule, the
Vitrified clay piping and fittings are used for
draftsman will often use symbols which closely
underground house drains and sewers and normally
approximate the shape of the actual fixtures rather
are noted in the plans as VCP or VP. VCP is
than the standard block or circle and the standard
sometimes used for soil and vent stacks in theater of
abbreviation.
operations construction. Pipes and fittings are made
with bell-and-spigot ends. Joints are made by
e. Distribution System Materials. Water
inserting the spigot end into the bell and caulking
distribution piping for interior installations is made of
with cement mortar.
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