Environmental Engineering Reference
In-Depth Information
Wall thickness
O.D.
I.D.
Length
figure 4.3 Pipe terminology.
Knowledge of the basic characteristics of the metals and nonmetals
used for piping provides clues to the uses of the piping materials with
which we work in water/wastewater treatment operations. Such knowl-
edge is especially helpful to operators, making their job much easier and
more interesting. In this section, metallic piping is discussed. Piping
joints, how to join or connect sections of metallic piping, and how to
maintain metallic pipe are also discussed.
4.8.2 Piping: The basics
Earlier, we pointed out that piping includes pipe, flanges, fittings,
bolting, gaskets, valves, and the pressure-containing portions of other
piping components. Piping also includes pipe hangers and supports and
other accessories necessary to prevent overpressurization and over-
stressing of the pressure-containing components. From a system view-
point, a pipe is one element or a part of piping. Accordingly, when joined
with fittings, valves, and other mechanical devices or equipment, pipe
sections are called
piping
.
Note:
A
pipe
is a tube with round cross-section conforming to the dimen-
sional requirements of ASME B36.10M (Welded and Seamless Wrought
Steel Pipe) and ASME B36.19M (Stainless Steel Pipe) (Nayyar, 2000).
4.8.3 Pipe sizes
With time and technological advancements (development of stronger
and corrosion-resistant piping materials), pipe sizes have become stan-
dardized and are usually expressed in inches or fractions of inches. As a
rule, the size of a pipe is given in terms of its outside or inside diameter.
Figure 4.3 shows the terminology that applies to a section of pipe. Pipes
are designated by diameter. The principal dimensions are as follows:
•
Wall thickness
•
length
•
outside diameter
(O.D.), which is used to designate pipe greater
than 12 inches in diameter
•
Inside diameter
(I.D.), which is used to designate pipe less than 12
inches in diameter
