CHAPTER 8
MECHANICAL SYSTEMS
To be able to prepare workable construction.
drawings, EAs should have the ability to recognize
and describe the materials used in mechanical
systems, to understand their uses and functions,
and to discuss the purpose and the development
of a mechanical plan in the context of plumbing
for water distribution and drainage systems.
This chapter will discuss only the plumbing
and drainage portions of the mechanical systems
and the various materials used. You will not be
expected to design the system; however, as an EA,
you may be called upon to prepare construction
drawings from sketches and specifications.
MECHANICAL SYSTEMS
(PLUMBING)
In general, plumbing refers to the system of
pipes, fixtures, and other appurtenances used
inside a building for supplying water and
removing liquid and waterborne wastes. In
practice, the term also includes storm water or
roof drainage and exterior system components
connecting to a source, such as a water main, and
a point of disposal, such as a domestic septic tank
or cesspool.
The purpose of plumbing systems is, basically,
to bring a supply of safe water into a building for
drinking, washing, and cooking, distribute the
water within the building, and carry off the
discharge of waste material from various
receptacles on the premises to sewers, leech basins,
and so forth, without causing a hazard to the
health of the occupants. Codes, regulations, and
trade practices define the plumbing specifications,
which vary from one location or place of
application to another. Although the National
Plumbing Code is widely accepted as a guideline
for the minimum requirements for plumbing
designs, you must also be familiar with applicable
local codes, especially when working with
mechanical drawings and plans.
AND PLAN
WATER DISTRIBUTION SYSTEM
The purpose of a water distribution system is
to carry potable COLD and HOT WATER
throughout a building for domestic or industrial
use. A typical water supply system (fig. 8-1)
consists of service pipe, distribution pipe,
connecting pipe, fittings, and control valves. The
water service pipe begins at the WATER MAIN.
The water distribution pipe starts at the end of
the service pipe and supplies the water throughout
the building.
Piping Materials
Several types of pipe are used in water
distribution systems, but only the most common
types used by the SEABEEs will be discussed.
These piping materials include copper, plastic,
galvanized steel, and cast iron. Some of the main
characteristics of pipes made from these materials
are presented below.
COPPER PIPE AND TUBING.— Copper is
one of the most widely used materials for tubing.
This is because it does not rust and is highly
resistant to any accumulation of scale particles in
the pipe. This tubing is available in three different
Figure 8-1.-Cross-sectional diagram of a water supply and
distribution system.
8-1
