The primary drawing is a detailed plan of the sand
3-4.
UNIT CONSTRUCTION AND
filter. The water is pumped from the sedimentation
PACKAGE UNIT PRINTS
basin to a surge tank and then to the sand filter. By
studying the drawing you can determine that the sides
Additional prints must be consulted for
of the sand filter are on a 2: 1 slope and that they are
construction or installation of unit structures and
drained by a series of 4-inch pipes. After the water is
equipment used in water supply and distribution
filtered, it is pumped to a storage tank and then to the
systems. The type of additional prints provided
distribution system. In other cases the water may be
depends on whether the unit is constructed in the
pumped to a water treatment plant before it goes to
field or is a "package unit" which is assembled in the
the distribution system. You can learn from the
field.
general notes that the capacity of each sand filter is
50,000 gallons per day so that one unit can supply the
The
a. Unit Construction Drawings.
rated capacity while the other is being cleaned. Other
information provided in lesson 2 for architectural
views that might be shown on a construction print are
drawings applies to the drawings used for structures
an elevation view of the sand filtration unit and
in water supply and distribution systems. Figure 3-3
additional details.
is a typical drawing of an elevated water storage
tower. From figure 3-3 you can determine the size of
the tower, the size of the steel beams, the size of the
dunnage beams, and the dimensions of the footings
3-3.
DISTRIBUTION SYSTEM
required to support three types of tanks. In addition,
Once the water in the water treatment plant
you can quickly determine all piping requirements
meets certain quality specifications, it is introduced
including the detailed plumbing connections for the
into the distribution system. Figure 3-2 shows a
float valve.
typical water distribution system for a hospital area.
The general location and size of the pipes are shown
Package units are
b. Package Units.
along with the valves, sumps, water tank, and other
assembled in the field and installed in accordance
fixtures. In general, the symbols used on distribution
with the manufacturers' instructions supplied with the
system plans correspond to those for water plumbing.
unit or units. In addition to the construction drawings
Additional symbols which may not be in common
and specifications supplied, a drawing similar to
use are explained by notes or a legend on each
figure 3-4 usually is supplied. You can see that
construction print on which they appear. The exact
several package units have to be installed and
location of pipelines and equipment, as shown by the
connected together to form a water treatment plant.
symbols on the prints, is determined by the pipefitter
The standard plumbing drawing would be required
in the field. Details, such as the depth of waterline
before you could attempt to assemble and install the
installations, construction of supporting saddles or
package units. However, drawings similar to figure
mats, supports and bracing to prevent damage by
3-4 are required to enable field personnel to visualize
water-hammer and movements, are determined in the
the completed installation. The arrows indicate the
field based on climate, terrain, and good plumbing
main flow path of the water and help to explain how
and construction practice.
the plant operates. The other lines are chemical
feeders, drains, and filtered water return lines.
101
Previous Page
