124 Chapter 6
Drainage and Utility Plans.
Utility drawings show locations of the water, gas, sanitary sewer, and electric utilities that will service
the building (Figure 6.7). The location of existing underground utilities is important so that they can be
protected during excavation and construction. Drainage plans detail how surface water will be col-
lected, channeled, and dispersed on- or offsite. Drainage and utility plans illustrate in plan view the size
and type of pipes, their length, and their connections or terminations. The elevation of a particular pipe
below the surface is given with respect to its invert. The invert of a pipe is the bottom trough through
which the liquid flows. This is typically noted with the abbreviation for invert and an elevation, for ex-
ample, “INV.123 feet.”
Invert levels are shown at the intersections of pipes or other changes in the continuous run of pip-
ing, such as a manhole, sewer manhole, catch basin, etc. (Figures 6.8A and B). Inverts are normally
provided only for piping that has pitch or a gravity flow. The method of sewage disposal is normally con-
sidered to be an important element of a site plan. There are several alternative methods of sewage dis-
posal, including public sewers and private systems.
In addition to the plan view, a site plan will sometimes require clarification in the form of a detail,
similar to an architectural detail. Classic examples of site details are sections through paving, precast
structures, and curbing. Details are not limited to scaled drafting but occasionally for clarification pur-
poses appear in the form of not-to-scale perspective drawings.
Landscaping and Irrigation Plan.
Landscaping is usually the final stage of a site’s development. Landscaping plans show the location of
various species of plantings, ground cover, lawns, benches, garden areas, and fences. The plantings
are noted with an abbreviation, typically three letters, along with the quantity of the particular species
(Figure 6.9). The designation corresponds to a planting schedule that furnishes a complete list of the
plantings by common name, Latin or species name, and quantity and size of each planting. Certain
notes describing planting procedures or handling specifications accompany the planting schedule.
Landscaping plans have additional graphics and symbols unique to the profession, which the blueprint
reader should be aware of, particularly relating to plant symbols.
The irrigation plan often accompanies the landscape plan. It shows all the water lines, control
valves, and types of watering fixtures needed for irrigation. Regional climatic conditions will impact the
requirements for the type of irrigation system to be specified (Figure 6.10).
Site Improvement Drawings.
Large or complex projects often require separate drawings to clarify proposed site improvements in-
cluding curbing, walks, retaining walls, paving, fences, steps, benches, and flagpoles.
Paving and curbing plans indicate the various types of brick, concrete, and bituminous paving and
curbing to be used and the limits of each. This information allows for calculation and measurement of
paving and curbing. The legend symbols inform you where one material ends and another begins. No
assumptions should be made by the plan reader. Details showing sections through the surface are
used to differentiate between thicknesses and between material and the substrate below.