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Plumbing
Typical Plumbing System
Introduction
The residential plumbing system is often Typical Drainage System
taken for granted, but it is an
important part of the structure.
A complete plumbing system provides
an adequate supply of water and
removes waste.
There are three principal parts:
1. Water supply system.
2. Water and waste removal
system.
3. Plumbing fixtures.
Components of a residential drainage system
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Typical Drainage System
Components of a residential drainage system
Water and Waste Removal
Used water and other wastes are carried to the sanitary sewer or septic
tank through the waste removal system.
These pipes are isolated from the water supply system and must be sized
for sufficient capacity, have the proper slope and venting, and have
provisions for cleanouts.
Typically it is practical to drain as many of the fixtures as possible into a
single main drain.
The drainage system is not under pressure and depends on gravity to
carry the waste to the sewer.
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Water and Waste Removal
A vertical drain pipe that collects waste from one
or more fixtures is called a soil stack.
Soil stacks that drain water closets are called
main stacks.
• Every house must have at least one main
stack, which is generally 3" in diameter.
• Each bathroom must have a main stack.
Stacks that do not drain water closets are called
secondary stacks.
Secondary stacks are 1-1/2" diameter.
Water and Waste Removal
Fixtures are connected to the stack using a
branch main.
All stacks extend into basement and empty into
the house drain.
All structures must have at least one house
drain, but may have several.
The house drain becomes the house sewer
once it is outside the house. The house sewer
empties into the city sanitary sewer or private
septic system.
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Water and Waste Removal
Gases from the system dissipate
through the vent stack—12" above roof.
The vent stack provides an air inlet for
the drainage system to operate properly
A trap is installed below each fixture to
prevent gases from entering the house.
The trap is always filled with water.
Water closets have a built-in trap.
Each stack requires a cleanout at the
base.
Traps
TRAPS
The trap most commonly used with plumbing
fixtures is the P-trap. The P-trap gets its name
because of its general shape-that of the letter P.
Traps are required because they prevent sewer
gases from entering a building and causing serious
illness or death.
The term Trap Seal refers to the water being held in
the bent portion of a fixture trap. The trap seal
forms a seal against the passage of sewer gases
through the trap and into the building.
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Traps
Examples of P-Traps
House Drain
A house drain is the pipe that receives all waste
and water discharged by the soil stacks and
waste lines.
This house drain is laid from a point just outside
the building foundation wall where it connects to
the house sewer, then through the wall, and
either along or under the cellar floor to the point
where connection with the soil stack is made.
Before laying this drain, determine its overall
length and how much pitch to give it so that it
will drain as it should.
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House Trap
Building (House) traps shall be provided with a
cleanout and a relief vent or fresh air intake on
the inlet side of the trap.
Relief vents or fresh air intake shall be carried
above grade and shall be terminated in a
screened outlet located outside the building.
The size of the relief vent or fresh aid intake
shall not be less than one-half the diameter of
the drain to which the relief vent or air intake
connects.
House Drains and House Traps
002.6 Building traps.
Building (house) traps shall be prohibited, except
where local conditions necessitate such traps.
Building traps shall be provided with a cleanout
and a relief vent or fresh air intake on the inlet
side of the trap. The size of the relief vent or fresh
air intake shall not be less than one-half
the diameter of the drain to which the relief vent
or air intake connects. Such relief vent or fresh
air intake shall be carried above grade and shall
be terminated in a screened outlet located
outside the building.
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Soil stacks and waste stacks
A soil stack is a vertical drain pipe that
carries soil waste from sanitary units
(i.e. toilets.
A waste stack is any other vertical
drain pipe that doesn’t carry soil from a
sanitary fixture.
Cleanouts
A plumbing cleanout is a cleanout
fitting with a removable plug that is
found in a roughed in waste
system. It is designed to help keep
clear any type of debris that could
cause any type of stoppage in the
water drain lines.
Cleanouts are usually placed at the
connection point between the
sewer lines and the drain lines
where the base is located of a
vertical stack and at all places
were the pipe direction changes at
90 degrees.
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Cleanouts
Cleanouts are required at base of
all stacks.
Vents
VENTS
To prevent the siphonage of a trap seal in fixture traps
and allow gravity flow of drainage, you must let
atmospheric air from outside the building into the piping
system to the outlet (or discharge) end of the trap. The air
is supplied through pipes called VENTS. This air provides
pressure on the outlet end of the seal equal to pressure
on the inlet end.
Since the air supplied by the vent to the outlet end
provides a pressure equal to that at the inlet end of the
trap, the trap seal cannot escape through siphonage.
All vent systems should be provided with a main vent or
vent stack and a main soil and waste vent. A “main vent”
may be defined as the principal artery of the venting
system, and vent branches may be connected to the
main vent and run undiminished in size as directly as
possible from the building drain to the open air above the
roof.
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Vents
The term main soil and waste
vent, or soil stack vent, refers to
the portion of the stack extending
above the highest fixture branch.
In the figure, this vent extends
through the roof. Actually, it is an
extension of the main soil and
waste stack.
Vents
An INDIVIDUAL VENT is
a vent that connects the
main vent with the
individual trap
underneath or behind a
fixture
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Vents
A COMMON VENT vents two traps
to a single vent pipe.
The unit vent can be used when a
pair of lavatories are installed side
by side, as well as when they are
hung back to back on either side of
a partition
Riser Diagram
Riser diagrams are used as supplementary details on
working drawings in order to show more clearly how the
plumbing system is to be installed.
Riser diagrams of plumbing systems can be shown in both
orthographic and isometric views. The most commonly
used type of riser diagram for plumbing is the isometric riser
diagram. The isometric riser diagram provides a three-
dimensional representation of the plumbing system.
A riser diagram is not drawn to scale but should be correctly
proportioned.
The proper use of symbols for the piping and fittings makes
it easier to read and interpret the drawing.
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Riser Diagram
Typical
isometric Riser
Diagram
Riser Diagram
Typical Riser Diagram in elevation
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Plumbing Plans
The Plumbing Plan is a plan view that shows the complete
plumbing system. The plumbing plan shows the location, size,
and type of all plumbing equipment.
The plumbing plan should include:
Waste lines and vent stacks.
Drain and plumbing fixture locations.
Size and type of pipe to be used.
A plumbing fixture schedule.
Symbols Legend.
General notes.
A plumbing plan is required for each floor of the house.
Plumbing Symbols
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PIPING LABELS
PIPING LABELS
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PIPING LABELS
PIPE FITTINGS
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GENERAL SYMBOLS
VALVES
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Plumbing Fixture Schedule
SANITARY DRAINAGE CALCULATION
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PLUMBING CONNECTIONS
DOMESTIC WATER SERVICE
CALCULATION
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Plumbing Plan
Septic Tank Details
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