The document discusses the principles and components of house drainage systems. It explains that house drainage collects and conveys wastewater by gravity to a public sewer or septic tank. The key principles are minimizing pipe lengths, avoiding sharp turns, using sufficient slope for self-cleansing flow, and including traps to prevent gas entry. Pipes in drainage systems include soil pipes for human waste, waste pipes for liquid waste, vent pipes for ventilation, and rainwater pipes. Traps with a water seal are used throughout to block gas flow while allowing wastewater passage.

1. Sanitary Fitting

2. SANITARTY FITTING
Pipes & Traps
House Drainage: General Principles
The arrangement provided in a house or
building, for collecting and conveying
wastewater through drain pipes, by gravity,
to join either a public sewer or a domestic
septic tank, is termed as house drainage or
building drainage.

3. SANITARTY FITTING
Pipes & Traps
Aim of house Drainage:
House drainage is provided in order:
 To maintain healthy condition in the building
 To dispose off wastewater as early and quickly as
possible
 To avoid the entry of foul gases from the sewer or the
septic tank
 To facilitate quick removal of foul matter (e.g, human
excreta)
 To collect and remove wastewater systematically

4. SANITARTY FITTING
Pipes & Traps
Principles of House Drainage
The following principles are adopted for the efficient
system:
 The lavatory blocks should be so located that the length
of drainage line is minimum.
 The drainage pipes should be laid by the side of building
rather than below the building
 All the drains should be aligned straight between the
successive inspection chambers. All sharp bends and
junctions should be avoided except through chambers.
 The slope of the drains should be sufficient to develop
self cleansing velocity.
 The size of the drain should be sufficient, so that
flooding of the drain does not take place while handling
the maximum discharge.

5. SANITARTY FITTING
Pipes & Traps
Principles of House Drainage
 The drainage system should contain enough
number of trap at suitable locations.
 The house drain should be disconnected to the
public sewer by the provision of an intercepting
trap.
 Rain water pipes should drain out rain water directly
into the street sewers.
 All the connections should be water tight.

6. SANITARTY FITTING
Pipes
In a house drainage system, a pipe may have the following designations,
depending upon the function it carries:
1- Soil Pipe: A soil pipe is a pipe though which human excreta flows either from the
toilet or sink to a soil drain or sewer.
2- Waste Pipe: It is a pipe which carries only the liquid waste. It does not carry
human excreta.
It transport the wastewater from sinks, shower, washing machine or
dishwasher.

7. SANITARTY FITTING
Pipes
3-Vent Pipe:
 It is a pipe which is provided for the
purpose of the ventilation of the system.
 It is open at top and bottom to facilitate
the exit of foul gases.
 It is carried at least 1m higher than the
roof level.

8. SANITARTY FITTING
Pipes
4- Rainwater Pipe: It is a pipe which carries only the rainwater.

9. SANITARTY FITTING
Pipes
5- Anti-Syphonage Pipe: It is a pipe
which is installed in the house drainage to
preserve the water seal of traps.
An extra pipe connected to the outlets of
toilet seats of all the floors, the other end of
which is exposed to the atmosphere is
called anti-syphonage pipe.

10. SANITARTY FITTING
Traps
 It is a depressed or bent fitting which when provided in a drainage system
always remains full of water, thus maintaining a water seal.
 It prevents the passage of foul air or gas through it, though it allows sewage or
wastewater to flow through it.

11. SANITARTY FITTING
Traps
 The depth of water seal is the vertical distance
between crown and dip of a trap.
 The depth of water seal represents its strength
or effectiveness.
 Greater the depth of water seal, more effective
is the trap.
 Note: The depth of water seal varies from
25mm to 75mm.

12. SANITARTY FITTING
Traps
Characteristics of Traps:
 It should possess adequate water seal at all times, to fulfill the purpose of its
installation. However it should retain minimum quantity of water for this
purpose.
 It should be of Non-absorbent material.
 It should be free from any inside projections, angles or contractions, so that the
flow is not obstructed or retarded.
 It should be simple in construction, cheap and easily available.
 It should be self-cleansing.

13. SANITARTY FITTING
Traps
Classification of traps
a) Classification according to shape
1. P-Trap: This resembles the shape
of letter P , in which the legs are at
right angles to each other.

14. SANITARTY FITTING
Traps
Classification of traps
a) Classification according to shape
2. S-Trap: This resembles the letter S in
which both the legs are parallel to each other,
discharging in the same direction.
Used in fixing water closet in laterines.

15. SANITARTY FITTING
Traps
Classification of traps
a) Classification according to shape
3. Q-Trap: This resembles the shape of
letter Q in which the 2 legs meet at an angle
other than a right angle.
Toilets other than Ground floor.

16. SANITARTY FITTING
Traps
Classification of traps
b) Classification according to Function
1. Floor Trap: It is used to collect wash water
from floors, kitchens and bathrooms.
 It forms the starting point of wastewater
floor.It is made of cast iron, with a gravity at
top, to exclude entry of solid matter of big
size.
 This cover can be removed to do frequent
cleaning of the trap.

17. SANITARTY FITTING
Traps
Classification of traps
b) Classification according to Function:
2. Gully Trap: It thus receives wastewater from kitchen, baths etc. and pass it on
to the house drain carrying discharge from water closets etc.

18. SANITARTY FITTING
Traps
Classification of traps
b) Classification according to Function
3-Intercepting Trap: This is a special type of trap provided at the junction of
house drain with the public sewer or septic tank.
It has a deep water seal of 100 mm, so as to effectively prevent the entry of
foul gases from public sewer into the house drain.