1. The site plan of the building should be drawn to a
convenient scale and positions of gully traps should be marked on it. The building site
plan is normally drawn at a scale of 1: 1000.
2. The longitudinal section of the proposed sewer line should be
drawn at a scale of 1: 100. The size of drain pipes should be at least 10 cm but
normally 15 cm diameter pipes are adopted.
3. The longitudinal section should show distances, ground
levels, invert levels, depth of cutting, size of chambers and manholes, size
and gradient of pipes.
4. The position of public or municipal sewer should be
clearly shown on the Building site plan. It is advisable to join the house drain at a
manhole on the public sewer line.
5. Detailed Building design plans of different floors of buildings show the
positions of floor traps, sanitary fittings, etc. They are to be connected by
keeping in mind the general principles of house drainage.
6. House drains are laid as per details on the approved drainage plan of the building.
7. House drains are tested for water tightness
and trenches are lastly filled up.
In a multistoried building, Lavatory blocks on different
floors are usually arranged one above the other, so that the same soil pipe and
vent pipe may serve all of them. A water storage tank is built at the top of the
building and clear water is pumped into it from the ground storage reservoir.
Ground storage reservoir gets water from the public water supply system. Water from
the top storage tank flows under gravity through the pipe to W.Cs and other
fitments automatically. The waste discharge from all these sanitary and soil
fittings is carried away by a vertical pipe fixed against an outside wall of the
building. The discharge flows down through soil pipe into the house-drain which
in turn leads it to the municipal street sewers. An inspection chamber is
provided at the ground where the soil pipe joins the house-drain. In addition
to the soil pipe, a vent pipe or anti siphonage pipe is also provided to
preserve the water seals of house fittings. The soil pipe is provided with a
wire cage at the top so as to prevent the entrance of birds in them.
How to test Building drains?
Testing of House drains
After laying, the house drains are tested to ascertain their
water tightness. The drains are usually tested in sections between successive
chambers and the vertical pipes are tested in groups, each group having one
common inspection chamber.
1. Air test for the House drains -In this test, the pipe is kept plugged both at
lower and upper ends and the air is forced into the pipe with the help of a pump.
All the joints of the drain are coated with the soapy solution. If any joint is
leaking it will form bubbles at the joints.
2. Water test for the House drains - In this test, the drain is plugged at the lower inspection chamber, and water is filled in the pipe to cause a pressure equivalent to a head of 1.5 m. There should not be any visible drop in water level within ten minutes.
3. Smoke test for the House drains - This test is carried out to detect the leakage of rain-water-pipes and other vertical waste pipes. In this test, the smoke is forced into the pipe with the help of blowers. Leakage can be sighted by smell or vision of the smoke emitting through the joints.
How to maintain the house drainage system?
Maintenance of House Drainage System
To maintain the efficiency of the house drainage system, it
should be regularly inspected and repaired if need be. Maintenance of the house
drainage system may be carried out under the following steps:
1. Entry of undesirable elements. The user of the house
should be careful in discharging undesirable elements like hairs, sand, grit,
vegetable peelings, rage, etc. into the house drainage. These elements will
cause blocking of the fitments and affect the efficiency of house drainage.
2. Flushing. All the drains should be flushed with an adequate
quantity of water at least twice a day.
3. Inspection. Various sections of the house drainage system
should be inspected at regular intervals. If any obstruction or breakage is
noticed during inspection, it should be immediately made good.
4. Quality of material. Materials used in house drainage
should be of good quality. The internal surface of the sewers or drains and
fittings should be smooth.
5. Use of disinfectants. To maintain better hygienic
conditions, lavatory blocks, bathrooms, W. C’s, urinals, etc. should be
disinfected from time to time.
6. Workmanship. Only licensed or authorized plumbers should
be allowed to take up the plumbing work.
Post a Comment