Lesson 10 : Water supply system, drainage system and drainage bye laws
Water supply in independent house and multistoreyed buildings
Water Supply In Residential Buildings
Public water supply system consists of collection, conveyance, treatment and distribution.
Water is distributed for consumption in a building through internal water distribution system.
Water supply in a building depends on the size and height of the building.
Water piping system may be basically horizontal or vertical systems above the main or pressure tank are called up feed systems.
In tall buildings water is pumped to elevated tanks, so that it can flow down.
Before designing building water requirement should be calculated keeping the present and future needs of the occupants.
Availability of sufficient quantity of water sources like municipal water, ground water and surface water should be found.
Normally municipal water is treated and supplied, whereas ground and surface water should be properly treated as per the need of the users.
Distribution of water is done with pipes internally in a building.
Residential buildings are normally one, two or three –storeyed constructions.
Individual residences are connected to the public water main by a service pipe.
A water meter is connected to the service main.
Once the service pipe emerges from the floor level of the building, it is referred as the rising main.
The service pipe can supply to upper floors depending upon the available water pressure.
If adequate pressure is not available, then water can be collected in a stump, which can be constructed below the ground floor level and pumped up to the elevated water tanks with a motor.
From these tanks, water can be distributed down with gravity pressure.
Water storage tanks located on the terrace should be properly covered and protected from contamination.
Plastic water tanks are preferred for storage purpose.
Water Supply in Multi Storeyed Buildings
Water supply pressure from the main will not be sufficient to reach the upper floors on many occasions, so it is necessary to pump it to reach the upper floors.
The water requirement in such buildings is very high for both drinking and general use.
Thus there is a need to store water and supply it with gravity pressure.
The storage of water is possible only on the terrace of the building.
Pumping of water from the main becomes a necessity, but continuous operation would be costly and difficult to maintain.
To avoid this, storage techniques are employed to prevent continuous pumping. Most common storage systems used are:
The header storage system
Enclosed tank system
The header storage system
Inthis system, water is pumped through the rising main to the terrace of the building, where two storage tanks are placed.
One is meant for drinking water, and the other overflowing water from this tank is connected in another storage tank for general use.
The storage water is supplied with gravity pressure in separate pipes for drinking and general use.
Enclosed Tank System
Normally drinking water is directly taken from the main because storage can lead to contamination.
However, storage of drinking water is inevitable due to various reasons for daily use. So it should be stored in enclosed, insulated and ventilated tanks to avoid contamination.
There are two common storage systems adopted for this purpose.
In one system, two separate tanks are located for drinking water and general use at the ground or basement floor level.
The capacity of the tanks at the roof level can be dwelling unit-wise or floor-wise or one for all the dwelling units.
In another system, a large tank is located in the ground or basement floor to supply both drinking water and general purpose water.
From this tank, water is pumped to the roof level for storing separately for drinking and general use.
From these storage tanks, water is supplied by gravity pressure in separate pipes for drinking and general use.
In both the systems water is pumped to the roof level with motor.
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