Types of Plumbing and Drainage Systems in Buildings
Vinay Jain
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Plumbing system is used for water supply in building .It supplies water to kitchen toilet outlets via distribution system of pipes. Drainage system is used to get rid of human wastes through well-arranged network of drainage pipes.
For distribution system pipes generally used are GI, copper, HDPE, CPVC, mostly now a days CPVC plastic pipes are used as they don’t get rusted, light weight, easy installation and maintenance and economic.
Types of Plumbing Systems in Buildings
Plumbing system in buildings consists of underground tank which is supplied water via municipal or water department supply lines, from there with the help of pumps and piping distribution system water is supplied to overhead tank and thereby due to gravity water reaches to home outlets.
The overhead tank can however be eliminated if water is supplied directly from underground tank to kitchen toilet outlets, there comes the need of pumps which can give uninterrupted supply of water with required pressure to outlets so that when one opens the tap he gets continuous supply of water. Such pumps are called hydro-pneumatic system.
Such pumps consists of small steel tank with water on one side and air on another separated by a rubber membrane .As the pump starts it supplies water to the wet side thus causing rubber membrane to expand and air compresses on other side thus causing extra pressure on wet side which is connected to water supply line. So as one opens the tap , gets the required quantity of water. This causes the pressure to drop and the pump is automatically switched on again thereby maintaining the pressure of water and at same time supplying the water to outlets .
The advantage of such plumbing system in buildings is that requirement of overhead tanks is eliminated. Secondly these pumps are designed to get the required equal pressure to all floors, unlike in traditional way water flows from underground tanks to overhead tanks and the upper floors gets water with less pressure and lower& ground floor gets high pressure due to gravity and more height.
This gives energy conservation also because it eliminates the need of supply of water ten or twenty floors to overhead tank and then supply by gravity to all floors.
Continuous power supply backed up with generator is required to operate this system efficiently, else if no power no supply of water.
Pumps are of two types:
Submersible pumps, and
Open type Pumps
Submersible pumps are used inside the water and require very less maintenance. Both types can be used for traditional as well as hydro-pneumatic system.
Submersible Pump System
Types of Drainage Systems in Buildings
Drainage system is of two types:
1. Waste water is from showers, basins, kitchen sinks, washing machines, and the like.  This is also called grey water. Normally a minimum of 75 mm dia. pipes are used for drainage of waste water.
2. Soil water or sewage is from WCs and urinals. This is also called black water. Minimum of 100 mm diameter pipes are used for waste water. When run horizontally, soil water pipes should be run at a steeper slope, such as 1:40, as they have solids. These can be of cast iron or of PVC.
A grease trap should be used when draining waste from kitchens, grease should not be allowed to enter the normal drainage system. A grease trap is nothing but a small inspection chamber. The grease floats, and should be removed manually on a daily basis. The inlets and outlets into this chamber should be designed in a way that minimizes disturbance of the floating grease layer.
Stone ware (ceramic) pipes are used when soil and waste water is to be transported in external soil. An inspection chamber is used to clean blockage in the line and change direction of pipes. Inspection chamber is a short version of manholes which are used on the streets.
If municipal government drainage is not available on a small project, or exterior of city, provide a septic tank and a soak pit. A septic tank is a rectangular underground tank with compartments. It is always full of sewage that can be removed manually. The less water put into a septic tank, the better it will function. The effluent that flows out of this, which is about 70% purified, is then put into a soak pit. A soak pit is a cylindrical tank with porous brick walls surrounded by a layer of gravel.
A soak pit should not be placed near any occupied structure, water body, or water supply pipe. It also cannot be used where the water table is high, as groundwater will then enter and flood the pit through the porous walls.
An overall view of complete sewage treatment of a complete city
