Plumbing is any system that conveys fluids for a wide range of applications.
Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids.
Different types of plumbing pipes are used in building construction works for various purposes such as water supply,
drainage, waste disposal made of different materials.
In every building, sufficient quantity of water should be available at required locations to meet various needs of occupants.
So, water needs must be properly computed before the construction of structure.
The transmission water is carried through pipes within the structure above or below the ground.
At the same we must compute the proper drainage facilities to drain the wastewater through pipes.
The Plumbing system comprises the whole system of pipe fittings and appliances used for water supply and drainage.
In this supply and drainage system different pipes are used for different purposes which are explained below.
- Supply or service pipes
- Drain pipes or waste disposal pipes
Supply Pipes or Service Pipes
The pipes which are leading from the distribution main of water supply to the plumbing system of house are known as service pipes.
These service pipes are made from different materials as classified below.
- Copper Pipes
- Galvanized Iron Pipes
- Polythene Pipes
- Lead Pipes
Copper Pipes :
When ground water is highly corrosive to metals then copper pipes are used.
Copper have high corrosive resistance when compared to other pipe metals and they also have considerable strength, reasonable ductility.
They are available in long lengths in the market. They can bare high pressure so; these pipes are also used for industrial purposes for heavy flows.
There are two types of copper pipes are available namely HEAVY GAUGE and LIGHT GAUGE pipes.
Heavy gauge pipes are used where pressure is very high, like as the leading pipe from distribution main, for large flows etc.
light gauge pipes are used when the pressure does not exceed 0.15N/mm2 that is for internal domestic pipes.
Galvanized Iron Pipes :
When compared to copper pipes, G.I pipes or steel pipes are very economical. But they corrode easily in soft and acid waters.
In the other case galvanized iron pipes are much stronger than copper pipes so, we can use this pipes in places where chance of corrosion is less or in hard water areas.
Hammering is needed to remove the scales formed by hard water.
Polythene Pipes :
Polythene pipes or plastic pipes are used for cold water services. Nowadays, plastic pipes dominate the others by some advantages as follow
- Do not corrode
- Cheap in Cost
- Less Weight
- Ease of Installation
- Do not Require Threading
- Resistant to bacterial scale
Lead Pipes :
Lead pipe has high corrosion resistance, flexibility and hydraulic coefficient of flow.
But lead content in water may leads to poisoning effects which are harmful for people.
So, it is not preferred.
Drain Pipes or Waste Disposal Pipes :
Generally, in a house waste water is produced from different places like kitchen, bathrooms, etc.
these whole waste is does not carried by single pipe instead of different pipes are arranged to dispose the waste.
The types of waste water pipes are described below.
- Soil pipe
- Rain Water pipe
- Waste Water pipe
- Vent pipe
- Anti-siphon age pipe
A pipe which carries human excreta from water closet to septic tank is called soil pipe.
It is not connected to any other pipes except vent pipe.
Soil pipe should have 100mm diameter.
Rain Water Pipe
A pipe which carries rainwater from roofs during rains is called rain water pipe.
By providing this type of pipe we can prevent the accumulation of water on roof top.
The water collected is useful for gardening or farming. 75mm diameter pipe is preferable for rain water disposal.
A pipe which carries only liquid waste from kitchens, wash basins etc. is called waste pipe.
It does not carry human excreta.
Horizontal waste water pipes are having 30 to 50mm diameter and vertical wastewater pipes have 75mm diameter.
A pipe which is provide for the ventilation purpose to facilitate the exit of foul gases into atmosphere.
It is opened at top and bottom. It is provided at least 1m higher than roof level.
Generally, 50mm diameter pipes are provided as vent pipes.
A pipe which is installed for the purpose of preserving the water seal of traps in drainage system is called anti siphonage pipe.
So, this is very helpful to seal the back flow of drainage. Anti-siphon age pipe connected to soil pipe should have 50mm diameter,
connected to waste water pipe should have 40mm diameter.
Drainage Pipes Based on Material of Manufacturing
Pipes used in drainage system are made of different materials. Which are as follows
- Concrete Pipes
- Cast Iron Pipes
- Stone Ware Pipes
- PVC Pipes
- Asbestos Cement Pipes
For heavy drainage water disposal, concrete pipes of large diameters are used.
Smaller diameter pipes are used for small flows.
These are made of concrete only; no reinforcement is provided.
These are pre casted pipes.
Cast Iron Pipes
These are made by pouring molten iron into sand molds.
These are used for rain water disposal, waste water disposal etc. they are available only in shorter lengths
Stone Ware Pipes
These are manufactured in ceramic industries by burning soft soil in high temperature.
These are used for carrying drainage in underground.
For installation of stoneware pipe skilled workers are required.
These are used for both supply system and drainage system.
These are very economical and easy to maintain.
Soil pipes, kitchen waste pipes are generally PVC pipes.
These pipes are very cheap compared to all but they can break easily.
They are provided as vent pipes, soil pipes, rain water pipes etc
Factors Influencing Selection of Water Distribution Pipe Size in Buildings
- Cost effectiveness
- Pressure at the source of water supply
- Required pressure at each outlet fixture (examples of outlet fixture are bathtubs, channel drains, bidets, drinking fountains, kitchen sinks, bathroom sinks, showers and others)
- The loss of pressure of outlets placed above water source. Loss of pressure is commonly caused by friction of water. The friction is occurred due to flow of water in pipes, water flow meter, and backflow preventer.
- Restriction on water flow velocity to avoid noises and pipe erosion.
- Extra capacity of possible expansion in the future. Generally, the additional capacity if around 10 percent.
- Economic considerations govern the selection process to a great extent. But other factors explained above may enforce the use specific pipe size other than the most economical ones.