Prepared By:- SUSHIL KUMAR

INTRODUCTION

The pipes are hollow circular cylinders are used for transporting various fluids such as water, steam, gases, oils and other chemicals from one place to another.

The pipes are usually connected to vessels from which they transport the fluid.

The extensive use of pipes is found in water supply and sewage disposal system, oil refineries, food processing plants, chemical plants and power stations.

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The pipes are also used as structural elements such as columns and hand rails.

The pipes are made of large no. of materials such as cast iron, wrought iron or malleable iron, steel, brass, copper, aluminium, lead, concrete, plastic, rubber etc.

The choice of material depends upon the purpose for which the pipe is used.

Metal pipes. Plastic (PVC) pipes in USA

Classification Of PipesThe pipes, according to the material and

their use, are classified as follows :- Cast iron pipes :- The cast iron pipes are

used only for low pressures application because of its low resistance to shocks.

They are best suited for water, gases and sewage systems.

The C.I. pipes for water, gas and sewage are available in various sizes from 80 mm to 1500 mm nominal bore and lengths upto 4 meters.

Wrought iron pipesThe wrought iron pipes are used for carrying

water and gas at low pressure for domestic purpose.

The pipes are galvanised by dipping them in a molten zinc. Such pipes are also known as galvanised iron pipes.

Galvanizing prevents corrosion of pipes.The pipes are available in various sizes from

6 mm to 150 mm nominal bore and length from 4 to7 meters.

Steel PipesThe steel pipes are used for carrying water,

steam, gas, sewage and air at a high pressure.

As compared to cast iron and wrought iron pipes , the steel pipes have greater strength, less liable to breakage and longer length upto 12 meters.

Steel pipes are available in various sizes from 50 mm to 1800 mm nominal bore.

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A complex arrangement of rigid steel piping, stop valves regulate flow to various parts of the building.

Copper and Brass pipesThe copper and brass pipes are generally

used for hot water systems, refrigeration systems and general plumbing work.

Copper and brass pipes corrosion resistant and are suitable for processing plants where scale and oxidation of steel pipes are harmful.

The copper and brass pipes can easily bent or coiled to the desired shape.

These pipes are available in straight lengths upto 4 meters.

It may be noted that the copper pipes of less than 50mm diameter are called tubes.

Aluminium pipesThe aluminium pipes are used in aircraft and

marine applications, because of its light in weight.

They are also used for furniture and decorative work.

Lead pipes The lead pipes are used for sanitary purposes

.These pipes are made by expanding molten

lead through die over a mandrel. The lead pipes can be easily bent to the

desired shape.The lead pipes are available with nominal

internal diameter ranging from 10 mm to 125 mm and thickness from 2 to 10mm.

An original Roman lead pipe with a folded seam, at the Roman Baths in Bath, UK.

Concrete pipesThe reinforced cement concrete pipes are widely used

for water mains , sewers, culverts and in irrigation.These pipes are made in three types i.e. light duty,

medium duty and heavy duty.The light duty pipes made with nominal internal dia.

Ranging from 80 mm to 2200 mm and thickness from 20 to 110 mm

The medium duty pipes have 80 mm to 2600 mm nominal internal dia. And thickness from 25 mm to 215 mm.

The heavy duty pipes have 80 mm to 1200 mm nominal internal dia. And thickness from 25 mm to 65 mm.

Plastic pipes The plastic pipes are also called P.V.C. pipes.These pipes are cheap and light in weight.They are extensively used for sanitary

purpose and electric wire conduits.These pipes are resistant to most inorganic

acids, alkalies and salts as well as to many organic chemicals and do not corrode.

Plastic pipes are widely used in chemical industry.

Rubber pipes The rubber pipes are flexible and are

available in coils.

These pipes are used in household work for

water, oil and gas.

Indian Standard Specification for PipesAccording to Indian Standards [IS : 1239

(Part I )-1990] the pipe size is designated by the nominal bore of the pipe.

For example, a 15 mm pipe means that the dia. Of bore is 15 mm.

For each nominal bore, there are three types of pipes, i.e. light , medium and heavy depending upon the wall thickness of the pipe.

Pipe Fitting

PIPE FITTINGSThe pipe fittings are used to join adjacent

lengths of pipes.They are also frequently used to provide

change in direction, to provide branch connections at different angles or to effect a change in size.

They are made of cast iron, malleable iron, cast or forged steel, non-ferrous alloys and other materials for special application.

The non-ferrous are made for threaded, solder and flanged joints.

The various screwed fittings commonly used with malleable iron or steel pipes are as follows:

1.Tee- It is used to connect a branch pipe at right angles to the main pipe line. The tee may be of equal size or of reducing size.

2. Elbow – It is used to connect pipes at right angles. The elbow may be of equal size or of reducing size.

3. Cross – It is used to connect four pipes at right angles to each other.

4. Socket- It is used to connect two pipes of same diameter.

5. Reducing socket – It is used to connect two pipes of different diameters.

6. Nipple or coupler – It is a small length pipe having outsode threads at the ends. It is used to get extra length of pipe , by screwing it with the two pipes having internal threads.

7. Union – It is used to connect two pipes and can be disconnected easily when desired.

8. Plug – It has external threads and is used with a tee or cross to close the opening of ba pipe which is left for further use.

9. Cap – It has internal threads and is used to close the threaded end of the pipe.

Pipe jointsWe have already discussed that the lengths of pipes

available are limited .Therefore various lengths of pipes have to be joined to suit

any particular installation. There are various forms of pipes joints used in common

practice ,but the most common of them are discussed below :

Socket or coupler joint : The most common method of joining pipes is by means of a socket or a coupler .

A socket is a small piece of pipe threaded inside . It is screwed on half way on the threaded end of one pipe and the other pipe is then screwed in the remaining of the socket .

In order to prevent leakage ,jute or hemp is wound around the threads at the end of each pipe.

This type of joints is mostly used for pipes carrying water at low pressure and where the overall smallness of size is most essential.

Nipple joint

In this type of joint , a nipple which is a small piece of pipe threaded outside is screwed in the internally threaded end of each pipe.

The disadvantage of this joint is that it reduces the area of flow.

Spigot and socket jointA spigot and socket joint is chiefly used for

pipes which are buried in the earth.These joints are adopted for connecting cast

iron pipes in underground installations.One of the important feature of this joint is

its flexibility as it as it adopts itself to small changes in level due to settlement of earth which takes place due to climate and other conditions.

Expansion jointsThe pipes carrying steam at high pressure

are usually joined by means of expansion joints.

This joint is used in steam pipes to take up expansion and contraction of pipe line due to change of temperature.

Flanged jointIt is one of the most widely used pipe joint.The flanges are connected by means of bolts.The flanged have been standardised for

pressure upto 2N/mm².The joint may be made leak proof by placing

a gasket of soft material, rubber between the flanges.

The flanges are made thicker than the pipe walls, for strength.

Hydraulic pipe jointThe flanged joint, which is used on high –

pressure water pipes and is called “Hydraulic Pipe Joint”

This type of joint has oval flanges and are fastened by means of two bolts.

The oval flanges are usually used for small pipes upto 175 mm dia.

Such joints are used to carry fluid pressure

varying from 5 to 14 N/mm².

Cementing

Cementing and gluing is a common method of connecting plastic pipes.

It is easy and takes no special tools and skills.

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Welded jointsThese can be subjected to high pressure, but

cannot be assembled.Copper and brass pipes are usually

connected by soldering. Welded joints are light weighted and less bulky than screwed flanged fittings.

De)soldering a contact from a wire

SolderingSoldering is a process in which two or more

metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a relatively low melting point.

Soft soldering is characterized by the melting point of the filler metal, which is below 400 °C (752 °F).]

The filler metal used in the process is called solder.

soldered copper pipes

Pipe WrenchesPipe wrenches are used to turn pipes , round

bars etc. or for assembling and disassembling them from fittings.

Pipe wrenches are made in several designs but most commonly used are adjustable type wrenches, which have movable part and a main body.

The opening of jaws , depend upon the movable part of the wrench.

Pipe CuttingThe pipes are available in standard lengths in

markets. In order to meet the requirements, it is

sometimes desired to cut or extend the standard lengths to suit our requirements.

Pipes can be cut by two tools :

Hacksaw and pipe cutter