Laying, jointing and testing of pipes

SATHYAN S
CIVIL ENGINEERING
KIOT,SALEM.

The water supply system made by pipes of different
lengths which are connected to form a one continuous
length of pipe line. Such connections are called as pipe
joints.
The design of these joints mainly depends on the condition
of the pipe, internal water pressure and the condition of
the support.

Spigot and socket
joint
Expansion joint
Flanged joint
Mechanical joint
Flexible joint
Screwed joint
Collar joint
A.C pipe joint

 Bell and spigot joint
 Used for cast iron pipes
 Enlarged end – socket
 Normal end - spigot
 A few strands of jute is wrapped
around the spigot .
 Remaining space b/w socket
and spigot is finally filled with
molten lead .
 Quantity of lead needed per
joint
- 3.5 to 4 kg for 15cm dia pipe,
- 45 to 50 kg for 1.2m dia pipe.

 Used at places where the
pipes expand or contract
due to change in
atmospheric temperature
and thus setting of thermal
stresses in pipes.
 Socket end is cast flanged
 Spigot end is plain
 On expansion, socket end
moves forward, the gap just
closed.
 On contraction, the socket
end moves backward
creating gap.

 Rigid and strong
 Expensive and mostly
used for indoor works
– pumping stations,
filter plants.
 They are fixed by
means of nuts and
bolts.
 It can be disjointed if
needed .

 Used to join the
plain ends of CI
pipes
 Strong and rigid
 Can withstand
vibrations - useful
for pipes to be
carried over
bridges or below
bridges in
hangers.

 Used where large
scale flexibilities
are required.
 Ex: River with
uneven beds, on
curves.
 Socket – spherical
 Spigot – plain end
having bead.

 Used for connecting
smaller dia of cast iron
, wrought iron
,galvanised pipe .
 It has internal
threads.
 The joint zinc paint or
hemp yarn should be
placed on pipe .

Used to joint big dia. Concrete and
asbestos cement pipe.
1:1 cement mortar is filled in space .

Laying, jointing and testing of pipes

1. Detailed map preparation.
2. Centre line marking.
3. Unloading.
4. Storing.
5. Cutting.
6. Trenches.
7. Laying
8. Back filling and tamping.

 Map showing all roads, cable lines, lanes etc., is prepared.
 Pipe line with size and length is marked.
 The position of existing pipe lines, curb lines, sewer lines will also be marked .

 Transformation from map to site.
 Stakes driven at 30m interval on straight line .
 stakes will be 7-15m on curves.

 Up to 60kg – 2persons .
 Above 60 kg – wagon/truck by holding it in rope and slides over
planks set not steeper than 45°.
 One pipe at a time.
 It may use carriers or be dragged or rolled along hard surfaces.

 To avoid damage.
 It should be stored horizontaly .
 It should be stored in layer
 Mark with a chalk at the point o cut.
 Cut with carpenter’s saw or hack saw .
 It must be a proper uniform cut.

It may be done either hand or
machine.
It must be done with required
gradient and depth.
When it is under a road way min.
cover of 1m is recommended.
Width at the base not less than
200mm on both side of the pipe.
Width may extend for joints .

 Pipes shall be lowered into the trenches by
means of suitable pulley blocks , shear legs,
chains, ropes .
 in no case the pipe shall be rolled and
dropped into the trench.
 Spigot of one pipe is carefully centred into
the socket of other pipe.
 In some clay soil (black cotton soil ) envelope
of 10 cm minimum tamped sand shall be
made around the pipe line.

Back filling must be done carefully to
avoid damages in pipe form falling of
boulders, lifting of pipes from sudden
floods.
Soil under and around the pipe line is
tamped to give continuous supports to
the pipe.
It may be done by tamping rod or
water consolidation.
The initial backfill done for 10 cm
thick.

 Step 1: From section to section. One section at a time.
 Step 2:Downstram valve is closed , upstream valve is opened to fill the water. Air
valves must be properly operated during filling.
 Step 3:Boththe sluice gates are closed .
 Step 4:Pressure gauge is fitted along the length of the pipes at holes which is left
for this purpose.
 Step 5:Section is connected to the delivery side of the pump through a small by-
pass valve to develop pressure in the section.
 Step 6:By-pass valve is closed.
 Step 7: It kept under pressure for 24 hours and inspected for possible defects
,leakages and joints.
 Step 8: Pipe line is disinfected . Add chlorine 50mg/l for 12 hours and the pipe is
emptied and flushed with treated water.

 HEAD LOSS DUE TO FRICTION .(major)
Manning’s formula
Darcy weisbach formula.
Hazen William’s formula.
Modified Hazen William’s formula.
 HEAD LOSS DUE TO BENDS AND CONSTRUCTION(MINOR)

 Internal water pressure
 External water pressure
 Temperature stress
 Water hammer.

 f=pd/zt.
 Above undisrubted soil(cohesion less soil)
 w=C

 Sluice valves / gates .
 Scour valves or blow of valves.
 Air valves.
 Pressure relief valves.
 Check valves
 Automatic shut of valves.
 Manholes.
 Insulation joints.
 Expansion joints.
 Anchorages.

Laying, jointing and testing of pipes

More Related Content

What's hot (20)

Similar to Laying, jointing and testing of pipes (20)

More from sathyan s (7)

Recently uploaded (20)

Laying, jointing and testing of pipes