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LAYING AND JOINTING
GENERAL
Lifting and handling pipe and working in trenches are hazardous operation.
The following instruction are designed to ensure that during laying and
jointing the quality of the pipes and the fittings is not impaired, nor
the actual jointing procedure compromised. It is essential that these
operations are carried out by persons skilled in these procedures. The
work must be supervised and conform to all relevant health and safety
regulation.
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ASSEMBLY OF PUSH ON JOINTS
Pipes should at all times be handled with care in accordance with the
manufacturer’s recommendations. Pipes should be lowered into the
trench with tackle suitable for the mass of the pipes. A mobile crane
or a well designed set of shear legs should be used and the positioning
of the sling checked, when the pipe is just clear off the ground, to
ensure a proper balance. When lifting equipment is not available,
smaller diameter pipes should be lowered using suitable ropes.
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All persons should vacate the section of the trench
into which the pipe is being lowered.
All construction debris should be cleared from the inside of the pipe
either before or just after a joint is made. This can be done by passing
a pull – through along the pipe, or by hand, depending on a diameter
of the pipe. When laying is not in progress, a temporary end closure
should be fitted securely to the open end of the pipeline. This may make
the pipes buoyant in the event of the trench becoming flooded, in which
case the pipes should be held down either by partial re – filling
of the trench or by temporary strutting.
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General instructions for jointing Push on joints
are listed below, followed by the various methods for closing the
joint
Before assembly, the outside of the spigot
and the inside of the socket of the two pipeline components
to be joined must be thoroughly cleaned. Where there are no
minimum and maximum insertion distances on the pipe, these
should be marked according to the table.
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Insertion of the gasket can be facilitated by
the prior application of a thin film of lubricant to the bulb
seating inside the socket. It is important not to apply lubricant
to the heel area of the gasket.
The gasket should be inspected to ensure it
is not deformed or damaged. The rubber gasket should be cleaned,
flexed and then placed in the bottom of the socket with the bulb
leading. Care must be taken to ensure that the groove in the
ring is located on the retaining bead in the socket and the heel
of the ring is firmly bedded in its seat. Make sure the joint
ring fits evenly around the whole circumference and smooth out
any bulges which would prevent the proper entry of the spigot
end.
In the larger diameters this operation may be assisted by forming
two or four loops in the ring, then pressing the loops flat one after
the other.
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Apply a thin film of lubricant to the inside
surface of the joint ring where it will come into contact with
the entering spigot, which may also be covered with a thin film
of lubricant for a distance of 75 mm from the end.
The incoming spigot must be aligned and entered
carefully into the socket until makes contact with the joint
ring. Final assembly of the joint is completed from this position.
The joint is then made by forcing the spigot
of the entering pipe past the joint ring of the receiving pipe,
thus compressing the ring, until the socket face is positioned
between the minimum and maximum insertion distances (see table
below). Insertion distances should be marked if they are not
present.
If this final assembly cannot be attained by the
application of reasonable force, the spigot should be withdrawn and
the position of the joint ring examined. Where necessary the spigot
can be withdrawn from the bottom of the socket by moving the far
end of the pipe upwards and sideways for a distance of about 150
mm, and then returning to the straight position.
Click here for
information on Jointing Tackle
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Jointing Parameters
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Insertion Depth
For Pipes (mm) |
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Insertion Depth
For Fittings (mm) |
DN<
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Max.
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Min.
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Max. Joint
Deflection in Deg.
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Max. |
Min.
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80
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87
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58
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5
|
73 |
49
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100
|
87
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58
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5
|
74 |
50
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| 150 |
87 |
68 |
5 |
75 |
51 |
| 200 |
95 |
70 |
4 |
81 |
58 |
| 250 |
100 |
75 |
4 |
89 |
61 |
| 300 |
105 |
77 |
4 |
97 |
66 |
| 350 |
105 |
77 |
3 |
96 |
68 |
| 400 |
110 |
82 |
3 |
106 |
74 |
| 450 |
115 |
82 |
3 |
102 |
75 |
| 500 |
120 |
90 |
3 |
112 |
82 |
| 600 |
140 |
100 |
3 |
120 |
87 |
| 700 |
145 |
102 |
2 |
140 |
94 |
| 800 |
155 |
105 |
2 |
145 |
89 |
| 900 |
170 |
125 |
1o30' |
155 |
89 |
| 1000 |
180 |
135 |
1o30' |
155 |
89 |
| 1100 |
185 |
140 |
1o30' |
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