TT PE & TT PUX coatings ITA

TT - PE and PUX

Standard TT pipes are just as easy to lay as STANDARD joint pipes. The few operations and precautions specific to STANDARD TT pipes are described in this section.

Storage

Pipe and fitting storage

Pipes and fittings must be stored on flat ground free of any stones.

• Pipes DN 60 to 300 (polyethylene coating)

The pipes are delivered in bundles. They can be stored secured by timber wedges.
Stacked height should not exceed 2.50 m. Between two adjacent bundles, the pipes must be laid alternately spigot to socket, and aligned to ensure there is no contact between the pipes.

• Pipes DN 350 to 700 (polyethylene coating) and pipes DN 800 to 2 000 (polyurethane coating)

Pipes DN 350 to 2 000 are delivered individually. Pipes must be stored as follows:
– the pipes in the same layer are placed spigot to socket alternately to the layer below (without any timber wedges between layers) ;
– the first layer rests on timbers 120 mm wide secured by timber wedges.

Fittings

Fittings should be stored by type and by diameter on timbers or boards.
Avoid stacking fittings, or make sure there is intermediate protection to avoid damaging the epoxy coating.

Earthworks

If the extant soil presents any risks to the coating (rocks, stones, etc.), it is necessary to prepare the trench bottom with a minimum thickness of 10 cm.
After having laid the pipe, the same precautions must be taken with regard to the pipe surround and backfill.

Assembly

Protection of joints

– Check the spigot chamfer.
– Slide the sleeve onto the pipe spigot.
– If necessary use lubricating paste.
– Turn the sleeve back so it is ready for joint assembly.

Joint protection

After jointing and checking, turn the sleeve over the joint to protect it.

• Pipes and fittings DN 350 to 700 (polyethylene coated pipes)

Install the RAYCHEM-type heat-shrink tubular sleeve:
– Check the spigot chamfer.
– Place the sleeve behind the socket.
– Joint the two parts and check.
– Clean with a rag the area to be protected.
– Roughen the polyethylene surface with emery paper over the same area as the sleeve width.
– Pre-heat the roughened polyethylene area with a gas flare. Raise the temperature without going beyond 60°.
– Remove the protective sheet from inside the sleeve.
– Centre the sleeve on the joint to be protected.
– Using the gas flare (soft flame), start shrinking the sleeve by successive sweeps across the entire surface, starting with the largest section of the joint diameter.
– The operation is complete when the adhesive starts to run out each side of the sleeve. Smooth the sleeve with a gloved hand, if necessary.

• Pipes and fittings DN 100 to 2 000 (polyurethane coated pipes)

Given the coating applied to these pipes and fittings, no protection is required for conventional joints of these products.

Cutting

Cutting pipes DN 60 to 700 (polyethylene coating)

It is impossible to joint with the polyethylene coating. The polyethylene coating must therefore be removed and the cut prepared as follows.
If the pipe must be cut, only use so-called “calibrated” pipes. These pipes must be stipulated on ordering.
Take into account the jointing depth when marking the cut. Cut the pipe.

• Polyethylene area to be stripped

Mark the maximum distance from which the polyethylene must be stripped (CPe).

• Cutting the polyethylene coating

Cut the polyethylene coating through to the ductile iron. Use a chisel, a cutter or a pipe cutter (be careful not to cut into the iron). If using a pipe cutter, bring the wheel into contact with the iron, then release by a half turn before cutting.
Also make a lengthwise cut, so the polyethylene can be stripped.

• Preheating and stripping the polyethylene

Use a gas flare to preheat the area from which the polyethylene is to be stripped working from inside the pipe and without damaging the cement mortar coating.
Gradually raise the temperature without exceeding 40°C (you should be able to lay your hand on the heated cement lining).
Once the pipe has warmed through, lift one edge of the polyethylene with a chisel and then strip it off in a single piece. The adhesive should remain attached to the polyethylene.

Cutting pipes DN 800 to 2 000 (polyurethane coated pipes)

It is possible to joint with the polyurethane coating. If so-called “calibrated” pipes were not specified on the order, it is essential to first measure the outside diameter of the pipe where it is to be cut, with a circumference tape.
The maximum outside diameter, including the polyurethane coating, should not exceed the following values: