Digging Technique

The details for the digging of the pre-insulated Nimka pipes are shown at the table. Grounds which were not strong enough must be prepared for the lining of the pipe. Underneath the pipe min. 10 cm sand had to be applied and paved.

Lining of the steel pipe

The welding of the steel pipe had to be made according the EN 288-1 standard. The welder had to be certified according the EN 288-1 standard. The radiographic inspection had to been made according EN 444 and EN 1435.

Insulation of the joint-parts

1. Before the lining of the steel pipe the joints must be pulled over the overcoating protection pipe. After the welding of the steel pipes and necessary test have been applied the PE - surfaces on which the joints will come must been cleaned with solvent or alcohol.



2. The joints must overlap min. 10 cm over the steel over coat, contracting tape must be surrounded, surfaces cleaned, the PE surfaces  must be cleaned with a metal brush till the shine of the surface removes and had to be cleaned with solvent and be heated up to 60°C with a big mouth blower.



3. The shrink tapes must be applied at the heated surface with the welding torch. At degrees less than 10°C or over 40°C the shrink tape should be not heated. Tightness test had to been applied and with the polyurethane injection kit the fitting had to be complete.

Notice: With the special produced self contraction unification kits the intermediate parts insulation can be made and for security heat shrink tapes can be surrounded to complete the joints.

Filling

After the intermediate part insulation is complete minimum 10 cm sand filling must be done, on it a security tape has to been placed and at least filled up with earth. The filling should be pressed manually or by machine.


Transport and Storage

While carrying and loading the pipes, nylon alloyed ropes having the sufficient capacity should be used. Some items, such as chain, etc. might cause a risk and danger. During loading and reloading, all safety precautions should be taken and followed.

During the storage of the pipes padding should be done and what is shown in the figures below. Pipes should not be kept under sun light and rain for long and abstained from dust and soil.