Muffling of district heating pipes shall be carried out by personnel with an approval socket certificate. Sleeve assembly and insulation of the connection shall be carried out in accordance with the requirements set out in NS-EN 13941, chapter 7.7 and in accordance with the pipe manufacturer’s installation instructions for the individual product. The documents for each project will indicate the type of sleeves to use.
When the joint is mounted and checked, the installer must apply the No./ID on the sleeve with a marker pen.
The contractor shall carry out socket joints so that message threads are not crossed. See separate point regarding alarm system.
The trenches are kept open for visual inspection of the joint work. The contractor must notify the client before the socket work is carried out, so that he can be present during the work of the socket work.
Leak monitoring and alarm system
Message wiring systems shall be installed in accordance with the manufacturer’s instructions.
Pre-insulated pipes with embedded alarm wire are used. The alarm wires must be collected according to the current message thread drawing
Reporting system for leak detection shall be built according to the design documentation. The message wires must be inserted into junction boxes so that the distance between each junction box, including branches, does not exceed 800 m.
The length of the outlet cable should be minimized and recorded accurately for each junction box. The socket cable placed in the ground must be protected against over excavation by placing a cover plate 200 mm above the cable. The cable should be laid with sufficient pig tail to avoid any problems if the district heating pipe moves.
The junction boxes are mounted as follows in order of priority:
- Inside customers
- In valve chamber
- In suitable cabinets along the path
In pipe ends and in customers where the message wires are not removed in connection boxes, the message wires must be connected in a loop inside a socket. When removing message wires from customers, the message wires must not come into direct contact with the steel pipe or any metallic sheath on the pipes.
Message boxes and outlet cables must be numbered and marked according to the prepared message wire form/drawing.
The contractor shall, on a continuous basis, and before the trench is closed, perform necessary control measurements of the message threads. The contractor must check all connections in the message wiring system. As part of the documentation, a protocol must be present with measurements showing that control of message threads has been carried out.
Before laying pipes in road crossings and the like the message wires must be checked for wiring and short circuits against the steel pipe.
If leakage detector and monitoring systems are installed, their function should be checked during installation according to the manufacturer’s instructions.
The client makes measurements of dry pipe before commissioning.
We say today control 6-10 weeks after the pipe is commissioned due to moisture.