DynTec (close-fit-lining)

DynTec is a procedure (DVGW work sheet GW 320-2) where standard PE pipes are temporarily and uniformly reduced in diameter on site and inserted into the existing old pipe.

DynTec is a trenchless procedure for installing a new pipe. It is most suitable for the elimination of internal corrosion and the repair of leaks, the improvement of corrosion resistance and the increase of nominal pressure as well as for the renovation of gas, water and sewagepipes being at risk of breakage and collapse. Depending on the technical capacity of the reducing device, pipe lengths of up to 1 000 m with nominal diameters between DN 80 and DN 1 200 and pressure stages between SDR 33 and SDR 11 can be realised.

In order to reduce the diameter of the PE pipe run, it is drawn through a conical swage ring – this is a cold process or is facilitated by the controlled addition of heat. Once installed, the material is automatically expanding which leads to a close-fit connection with the old pipe.
 
The DynTec procedure does not show the annular gap, which is typical for other relining methods. The fact that the PE material regains the inside diameter of the old pipe allows the maximum utilisation of the existing cross section. Depending on the length of the section and the diameter of the pipe, rehabilitation work can be finished within one or two days. After the pressure test, the connection with the existing network is carried out by using standard formed parts.

The result of the rehabilitation using the DynTec procedure comes up to the installation of a statically self-supporting new pipeline. Due to the fact that the new pipe forms a close-fit connection with the old pipe wall, there is hardly any reduction of cross section. The economic efficiency results from the low construction costs and the short construction time. The rehabilitation takes place without an considerable impairment of residents, road traffic and environment.