High Performance Fabric In Old Piping: Quick, Durable Restoration Of Operational Safety

By Andreas Hüttemann, Qualified Engineer Director, R&D/Quality Management, Karl Weiss Technologies and Brian Mattson, Business Development Manager, GTI | December 2009 Vol. 64 No. 12
Fig. 6 Woven fabric reversion of pit three toward pit one with a length of 994 feet.

In Berlin, just two to 3 percent of recorded water losses occur through distribution of drinking water. This very low figure, by national and international standards, is a result of systematic maintenance and upkeep of the pipes and fittings. For example, it is in this way that one percent of the pipe network will be repaired each year. Likewise, the number of damages to mains and supply pipelines has continually decreased as a result of these measures. Currently, the rate of pipe damage is less than 0.11 pipe damages per mile, per year. This is a comparatively low value even in relation to the appropriate standard. Nevertheless, pipe damages cannot be prevented even through consequential maintenance. However, the following report shows that Berlin Water Works does not just repair pipe damage. On the contrary, depending on the damaging event and condition of the pipe, the most appropriate methods will be selected so that the necessary operational safety and hygiene of the affected section of piping can be restored.

For this project, expectations were met when Starline HPL-W woven fabric relining was used to rehabilitate a 20-inch cast-iron drinking water pipe. Apart from the fulfilling hygienic requirements, the provisions for design in DVGW worksheet GW 327 were adhered to. For this reason, the prerequisites for a permanent rehabilitation of necessary operational safety are given. Savings on underground work have led to an expected reduction of building time and significant reduction of costs. Only approximately 50-60 percent of the costs that would have been incurred from an exchange in open construction have materialized through use of the woven fabric liner.

Fig. 1 (1) Outlet of a crusted and decrepit local drinking water pipes.
(2) Grey cast-iron cleaned by sandblasting.
(3) Reversion of the adhesive filled woven fabric liner.
(4) Long-term, crease-free and burst-proof lined pipe.

Chronology of pipe damage, repair strategy
Feb. 10: When two teams playing football noticed the grass around a penalty spot was starting to get moist and wet, Berlin Water Work’s fault-clearing service was called out. They immediately ascertain that there was pipe damage to a grey cast iron 20-inch (DN 500) drinking water main. The 1,706-foot section of piping affected runs alongside a school and continues under four sports fields. The pipeline was constructed in 1926 and transports drinking water from a water works facility in the eastern region of the city to the inner city.