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.

Summary
Woven fabric relining is carried out with the aim of preserving the existing pipe. Upon the right selection and application with fluid engineering characteristics and technical grading, the pipes lined with woven fabric liner are close to being renewed to new pipes with the same dimensions. The advantage this has over a conventional exchange is particularly to do with a rapid construction and a saving of 90 percent on earthworks. Water pipes made out of grey cast iron, steel, reinforced concrete or asbestos cement are permanently lines with pressure-resistant, smoothly woven textile fabric liner. In future, burst pipes as well as local corrosion damage with a diameter of up to 2-inches will be permanently and securely bridged through the high-strength texture.

Expectations for rehabilitation of a grey cast-iron 20-inch water pipe, by means of Starline HPL-W woven fabric relining, were completely fulfilled. Apart from the fundamentally necessary fulfilling of 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 in 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.

Furthermore, negative accompaniments entailed through conventional underground work, e.g. restriction of space, have been significantly reduced. Moreover, relevant environmental aspects have an ever increasing impact. Only the positive effect of the trenchless construction in relation to the associated reduction in CO2 emissions is referred to. A clear saving on carbon dioxide through the elimination of underground work and transport journeys for ground storage and change of grounds within the inner-city area is to be noted. In this case, only five pits with a total length of 53 feet have been constructed for the rehabilitation of a 1,716-foot long section of piping.