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.

As with all trenchless methods, the advantages of woven fabric relining can only be used if systematic quality assurance is in place. This must take into account the suitability of materials used with regard to hygiene, durability and mechanical features as well as their usage, i.e. implementation at the construction site. Furthermore, trenchless operations must be carried out with the same general knowledge and same quality as classic pipe construction. This is achieved through a controlled and documented procedure, qualified and trained staff and state-of-the-art equipment. In the DVGW worksheets for trenchless construction, there is a set of regulations in which requests specific to the operation, quality assurance on the construction site and necessary tests are defined. Using this set of regulations it can be ensured that upon intended use, the quality of a pipe constructed using classic construction techniques.

The absolutely necessary prerequisite for the choice of procedure was the present proof of harmlessness in hygienic drinking water with regard to physiology and microbiology. For this reason, requirements according to DVGW worksheet W 270, the epoxy resin guideline as well as the KTW guideline and KTW recommendation of Germany’s Federal Authority of Health were to be fulfilled. It must be ensured that the coated woven fabric liner joined with the adhesive (i.e. stuck to the pipe), fulfils the hygienic and microbiological requirements for pipes in the corresponding diameter category. A further obligatory prerequisite for the rehabilitation of the approximately 1,706-foot-long pipe section was the allowance for the yet to be published GW 327 worksheet “Lining of gas and water pipes with pasted woven fabric liners” which was worked on as a part of the DVGW project entitled Trenchless Construction.