AWWA INF52151

The use of cement mortar and, more recently, epoxy resin materials for in situ lining of potable water mains has increased in the United Kingdom (UK) to a point were they are valuable tools in many water utilities rehabilitation programs. Epoxy resins have a demonstrable track record providing a thin, smooth coating with excellent carrying capacity and proven durability. The main limitation of these materials is the extended cure period of 16 hours before return to service which results in a 36 hour period in the UK when customers are without water and in North America the need to lay rider mains and temporary supplies to each property. A number of manufacturers have been working on the development of rapid setting products based on polyurethanes, polyureas and other isocyanate cured materials and one manufacturer now has a fully approved lining material. This product has a gel time of 30 seconds, can be closed circuit television (CCTV) surveyed in 30 minutes and may be chlorinated and returned to service after 2 hours. This paper describes the material and its application, outlines the requirements for lining rig design and associated ancillary equipment and details some of the requirements for quality assurance and accreditation of contractors. The perceived benefits of rapid setting polymeric linings are discussed. Includes 7 references, figures.