Demonstration and evaluation of an innovative water main rehabilitation technology: spray-on polymeric lining

Many utilities are seeking innovative rehabilitation technologies to extend the life and fix larger portions of their water distribution systems with current funding levels. The information on the capabilities and applicability of new technologies is not always readily available or easy to obtain from an independent source. To meet these needs, the U.S. Environmental Protection Agency (EPA) developed an innovative technology demonstration program to evaluate rehabilitation technologies that have the potential to reduce costs and increase the effectiveness of the operation, maintenance, and renewal of aging water distribution and wastewater conveyance systems. This paper provides an impartial assessment of the effectiveness and cost of a spray-on polymeric lining technology for water main rehabilitation. The spray-on lining technology ultimately resulted in a liner failure, which was discovered during the post-rehabilitation flow test, which was part of the demonstration protocol QA/QC activities. The failure discovery was important in helping to identify material formulation issues and subsequent analysis of the potential causes of the failure indicated that moisture conditions (previously not experienced in product development and use) prevented a proper chemical reaction from occurring, which greatly reduced the material properties, resulting in a lining collapse. Recommendations for the study of important issues such as the effect of ambient conditions on the resin curing process, cleaning requirements for surface preparation, and other key issues in order to help to better understand the technology are made to help avoid the occurrence of future failures with this technology.