AWWA ACE54242

This paper describes the results of an 18-month investigation that was performed with the participation of thirty water purveyors to study the impacts of Class 1and Class 2 wet-pipe fire sprinkler systems on drinking water in distributionmains. Based on water samples taken from a variety of commercial wet-pipe fire sprinkler systems, water quality was found to exceed the primary standard for lead and cadmium, and secondary standards for iron, manganese, sulfate, color,odor, and total dissolved solids. Field-scale backflow simulation evaluations indicated that approximately 100 gallons of water backflowed from a wet-pipe fire sprinkler system when the check valve had failed in the open position during anaverage 3-minute hydrant-flow test. The estimated relative risk of being seriously injured in non-residential fires is thirty-three times greater than the increased risk of contracting a waterborne illness if a backflow event were to occur. The cost to retrofit existing Class 1 and Class 2 wet-pipe fire sprinkler systems that do not currently have backflow prevention assemblies wouldapproximate between $4.4 billion and $6.0 billion nationwide, and was deemed not cost-effective. Cost-benefit-risk evaluations indicate that the retrofit installation of a backflow prevention assembly on existing wet-pipe fire sprinkler systems having functioning, non-lead-containing alarm check valves is not cost-effective. However, implementation of cross-connection control in the design and construction of new non-lead containing Class 1 and Class 2 wet-pipe fire sprinkler systems using approved backflow prevention assemblies should be vigorously pursued. Includes 27 references, tables, figures.