AWWA JAW49863

This article describes the results of an 18-month collaborative investigation with 30 water purveyors that studied the effects of Class I and Class 2 wet-pipe fire sprinkler systems on drinking water in distribution mains. In water samples taken from a variety of commercial wet-pipe fire sprinkler systems, water quality exceeded the primary standard for lead and cadmium and the secondary standards for iron, manganese, sulfate, color, odor, and total dissolved solids. In field-scale backflow simulations of an average 3-min hydrant-flow test, about 100 gals (0.4m3) of water backflowed from a wet-pipe fire sprinkler system when the check valve was caused to fail in the open position. The estimated relative risk of being seriously injured in nonresidential fires is 33 times as great as the increased risk of contracting a waterborne illness after backflow has occured. Retrofitting existing Class 1 and Class 2 wet-pipe fire sprinkler systems that do not currently have backflow prevention assemblies would cost about $4.4-6.0 billion nationwide and was deemed not cost-effective. Includes 27 references, tables, figures.