AWWA C900:2007
AWWA C900:2007 Polyvinyl Chloride (Pvc) Pre Polyvinyl Chloride (Pvc) Pressure Pipe And Fabricated Fittings, 4 In. Through 12 In. (100 Mm Through 300 Mm), For Water Transmission And Distribution Specifies dimension ratios (DRs) 14, 18, and 25 for nominal pipe sizes ranging from 4 in. (100 mm) through 12 in. (300 mm).