Both the AWWA and ANSI have thorough standards for pipe flanges, the two standards are different in several ways. The AWWA standards provide flange properties intended for potable water use only, while the ANSI standards are designed for industrial flange applications. The AWWA flange ratings are only applicable at atmospheric temperatures. The ANSI ratings cover flange installations from -20* F to 1500* F. ANSI flanges are covered by numbered pressure ratings from 150 psi to 2500 psi. The AWWA standard uses lettered ratings, Class B, Class D, Class E and Class F. The AWWA standard only encompasses ring, hub and blind flanges. The ANSI standard includes all flange types as well as welded auxiliary connections and tapping. There are currently 180 standards covered by the AWWA, C207 for carbon steel flanges and C228 for stainless steel flanges. The C228 standard for stainless steel flanges was introduced in 2008 for flanges to be used in conjunction with stainless steel pipe in waterworks service. Pressure ratings for water service are SA-50 psi, SB-86 psi, SD-150 psi and SE-275 psi. Call one of our sales rep’s with any questions or a quote tailored to your requirements.