This standard establishes minimum requirements for rubber-seated butterfly valve assemblies, 78 in. (2,000 mm) diameter and larger with flanged ends for fresh and reclaimed water having a pH range from 6-12 and a temperature range from 33°-125°F (0.6°-52°C) and suitable for a maximum steady-state fluid working pressure of 250 psig (1724 kPa [gauge]), a maximum steady-state differential pressure of 250 psi (1724 kPa), and a maximum full open fluid velocity of 16 ft/sec (4.9 m/sec) based on nominal valve size. Major revisions made to the standard in this edition include the following: AWWA Pressure Class 250B was added; additional advisory information on installation was added to the Foreword; body shell thickness requirements were revised; use with reclaimed water was added; and alternate purchaser specified test requirements were added.