This Standard Practice covers quarter-turn eccentric cast iron plug valves having flanged@ threaded@ mechanical joint@ or grooved end connections. This Standard Practice is intended for resilient seated valves with a circular@ rectangular@ or other geometric seat configuration@ having no visible evidence of leakage. The size range covered is NPS 3 through NPS 72 (DN 80 through DN 1800). Typical applications are sewage@ sludge@ waste water@ and water service. The manufacturer should be consulted for other applications. Conditions of water hammer@ hydraulic pulsation@ and excessive operating noise are results of the system design rather than valve design and require special design and construction considerations.