The Type 578 Butterfly Valve shall be lug style compatible with ANSI B16.5 150 lb flange pattern.  The operation shall utilize double eccentric design principles.  The shaft shall be non-wetted by a bushing assembly with double o-ring seals.  The face seal shall be a Q-ring compatible with flat and serrated flange adapters.  The face, disk, and shaft seals shall operate independently.  The wetted body and disk shall be of like materials.  The outer body shall be glass-filled polypropylene with over-molded 316 stainless steel lug inserts.  Valves shall be rated for bidirectional use.  All valves shall be tested in accordance with ISO9393 and designed to ISO16136 standards.  All valves shall be manufactured under ISO9001 for Quality and ISO14001 for Environmental Management.  Following assembly, every valve shall be tested and certified bubble-tight exceeding Class VI standards.