The DIASTAR 025 shall be rated for bidirectional pressure.  The valve body shall be a fully molded, single-piece fixed flange design.  The actuator shall be fully molded glass-filled polypropylene and available in a fail-safe to close, fail-safe to open, and double-acting configurations.  The stroke shall be indicated by an optical indicator.  The body to actuator connection shall be of square type, utilizing metal body bolts.  The pilot solenoid connection shall be of NAMUR type.  DIASTAR 025 ANSI versions shall meet ANSI B16.5 150lb standards.  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.  PVC valves shall meet ASTM D1784 cell classification 12454 standards.  CPVC valves shall meet ASTM D1784 cell classification 23447-B standards.  PP valves shall meet ASTM D5847-14 cell classification PP0510B66851 standards.  PVDF valves shall be type 1, grade 2 according to ASTM D3222 standards.  Valves of all materials shall be RoHS compliant.