ANSI Marine Butterfly Valve
A quarter-turn valve designed specifically for shipboard piping systems and manufactured to American National Standards Institute (ANSI) and related ASME standards. It ensures full dimensional compatibility with ASME B16.5 flanges (Class 150 and Class 300) and delivers proven, reliable shutoff performance in seawater, fuel oil, ballast, and bilge applications aboard vessels built to imperial-standard piping.
Overview
1. Applicable Standards and Design Basis
Our ANSI Marine Butterfly Valves are designed and manufactured to the following core standards:
ASME B16.34: Valves – Flanged, Threaded, and Welding End, establishing pressure-temperature ratings.
API 609: Butterfly Valves – Double Flanged, Lug- and Wafer-Type, defining design, face-to-face dimensions, and performance categories.
MSS SP-67: Butterfly Valves, providing additional face-to-face dimensions for wafer and lug bodies.
ASME B16.5: Pipe Flanges and Flanged Fittings (NPS 1/2 through 24), covering Class 150 and 300 steel flange drilling and facing.
API 598: Valve Inspection and Testing, specifying shell strength and seat leakage acceptance criteria.
2. Material Selection for Aggressive Marine Environments
Body: ASTM A536 Grade 65-45-12 ductile iron with high-build epoxy coating, or ASTM A351 CF8M (316 stainless steel) for direct seawater resistance.
Disc: Aluminum bronze ASTM B148 C95800, duplex stainless steel, or CF8M, selected for excellent pitting and crevice corrosion resistance in seawater.
Seat/Liner: Replaceable vulcanized EPDM (standard for seawater and freshwater), NBR/Buna-N (for oil service), or FKM/Viton® (for chemical compatibility). The liner extends fully across the flange face to form a built-in gasket.
Shaft: ASTM A276 Type 316 stainless steel or Monel® (ASTM B164 N04400), with an anti-blowout shoulder. Shaft runs on self-lubricating, non-metallic bearings that isolate the shaft from the body, preventing corrosion and seizure.
3. Key Technical Features
Bubble-Tight Shutoff: Bidirectional zero-leakage sealing verified per API 598, achieving no visible leakage at the seat test pressure.
Compact Wafer/Lug Body: Short face-to-face dimensions per API 609 / MSS SP-67 Category A save critical space in engine rooms and pump rooms. Lug-type provides dead-end service capability.
Self-Gasketing Connection: The full-face elastomer liner forms a complete, gasket-free seal against ASME B16.5 raised-face flanges, eliminating the need for separate flange gaskets.
Actuator-Ready Design: Standard ISO 5211 top mounting pad allows direct attachment of manual levers, worm gearboxes, or automated pneumatic and electric actuators.
Low Maintenance: The isolated shaft and non-metallic bearings require no lubrication and eliminate corrosion-induced sticking, even after prolonged idle periods.
4. Typical Marine Applications
Main and auxiliary seawater cooling circuits
Ballast water and bilge handling systems
Fire main and foam ring-mains
Fuel oil and lubricating oil transfer and storage
Fresh water and potable water distribution
Overboard discharge and tank vent lines
5. Quality Assurance, Testing, and Certification
Testing: Every valve undergoes a hydrostatic shell test at 1.5 times the cold working pressure (CWP) and a seat tightness test at 1.1 times the CWP, strictly per API 598.
Material Traceability: Full ASTM material test reports (EN 10204 Type 3.1 equivalent) are provided for all pressure-containing and wetted components. Each body is permanently marked with the heat number, NPS, class rating, material grade, and manufacturer’s identification per MSS SP-25.
Class Approvals: The valves can be supplied with type approval certificates from all major classification societies (ABS, DNV, Lloyd’s Register, BV, USCG, and other IACS members) upon request.
