Marine Butterfly Valves –
Seawater & Corrosion-Resistant Excellence from Flowtorq

Name: Marine Butterfly Valves
Brand: Flowtorq
SKU: BFV
Rating: 7 (29 reviews)

In-Depth Performance in Harsh Marine Conditions

Marine butterfly valves handle seawater, ballast, bilge, cooling, fire, and gray water on ships, offshore platforms, FPSOs, and desalination facilities. Valves are designed and manufactured as per ASME, API, JIS, EN, etc.
Flowtorq is a leading manufacturer and supplier of marine butterfly valves certified to ABS, DNV, BV, and Lloyd’s.

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Key Features, Specifications & Technical Nuances of Marine Butterfly Valves

Pressure Ratings (JIS K Classes)

JIS 5K: ~0.5 MPa (72.5 psi) at ambient
JIS 10K: ~1.0 MPa (145 psi) at ambient – most common rating
JIS 16K: ~1.6 MPa (232 psi)
JIS 20K: ~2.0 MPa (290 psi) for higher-pressure services Pressure-temperature derating applies per JIS B 2032/B 2064 tables (e.g., ductile iron with EPDM seats typically limited to ~120°C).

Body & Connection Styles

Wafer type (shortest face-to-face, fits between JIS flanges)
Lug type (tapped lugs for dead-end service and easy removal)
Flanged type (integral raised-face flanges per JIS B 2212/B 2213)

Materials & Construction

Body: Ductile cast iron (FCD-S or FCD450), cast iron (FC200), carbon steel (SCS13A/SCS14A equivalents), stainless steel (SCS13/SCS14)
Disc: Ductile iron (nickel-plated or nylon-coated), 304/316 stainless steel, aluminum bronze (for seawater)
Stem: 410/420/316 stainless steel (anti-blowout design)
Seat: EPDM (water/general), NBR (oils), Viton/FKM (chemicals/heat), Silicone (high/low temp), PTFE/RPTFE (corrosive/high-temp)

Seating Performance

Bubble-tight bidirectional shutoff (zero visible leakage per JIS leak test)
Concentric (rubber-lined) or double-eccentric (high-performance) disc geometry to minimize seat wear and operating torque

Size Range

DN50 (2") to DN1200 (48") and larger in flanged versions

Face-to-Face Dimensions

Strictly per API 609, BS 5155, JIS B 2032 (wafer/lug) or JIS B 2064 (flanged) for drop-in replacement

Actuation Compatibility

ISO 5211 mounting pad standard
Manual lever, worm gearbox, pneumatic (double-acting or spring-return), electric (on/off or modulating)

Testing & Compliance

API 598, EN 1092 PN10, PN16, JIS B 2032 / B 2064 pressure & leakage testing

Optional: JIS G 5502 material certification, third-party inspection (SGS, Bureau Veritas), WRAS/ACS equivalents for potable water
Nuances: JIS 10K is the most widely specified rating in Japanese industrial plants, equivalent in pressure capability to PN10/ANSI Class 150 but with different bolt patterns and face-to-face lengths. Double-eccentric designs significantly reduce torque and extend seat life in throttling or frequent cycling applications.

SHIPYARDS

Proven and approved by leading shipbuilding and ship repair companies. Used by leading Shipyards.

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Advantages of Aluminum Bronze & Other Materials for Marine Butterfly Valves

Corrosion Resistance — Aluminum bronze (C95800) forms protective oxide film, resisting pitting, crevice corrosion, erosion, and biofouling in seawater far better than standard bronze or steel.
Strength & Weight — High tensile strength with lower density than stainless; ideal for weight-sensitive vessels.
Cavitation/Erosion Resistance — Superior in high-velocity ballast/cooling lines.
Nuances: Monel stems/discs for extreme duty; avoid carbon steel without heavy coating.