Supreme Valves India engineers and supplies API 598 Tested Butterfly Valve for EPC contractors, plant engineers, and procurement teams in oil & gas, petrochemical, power, desalination, pharmaceutical, food, and municipal water sectors. From our Ahmedabad facility we support projects across India, the GCC (UAE, Saudi Arabia, Qatar, Oman, Kuwait), Southeast Asia, Africa, Europe, and the Americas with application-based selection, EN 10204 3.1 material traceability, and export-grade documentation.
Butterfly valves are quarter-turn rotary valves with a disc that rotates 90° between open and closed positions. Compared to gate valves of the same nominal size, they offer lower weight, shorter face-to-face dimensions, and faster operation — making them preferred for large-diameter water, HVAC, cooling water, and many process isolation duties. When your datasheet specifies API 598, body material WCB / CF8M / NAB, and rating Class 150–600, our team maps your P&ID line to the correct end style (All end connections) and seat system.
API 598 Design Requirements for Butterfly Valves
Industrial butterfly valves for petroleum, chemical, and power service are commonly specified under API 598 together with ASME B16.34 for pressure-temperature limits and MSS SP-67 / MSS SP-68 for end connections and high-performance categories. Category A butterfly valves (concentric disc) are widely used in water and general HVAC. Category B designs include offset disc geometries that improve shutoff and extend temperature capability — often referenced as high-performance or triple-offset valves for critical hydrocarbon service.
For procurement engineers, the distinction matters in three areas: seat leakage class, fire-safe requirements (where API 607/6FA may be invoked on product datasheets), and actuator interface per ISO 5211. Supreme Valves documents the selected category, bore, and test standard on each quotation and matches hydrostatic test pressures to API 598 unless API 6D or a project-specific ITP overrides shell/seat hold times and acceptance criteria.
- Body & disc materials: WCB / CF8M / NAB — selected per media, chlorides, and temperature from ASME B16.34 tables.
- Pressure class: Class 150–600 — flange thickness, bolting, and seat design follow B16.34 for the stated class.
- End connections: All end connections — wafer valves suit sandwiched installation; lug valves allow dead-end removal; double-flanged valves suit large bore waterworks and buried service.
- Testing: Shell and seat tests per API 598; optional pneumatic seat test and PMI on alloy bodies.
API 598 Test Pressures and Acceptance
API 598 defines inspection and pressure tests for gate, globe, check, plug, ball, and butterfly valves. Shell tests prove body integrity; seat tests prove closure at defined differential pressure. Test fluid is normally water; pneumatic seat tests may be specified for gas service or residual leakage verification. Hold time and allowable leakage must match the project ITP — default API 598 acceptance is used only when the ITP is silent.
Read our full engineering article: Valve Pressure Testing: API 598 Complete Guide. All API 609 butterfly valves from Supreme Valves are quoted with API 598 testing unless otherwise specified.
Body, Disc, Stem, and Liner Materials
Material selection drives both corrosion resistance and cost. ASTM A216 WCB carbon steel bodies are standard for water, HVAC, and many hydrocarbon applications to moderate temperature. ASTM A351 CF8 (SS304) and CF8M (SS316) cast stainless bodies resist oxidizing chemicals and are typical in pharma, food, and chloride-bearing cooling water when molybdenum is required. For seawater, brine, and desalination, nickel aluminium bronze (NAB) discs and bodies reduce galvanic risk compared to carbon steel.
Soft-seated butterflies use elastomer liners (EPDM, NBR, Viton) or PTFE-based seats for bubble-tight shutoff at lower torque. Metal-seated high-performance valves use stainless or Stellite-inlaid seating for high temperature and abrasive media. Lined valves (PTFE, FEP, PFA) isolate aggressive acids where even SS316 is insufficient — Supreme Valves cross-references chemical compatibility with your process datasheet before quoting liner grade.
All pressure-boundary castings are supplied with EN 10204 Type 3.1 mill test certificates showing heat numbers, chemistry, and mechanical properties traceable to foundry MTRs — a mandatory requirement for most Middle East NOC and international EPC projects.
Pressure Class, Flange Ratings, and Face-to-Face
ANSI/ASME pressure classes (Class 150–600) define maximum allowable working pressure versus temperature per ASME B16.34. Class 150 butterflies are dominant in water distribution, fire protection, and HVAC. Class 300 and higher classes require reinforced bodies, offset disc designs, and often metal seats for hydrocarbon and steam-adjacent duties.
Face-to-face dimensions for wafer and lug valves follow MSS SP-67; double-flanged large valves may follow AWWA C504 for waterworks. When retrofitting existing piping, confirm flange standard (ASME B16.5 RF/RTJ), bolt circle, and whether the valve must support dead-end service (lug type) or only sandwiched loads (wafer type). Mis-specification of lug versus wafer is a frequent site issue — our engineering team verifies line list data before release to production.
Factory Testing per API 598
Unless your inspection test plan specifies otherwise, butterfly valves undergo shell and seat closure tests per API 598. Shell test pressure is typically 1.5× the maximum allowable pressure at 38°C (100°F) for the rated class; seat test pressure verifies closure integrity on the low-pressure side. Soft-seated valves may require resilient seat test procedures; metal-seated high-performance valves may use allowable leakage rates per MSS or project annexes.
Supreme Valves issues hydrostatic test reports referencing valve serial numbers, heat numbers, and test gauges calibrated per project requirements. For critical service, add pneumatic seat tests, radiography on weld ends, PMI on stainless bodies, and third-party witness (TPI) hold points — we coordinate with Bureau Veritas, TÜV, SGS, or client-nominated inspectors at agreed milestones.
Applications for Plant Engineers and EPC Contractors
Oil & gas and petrochemical: Isolation on cooling water, firewater, and utility headers; high-performance butterflies on unit boundaries where space and weight matter. Specifiers often pair API 609 design with Class 300 metal seats for hydrocarbon media.
Chemical and pharmaceutical: CF8M bodies with PTFE or PFA linings for acids; sanitary tri-clamp butterflies for batch processes. See chemical process valves and pharmaceutical valves hubs.
Power and steam auxiliaries: Condenser cooling water, CW blowdown, and auxiliary steam condensate — typically WCB or DI wafer/lug designs Class 150. High-temperature steam headers generally use gate/globe per plant standards; butterflies remain on large-diameter low-pressure circuits.
Water treatment and desalination: Double-flanged large bore valves on raw water and RO headers; NAB or super duplex trim on seawater intake. Refer to desalination valves and water treatment valves.
HVAC and fire protection: UL/FM listed wafer and lug butterflies for sprinkler and HVAC isolation — see fire protection valves and HVAC valves.
Valve Selection Checklist for Procurement
- Confirm media, temperature, pressure, and chloride content (material upgrade trigger).
- Select end type: wafer (sandwiched), lug (dead-end), or double flanged (large bore / waterworks).
- Match pressure class to piping spec — do not downgrade class below flange rating.
- Specify seat: soft (EPDM/NBR/PTFE) vs metal-seated high performance for hydrocarbons.
- Define operator: manual lever, gearbox, pneumatic, or electric actuator with fail mode.
- List design standard (API 598), test standard (API 598), and documentation (MTC 3.1, ITP, TPI).
- Include quantity, delivery port, and Incoterms for export pricing.
For category-level comparison, visit butterfly valve manufacturer India or the butterfly valve standards hub linking all standard-specific pages.
Export Documentation and Middle East Project Support
Supreme Valves has exported industrial valves since 1986. Typical export packs include commercial invoice, packing list, bill of lading, certificate of origin (when required), EN 10204 3.1 MTCs, and hydrostatic test certificates. For Saudi Arabia projects we support SABER product conformity data; for UAE and Qatar EPCs we align with ADNOC/QP material submittal formats where provided templates exist.
Wooden case packing with silica gel, face protectors on flanges, and lifting lugs are applied per project spec. Shipping ex-works Ahmedabad or FOB Mundra / Nhava Sheva with CIF/DDP options on request.