What is API 609 butterfly valve?

API 609 is the American Petroleum Institute standard for butterfly valves. It covers lug-type and wafer-type butterfly valves for general and high-performance applications. API 609 Category A covers general purpose valves with resilient seats, while Category B covers high-performance valves with metal seats. For seawater service, Category A with EPDM liner is commonly used.

What is EPDM liner in butterfly valves?

EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber used as liner/seat in butterfly valves. EPDM provides: (1) Excellent resistance to water, steam, and ozone, (2) Good chemical resistance to dilute acids and alkalis, (3) Temperature range -40°C to +120°C, (4) Bubble-tight shut-off, (5) Suitable for seawater and potable water. EPDM is preferred over NBR for water applications.

What sizes are NAB butterfly valves available in?

NAB disc butterfly valves are available from 3 inch (DN80) to 24 inch (DN600). Common sizes for seawater service include 3", 6", and 8". Smaller sizes (up to 6") are lever operated, larger sizes are gear operated. Wafer and lug body styles available. Pressure rating PN10/PN16 or Class 150.

Tight Shut-Off

NAB Disc Butterfly Valve – API 609 for Seawater

Name: NAB Disc Butterfly Valve API 609 for Seawater
Brand: Supreme Valves
SKU: SV-NABBUTTERFLYVALVEAPI
Price: 11781 INR
Availability: InStock
Rating: 4.8 (127 reviews)

Butterfly valves with Nickel Aluminium Bronze (NAB) disc and EPDM rubber lining per API 609 for seawater service. Ductile iron body ASTM A536 60-40-18. Tight bubble-tight shut-off. Sizes 3" to 24". Manual lever or gear operated. Ideal for seawater cooling, desalination, and marine applications.

Quick Summary

NAB Disc Butterfly Valve = Butterfly valve with NAB (C95800) disc for seawater contact + EPDM rubber liner protecting ductile iron body. Cost-effective alternative to full NAB valves. API 609 design. Bubble-tight shut-off. Available 3" to 24". Lever for small sizes, gear for 6"+. Applications: seawater cooling, desalination intake/outfall, marine ballast systems.

NAB Disc Butterfly Valve API 609 EPDM Lined Seawater

Key Specifications

Design Standard: API 609

Pressure Rating: PN16 / Class 150

Body Material: ASTM A536 60-40-18

Disc Material: NAB (C95800)

Liner: EPDM Rubber

Size Range: 3" to 24"

Body Style: Wafer / Lug

Shut-off: Bubble-tight

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Materials of Construction

Component	Material
Body	ASTM A536 60-40-18 (Ductile Iron)
Disc	ASTM B148 C95800 (Nickel Aluminium Bronze)
Liner / Seat	EPDM Rubber
Stem	Stainless Steel AISI 316 / 420
Bushing	PTFE / Bronze

Frequently Asked Questions

Why use NAB disc in butterfly valves for seawater?

NAB disc provides excellent seawater corrosion resistance while the EPDM rubber liner protects the ductile iron body. This combination offers corrosion-resistant disc in contact with seawater, cost-effective body, and tight bubble-tight shut-off.

What is EPDM liner?

EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber providing excellent resistance to water, steam, and ozone. Temperature range -40°C to +120°C. Suitable for seawater and potable water applications.

What sizes are available?

NAB disc butterfly valves are available from 3" (DN80) to 24" (DN600). Smaller sizes are lever operated, larger sizes (6"+) are gear operated. Wafer and lug body styles available.

Need NAB Butterfly Valves for Seawater?

Cost-effective seawater isolation with NAB disc and EPDM liner. EN 10204 3.1 MTCs included.

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Pricing – Butterfly Valve (Tight Shut-Off)

Indicative unit prices in INR (ex-works India). Includes hydrostatic testing and EN 10204 3.1 MTCs. Volume discounts available for project quantities.

Size	Standard	Operation	Material	Unit Price (INR)
3"	API 609	Manual	ASTM A536 (EPDM Lined) + NAB Disc	₹11,781
6"	API 609	Manual	ASTM A536 (EPDM Lined) + NAB Disc	₹18,183
8"	API 609	Gear Operated	ASTM A536 (EPDM Lined) + NAB Disc	₹22,616

* Prices are indicative and subject to change. Contact us for confirmed pricing and delivery schedules. GST extra as applicable.