The 20 inch AWWA C504 rubber seat butterfly valve provides dependable quarter-turn isolation where large water pipelines require low installed weight, a short face-to-face length, and reliable rubber-to-disc sealing. This DN500 valve uses the proven concentric design: the shaft and disc centerline pass through the bore centerline, and the disc edge engages a full-circumference EPDM seat when closed.
The rubber seat is vulcanized directly to the ductile iron body, creating a strong chemical and mechanical bond that resists seat movement, extrusion, and blowout. The configuration is well suited to treated water, raw water, reclaimed water, and other municipal waterworks services.
AWWA C504 covers rubber-seated butterfly valves for water supply service. The standard addresses materials, fabrication, pressure ratings, testing, and application requirements. For the 20 inch valve, the standard rubber-seat arrangement provides several practical advantages:
Designed, manufactured, and tested as a rubber-seated butterfly valve for waterworks service.
EPDM seat is bonded to the body for stable sealing and resistance to movement, extrusion, and blowout.
ASTM A536 Grade 65-45-12 body provides strength, impact resistance, and dependable flange integrity.
Internal and external fusion-bonded epoxy coating meets AWWA C550 requirements for waterworks service.
Double flange body and rubber seat support full-pressure isolation with flow in either direction.
Direct mounting for gear operators, electric actuators, hydraulic cylinders, and pneumatic actuators.
The following values describe the standard 20 inch AWWA C504 Class 150B short-body configuration. Final dimensions, flange drilling, pressure class, and materials should be confirmed by Laux Valve engineering for the selected installation.
| Item | Specification |
|---|---|
| Nominal Size | 20 inch / DN500 |
| Valve Design | Concentric, rubber-seated butterfly valve |
| Body Style | Flange / double flange |
| Design Standard | ANSI/AWWA C504 |
| Pressure Class | Class 150B standard / Class 250B available |
| Design Pressure | 150 psi (10.3 bar) for Class 150B |
| Cold Working Pressure | 200 psi (13.8 bar) for Class 150B |
| Body Material | Ductile Iron ASTM A536 Grade 65-45-12 |
| Disc Material | Ductile Iron ASTM A536 / optional stainless steel edge |
| Seat | Vulcanized EPDM rubber, bonded to body |
| Optional Seat Material | NBR / Hypalon / FKM |
| Shaft | Stainless Steel ASTM A276 Grade 316 / 17-4PH |
| Shaft Bearings | Self-lubricating, lead- and zinc-free |
| O-Rings | EPDM |
| Body Coating | Fusion-bonded epoxy, internal and external, AWWA C550 |
| Flange Drilling | AWWA C207 / ANSI B16.1 Class 125 compatible |
| Face-to-Face | 5.0 in / 127 mm, short body |
| Flange Outside Diameter | 27.6 in / 700 mm |
| Bolt Circle | 25.0 in / 635 mm |
| Number of Bolts | 20 |
| Bolt Size | 1-1/8 in - 7 UNC |
| Seat Leakage | Bubble-tight, bidirectional |
| Shell Test | 300 psi (20.7 bar) for Class 150B |
| Seat Test | 220 psi (15.2 bar) for Class 150B |
| Temperature Range | -20°C to +110°C with EPDM seat |
| Actuator Mounting | ISO 5211 top flange |
| Operation | Manual gear / electric / hydraulic / pneumatic |
| Component | Standard Material | Available Options |
|---|---|---|
| Body | Ductile Iron ASTM A536 Grade 65-45-12 | Custom flange drilling |
| Disc | Ductile Iron ASTM A536 | Stainless steel edge / CF8M disc |
| Seat | Vulcanized EPDM | NBR / Hypalon / FKM |
| Shaft | SS316 | 17-4PH / Monel / duplex stainless steel |
| Bearings | Self-lubricating sleeve bearing | Bronze or corrosion-resistant bushing |
| O-Rings | EPDM | NBR / FKM |
| Coating | Fusion-bonded epoxy, internal and external | Project-specific coating system |
| Actuator | Typical Use |
|---|---|
| Manual Gear Operator | Local operation where high output torque and controlled opening speed are required |
| Electric Actuator | Remote on-off or modulating control in treatment plants and pump stations |
| Hydraulic Cylinder | High-torque operation for large waterworks valves or buried installations |
| Pneumatic Actuator | Fast automated isolation where compressed air is available |
Actuator selection is based on the valve torque curve, differential pressure, cycle frequency, and available power supply. Laux Valve can supply factory-mounted actuators with full travel and leak testing.
Standard inspection and testing may include:
It is a 20 inch DN500 flanged butterfly valve designed, manufactured, and tested for rubber-seated waterworks service under AWWA C504. It combines a ductile iron body with a vulcanized EPDM rubber seat for bubble-tight isolation in municipal water systems.
The standard configuration is AWWA C504 Class 150B, with Class 250B available where higher cold working pressure is required. Final pressure class, flange drilling, and face-to-face dimension should be confirmed for the project specification.
The standard construction uses an ASTM A536 ductile iron body and disc, a vulcanized EPDM rubber seat, an ASTM A276 stainless steel shaft, internal EPDM O-rings, and internal and external fusion-bonded epoxy coating. NBR seat material and alternative disc materials are available.
Yes. The ISO 5211 top flange supports manual gear operators, electric actuators, hydraulic cylinders, and pneumatic actuators. Factory mounting and complete stroke testing are available.
Typical applications include water treatment plant isolation, pump station suction and discharge headers, transmission mains, raw water intake, reservoir inlet and outlet, and other municipal waterworks services.
Yes. With the AWWA C550 epoxy coating, extension stem, and suitable valve vault or floor box, the 20 inch valve can be installed in buried waterworks applications.
Standard testing includes shell hydrostatic test, bidirectional seat leakage test, coating thickness and holiday inspection, dimensional inspection, and an operational open-close cycle test. Test reports and EN 10204 3.1 material certificates are available.
Yes. Laux Valve can supply custom flange drilling, seat and shaft materials, actuator integration, extension stems, coating, nameplate, logo, and project-specific packaging.
Contact Laux Valve for dimensional drawings, torque calculations, material selection, actuator integration, test reports, and OEM waterworks butterfly valve support.
From raw material inspection to final delivery, every butterfly valve undergoes a comprehensive quality inspection to ensure reliable performance and compliance with international standards.
