The C504 standard applies to general-purpose rubber-seat butterfly valves with diameters from 3 inches to 72 inches (75 mm to 1,800 mm), which are widely used in conventional water treatment systems; while the C516 standard is designed for extra-large diameter valves, specifying butterfly valves with dimensions of 78 inches (2,000 mm) and above, which are suitable for high-flow, large-diameter main water supply or drainage projects.
AWWA C504: Covers medium to large-sized butterfly valves ranging from 3 to 72 inches (75 to 1,800 mm), suitable for urban water distribution networks, pumping stations, and water plant process sections under normal pressure and flow rates. It is one of the most common butterfly valve standards in water systems.
AWWA C516: Specifically designed for extra-large diameter valves of 78 inches and above (over 2,000 mm), used in high-flow control scenarios such as main water supply pipelines, large-scale water diversion projects, and reservoir outlets. It solves the problem of ordinary butterfly valves failing to guarantee sealing and structural stability in extra-large sizes.
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Comparison Table: AWWA C504 vs. AWWA C516
| Comparison Dimension | AWWA C504 | AWWA C516 |
| Full Standard Title | Rubber-Seated Butterfly Valves | Large-Diameter Rubber-Seated Butterfly Valves |
| Size Range | 3" to 72" (DN80 - DN1800) | 78" and larger (DN2000 - DN3600+), typically up to 144" |
| Pressure Classes | Class 25, 75, 150, 250 | Class 25, 75, 150, 250 |
| Body Configurations | Common: Flanged, Wafer, Lug, Mechanical Joint (MJ) | Almost exclusively Flanged, to ensure structural stability in ultra-large sizes. |
| Face-to-Face Dim. | Categorized into Short-body and Long-body types. | Follows specific dimensions required for structural support of massive weight. |
| Disc Material | Ductile Iron, Cast Steel, Stainless Steel, Aluminum Bronze, etc. | Emphasis on Ductile Iron or Welded Fabricated Steel structures. |
| Seat Design | Rubber (NBR, EPDM) can be located on the body or the disc. | Usually features adjustable or mechanically retained seats for in-line maintenance. |
| Shaft Design | Diameter calculated based on torque and max differential pressure. | More rigorous calculation, accounting for deflection and eccentric loads of massive discs. |
| Performance Testing | Cycle test requirements (e.g., 10,000 cycles). | Greater focus on structural integrity and large-scale hydrostatic factory tests. |
| Typical Applications | Urban distribution networks, pump stations, internal water plant piping. | Raw water transmission mains, reservoir outlets, power plant cooling systems. |
Selection Guide
Choose [AWWA C504] if:
The project involves standard water/wastewater sizes of 72" (DN1800) or smaller.
A short-body (Wafer or Short-flanged) design is needed to save installation space.
The system requires UL/FM certification for fire protection.
Choose [AWWA C516] if:
The project involves ultra-large transmission mains 78" (DN2000) or larger.
The application is a large-diameter shut-off point for long-distance water diversion.
Extreme structural strength is required to support the valve over a large span.
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FAQ
What is awwa C504?
AWWA C504 butterfly valve is mainly used in water treatment projects, the required medium is water without impurities, the characteristics of the rubber seal strengthen the sealing performance of the valve, so that the valve can achieve 0 leakage.
What does AWWA stand for?
The American Water Works Association (AWWA) is the largest organization of water supply professionals in the world. AWWA believes that every water professional deserves to feel empowered and have the tools and resources necessary to provide their communities with safe and clean water.