AWWA C504 is primarily used in municipal water systems, focusing on rubber soft seals and low to medium pressure conditions; API 609, on the other hand, is geared towards industrial applications, covering both metal and soft seals, and supporting higher pressure and more demanding media environments.
Comparison Table: AWWA C504 vs. API 609
| Comparison Feature | AWWA C504 | API 609 |
| Standard Name & Issuing Body | American Water Works Association (AWWA) Standard for Rubber-Seated Butterfly Valves | American Petroleum Institute (API) Standard for Butterfly Valves: Double-Flanged, Lug- and Wafer-Type |
| Primary Applications | Municipal water supply, water plants, raw water, freshwater. | Oil, natural gas, chemical, refining, power generation. |
| Design Philosophy | Long service life (30–50 years), wear resistance, low maintenance. | High pressure, high temperature, anti-static, fire-safe, corrosion resistance. |
| Size Range (NPS) | 3" – 72" (Larger sizes covered by AWWA C516) | 2" – 60" (and above) |
| Pressure Ratings | Class 25, 75, 150, 250 (psi-based ratings) | Category A (Manufacturer's rating) / Category B (ASME Class 150, 300, 600) |
| Velocity Classes | Class A (8 ft/s) / Class B (16 ft/s) | Not typically classified by velocity; defined by ASME Pressure-Temperature ratings. |
| Sealing Type | Rubber-Seated (Soft-Seated): EPDM, Buna-N (Nitrile) | Metal-Seated (Triple Offset), PTFE (Teflon), Fire-safe seals. |
| Disc Design | Concentric or Double Offset; streamlined design. | Usually Triple Offset (TOV) to achieve torque-based sealing. |
| Face-to-Face (F-to-F) | AWWA C504 Short Series / Long Series tables. | Category A (Manufacturer standard) / Category B (ISO 5752 / ASME B16.10). |
| Bearings / Bushings | Self-lubricating bronze or PTFE to prevent corrosion/rust. | Heavy-duty bearings for high-temp/high-pressure; often includes packing glands. |
| Testing Requirements | Proof-of-Design (Cycle Life Test): 5,000–10,000 cycles. | API 598 (Valve Inspection and Testing), API 607 (Fire-Safe Test). |
| Typical Media | Potable water, circulating water, filtered wastewater. | Crude oil, refined products, steam, chemicals, natural gas. |
Selection Guide: Choosing the Right Standard
| Scenario / Application | Recommended Standard | Reason / Justification |
| Municipal Underground Potable Water Networks | AWWA C504 | Must comply with NSF/ANSI 61 for potable water safety; designed for 30+ years of maintenance-free buried service. |
| Desalination Plants (Finished Water / Permeate Section) | AWWA C504 | Highly cost-effective; rubber-seated design achieves zero-leakage (bubble-tight) shutoff for water. |
| Refinery High-Temperature Steam Lines | API 609 | Requires metal-to-metal seating and fire-safe design (API 607); AWWA valves cannot withstand these extreme temperatures/pressures. |
| Offshore Oil & Gas Platforms | API 609 | Must withstand extreme pressures and severe corrosion; typically utilizes Duplex Stainless Steel or Triple Offset metal-seated valves. |
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FAQ
What is API 609 standard?
The API 609 standard covers butterfly valves that can be used in various pressure classes and sizes, making them suitable for a wide range of applications, including those in the petroleum, natural gas, and related processing industries.
What is the pressure rating of API 609?
Pressure Rating:
Class 150/300/600.
Is API 609 fire safe?
Engineered with a unique "Dual-Defense" Safety Philosophy to ensure proactive zero-leakage in daily operations and certified structural integrity and sealing performance during extreme fire emergencies.
What is the AWWA C504 standard?
AWWA C504 Butterfly Valve, rubber seated, Fusion bonded epoxy coated, or hard rubber lined, is applied in the water industry, municipal engineering, water conservancy project, drinking water engineering, sea water treatment and desalination. DESIGN. Design standard: AWWA C504.