Butterfly valves are quarter-turn valves widely utilized in flow control industrial applications.
There are six criteria to be taken into account while selecting an appropriate valve for your project. Being a procurement engineer, you need to assess fluid type, pressure/temperature, valve application, valve dimensions, compatibility with materials, and valve operation method.
This butterfly valve selection guide gives procurement managers and engineers a clear framework. It covers valve parts, connection types, seat materials, and operating conditions.
What are the Components of a Butterfly Valve?
Each type of butterfly valve has the same five core components. Knowing the different butterfly valve parts prevents specification errors and costly repairs or replacements.
Study the diagram below to help you understand how the different components work:
Butterfly Valve Types by Body and Connection Style
Connection style determines how the valve mounts to your pipeline. It also affects maintenance access and pressure capability.
There are three standard body types, plus two high-performance eccentric designs for demanding service.
Wafer Butterfly Valve
The wafer butterfly valve sits between two pipe flanges. Through-bolts clamp it in place.
It is the lightest and most cost-effective design. Best for water treatment, food processing, and chemical transfer lines. However, it is not suitable for dead-end service. Both flanges must remain in place.
This valve type is also referred to as a BF valve. “BF” is shorthand for “Butterfly.” However, different manufacturers have different meanings depending on their industry context.
A lug butterfly valve has threaded inserts in the valve body that accept bolts from each flange independently. This allows downstream pipe removal without disturbing the valve.
Lug valves are used where maintenance access is frequent or where dead-end isolation is needed.
Flanged Butterfly Valve
A flanged butterfly valve has integral flanges that bolt directly to matching pipe flanges. This design handles higher pressure and temperature ratings.
This design is preferred for refineries, petrochemical pipelines, and high-cycle industrial processes.
Double-Eccentric and Triple-Eccentric Designs
Double-eccentric (double-offset) valves reduce seat wear and suit throttling at pressures up to Class 300.
Triple-eccentric valves use metal-to-metal sealing. They handle steam, flue gas, and abrasive media at temperatures up to 600°C. These valves align with butterfly valve seat types that require hard-face alloy seating rather than elastomeric materials.
Butterfly Valve Seat Types and Seat Material Compatibility Chart
The seat creates the primary seal between the disc and the valve body. The wrong seat material causes early failure, leaks, or chemical contamination.
Five-seat materials cover most industrial applications. Each has a defined temperature ceiling and chemical compatibility profile.
This butterfly valve seat material compatibility chart is a starting point. For concentrated acids or mixed-media service, request a material compatibility review from your valve supplier.
Butterfly Valve Seat Material Compatibility Chart
| Seat Material | Temperature Range | Compatible Media | Avoid | Pressure Class |
| EPDM | -20°C to +120°C | Water, steam, mild chemicals | Oils, solvents | PN10–PN16 |
| NBR (Nitrile) | -20°C to +80°C | Oil, gas, fuels | Acids, ozone | PN10–PN16 |
| PTFE | -40°C to +180°C | Chemicals, acids, corrosive media | Abrasives | PN10–PN25 |
| Viton (FKM) | -20°C to +200°C | Solvents, acids, high-temp fluids | Ketones | PN10–PN25 |
| Metal (Stainless / Alloy) | Up to +600°C | Steam, high-temp gas, abrasive slurries | — | Class 150–600 |
PTFE seat temperature range: -40°C to +180°C (356°F). PTFE resists virtually all acids, solvents, and corrosive chemicals. It is the standard choice for chemical processing and high-purity pharmaceutical lines.
EPDM is the workhorse seat for water and steam service up to 120°C. NBR handles hydrocarbon media well but degrades quickly in acid or ozone exposure.
Viton (FKM) extends the working ceiling to 200°C. Use it for hot solvents and aggressive chemical service where PTFE seat limitations apply.
Metal seats (stainless or Stellite-overlay alloy) are specified for triple-eccentric valves in high-temperature steam, power generation, and abrasive slurry lines.
Five Key Influences for Right Butterfly Valve Selection
If you want your industrial piping system to run efficiently, follow this checklist for all your projects.
- Fluid Characteristics. Identify temperature, pressure, viscosity, and chemical composition. Confirm whether the media contains solids or abrasive particles. These factors set both body material and seat material requirements.
- Operating Pressure and Pressure Class. Match the valve pressure rating to the system design pressure. Common ratings: PN10, PN16, PN25, Class 150, and Class 300. Always include a safety margin above peak operating pressure.
- Pipeline Size and Flow Rate. Valve bore must match pipe bore. Undersized valves create excessive pressure drop. Oversized valves lose throttling control at low flow.
- End Connection Standard. Confirm the flange drilling pattern: ANSI/ASME B16.5, DIN EN 1092-1, JIS B2220, or BS 4504. Mismatched standards require adapters and create leak points.
- Actuation and Control Requirements. High-cycle or remote-controlled lines need pneumatic or electric actuators with ISO 5211 mounting pads and positioners. Low-cycle manual service uses a handwheel or gear operator.
How to Match Butterfly Valve Specifications to Your Industry
There are very big differences in valve specifications depending on which industry you work in. The same valve type may require different seat, disc, or actuator types.
Below are real-world applications of butterfly valves:
Oil and Gas
Specify triple-eccentric or double-offset valves with metal seats. API 609 compliance is mandatory. Working pressures often reach Class 300 or Class 600.
You may be aware of the XXV valve, which is a safety-critical emergency shutdown valve used in oil & gas, chemical plants, and industrial facilities. The “XXV” designation represents a valve tagging system that clearly reflects function and safety criticality.
Water Treatment
Wafer valves with EPDM seats handle municipal water service. Specify NSF/ANSI 61 certification for potable water contact. Verify leakage class per EN 12266-1.
Chemical Processing
PTFE-lined or PTFE-seated valves are standard. The PTFE seat temperature range of -40°C to +180°C covers most chemical process lines. Specify a full-bore disc design to eliminate dead legs.
Food and Beverage
Seat and disc materials must meet FDA 21 CFR or EU 1935/2004 food-contact compliance. Specify smooth surface finishes (Ra ≤ 0.8 μm) for CIP/SIP cleanability.
HVAC and Building Services
Wafer valves with EPDM seats cover most chilled water and hot water circuits. Select valves rated for PN10 or PN16. Low weight and compact face-to-face dimensions reduce installation cost.
Conclusion
The butterfly valve selection guide helps engineers and procurement teams match the valve to the system.
Fluid medium, temperature, pressure rating, connection type, and actuation type are the factors that shall determine the valve to be used for your application. All these criteria must be met when buying any valves.
Xintai Valve manufactures to ISO 9001 quality management standards. Our products carry CE marking and are manufactured to API, ANSI, DIN, JIS, and BS standards. This means Xintai valves fit international pipeline systems without conversion hardware or custom adapters.
