A nominal size and pressure class are not enough to select a butterfly valve. Two systems that both say “water, DN100, PN16” can have different temperatures, treatment chemicals, flange dimensions, operating frequency and automation requirements.
Use the sequence below to turn a broad application into a reviewable valve duty.
1. Define the medium
Write down the actual fluid, not only the system label. For water and HVAC services, include glycol percentage, water-treatment chemicals, suspended solids and any cleaning fluid. For equipment systems, identify every medium the valve will see during operation, flushing and maintenance.
The medium drives the review of seat, disc, shaft and body compatibility.
2. Record normal and maximum pressure
State normal operating pressure, maximum possible pressure and, where relevant, differential pressure across the closed or partially open valve. Also identify pressure transients and the project's required pressure-test standard.
HF-520 is available with 0.6, 1.0 and 1.6 MPa working-pressure options. Confirm the required size, trim and operator combination for the duty.
3. Confirm nominal size and connection
Specify DN or NPS size, pipe schedule if relevant, flange standard, pressure designation and the mating-flange arrangement. A wafer valve must physically align and seal between the intended flanges.
HF-520 connection references include ASME B16.5 Class 125/150, EN 1092-1 PN6/10/16 and JIS 5K/10K/16K flange systems. State the exact mating-flange standard in the inquiry.
4. State both normal and maximum temperature
Temperature affects elastomer capability, pressure limits, actuator sizing and environmental requirements. Provide the normal temperature, design maximum and any low-temperature or thermal-cycling condition.
5. Select the wetted materials as a system
Body, disc, seat and shaft work together. The HF-520 datasheet lists an ADC12 aluminum body, 304/316 stainless or nickel-plated ductile-iron disc options, a 410 stainless / EN 1.4057 shaft reference and EPDM, NBR, HEPDM or FKM seat options.
Do not select an elastomer only by a temperature table. Medium chemistry, concentration, exposure time, cleaning and decompression conditions can also matter.
6. Define the valve duty
State whether the valve will provide isolation, frequent on/off cycling or modulating control. Include expected operating frequency, normal position, direction of flow and any shutoff requirement. Define the required leakage standard, class and test conditions.
7. Choose an operator package
| Operator route | Information to provide |
|---|---|
| Bare shaft | Actuator interface, required torque basis and customer-supplied actuator details. |
| Handle | Access, operating frequency, locking/position requirement and size. HF-520 handle reference: DN32–DN150. |
| Worm gear | Orientation, indication, locking and environmental conditions. |
| Pneumatic | Air pressure, spring-return/double-acting, fail position, solenoid, position feedback and controls. |
| Electric | Voltage, phase, frequency, control signal, duty, enclosure, feedback and manual override. |
8. Add environment, quantity and documents
State whether the valve is installed indoors or outdoors, exposed to weather, washdown, dust, vibration or unusual ambient temperatures. Then add quantity, target delivery date, inspection plan, certificates, drawings and any customer-approved vendor requirements.
Selection worksheet
- Medium and concentration
- Normal and maximum pressure
- DN/NPS size and mating-flange standard
- Normal and maximum temperature
- Body, disc, seat and shaft preferences
- Isolation, on/off or modulating duty
- Manual, pneumatic or electric operation
- Utilities, controls, fail position and feedback
- Environment, quantity, delivery and documentation
A strong valve RFQ describes the service and the interface. It does not force the supplier to infer chemistry, temperature, flange dimensions or automation requirements from a short part description.