Valve Selection Guide

Practical valve selection support for process piping applications

Step 1 of 5Line Data

End Connection, Size & Pressure Class

Pipe size and pressure class drive ASME B16.5 P-T validation and end connection style.

Nominal pipe size of the line.

B16.5

ASME B16.5 / B16.34 rating class.

End Connection

Recommended
Flanged (RF)Recommended

Raised Face (RF) flanged ends are standard for Class 150–600#. The spiral wound gasket on the raised face provides reliable sealing with normal bolt loads. ASME B16.5 covers NPS ½" through 24".

Operator

Recommended
Gear OperatedRecommended

Gear operator required for larger quarter-turn valves (5"–12", Class 150–600). As valve size and pressure class increase, the seating/unseating torque rises rapidly. Gear operators (worm gear) multiply the input handwheel force by the gear ratio, making operation safe and practical. They also prevent sudden opening/closing.

Computed end-connection package

End connection
Flanged (RF)
End standard
ASME B16.5
Flange standard
ASME B16.5
Operator
Gear Operated
Why this was selected
ASME B16.5 recommendation: Group 1.1 - Carbon Steel: 300# rated 44.2 barg at 120 deg C (screening factor 0.864; basis ASME B16.5 Table 2-1.1)

Learning moment

Pressure class isn't just a number — ASME B16.5 derates allowable pressure as temperature rises. A Class 300 flange holding 740 psi at ambient may only hold ~600 psi at 400 °C. Always check the P-T table at design temperature, not ambient.

ASME B16.5 caution

ASME B16.5 Caution: Design pressure (40 barg) is within 15% of the Class 300 Group 1.1 - Carbon Steel screening limit (44.2 barg at 120 deg C). Confirm final P-T rating against ASME B16.5 Table 2-1.1.

Why this was selected
End connection: Raised Face (RF) flanged ends are standard for Class 150–600#. The spiral wound gasket on the raised face provides reliable sealing with normal bolt loads. ASME B16.5 covers NPS ½" through 24".
Why this was selected
Operator: Gear operator required for larger quarter-turn valves (5"–12", Class 150–600). As valve size and pressure class increase, the seating/unseating torque rises rapidly. Gear operators (worm gear) multiply the input handwheel force by the gear ratio, making operation safe and practical. They also prevent sudden opening/closing.

ASME B16.5

ASME B16.5

ASME B16.5

ASME B16.5

ASME B16.20

ASME B16.20 (SWG)

Engineering Decision Support Tool - Screening / Internal Review Use unless independently validated.

Outputs are generated for engineering screening and decision support only. Final responsibility for standards compliance, engineering judgment, specification verification, and approved project use remains with the user organization and qualified reviewing engineer.