Maximum Allowable Stem Torque (MAST) for Ball Valves

08.20.2025 |

Understand Maximum Allowable Stem Torque (MAST) and why it matters for long-term ball valve performance. This guide explains how engineers and specifiers use MAST values and highlights SVF technical briefs that document torque capacities, outlining how to use these reports to identify valve series and stem materials, reference MAST values, compare actuator output, and apply recommended safety factors to prevent performance failure.

Why MAST Matters

Engineers and specifiers rely on published MAST values when selecting and automating valves. Compliance with standards such as API 608 requires specific torsional safety factors, making accurate stem torque data critical in system design.

SVF MAST Technical Briefs

SVF Flow Controls has performed extensive testing on valve stems and publishes detailed reports that document torque capacities and safety factors. These reports are essential tools for engineers working on actuator sizing and valve specification.

How to Use These Reports

• Identify the valve series and stem material being specified.
• Refer to the MAST values provided in the report.
• Compare against actuator maximum torque output.
• Apply the recommended safety factors from the reports.

Conclusion

For accurate torque data and reliable valve automation, always consult published MAST test reports. SVF’s technical briefs provide the engineering foundation for safe and efficient actuator sizing.