Automation begins with the valve duty and worst operating condition. It does not begin with nominal size. The package supplier needs enough process, mechanical and control information to size the actuator, check the mounting kit and test the assembled unit.
01 / Duty
Isolation, cycling and emergency action produce different packages.
State whether the valve provides routine isolation, frequent sequencing, emergency shutdown or modulation. Include cycle frequency, required stroke time and whether a fast closure could create a pressure surge. Define the fluid, differential pressure and temperature at each operating case.
If the valve may remain stationary for long periods, ask how the torque basis accounts for time at rest, deposits or seat memory. A clean-water shop cycle is not the same as breakaway after months in service.
02 / Torque
Size from the torque curve and the weakest supply condition.
Obtain valve break-to-open, running, end-to-close and maximum allowable stem torque where available. Check actuator output across its stroke at minimum pneumatic pressure or worst electrical supply. Spring-return actuators require separate review of powered and spring strokes.
Apply the project sizing factor to the correct torque case, but do not let an oversized actuator exceed the stem, coupling or mounting interface capacity. Record the calculation and source data.
| Input | Supplier should state | Common omission |
|---|---|---|
| Valve torque | Basis, differential pressure, temperature and seat. | One catalogue number with no condition. |
| Actuator output | Output by stroke at minimum supply. | Output quoted at nominal supply only. |
| Interface capacity | Stem, coupling, ISO flange and bracket limits. | Flange pattern checked; torque capacity ignored. |
| Stroke time | Opening and closing time under load. | Free-running bench time only. |
03 / Mounting
Check the complete mechanical load path.
The flange pattern, drive dimensions and orientation must match, but so must coupling engagement, key or square fit, bracket height, fasteners and corrosion protection. Misalignment can side-load shafts and create lost motion between the indicator and the ball.
Require a package general arrangement drawing showing valve, mounting kit, actuator and accessories. If a stem extension or stacked mounting arrangement is used, demand a specific design review rather than assuming the base interface covers it.
04 / Controls
Define what “fail closed” means for each lost utility.
State the required position on loss of electrical power, instrument air and control signal. A double-acting pneumatic actuator, spring-return unit and electric actuator respond differently. Define manual override, local indication, limit switches, continuous feedback, solenoid arrangement and hazardous-area requirements.
The electrical or pneumatic schematic should identify terminal numbers, tubing connections, supply ratings and alarm states. These details prevent field modifications that were never part of the package test.
On/off, three-point or modulating signal and protocol.
Open/closed contacts, position transmitter and diagnostic requirement.
Ingress protection, temperature, corrosion and hazardous-area certification.
Behaviour for each lost utility and permitted stroke time.
05 / Package test
Test the assembly against the approved cause-and-effect.
Confirm direction, mechanical stops, indicators, switches, feedback, manual override and stroke time. Record the actual air pressure or voltage. Exercise the defined failure states where practicable and verify that the valve reaches its required seat position.
Keep the valve pressure-test record and actuator functional test distinguishable. A shell/seat certificate does not prove wiring or fail action; an actuator cycle does not prove seat leakage.
Supply valve, mounting kit, actuator and controls as one engineered package. Submit torque sizing, interface checks, general arrangement, schematic and functional test procedure. Package test shall verify direction, indication, feedback, stroke time and specified failure response.
Sources / editorial control
Source basis
- ISO 5211:2026 — part-turn actuator attachments. Official current edition and scope.
- ISO 5640:2024 — mounting kits. Official scope for metallic part-turn mounting kits.
- ISO 5115:2023 — part-turn valve actuation. Official package-level actuation scope.
Review limit: Actuator sizing requires the offered valve torque data and project operating cases. This page does not provide a sizing factor or approve an actuator model.