“Electric or pneumatic?” is the first question on every automated valve package — and the wrong default costs money for the life of the plant. Here is the decision logic we walk through with buyers, based on the packages we quote with our actionnement et automatisation range.
Start With Fail Action, Not Power
If the process must fail closed (or open) on power/air loss — ESD, fire-water, burner trains — a spring-return pneumatic actuator is the natural answer: the spring IS the safety. Electric fail-safe exists (spring-return electric, battery/capacitor packs) but costs more per unit of torque.
Then Infrastructure
- Plant air available → pneumatics are cheap, fast and robust; add a solenoid + limit switchbox and done.
- No air network (remote sites, buildings, terminals) → electric avoids building a compressor system for a handful of valves.
Then Duty
| Requirement | Pneumatic | Électrique |
|---|---|---|
| On/off isolation | Excellent, fastest | Good |
| Modulating control | With positioner | Excellent (precise, no positioner air) |
| High cycle frequency | Excellent | Duty-cycle limited (check S2/S4 rating) |
| Hazardous area | Simple (air is inert) | Ex-certified motors required |
| Stroke speed control | Flow restrictors | Fixed by gearing |
Sizing Basics Buyers Should Check
- Actuator torque ≥ valve breakaway torque × safety factor (1.25–1.5 on/off; more for slurry/steam).
- ISO 5211 mounting pad match (F07/F10/F12…) — direct mount beats brackets.
- Supply: air pressure actually available at the valve (not at the compressor), or voltage/phase on site.
- Accessories included? Solenoid, switchbox, positioner, air set — the “cheap” actuator quote usually excludes them.
Foire aux questions
What about hydraulic actuators?
Reserved for very high torque (large pipeline valves) or where existing hydraulic power units justify them.
Can you mount and test actuators before shipment?
Yes — mounted, stroked and function-tested packages with test reports are standard on request; single supplier responsibility avoids the classic valve-vs-actuator warranty dispute.
Automating a valve package? Send the valve list and site utilities — we return a mounted-package quote.
