15 Technical Specifications You Must Know for Pneumatic Actuators

2026-05-19

This guide offers practical, concise advice for selecting pneumatic actuators, covering 15 key parameters. These include actuator type, action mode, supply pressure, torque, safety factors, materials, temperature limits, failure position, and accessories like handwheels and stroke limiters. For each parameter, it clarifies the information customers need to provide and explains its importance—ensuring actuators are sized accurately and cost-effectively. Engineers and procurement specialists can use this guide directly as a checklist.

These selection principles apply across multiple industries, including petrochemicals, natural gas, power generation, pharmaceuticals, water treatment, and food and beverage. As the core drive for automated valves, pneumatic actuators are commonly paired with two main valve types:

Quarter-turn valves (ball, butterfly, plug, eccentric rotary) – These require rotary torque output, typically for 0°–90° motion (and up to 180° in some cases).
Linear valves (globe, gate, control, diaphragm) – These need thrust output to drive linear stem movement.

Practical selection also demands accounting for on-site conditions: whether the actuator will be used indoors or outdoors, in hazardous areas, corrosive environments, high/low temperature settings, humid conditions, or dusty locations. These factors determine the appropriate enclosure rating (e.g., IP67/IP68) and explosion-proof certification (e.g., Ex d, Ex ia). For critical control loops, accessories such as positioners, limit switches, solenoid valves, and air treatment units are often necessary—these enable precise regulation, position feedback, and interlocking protection.

Understanding how valve type, process requirements, and actuator characteristics align is critical to building a safe, reliable, and cost-effective system. The 15 selection tips in this guide are based on real-world engineering needs, helping users avoid performance gaps, unnecessary costs, or safety risks caused by missing or incorrect parameters.

No.	Parameter	Options / Description
1	Actuator Type	• Diaphragm type • Cylinder type • Special type Typically specified by the client; if not, choose based on experience or common products.
2	Action Type	• Single-acting cylinder • Double-acting cylinder • Special type Must be clearly described for accurate selection.
3	Brand Requirement (for quarter-turn actuators)	• Manufacturer’s choice (preferably own product) • Bettis / BIFFI • Rotork • Limitorque • Other specified brands (e.g., Pro-control, Neles) Choose based on actual request.
4	Air Supply Pressure	• 2 bar • 3 bar • 4 bar • 5 bar • 6 bar Note: For diaphragm actuators, typically 1.4–4.0 bar; for cylinder types, 3–6 bar. Refer to inquiry document.
5	Torque or Thrust Value	• For linear valves: provide thrust value. • For quarter-turn valves: provide at least 5–6 torque values (e.g., BTO, BTC, RUN, ETO, ETC, MAST). This is one of the most important parameters for actuator sizing.
6	Valve Stroke	• For linear valves: provide accurate stroke length. • For quarter-turn valves: confirm rotation angle (0~90° or 0~180°).
7	Safety Factor	• 1.0 (value already includes safety factor) • 1.25 times • 1.3 times • 1.5 times • 2.0 times • Customer’s special requirement Must be provided by the customer.
8	Actuator Housing Material	• Cast aluminum • Cast iron • Carbon steel • Stainless steel • Other special materials Usually selected by manufacturer unless specified.
9	Actuator Seal Material	• Natural rubber • Nitrile rubber • Viton rubber • Other special materials Important for low/high temperature applications.
10	Ambient Temperature Requirement	• Normal (no low temp requirement) • Low temp ≥ -20°C • Low temp ≥ -40°C • Low temp ≥ -60°C • High temp (specify value) • Other special conditions Temperature affects model, series, and price – confirm first.
11	Handwheel Mechanism	• Not required • Top-mounted handwheel • Side-mounted handwheel • Special requirements Significantly affects price and actuator model.
12	Stroke Adjustment / Travel Limit	• Adjustment needed at 0° and 90° positions (e.g., ±5° or ±10°)? Especially necessary for triple offset Butterfly Valves and trunnion mounted ball valves.
13	Failure Position – Air Loss	• Fail Close (FC) • Fail Open (FO) • Fail Last (FL-1) • Fail Lock (FL-2) • Other (specify) Note: “FL” can mean Fail Last or Fail Lock – different circuits.
14	Failure Position – Power Loss	• Fail Close (FC) • Fail Open (FO) • Fail Last (FL-1) • Fail Lock (FL-2) • Other (specify) If not specified, assume same as air loss failure position. If different, an air reservoir may be needed.
15	Other Requirements	Any special customer requirements not covered above.