Explosion-Proof Actuators for Dampers and Valves
Buying a new explosion-proof damper actuator or replacing one that is no longer made?
We handle both. We match the torque, division, gas group, control signal, and fail position to your damper or valve.
For a replacement, send us a photo of the nameplate. For a new build, send the damper or valve schedule and the area classification. We return a selection ready for submittal.
Our offices are in Houston and Dallas-Fort Worth, serving Texas and the Gulf Coast, and we ship nationwide.
Explosion Proof Actuators for Sale
Contact us now for a quick quote and get the right product the first time!
Watch an actuator in action!
Key Takeaways
Explosion-Proof Actuators We Supply
| Actuator | Range | Where it goes |
|---|---|---|
| Quarter-turn damper actuator, on/off or modulating | 5 to 150 Nm, 24 to 240 V AC/DC, on/off, 0-10 V or 4-20 mA | Exhaust and supply control dampers in classified rooms |
| Spring-return fail-safe actuator | Drives open or closed on loss of power | Emergency exhaust and shut-off dampers |
| Fire and smoke damper actuator | Fail position set by the life-safety design | Fire and smoke dampers in hazardous areas |
| Rated actuator on a corrosion-resistant damper | Same torque range, mounted on an FRP damper | Chemical and wastewater exhaust on fiberglass control dampers |
| Linear actuator | 500 to 3,000 N | Dampers with linkage and globe valves |
| Quarter-turn and multi-turn valve actuator | Higher torque on request | Ball, butterfly, and gate valves on process lines |
| Explosion-proof housing over a standard actuator | NEMA 7 and 9, Class I and II, Division 1 and 2 | Retrofits where the damper stays in place |
Every actuator is picked for the division and gas group on your drawings. If your torque or force falls outside these ranges, send the schedule anyway. We source past them.
Looking for a Specific Actuator?
Contact us now for a quick quote and get the right product the first time!
Division 1 or Division 2: Which Actuator Does the Damper Need?
A Division 1 area has ignitable gas during normal operation, so the damper actuator needs an explosion-proof housing. A Division 2 area has gas only after a leak or an equipment failure. In Division 2, a non-incendive actuator is allowed, and it is smaller and usually costs less. Both definitions come from NEC Article 500.5.
Many rooms are rated Division 2 because exhaust ventilation keeps the gas below the ignitable level. In those rooms, the exhaust damper actuator is part of what holds the rating. Set its fail position on power loss with that in mind.
| Division 1 | Division 2 | |
|---|---|---|
| When gas is present | In normal operation, during repair, or from routine leaks | Only after a failure or abnormal operation |
| Actuator protection | Explosion-proof housing, NEMA 7 for gas or NEMA 9 for dust | Non-incendive design, or any Division 1 unit |
| Typical location | Inside the hazardous room or at the process vent | Rooms kept safe by ventilation, and areas next to Division 1 |
| Size and cost | Larger, heavier housing | Smaller and usually lower cost |
The division is only part of the rating. The nameplate also carries the gas group and the temperature code. Group D covers propane, gasoline, and natural gas. Group B covers hydrogen. The temperature code sets the highest surface temperature the actuator can reach. T4, for example, means 135°C or lower.
If your drawings use the Zone system under NEC Article 505, send them as they are. We match the Zone rating the same way.
Actuator Types for Hazardous Areas
Quarter-Turn and Rotary Actuators
Quarter-turn actuators rotate 90 degrees to open or close ball, butterfly, and plug valves and most dampers. We supply electric units from 5 to 150 Nm for dampers, and high-torque models for large valves in refineries and on oil and gas lines.
Multi-Turn Actuators
Multi-turn actuators turn the valve stem many times to move gate and globe valves. They fit water, steam, and process lines where the valve travels a long way from open to closed.
Linear Actuators
Linear actuators push and pull in a straight line, from 500 to 3,000 N. They drive globe control valves and dampers with a linkage in chemical plants and treatment plants.
Pneumatic and Hydraulic Actuators
Pneumatic actuators run on plant air, so the actuator itself has no electrical parts. Only the solenoid valve and limit switches need the hazardous rating. Hydraulic actuators give high force for large pipeline valves in oil and gas service.
Common Questions
What markings must an explosion-proof actuator carry?
An explosion-proof actuator must be marked with its class, its gas or dust group, and its temperature code under NEC 500.8. The temperature code shows the highest surface temperature the actuator can reach. A T4 marking means 135°C or lower, which must stay below the ignition temperature of the gas in the area.
Can I put a standard damper actuator in an explosion-proof housing?
Yes, a standard direct-coupled damper actuator can go inside a listed explosion-proof housing. Housings of this type are rated NEMA 7 and 9, for Class I Division 1 and 2, Groups B, C, and D. The housing adds size and weight, so check the space at the damper shaft before you order.
What is the difference between explosion-proof and intrinsically safe actuators?
An explosion-proof actuator contains any spark inside a heavy housing, while an intrinsically safe device limits its own energy so no spark can ignite the gas. Intrinsically safe design, covered by NEC Article 504, suits low-power sensors and switches. Actuator motors need more power, so most hazardous-area actuators use explosion-proof housings.
Related Hazardous Location Ventilation and Heating Equipment
- Explosion proof fans – Spark resistant exhaust for the same classified room
- Explosion-proof heating – Space heating inside the classified envelope
- Explosion proof duct heaters – Heating the supply air into a classified space
- Explosion proof immersion heater – Process and tank heating in hazardous service
- Heat trace – Freeze protection for pipes and valves
- HVAC oil and gas – Process area ventilation and control room pressurization
- Wastewater treatment ventilation – Digester and headworks exhaust where gas and corrosion meet
- Offshore HVAC – Platforms and rigs