Failure of Control Valve Actuator

Cause & Consequence

• Failure of vessels or pipework

Incident Location

Any Location Type

Incident Activity

Drilling, workover

Incident Info Source

Graeme Adamson (Instrument Technical Authority) - 01224 371289. graeme_adamson@nexeninc.com

Specific Incident Equipment

Emerson (Fisher) Control Valve 8” EHD-667 incl. 667-100 Spring & Diaphragm Actuator, 3582i Positioner, 67AFSR Air Regulator.

Lessons Identified

No details available

Incident Recommendations

1. Check that screws on all other 67 AFSR regulators are not loose.

2. Identify other installed valve actuators (on an application by application basis) which may be vulnerable to the same type of failure.

3. Where required by application, ensure regulators have full internal relief or fit external relief devices between regulator and positioner.

4. Add inspection of regulators to maintenance procedures

5. Raise awareness that for some control valves the correct operation of them regulator is critical.

6. Ensure pressure relief is included as part of the specification for future control valves where the actuator cannot withstand the specified maximum instrument air pressure.