ESD Valve Proof Test SOP
A proof test procedure for emergency shutdown valves in safety instrumented functions: full stroke from the logic solver, stroke time against the requirement, feedback and seat tightness.
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- Document control header (SOP SIS 001)
- Purpose, scope and references
- Safety, tools and prerequisites
- Numbered step by step procedure
- Acceptance criteria and records
- Approval block for sign off
1. Purpose
To reveal dangerous undetected failures of shutdown valves at the proof test interval assumed in the SIL verification.
2. Scope
On/off shutdown valves (ESD, SDV, XV) with solenoid valves and spring return actuators that form part of a SIF.
3. References
- IEC 61511 (proof testing of SIS)
- Safety requirements specification (SRS) of the SIF
- Valve and actuator manuals
4. Responsibilities
- Instrument technician: carries out the work and records results.
- Instrument engineer or supervisor: reviews and approves the records.
- Operations: grants the permit, isolates the process and returns the equipment to service.
5. Safety Precautions
- Work only under a valid permit to work and follow the site isolation (lockout tagout) procedure.
- Wear the PPE required for the area: safety helmet, glasses, gloves and safety shoes as a minimum.
- In hazardous areas use certified or intrinsically safe test equipment, or obtain a gas free certificate and hot work permit.
- Inform the control room before starting, and before returning the instrument to service.
- Bypassing a SIF reduces protection: apply compensating measures and get written authorisation as per the bypass procedure.
- Only test with the process in a safe state or isolated.
6. Tools and Equipment
- Stopwatch or SIS sequence of events records
- Communication with the control room (radio)
- Leak test equipment if seat tightness is part of the test
7. Prerequisites
- Proof test plan approved; required closing time from the SRS.
- Operations agreement and bypass authorisation where needed.
8. Procedure
8.1 Preparation
- Review the previous proof test record and any open defects.
- Confirm the required stroke times and fail action from the SRS.
8.2 Full stroke test
- Initiate the trip from the SIS logic (through the solenoid valve) as the real demand would.
- Time from the command to the closed limit switch.
- Confirm the closed feedback in the SIS and DCS.
- Reset and open the valve; time the opening stroke and confirm the open feedback.
- Repeat as required by the test plan.
8.3 Additional checks
- Check the solenoid valve vents freely and the actuator has no air leaks.
- Perform a seat leak test if the SRS requires tight shut off.
8.4 Completion
- Remove all bypasses with operations confirmation.
- Record the results against the SIF and report any failure as a dangerous failure.
9. Acceptance Criteria
- Closing time within the SRS requirement.
- Feedback correct; smooth travel without sticking.
- Seat leakage within the specified class (where tested).
10. Records
Related tools
This is a generic procedure. Adapt it to your site permit system, the manufacturer instructions and your quality system before use.
Frequently Asked Questions
What is proof testing?
A periodic test that reveals dangerous failures the system cannot detect by itself, so the SIF keeps its SIL.
Is a partial stroke test enough?
No. It covers part of the failures; full stroke and seat tests are still needed at their intervals.
Where does the closing time requirement come from?
From the SRS, based on the process safety time.
Learn more on the blog
Partial stroke testing of ESD valves
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