How to Perform Valve Maintenance

Valve maintenance ensures that valves operate reliably and seal properly throughout their service life. A structured program includes routine inspection, preventive maintenance, and corrective actions based on valve type and service severity.

Valve Maintenance Procedure: Step by Step

1. Isolate the valve: Depressurize the line and isolate the valve from the process using upstream and downstream block valves. Confirm zero energy (pressure and temperature) using a bleed valve or gauge.
2. Lock out / tag out (LOTO): Apply lockout/tagout per the plant safety procedure. For actuated valves, disconnect the power supply (pneumatic, hydraulic, or electric).
3. External visual inspection: Check the valve body for external corrosion, paint deterioration, leaks at the packing gland, flange connections, and body-bonnet joint.
4. Operate the valve: Cycle the valve from fully open to fully closed and back. Check for smooth operation, excessive handwheel effort, unusual noise, or vibration.
5. Check packing gland: Inspect the gland for leaks. If the packing is leaking, repack the valve by replacing the packing rings.
6. Inspect the seat and disc: For valves removed from the line (or with an accessible bonnet), inspect the seating surfaces for erosion, corrosion, pitting, or scoring. Lap the seat if reconditioning is needed.
7. Check the stem: Inspect the valve stem for scoring, corrosion, or bending. Verify stem thread condition and backlash.
8. Inspect the actuator (if applicable); For actuated valves, check the actuator for air/oil leaks, proper stroke length, and correct position indication.
9. Reassemble and test: Reassemble the valve, torque bonnet bolts to specification, and perform a seat leak test and a shell (body) test before returning to service.
10. Document and record: Record all findings, repairs, and replacement parts on the valve maintenance record.

Maintenance Tasks by Valve Type

Valve Type	Key Maintenance Tasks	Common Failure Modes
Gate valve	Packing replacement, seat lapping, stem lubrication, wedge inspection	Seat erosion, packing leak, stem corrosion
Globe valve	Disc/plug replacement, seat lapping, packing replacement	Disc erosion, packing leak, stem wear
Ball valve	Seat ring (seal) replacement, stem seal replacement, cavity drain check	Seat seal degradation, stem leak, cavity pressure
Butterfly valve	Seat (liner) replacement, disc inspection, shaft seal replacement	Liner wear, disc edge erosion, shaft leak
Check valve	Hinge pin inspection, disc/clapper replacement, seat lapping	Disc wear, hinge pin corrosion, slamming damage
Plug valve	Plug and sleeve lubrication, sealant injection, plug taper adjustment	Sealant degradation, plug seizure, body erosion

Pro Tip

Establish a preventive maintenance schedule based on valve criticality. Safety-critical valves (emergency shutdown valves, pressure relief valves, blowdown valves) should be tested at least annually. Non-critical utility valves may be maintained on a 3-5 year cycle or on a condition-based schedule.

Preventive Maintenance Schedule

Activity	Frequency	Applies To
External visual inspection	Every 6 months	All valves
Packing gland adjustment or replacement	Annually or as needed	All manual and actuated valves
Full stroke test	Annually	Actuated valves (ESD, control)
Seat leak test	Every 2-3 years	Block valves, isolation valves
Full overhaul (disassembly)	Every 5-10 years	All valves (based on condition)
Safety relief valve testing	Annually to every 3 years	PSVs, PRVs

Key Points

• Follow the manufacturer’s maintenance manual for specific procedures, torque values, and replacement parts.
• Keep a valve register with tag numbers, specifications, and maintenance history.
• For valve components and terminology, refer to API 600, API 602, and API 608.
• Deferred maintenance is a leading cause of process safety incidents. Prioritize safety-critical valves.

Read the full guide to piping inspections