Changing Out a Valve Using Hand Tools
This scenario simulates a common offshore maintenance task: safely removing and replacing a valve using basic hand tools.
This exercise emphasizes tool selection, body positioning, hazard control, and correct torque application.
1. Task Overview
Valve replacement may be required due to:
- Leakage
- Blockage
- Wear and tear
- Scheduled maintenance
Although the job appears simple, it involves several hazards:
- Stored pressure
- Tight bolt connections
- Pinch points
- Unexpected movement
- Incorrect posture
- Dropped objects
2. Required Tools
- Combination wrenches
- Ratchet and socket set
- Torque wrench
- Screwdrivers
- Pliers
- Soft mallet
- Tag-out equipment
- PPE (gloves, safety glasses, etc.)
3. Step-by-Step Procedure
Step 1: Preparation and Isolation
- Verify system is depressurized
- Confirm LOTO (Lockout/Tagout) is in place
- Perform gas test if necessary
- Position tools near the job but not in walkways
Hazard controls:
- Stored energy
- Pressure release
- Chemical exposure
Step 2: Inspect Tools Before Use
- Ensure correct wrench/socket sizes
- Inspect for cracks, wear, rust
- Confirm no slop or rounding issues
Step 3: Loosen Flange Bolts
- Use closed-end wrench or socket
- Apply steady, controlled torque
- Loosen bolts in a crisscross pattern
- Keep hands away from pinch points
Hazards:
- Bolt snap
- Kickback
- Slippage
Step 4: Remove the Valve
- Support the valve while removing the final bolts
- Use both hands for stability
- Maintain correct body posture
- Avoid placing hands under the valve
If valve is heavy → use lifting aids.
Step 5: Prepare for Installation
- Clean flange surfaces
- Inspect gasket seating area
- Ensure alignment is correct before bolting
Step 6: Install New Valve
- Position valve carefully
- Insert bolts by hand before tightening
- Use correct torque sequence
- Check alignment while tightening
Step 7: Final Checks
- Confirm all bolts are torqued to spec
- Remove tools from area
- Remove tags after authorization
- Conduct leak test if required
4. Common Mistakes to Avoid
- Using the wrong-size wrench
- Over-torquing or under-torquing bolts
- Working in poor body alignment
- Not supporting the valve properly
- Rushing the job
- Failing to isolate pressure
5. Learning Objectives
By the end of this scenario, trainees should be able to:
- Select proper tools for valve replacement
- Use safe body positioning and controlled movements
- Recognize pinch points and line-of-fire hazards
- Follow correct bolt removal and tightening sequence
- Apply JSA principles during real tasks