Unexpected Movement, Vibration & Stored Energy
Offshore installations involve constant vibration, mechanical forces, and equipment that can shift or move without warning.
Hand tool tasks become significantly more dangerous when tools or components release stored energy or react unexpectedly.
This lesson helps workers predict and control these dangers.
1. Understanding Unexpected Movement
Unexpected movement occurs when:
- A bolt suddenly breaks free
- Equipment shifts due to vibration
- A pipe springs back after tension is released
- A valve wheel moves when pressure equalizes
- A component is not fully isolated
Common risks:
- Hands struck against equipment
- Loss of balance
- Line-of-fire injuries
- Fingers caught between components
2. Vibration Hazards
Offshore machinery creates constant vibration:
- Pumps
- Compressors
- Generators
- Turbines
- Heavy rotating equipment
Vibration causes:
- Bolts to loosen or tighten unexpectedly
- Tools to slip
- Reduced grip strength
- Worker fatigue
Workers must anticipate vibration when applying torque or working in close contact with machinery.
3. Stored Mechanical Energy
Stored energy accumulates in:
- Bent or tensioned metal
- Pressurized systems (even after isolation)
- Springs
- Hydraulic accumulators
- Clamped components
Release of stored energy can cause:
- Snapback
- Tool ejection
- Sudden component movement
- Impact injuries
4. Recognizing Signs of Hidden Energy
Signs include:
- Components that appear slightly misaligned
- Vibrating or humming pipes
- Movement when applying light pressure
- Tight bolts that suddenly become loose
- Equipment that shifts with platform motion
Workers must assume energy is present unless proven otherwise.
5. Controlling Unexpected Movement
Before starting work:
- Secure or support loose components
- Use alignment bars instead of hands
- Use wedges or clamps
- Confirm proper isolation of systems
- Maintain stable footing
During tool use:
- Apply torque gradually
- Maintain line-of-fire awareness
- Keep hands clear of pinch points
- Stop if excessive resistance or movement is detected
6. When to Stop Work
Workers must pause the task immediately if:
- Components shift unexpectedly
- Vibration increases
- They lose control of a tool
- Stored energy is suspected
- Equipment begins to move or rotate
Stopping early prevents serious injuries.
Key Takeaways
- Unexpected movement is a major offshore hazard
- Vibration reduces control and increases risk
- Stored energy can release violently
- Proper awareness and securing components prevent incidents