What is Hazardous Energy?
Energy in any form becomes hazardous when it builds to a dangerous level or is released in a quantity that could injure a worker. Workers servicing or maintaining machines or equipment may be seriously injured or killed if hazardous energy is not properly controlled. Injuries resulting from the failure to control hazardous energy during maintenance activities can be serious or fatal! Injuries may include electrocution, burns, crushing, cutting, lacerating, amputating, or fracturing body parts, and others.
- A steam valve is automatically turned on burning workers who are repairing a downstream connection in the piping.
- A jammed conveyor system suddenly releases, crushing a worker who is trying to clear the jam.
- Internal wiring on a piece of factory equipment electrically shorts, shocking worker who is repairing the equipment.
Forms of Energy
Energy is the power for doing work. Energy exists in different types, but all are associated with motion. Regardless of the type, energy exists in two basic states:
- potential energy - Energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.
- Kinetic energy - Energy that a body possesses by virtue of being in motion..
Reference the infographic: Releasing the load causes it to drop, converting potential energy to kinetic energy. It's the harmful transfer of energy at impact between an object and the worker that can cause injury. Note: it's the "harmful transfer of energy" that is always the direct cause of injury in an accident event.
Understanding Potential and Kinetic Energy in Lockout/Tagout
Energy is the power that allows work to be done. All energy involves motion, and it exists in two basic states: potential and kinetic.
- Potential Energy – Energy stored in an object due to its position or condition. This energy has the potential to become kinetic and cause harm if released unexpectedly.
Examples of Potential Energy:
- Raised forklift forks – if not blocked properly, they can fall suddenly.
- Suspended loads – like a heavy item hanging from a crane or hoist.
- Compressed springs – inside mechanical equipment, ready to expand when released.
- Pressurized hydraulic systems – fluid held under pressure in equipment like lifts or presses.
- Elevated dump truck beds – which could drop if the hydraulic system fails.
- Kinetic Energy – Energy an object has because it is moving. Injuries often happen from the impact when moving objects hit a worker.
Examples of Kinetic Energy:
- Rotating blades or saws – still spinning when maintenance begins.
- Conveyor belts – that continue to move after being shut down if not locked out.
- Vehicles or carts – that roll unexpectedly if wheels are not chocked.
- Moving parts – like flywheels or fans that haven't fully stopped.
- Falling objects – from above due to gravity releasing stored potential energy.
Important Safety Note: The surface (direct cause) of injury in energy-related accidents is the harmful transfer of energy – when energy is suddenly released and comes into contact with a worker. This is why identifying both potential and kinetic energy sources is critical during lockout/tagout.
Knowledge Check Choose the best answer for the question.
1-7. What are the two basic states of energy?
You forgot to answer the question!