The Energy Wheel
Ten sources of energy. Used as a check after instinct, it finds the hazards crews have no category for.
The ten energy sources
- Gravity
- Anything that can fall, or that you can fall from.On site A person on a roof edge or an unprotected floor opening; a suspended load over a walkway; a trench wall; a stacked pallet.
- Motion
- Anything moving, including vehicles, plant, water and people.On site A reversing truck in a yard; a rail vehicle on a live track; an excavator slewing near a crew; a vessel at a wharf edge.
- Mechanical
- Rotating, pinching, cutting or stored mechanical energy.On site A conveyor drive with the guard off; a chainsaw; a tensioned winch cable; a spring under compression.
- Electrical
- Any live conductor, stored charge or arc potential.On site Overhead lines near a crane or an irrigator; a switchboard not proven de-energised; a battery bank.
- Pressure
- Compressed gas, pressurised liquid, or stored pressure in a system.On site A hydraulic ram on an excavator; a compressed air line; a water main under test.
- Temperature
- Heat enough to burn or scald.On site Steam lines in a dairy plant; hot bitumen; molten metal.
- Chemical
- Reactive, flammable, toxic or corrosive substances.On site Fuel vapour in a tank; chlorine at a water plant; ammonia refrigerant; silica dust from cutting.
- Biological
- Living things that can harm: animals, pathogens, plants.On site A bull in a dairy shed; sewage in a pump station; mould in a flood-damaged building.
- Radiation
- Ionising and non-ionising radiation, including sunlight and lasers.On site A density gauge on a roading job; a welding arc; UV on a summer roof.
- Sound
- Noise at levels that damage hearing.On site A rock breaker; a compressor room; a chainsaw for hours.
Examples are general illustrations. Every site must assess its own conditions.
Why a wheel
Gravity and motion are noticed almost without effort. Pressure, temperature, chemical, radiation and biological energy are routinely overlooked. In Hallowell's field study, crews with years of experience identified fewer than half of the hazards in front of them.
About 30% morehazards found when crews were given the wheel, in the categories they had been missing.
The wheel produces a complete inventory, not a priority order. Deciding which of those hazards can kill is the job of the high-energy threshold.
How crews use it
- Look at the task first. List the hazards you see.
- Go round the wheel. For each energy source, ask: is it here, and where?
- Mark the high-energy ones. Anything that could kill or cause a life-altering injury.
- Check the control. For each one, ask whether the control in place is a Direct Control, or whether you are relying on someone not making a mistake.
On your phone and your hard hat
EBS WheelhouseThe free field app: all ten energy types with what to look for and what a Direct Control has to be, a one-minute observation that tells you whether a hazard is uncontrolled, and a card to send to your supervisor. Offline, no login, iOS and Android.
Stickers with your logoUpload your logo, see it in the centre of the wheel, order the stickers. Design is free; you pay only for printing and shipping to site.
Where the wheel comes from
The Energy Wheel is most closely associated with Dr Matthew Hallowell and the Construction Safety Research Alliance at the University of Colorado Boulder, with earlier origins often attributed to Chevron. His book, Energy-Based Safety, sets out the research. GeneXR's wheel materials are original and written for New Zealand and Australian sites.