The Energy Wheel is a tool that encourages a scientific understanding of hazards and their energy sources. On the job site, energy can be found in moving materials, transferred by cranes or released by excavating a trench, to name a few examples. Workers also have energy from their center of gravity as they stand upright. 

The Energy Wheel breaks down the 10 most common energy sources that can be found on the job site: 

• Gravity: uneven work surfaces, work at heights, unsecured material
• Motion: traffic, mobile equipment 
• Mechanical: cable, chain fall, gears
• Electrical: wires, power lines, transformers
• Pressure: pneumatic tires, piping systems
• Sound: heavy machinery, power tools
• Radiation: welding, sun exposure
• Biological: pests, animals
• Chemical: solvents, silica, wood dust
• Temperature: friction, engines, steam

Why is this important?

On the job site, it is critical that workers can recognize hazards. Situational awareness, the process of perceiving a stimulus, understanding it and then anticipating possible outcomes, is key to identifying hazards. 

According to “The Energy Wheel: The Art and Science of Energy-Based Hazard Recognition” by Matthew R. Hallowell, “Translated to the context of safety, this process involves: 

1. Recognizing the presence of a danger (i.e., hazard recognition); 
2. Judging the level of danger posed by the hazard (i.e., risk perception); and 
3. Deciding how to behave around the hazard (i.e., risk tolerance).”

Why is this helpful?

Some of these hazards are easy to see and understand (gravity, motion), but others can be more challenging (mechanical, pressure, chemical), so they require a larger cognitive effort to identify and longer processing times.

The Energy Wheel gives workers a set of reminders of what hazards can look like. For example, and according to the report, a crew can use the mechanical icon as a prompt to identify rotating machinery, vibration from tools and more. It encourages workers to think about hazards that might not come to mind naturally. Since not all hazards are seen or can be anticipated before work, the Energy Wheel can provide clear understanding when change occurs. Employers can ask their employees if a new source of energy is present and how to address it.

OSHA also has recommended practices for hazard identification and assessment and it urges employers to consider hazards in emergency or nonroutine situations, conduct periodic workplace inspections to identify new and recurring hazards and use the collected information to prioritize corrective actions. Worker participation is critical.

Discussion questions 

• What are five types of energy typically seen on the job site?
• What are some ways hazards can present themselves on the job site?

Sources: The Energy Wheel: The Art and Science of Energy-Based Hazard Recognition / OSHA recommended practices for safety and health programs