Many machines found on shop floors and in factories have moving parts that rotate, reciprocate, punch, slide, grind, use toxic or corrosive chemicals, or generate extreme heat, noise, and vibration. Guards are permanent devices fitted on the machinery and equipment to provide protection against direct contact with moving parts, mechanical failure, electrical failure, and human error. When guards are missing or improperly used, there is the potential for injuries ranging from severe cuts to crushed hands and arms, amputation or even death.
Safeguards include barrier guards, safety devices, shields, awareness barriers, and warning signage. Some examples include wire cages around fans, blade guards on table and band saws, and covers on drive belts and electrical switch boxes. These methods can be used on their own or in combination to protect the machine operator and other employees in the work area. In some equipment, there is a built-in interlock switch that does not allow the machine to be activated unless the machine guard is in place. Never disable the interlock switch!
Hierarchy of Controls
When selecting a safeguard or combination of safeguards, always start at the top of the hierarchy to control the hazards. Use a lower control method only when the more effective solution isn't possible.
Control method and examples from most effective to least effective:
Elimination - remove the hazard from the workplace
- Process design, redesign or modification including changing the layout to eliminate hazards
- Eliminate or reduce human interaction in the process
- Automate tasks, material handling (e.g., lift tables, conveyors, balancers), or ventilation
Substitution - replace hazardous materials or machines with less hazardous ones
- Machines that have energy containment
- Machines with lower energy (e.g., lower speed, force, pressure, temperature, amperage, noise, or volume)
Engineering controls - remove the hazard at the source
- Installation of safeguards
- Installation of complementary measures such as emergency stop devices, platforms, or guardrails for fall protection
Systems that increase awareness of potential hazards
- Lights, beacons, strobes
- Backup alarms, notification systems
- Hazard warning signs, placards, labels
Administrative controls - controls that alter the way the work is done
- Training
- Housekeeping processes
- Safe job processes, rotation of workers, changing work schedules
Personal protective equipment - equipment worn by individuals to reduce exposure
- Protective eyewear and face shields
- Hard hats
- Hearing protection
- Hand protection
- Protective footwear
Never operate any equipment without a machine guard in place. If the guard is missing, your hands, clothes or tools could contact the moving parts, hot spots or high voltage conductors. If you think a guard is missing, do not operate the tool. Report the situation to your supervisor.
Resources:
- Safeguarding – General fact sheet, CCOHS
- Safeguarding – Working around Machinery fact sheet, CCOHS
- Machine Guarding, Young Workers Zone, CCOHS
- Hazard Control fact sheet, CCOHS
- Safeguarding, WorkSafeBC
- Machine Guarding, Occupational Safety and Health Administration (OSHA)
- CSA Standard Z432-16 Safeguarding of machinery, CSA Group