Effective machine guarding is essential where injury-causing hazards from machinery operations cannot be eliminated or reduced to a safe level.
Machines provide a vital function in all sectors of the workforce, from construction to manufacturing, to retail, service and hospitality. They can perform repetitive tasks at high speeds and can use various energy sources to apply forces that shape, cut, bend, lift and move materials, some of which may otherwise not be humanly possible. Unfortunately, the attributes that can increase production, quality, safety and business profits, can also be the source of severe, life-altering injuries or fatalities if not properly designed and safeguarded.
Most machinery today comes with some level of guarding provided by the manufacturer, but this does not ensure it complies with current regulatory or consensus standards. In addition, manufacturer-installed guards do not replace an employer’s responsibility for providing a safe workplace by protecting employees from recognized hazards. Similarly, there is no “grandfather clause” for lack of proper guarding on older equipment relative to an employer’s safety obligations. Whether new, used, modified or original, it is the employer’s responsibility to ensure that all machinery used by employees is safe for operation.
Three Steps to Effective Machine Guarding for Mechanical Hazards
- Determine Risk Factors
- Identify Control Options and Priorities
- Evaluate and Maintain Safeguards
Determine risk factors
Whenever possible, read and understand the equipment manufacturer’s operations and user manuals. As the end-user you must identify and understand the potential risk factors. One way to do this is to conduct a machine risk assessment. Ideally, this should be done as part of the installation of machinery and whenever modifications to the machinery are made. This can also be done as part of a Job Hazard Analysis. A good assessment of potential risk factors should include consideration of all aspects of the machine’s operations and those who may be in the area of operations.
Control options and guarding priorities
Once the risk assessment is completed, the next step is to determine the best control options. Safeguarding priorities should follow the Hierarchy of Controls concepts. When possible, machinery hazards should be eliminated, substituted, or reduced by engineering controls to a safe level. This may be possible by using full or partial automation, making a process change such as increasing clearances to eliminate pinch points, or updating to safer equipment components. After this is done, safeguarding mechanisms must be used to protect against the remaining hazards. This can be a combination of barrier guards, devices and methods.
General principles for mechanical hazard guards
To be effective, machine guards should be constructed of materials capable of withstanding workplace conditions and expected forces. They should be designed in such a way as to:
- Prevent Contact — The guard should eliminate the possibility of any part of a worker’s body coming into contact with dangerous moving or otherwise hazardous parts. Workplace rules guiding safe work-practices should prohibit loose clothing, dangling hair, jewelry, or other exposures that could lead to pulled-into injuries.
- Be Secure — Guards should be secured in a fashion such that operators are unable to remove or tamper with them, and substantial enough to withstand the conditions of normal use.
- Protect from Falling Objects — The guard’s design should eliminate the chance of objects, such as tools or materials, from falling into moving parts.
- Create No New Hazards — A safeguard should not introduce any new hazards, such as sharp or jagged edges that could cause a laceration.
- Not Interfere — Guards that get in the way of a worker performing the job efficiently and comfortably are likely to be removed or overridden. Consult with workers when designing guards to identify any potential interference or with operations.
- Allow safe lubrication — Machine lubrication should be possible without removing guards.
When evaluating or developing guards, remember to use the acronym AUTO to ensure the guard prevents a person from being able to go Around, Under, Through or Over a guard to the hazard area.
Evaluate and maintain safeguards
After effective safeguarding measures have been determined and implemented, it is important to ensure they function as intended and remain in working order. This is done by conducting routine inspections of the guarding mechanisms, observations of work practices, and feedback from employees involved with using the machinery. Re-evaluations should be conducted whenever there is a machinery change or process revision to ensure it does not interfere with existing guarding or create additional hazards.