Machinery-related injuries can be devastating. Those operating or maintaining unguarded machines are at risk for crushed hands and arms, severed limbs and fingers, abrasions, amputations, and lacerations, or even death. Industries using dangerous machines (like power saws or milling machines) are required to eliminate or control any preset hazards. Machine guards serve as a safeguard to protect operators, workers in the area, and the facility from damage.
OSHA regulations for machine guarding outlined in 29 CFR 1910 Subpart O include technical definitions, general requirements, and rules for specific applications. Safeguards are grouped into two types: guards and devices. Additionally, safeguards must meet the minimum general requirements:
- Contact must be prevented: Hands, fingers, limbs, and any other body parts cannot make contact with moving parts.
- Guards must be secured: Machine guards should not be easily removable and should be durable enough to withstand the environment.
- No new hazards are created: Safeguards are meant to reduce and eliminate machine hazards and if the guard introduces a new hazard (like an exposed sharp edge) then it has defeated its own purpose.
- Allow safe lubrication: It is important to ensure that if needed, one can locate oil reservoirs and find the lubrication point so no one needs to enter the hazardous area for maintenance.
All machines have a point of operation, a power transmission device, and operating controls, but they do not always need to be safeguarded. Employers will need to perform a job safety analysis to identify the different machine hazards in their facility. It is important to observe the motions or actions that make a machine so dangerous and evaluate what kinds of safeguards would be most effective.
Guards are physical barriers that simply prevent access to dangerous parts of the machine. The general types of machine guards are:
Fixed guards are a type of safeguard permanently fixed to a part of the machine (not a moving part, typically where access is infrequent). This is the simplest form of machine guarding, can be constructed from sheet metal, plastic, screen, etc., and will usually require a tool for removal.
Adjustable guards are a more flexible kind of machine guard that can be constructed to suit specific applications or different sizes of stock. However, adjustable guards do not provide the same level of protection as fixed or interlocked guards, may require additional maintenance, and may actually interfere with visibility.
Interlocked guards will shut off moving parts/mechanisms or disengage power when the guard is open, allowing workers to reach into machine safely. Interlocked guards are the strongest kind of safeguards because they provide maximum protection, although these kinds of guards require meticulous adjustment and maintenance moving forward.
Devices are also used in machine guarding and unlike guards, can usually perform more than one function. Some common safety devices approved by OSHA include:
- Restraint Devices are devices that will only allow the operator’s hands to travel a certain distance and not away from the predetermined safe area.
- Safety Trip Controls are used to shut down a machine and protect the operator in the case of an emergency. If someone trips over a machine or an operator loses their balance, the pressure on the device will automatically stop operation.
- Two-Hand Controls, or two-hand trips, require the use of both hands for activation. This will keep hands away from machine hazards prevent them from entering dangerous areas.
- Gates are large moveable barriers that prevents workers from reaching into or even walking into the hazardous area. They are typically interlocked so the machine only functions when the guard is in place. Some facilities use gates as a component of a perimeter safeguarding system that also protects pedestrian traffic.
Machine Guarding Program
OSHA’s requirements for machine guarding are the minimum workplaces must meet but is not the limit. Providing additional safety considerations is beneficial to both the employer and employee and will ensure the effectiveness of a machine guarding program. If you have a more elaborate system in place, it is important to provide comprehensive training so everyone in the workplace understands the importance of machine guarding, hazards associated with specific machines, and how to use safeguards.
You can also strengthen your machine guarding program with the aid of visual communication. One example of this is called an awareness barrier which is not a physical barrier, but rather a reminder to the worker that they are approaching a hazardous area. Using inline printed floor tape, you can convey specific equipment-related messages while effectively alerting individuals. Posting signs in the area that remind workers to keep guards closed, not to operate without safety guards in place, etc.
Machines are one of the leading causes of workplace injuries and often times is a result of unsafe operation. Implementing machine guards is an effective method for controlling machine hazards and protecting workers. It will reduce machine-related injuries and operators will feel more confident in a safe facility.
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