Keeping Operators Safe with Machine Guarding

Dec. 30, 2024

Keeping Operators Safe with Machine Guarding

The lack of proper machine guarding leads to approximately 800 deaths each year. This doesn&#;t count the numerous instances of serious injuries such as lacerations, crushed appendages, abrasions, blindness, and even instances of amputation. For that reason, safeguarding machines is incredibly important to minimize or eliminate these incidents.

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To begin, machine safeguards must meet minimum requirements to provide a safe environment for employees. These minimum requirements are:

Prevent contact: The safeguard must protect employees from having any part of their body caught in dangerous moving machine parts.
Secure: Guards and safety devices must be secured to the machine and not easily tampered with. They should also be made of durable material to withstand machine use.
Protect from falling objects: Safeguards must ensure that there is no possibility of tools falling into the machine to either become lodged inside the machine or become a projectile.
Create no new hazards: Any safeguard applied must not pose new hazards to workers. This can be in the form of jagged pieces, sharp edges, etc.
Allow safe lubrication: The guard should still allow for easy lubrication of the machine if possible. Eliminating the need to remove the safeguard prevents hazards involved with forgetting to put it back.

Staying compliant with OSHA's .212 regulation for machine safeguarding can be attained by any company if they utilize any of the five basic machine safeguarding mechanisms and keep best practice methods in mind. In the end, employees and the company both benefit from a diminished number of hazards present in the workplace. By not safeguarding machines, those hazards have the potential to lead to injuries that result in labor loss, monetary compensation for an injury on the company&#;s end, and potential product/equipment damage.

What are Machine Guards?

Machine guards are an engineering control that aims to keep workers safe from moving machine parts. Machine safeguarding can be seen being used most often in facilities where fabrication work is common. Most hazards that are considered dangerous to employees are contained in three places around heavy machinery. Those are the point of operation, the power transmission apparatus, and moving parts. Those three areas are where most machine guarding mechanisms are found since employees are often assigned tasks in these dangerous places.

There are numerous motions and actions machines perform that can become hazardous to the operator. Identifying the types of hazards present within the machine is the first step in determining the kind of machine guard that needs to be put into place. Hazardous motions can be anything involving:

Rotating
Reciprocating
Transversing

While machine actions that can become hazardous are:

Cutting
Punching
Shearing
Bending

These types of motions and actions are some of the hazards that need to be found and mitigated or eliminated to keep operators safe. Using any, or a combination, of the five basic means of safeguarding machinery will assist in getting rid of dangerous machine hazards.

The Five Basic Means of Safeguarding Machinery

There are five types of basic machine safeguarding techniques to choose from for maximizing employee safety. The first ones are physical machine guards. Machine guards are physical barriers that prevent operator contact. Guards can come in a handful of types, which are:

Fixed guards: these are permanently attached to machines and can be made of sheet metal, plastic, wire cloth, bars, or any other type of material that can stand up to the machine&#;s task. Fixed guards are the most preferred type of physical guard because they're simple and effective.

Advantages: Fixed guards can be constructed for many types of machines and applications, they provide maximum protection to employees, and they require minimal maintenance.
Drawbacks: Visibility may be reduced and when a machine needs to undergo maintenance the guard may need to be taken off which causes an additional safety hazard.

Interlocked guards: This type of guard relies on a tripping mechanism that shuts off power when the guard is opened or removed. The machine cannot be started back up until the guard has been put back into place. Interlocked guards can be electrical, hydraulic, pneumatic, or any of the three combined.

Advantages: Interlocked guards provide maximum protection to the operator and it allows for easy access to machine parts without needing to waste time removing fixed guards.
Drawback: There may be complications with adjustments and maintenance

Adjustable guards: Adjustable guards allow flexibility for accommodating different sizes of products. They can be made of the same material as fixed guards.

Advantage: It is adjustable and can be used in a variety of different productions.
Drawbacks: Operator protection is not complete because they may have to reach into the dangerous zone, they require frequent adjustments, the operator may damage the guard by not using it correctly, and it can obstruct the operator&#;s view.

Self-adjusting guards: This type of guard adjusts itself while the operator is putting through the material. After the item is removed the guard moves back into its original position to wait for the next item.

Advantage: This kind of guard is often commercially available.
Drawbacks: Self-adjusting guards don&#;t provide maximum protection, it may obstruct the operator&#;s view, and requires frequent maintenance and adjustment.

The next machine safeguarding options are sensing devices. Unlike guards that are a physical obstruction from the machine&#;s moving parts, sensing devices can shut off the machine when triggered by employees entering the dangerous area. There are also machine safeguards in this category that directly act upon the worker to prevent them from entering the hazardous zone.
specifications.

Presence-sensing: These can be photoelectric, radiofrequency, or electromechanical devices That shut off when interrupted. However, the time in which it takes employees to reach the danger zone before the machine can shut off needs to be taken into account before trying this type of machine safeguard.

Advantages: These types of safeguards allow the operator freer movement, they're well-liked for their simplicity, and they protect passersby.
Drawbacks: They don&#;t protect against mechanical failure and some require more adjustment to work properly.

Pullback and restraint devices: Pullback machine safeguards have the employee&#;s arms, wrists, or hands strapped to cables that allow for employees to manually feed a machine and then draw the worker&#;s hands away when the machine proceeds with the task. Restraints, the other type in this category, only allow employee's hands to move at a fixed point. The goal is to have them far away from the machine hazard.

Advantages: Pullback devices eliminate the need for barriers at the danger zone. Restraint safeguards have little risk of mechanical failure.
Drawbacks: The pullback method limits movement which may obstruct the work area. The restraint mechanisms have to be adjusted to the job as well as the employee, they require frequent maintenance and inspections, the operator needs supervision, and movement and workspace is limited.

Safety trip controls: These can be anything similar to a pressure-sensitive body bar, a safety tripod, or even tripwire. When activated by an employee who has lost their balance or has been drawn closer to the machine, it will be shut off.

Advantages: Safety trips are very simple and easy to implement
Drawbacks: The controls must be manually activated, they may be difficult to activate due to position, and they only protects the operator.

Two-hand controls/Two-hand trip: There are two methods to this machine safeguard technique, the requirement of pressure on both controls by both hands to work the machine or the requirement of concurrent application of both buttons to activate the machine. These must be a safe distance from the danger area as well as be far enough apart to where the operator must
use both hands to operate the machine.

Advantage: Both methods keep the operator&#;s hands away from the danger zone while it is not in motion.
Drawbacks: Both of these methods only protect the operator and they still have the possibility of reaching into the danger zone if something comes up.

Gates: These are the last option for machine safeguarding devices. A gate is a mobile barrier that is moved into place by the operator before the machine cycle has begun. These are designed to be used at every cycle.

Advantage: It prevents employees from reaching or walking into the danger zone.
Drawback: These may require frequent maintenance and inspections and may interfere with seeing the work that is being done.

The third available method for machine safeguarding is adjusting the machine location/distance farther awayfrom the worker. This type of machine guarding method aims to remove the worker and their task away from the hazardous area. Before this is attempted, a thorough job hazard analysis is absolutely necessary to identify all possible hazards.

Location: To use this method, the dangerous section of a machine must be placed in an area that is not accessible by employees. For example, the hazardous section of the machine can be placed against a wall while the employees work and walk around on the other side. Hazardous areas can be placed behind fences, walls, and even placed higher up to prevent employee exposure to those hazards.
Distance: If the process requires an employee to feed parts into a machine, distancing them from machine hazards can protect the worker. The positioning of the operator&#;s control station is a good option for distancing employees from hazards presented by the machine.

Automated feeding and ejection mechanisms are another good machine safeguard technique. Automatic feeding and ejection systems for machine safeguarding help employees avoid reaching into dangerous areas of the machine by either manually feeding material in with a specific mechanism or by having it be completely autonomous. However, this method does not replace the need for physical guards.

Automatic and semi-automatic feeding: Both of these greatly reduce the exposure of the operator to the machine&#;s dangerous moving parts by either making the process fully automatic or requiring the operator to use a special apparatus for feeding material into completely enclosed section of the machine.

Advantage: These almost eliminate the operator completely and therefore reduces hazard risk.
Drawback: These systems may require frequent maintenance and they don&#;t eliminate the need for a physical barrier guard.

Automatic and semi-automatic ejection: Automatic ejection is completed with either a mechanical or air pressurized system that releases the product from the machine while a semi-automatic ejection system often uses a plunger and an ejector leg.

Advantage: The worker does not have to enter a dangerous area to remove the completed work.
Drawbacks: The possibility of debris being blown towards the operator is high and guards are still needed.

Robots: Robots are able to do the work that employees would normally do in manufacturing processes.

Advantages: Robots can work in conditions where people can&#;t which reduces the risk of injury from hazards.
Drawbacks: Robots can create hazards themselves, they require more maintenance, and they are not suitable for every operation.

There are a few miscellaneous aids that can be implemented for safeguarding a facility, these include:

Awareness barriers which are simply reminders for employees that there is a dangerous area ahead. These are not adequate enough to be the only machine safeguard.
Shields can be used for power tools and other equipment to provide protection from flying particles and splashes.
Special hand tools can be used for grabbing or pushing objects from points of operation. They can be things such as feeding tongs, pliers, magnets, push sticks, etc. Again, these must be paired with other machine safeguards.

OSHA .212 + Operator Safety

If a facility has machines that pose risks to operators, the employer must be familiar with OSHA&#;s .212 standard which lays out the general requirements for proper machine safeguarding. .212 depicts the types of guards to be used, general requirements on where they are to be placed to provide maximum operator safety, and the machines that often need guards implemented. Some of the types of machines listed that need machine safeguarding are:

Shears
Power presses
Milling machines
Barrels, containers, and drums
Fans

Training Requirements for Machine Guarding

Guards don&#;t help mitigate or eliminate machine hazards if the proper training hasn&#;t been given to the operator. Operator training should involve a combination of hands on training and verbal instruction regarding the following:

Identification of the hazards involving certain machines.
The safeguards themselves, how they provide protection, and the hazards they are intended to mitigate or eliminate.
How to use the safeguards and why they are needed.
Circumstances in which safeguards can be removed, why they need to be removed, and the employees who are able to remove them.
What to do if a safeguard is damaged, missing, or not able to provide protection.

Best Practices for Protecting Operators from Machine Hazards

Aside from giving the employees proper training on the machine they will be assigned to, there are a few other best practices to consider for keeping employees safe while working with heavy machinery. With that being said, employees should not be working on machines they have not been trained on. Lack of training could result in horrific injury and even death; it is the employer&#;s job to provide all employees proper training on the machines they will be working with throughout the day.

The next best practice method to use in an environment such as this is machine labeling. Simply labeling machine hazards can be a lifesaver as they clearly communicate dangers to employees.

Lastly, requiring personal protective equipment should be considered as it can further protect employees from hearing, eye, skin, lung, and head injuries. However, PPE should be the last resort in protecting employees since any engineering controls implemented should have taken care of most hazards.

Overall, if the correct precautions are taken with machine safeguarding, then employees will have the correct tools to go about their day accident free. With that being said, OSHA&#;s .212 regulation, guard mechanisms, training procedures, and all the best practice methods should be taken into consideration before any operators are allowed to enter working zones for the first time, just in case hazards are still lurking alongside the heavy machinery.

UofR: EHS: Occupational Safety: Machine Guarding

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Machine Guarding

PURPOSE

Machine guarding is an essential element of providing a safe and healthful environment for employees and others in any facility. Serious injury can result from coming into contact with the moving parts of a machine. This policy outlines the requirements and describes methods to protect employees from machine hazards.

Thus, this policy has been established in order to:

Ensure the safety of employees who work on or use machines and/or tools.
Ensure that University employees understand and comply with safety standards applicable to this equipment.
Ensure that uniform practices are followed at the University.
Ensure the university complies with OSHA regulations.

PERSONNEL AFFECTED

This policy applies to all UR properties, UR sites, and work performed by University employees regardless of job site location.

DEFINITIONS

The following terms are defined in order to allow a better understanding of this program:

Belts - Belts include all power transmission belts, such as flat belts, round belts, v-belts, etc.

Belt Shifter - A belt shifter is a device for mechanically shifting belts from tight to loose pulleys or vice versa or for shifting belts on cones of speed pulleys.

Employee - Includes all permanent and temporary employees and Sub-contractor employees.

Enclosures - Guarding by fixed physical barriers that are mounted on or around a machine to prevent access to moving parts.

Exposed to Contact- An object or part is exposed to contact if it is located in such a way that a person is likely to come into contact with it and be injured.

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Fixed Shop Machinery - Fixed shop machinery is defined as any piece of machinery designed to perform work on material such as a drill press, bench grinder, table saw, or lathe which is mounted or fixed to the floor or a table.

Flywheel - Flywheels include flywheels, balance wheels, and flywheel pulleys mounted and revolving on crankshaft platform used for oiling, maintenance, running adjustment, or repair work, but not as a passageway.

Guard - An engineering control that uses either fixed or adjustable barriers to prevent personnel from contacting the moving parts of machinery or equipment.

Interlocking - A type of guard that, when opened or removed, causes the machine&#;s cycling mechanism or power to automatically shut off or disengage; the machine cannot be cycled or started until the guard is back in place.

Machine - An assemblage of parts that transmit forces, motion, and energy in a predetermined manner for performing a task.

Nip-Point Belt and Pulley Guard - A nip-point belt and pulley guard is a device that encloses the pulley and is provided with rounded or rolled edge slots through which the belt or pulley passes.

Point of Operation - The area on a machine where work is actually being performed upon the material being processed. On some machines, there may be more than one point of operation.

Power transmission equipment - Horizontal or vertical belts or shafts, pulleys, gears, sprockets, couplings, chains, clutches, connecting rods, flywheels, and other such equipment.

Prime Movers - Include steam, gas, oil, and air engines, motors, steam and hydraulic turbines, and other equipment used as a source of power.

RESPONSIBILITIES

DIRECTORS and MANAGERS

Support this policy and ensure that the requirements are followed.
Provide resources and personnel as necessary to ensure compliance. Annually verify that personnel authorized to use this equipment are doing so in a safe and efficient manner.
Provide for resources and personnel to assure all of their employees have received necessary training and instruction regarding their assigned roles and responsibilities to comply with this policy. Maintain training documentation.

ENVIRONMENTAL HEALTH and SAFETY SPECIALIST

Evaluate work being performed to determine compliance with this policy.
Provide or assist in task specific training if requested.
Periodically review and update this written policy.
Provide general training for work units on the content of this program.
Assist university facility work units in implementing the provisions of this policy.

OPERATIONS and AREA MANAGERS

Determine the applicability of this policy to activities conducted within their respective areas of jurisdiction.
Designate individuals responsible for the implementation of this policy within their areas.
Actively support this policy as part of the University of Rochester overall safety effort.
Notify EH&S of any incident or related injury.

TRADES SUPERVISORS

Ensure compliance in their functional areas with the requirements set forth in this policy.
Ensure employees receive appropriate training and maintain documentation of such training.
Develop and maintain a listing of all qualified employees under their supervision.
Ensure employees are provided with and use appropriate protective equipment.
Perform or have designee perform quarterly machine guarding inspections of all machinery.
Ensure defective and unsafe machinery is properly tagged and taken out of service.
Ensure that if employees wear badges around their necks while operating machinery, that only breakaway badges are used. It is best to not have anything hanging from the neck when operating machinery.

EMPLOYEES

Follow the work practices described in this document, including the use of appropriate protective equipment.
Attend all training required relative to this program.
Immediately report any concerns related to safety to supervision.
Operate the equipment safely and in accordance with manufacturer&#;s requirements.

REQUIREMENTS

General

Serious injury can result from coming into contact with the moving parts of a machine. This procedure outlines the requirements and describes methods to protect employees from machine hazards.
The safeguarding of any single machine depends on how and where it is used. Variables to consider include:

Manufacturers&#; recommendations
Government regulations
Production requirements
Accepted industry standards
Operator training and skill
Company practice
Environmental factors
Maintenance activities
Cost of safeguarding options

Machine Safeguarding

Machine safeguarding is the application of engineering, work practice, and administrative controls to prevent the injury of employees who operate machines or who are in the vicinity of machine operations. The primary steps of machine safeguarding are:

Identify hazards.
Predict injury and the probability of occurrence.
Develop and implement a systematic safeguarding program.
Develop, implement and maintain machine guarding training and awareness.

There are four major elements that should be understood about machine safeguarding:

Any part, function, or process that may cause injury must be safeguarded. Where possible, manufacturer-supplied means of guarding should be used.
When safeguarding machines, utilize methods that provide protection and good production processes.
Guards in themselves must not create a hazard.
Guards should be attached to the machine, if possible.

Common Methods of Guarding are:

Fixed barrier guards (preferred)
Adjustable barrier guards
Interlocking devices
Remote control and placement
Electronic safety devices
Removal devices
Pressure-sensing devices

Combinations of the above methods may be required for machine guarding and operational safety.

General machine guarding policies are as follows:

A guard shall be attached to each machine, if possible, and be designed so it does not offer an accident hazard. Guards must be secured with fasteners that require a tool to remove.
A guard device shall prevent the operator from having any part of the body contacting the moving parts of machinery or equipment during the operating cycle.
Special hand tools provide supplemental protection for employees when placing and removing material. They permit easy handling of materials and eliminate the need for operators to place a hand in the danger zone. Such tools do not replace guarding.
All revolving drums, barrels and containers shall be guarded by an enclosure that is interlocked with the drive mechanism.
All revolving shafts, wheels, pulleys and other revolving parts shall be guarded to prevent an employee from coming in contact with the moving part.
If the periphery of blades of a fan is less than seven feet above the floor or working level, the blades shall be guarded. The guard shall have openings that are no larger than ½ inch.
Machines designed for a fixed location shall be securely anchored to prevent walking, moving, and tipping.

Machine Operation Clearance

Machine operators and personnel performing maintenance should read and understand the applicable sections of a manufacturer&#;s owner/operator and maintenance manuals before operating the machine. If possible and if offered, machine operators and personnel performing maintenance shall receive training from the manufacturer of the machine with approved training before working with the machines, to include at a minimum:

Train operators in proper operation, safety procedures, hazard recognition, and emergency shutdown procedures for each machine that they are assigned to operate.
Train personnel performing maintenance in hazard recognition, safe maintenance work practices, and emergency shutdown procedures for each machine that they are assigned to service.
Identify multiple energy sources and explain machine-specific lockout/tagout procedures to all personnel assigned to work with that machine.
Identify personal protective equipment required for machine operators and maintenance personnel and give the equipment to affected personnel.
Instruct personnel working with machines that jewelry, watches, bracelets, rings, necklaces, and neckties should not be worn and that long hair should be contained to prevent its entanglement.
Managers shall maintain a current list of personnel authorized to operate each machine or unique piece of equipment.

Installation

When installing a machine, the following guidelines should be used:

Allow enough space between machines to ensure safe operation and material handling.
Install machines according to the manufacturer&#;s instructions. Secure machines for fixed locations to prevent them from traveling during operation or if struck by equipment or personnel.
Locate operator controls within easy reach of the operator. Operators should be able to get to controls without reaching over hazardous areas or points of operation.
Install a disconnect switch that can be locked in the off position.
Install exhaust systems, when applicable, and supplementary lighting, if needed, for safe operation before machines are approved for use.
Mount a placard on each machine that explains the safe work practices and procedures for that machine. If it is not practical to mount the placard on a machine, place the placard on the wall next to the machine in a location where the operator at the control station can easily see it.

Inspection

Employees who are assigned to machine operations or maintenance shall inspect machines before working with them.

Maintenance

A preventive maintenance program shall be implemented to maintain the reliability of the machines and their guards. The manufacturer, as appropriate, should be consulted to develop the frequency and method of preventive maintenance.

Guarding Methods

Any machine that grinds, shears, punches, presses, squeezes, draws, drills, cuts, rolls, mixes, or performs a similar action shall be guarded when possible. Safeguarding should prevent the operator and other employees from being struck, caught, burned, exposed to electric shock, or hit with chips or coolant.
If the manufacturer&#;s recommendations for safeguarding do not meet government or industry standards, additional safeguarding should be implemented to comply with these standards.
A machine shall be operated only when all safeguards are functional and in place. No control or component of the machine&#;s safeguarding system should be altered or bypassed, including limit switches, light curtains, interlocks, and presence-sensing devices, during normal operations.

Color Codes

Machines should be color-coded with safety orange where there is an intermediate level of hazard. For example:

Hazardous parts of machines that may cut, crush, or otherwise injure. Such hazards should be colored with an orange paint that shows when enclosure doors are open.
The insides of movable guards and transmission guards for gears, pulleys, chains, and the like.
Exposed parts (edges only) of pulleys, gears, rollers, cutting devices, power jaws, and the like.

Guards and protective covers should be color-coded with safety yellow. This designates that dangerous parts of machinery or energized electrical components are contained inside the guards and caution must be exercised. Exceptions include:

Portions of transparent shields designed to afford a clear view of the operation should not be painted.
Metal-mesh guards should be painted black to improve the operator&#;s visibility. The border of the guard should be painted with safety yellow.

General Rules for Guarding

Guarding should:

Protect the operator and other employees in the machine area from hazards such as those created by the point of operation, ingoing nip points, rotating parts, flying chips, and sparks.
Be attached to the machine or secured elsewhere if attachment is not possible.
Not pose an accident hazard in itself.
Conform to applicable government and industry standards. In the absence of such standards, it must be designed and constructed to prevent the operator and other employees from having any body part in the danger zone during the machine&#;s operating cycle.
Be secured by means not easily removed. Fasteners can only be removed using a tool.
Facilitate machine inspection as practical.
Permit maximum visibility of the point of operation

Power Transmission Apparatus

Hazards such as belts, gears, sprockets, chains, shafts, and pulleys that are associated with power transmissions apparatus must be guarded. Cover all moving parts of power transmission apparatus that are within 7 feet from the floor or working platform. Guard all exposed parts of horizontal, vertical, and inclined shafting that are within 7 feet from the floor or working platform. Use one of the following methods:

A stationary casing constructed of expanded, perforated, or solid-sheet metal
A helical-wound metal strip completely enclosing the shafting
A collapsible or telescoping guarding device unless the projection is less than one-half the diameter of the shaft and the projecting end is completely smooth.

For machines that require frequent oiling, use openings with hinged or sliding self-closing covers provided by the manufacturer.

Provide oil lubrication points at remote or ground level mechanisms.
Instruct regular oilers to wear tight-fitting clothing.
Whenever possible, oil machinery when equipment is not in motion.

Protect employees from projections in revolving parts by:

Removing the projections (preferred)
Making the projections flush
Guarding the projections with a metal cover

This does not apply to keys and setscrews already guarded within gear or sprocket casings.

Switches and Remote Controls

Switches and remote controls should be safeguarded as follows:

Clearly mark switches and operating controls in simple language to indicate their purpose.
Keep switches, operating controls, and control buttons in good operating condition at all times. If a component is damaged or missing, immediately repair or replace it.
Guard the sides and tops of foot-operated control pedals to prevent accidental activation.
Never use a foot-operated control to operate a machine unless safeguarding is installed to prevent hands or other body parts from entering the point of operation.