Employee-Driven Machines: Machines that have a “point of operation”, or area on or near the machine in which
work is performed by an employee.
Enclosures: Mounted physical barriers which prevent access to moving parts of machinery or
equipment.
Nip Points: In-running machine or equipment parts, which rotate towards each other, or where
one part rotates toward a stationary object.
Point-of-Operation: The area on a machine or item of equipment, where work is being done and material
is positioned for processing or change by the machine.
Power Transmission: Any mechanical parts which transmit energy and motion from a power source to the
point-of-operation. Example: Gear and chain drives, cams, shafts, belt and pulley
drives and rods.
Safeguards: Barriers or mechanisms that prevent employees from contact with moving portions
or parts of exposed machinery or equipment which could cause physical harm to the
employees.
Self-Driven Machines: Machines that do not have a specific “point of operation” and which do not have
an operator during normal operation.
Safety and Risk Management
Safety and Risk Management has the primary responsibility for the implementation and
enforcement of the Machine Guarding Program and is responsible for the following:
- Developing, reviewing, and updating the Machine Guarding Program.
- Reviewing that machines and machinery have appropriate guards installed as deemed
necessary, and are in good working order, suitable for the task, and do not pose a
hazard to the operator.
- Assisting departments with the selection of proper machine guards and personal protection
equipment (PPE) for the work.
- Developing and assisting as necessary with safety training.
Supervisors
Supervisors are responsible for providing the necessary direction and support to ensure
the effective implementation of the Machine Guarding Program for their work area.
Supervisors are responsible for the following:
- Ensuring that all machines are properly guarded in accordance with this program.
- Providing adequate guarding solutions for machines.
- Providing personal protective equipment to employees.
- Ensuring that unguarded machines are removed from service until all necessary guards
are in place.
- Ensuring that all employees have received training so employees understand the purpose
and function of the program.
- Ensure operators and nearby employees comply with the requirements of the program.
Employees
- Comply with the program and all requirements of machine guarding.
- Wear appropriate personal protection equipment (PPE) for the work task.
- Notify your supervisor of any machine that does not have appropriate guards in place.
- Refrain from using machines that do not have all necessary guards in place.
- Notify your supervisor of any machine that is damaged or malfunctioning.
- Wear appropriate attire that won’t cause entanglement around the machines and machinery.
Supervisors are responsible for ensuring that employees understand the requirements
of this program, and that employees are trained to recognize general machine-guarding
hazards. Training shall include at a minimum:
- A description and identification of the specific hazard(s) associated with particular
machines.
- The safeguards on the particular machines including, but not limited to: how they
provide protection; the hazards for which they are intended; and how to use them.
- How and under what circumstances safeguards can be removed, and
- What to do when a safeguard is damaged, missing, or unable to perform adequate protection.
- Maintenance personnel must be trained in knowing which machines can be serviced while
running and which ones need to be de-energized.
Training shall be provided to all new operators or when any new or altered safeguards
are put in service for equipment-driven machines, or the process presents a new hazard
or change in procedures.
Moving machine parts have the potential to cause severe workplace injuries. Safeguards
are essential for protecting workers from these preventable injuries. Any machine
part, function, or process that may cause injury must be safeguarded. When the operation
of a machine or accidental contact injure the operator or others in the vicinity,
the hazards must be eliminated or controlled. The Occupational Safety and Health
Administration (OSHA) regulates machinery, equipment, and mechanical power transmission
apparatus that are commonly used in machine shops, maintenance operations, and other
repair work environments.
Types of Machines
For the purposes of the program, machines are divided into two different categories
based on how the employee interacts with the machine. Machines that have a “point
of operation” as the point where the work is being performed on materials by an operator
are considered “employee-driven” machines. Employee-driven machines include portable
power tools, power saws, wood-working equipment, presses, etc.
Machines that do not have a specific point of operation and which do not have an operator
during normal operation are considered “self-driven”. Self-driven machines can include
elevators, pumps, exhaust fans, etc.
Types of Guards
Guards are barriers which prevent access to dangerous areas. There are four general
types of guards:
- Fixed guard: is a permanent part of the machine. It provides a barrier between the operator and
the point of operation or moving parts.
- Interlocked guard: When this guard is open or removed, the tripping mechanism and/or automatic shut
off engages, and the moving parts of the machine are stopped. The machine cannot cycle
or be started again until the guard is back in place.
- Adjustable guard: provides a barrier that may be adjusted to facilitate a variety of production operations.
- Self-adjusting guard: Provides a barrier that moves according to the size of the material entering the
danger area. The guard returns to its normal position when no material is entering
through.
General Requirements
- Guards shall be affixed to the machine where possible. The guard(s) shall be secured
elsewhere if for any reason attachment to the machine is not possible. The guard(s)
shall be designed and attached in such a way so that it does not present an accident
hazard in itself. Where mechanical hazards occur, it is required that those areas
on the equipment have safeguards affixed.
- The point of operation of machines that exposes an employee to injury, shall be guarded.
The guarding device shall conform to appropriate standards. In the absence of applicable
specific standards, the guards shall be designed and constructed as to prevent the
operator from having any part of their body in the danger zone during the operating
cycle.
- Revolving drums, barrels, and containers shall be guarded by an enclosure which is
interlocked with the drive mechanism, so that the barrel, drum, or container cannot
revolve unless the guard enclosure is in place (i.e. cement / mortar mixer).
- When the periphery of the blades of a fan is less than seven (7) feet above the floor
or working level, the equipment shall be guarded. The guard shall have openings no
larger than one-half (1/2) inch. Examples include: exhaust fans, window fans, portable
fans, wall-mounted fans, and industrial fans.
- Machines designed for a fixed location shall be securely anchored to prevent walking
or moving when in use.
Basic Safeguarding
All safeguards must meet the following requirements:
- Prevent contact: The safeguard must prevent hands, arms, and any other part of the employee’s body
from making contact with dangerous moving parts. A good safeguarding system eliminates
the possibility of the operator or another worker placing parts their body near the
hazardous moving parts.
- Secure: Employees should not be able to easily remove or tamper with the safeguards. Guards
and safety devices should be made of durable material that will withstand the conditions
of normal use. They must firmly be secured to the machine.
- Protect from falling objects: The safeguards should ensure that no objects can fall into moving parts. A small
tool which is dropped into a cycling machine could easily become a projectile that
could strike and injure someone.
- Creates no new hazard: A safeguard defeats its own purpose if it creates a hazards of its own such as a
shear point, jagged edge, or an unfinished surface which can cause a laceration.
The edges of guards should be rolled or bolted in such a way that they eliminate sharp
edges.
- Create no interference: Any safeguard which impedes an employee from performing the job quickly and comfortably
might soon be overridden or disregarded. Proper safeguarding can actually enhance
efficiency as it can relieve the worker’s apprehensions about injury.
- Allow safe lubrication: If possible, the employee should be able to lubricate the machine without removing
the safeguards. Locating oil reservoirs outsides the guard with a line leading to
the lubrication points will reduce the need for the operator or maintenance employee
to enter the hazardous area.
In addition to the basic safeguarding requirements specified above, all machines
and safeguards must also meet any applicable mandatory and non-mandatory machine-specific
guarding requirements specified within 29 CFR 1910.213, 215, 217 and 219.
Guard Construction
Manufactures of today’s single-purpose machines provide point of operation and power
transmission safeguards, but not all machines that are used in the various shops at
the University have built-in safeguards provided by the manufacturer.
Guards designed and installed by the manufacture offer two main advantages:
- They usually conform to the design and function of the machine.
- They can be designed to strengthen the machine in some way or to serve some additional
functional purposes.
However, user built guards are sometimes necessary for a variety of reasons. They
have these advantages:
- Often, with older machinery, they are the only practical safeguarding solution.
- They me be the only choice for mechanical power transmission apparatus in older plants,
where machinery is not powered by individual motor drives.
- They permit options for point of operation safeguards when skilled personnel design
and make them.
- They can be designed and built to fit unique and changing situations.
- They can be installed on individual feeding mechanisms.
- Design and installation of machine safeguards by employees can help promote safety
consciousness in the work environment.
Miscellaneous Aids
While these aids do not give complete protection from machine hazards, they may provide
the operator with extra margin of safety. Sound judgement is needed in their application
and usage. Examples include:
- Awareness barrier: serves as a reminder to a person that he or she is approaching the danger area.
Even though the barrier does not physically prevent an employee from entering the
danger area, it calls their attention to it. For an employee to enter the danger
area, an overt act must take place, that is, the employee must either reach or step
over, under or through the barrier. An example of an awareness barrier would be a
highly visible tape placed on a table saw a few inches away from the point of operation.
- Special hand tool: may be used to place or remove material, particularly from or into the point of operation
of a machine. Typically this use would be for reaching into the danger area of a
machine. Examples of special hand tools are push sticks, push block, etc.
Motions and Action Hazards
A wide variety of mechanical motions and actions may present hazards to the employee.
These can include the movement of rotating members, reciprocating arms, moving belts,
meshing gears, cutting teeth, and any movements that impact or shear. The different
types of hazardous mechanical motions and actions are present in varying degrees for
nearly all machines, and recognizing them is the first step towards protecting the
employee. The basic types of hazards are divided between mechanical motions and actions.
Motions
- Rotating motion: rotating shafts can grip hair and clothing and can force the hand and arm into a
dangerous position. The danger increases when projections such as set screws, bolts,
nicks, abrasions, projecting keys, or set screws are exposed on rotating parts. Collars,
couplings, cams, clutches, flywheels, shafts ends, spindles, meshing gears, and horizontal
or vertical shafting are some examples of common rotating mechanisms which may be
hazardous.
- In-running nip point: hazards are caused by the rotating parts on machinery. There are three main types
of in-running nip points:
- Parts can rotate in opposite directions while their axes are parallel to each other.
These parts may be in contact or in close proximity. Examples include: rolling mills,
gears, and calenders.
- Nip points are also created between rotating and tangentially moving parts. Some examples
would be the point of contact between a power transmission belt and its pulley, a
chain and a sprocket, and a rack and pinion.
- Nip points can occur between rotating and fixed parts which create a shearing, crushing,
or abrading action. Examples are spoked hand-wheels or flywheels, screw conveyors,
or the periphery of an abrasive wheel and an incorrectly adjusted work rest and tongue.
- Reciprocating motions: may be hazardous because, during the back-and-forth or up-and-down motion, a worker
may be stuck by or caught between a moving and a stationary part.
- Transverse motion: creates a hazard because an employee may be stuck or caught in a pinch or shear point
by the moving part. This refers to movement in a straight and continuous line. An
example is a stationary belt sander.
Actions
- Cutting action: may involve rotating, reciprocating, or transverse motion. The danger of cutting
action exists at the point of operation where finger, arm and body injuries can occur
and where flying chips or scrap material can strike the head, particularly in the
area of the eye or face. Such hazards are present at the point of operation in cutting
materials.
- Punching action: results when power is applied to a slide (ram) for the purpose of blanking, drawing,
or stamping metal or other materials. The danger of this type of action occurs at
the point of operation where stock is inserted, held, and withdrawn by hand. Typical
machines used for punching operations are power presses and iron workers.
- Shearing action: involves applying power to a slide or knife in order to trim or shear metal or other
materials. A hazard occurs at the point of operation where stock is actually inserted,
held, and withdrawn. Examples of machines used for shearing operations are mechanically,
hydraulically, or pneumatically powered shears.
- Bending action: results when power is applied to a slide in order to draw or stamp metal or other
materials. A hazard occurs at the point of operation where stock is inserted, held,
and withdrawn. Equipment that uses bending action include power presses, press brakes,
and tubing benders.
The maintenance employees must never fail to replace the guards before the job is
considered finished and the machine is released from Lockout/Tag-out. The following
safeguarding measures should be taken in order to prevent hazards while servicing
machines:
- Notify all affected employees (usually machine or equipment operators or users) that
the machine or equipment must be shut down to service the machine or perform maintenance.
- Stop the machine.
- Isolate the machine or piece of equipment from its energy source.
- Lockout/Tag-out the energy source.
- Relieve any stored or residual energy.
- Verify that the machine or equipment is isolated from the energy source.
The following list are exceptions to the above general rules in regards to safeguarding
measures that should be taken in order to prevent hazards:
- When the servicing or maintenance is not hazardous for an employee.
- When the servicing which is conducted is minor in nature.
- When servicing is done as an integral part of production.
- When the employer utilizes alternative safeguards which provide effective protection
as required by 29 CFR 1910.212 or other specific standards.
When the servicing or maintenance is completed, there are specific steps which must
be taken to return the machine or piece of equipment to service. These steps include:
- Inspection of the machine or equipment to ensure that all guards and other devices
are in place and functional.
- Checking to ensure that energization and start-up of the machine or equipment will
not endanger employees.
- Removal of the lockout devices.
- Re-energization of the machine or equipment.
- Notification of affected employees that the machine or equipment may be returned to
service.
Employee driven machines shall be visually inspected prior to each use by the operator
to ensure all necessary guards are in place and to mitigate hazards including those
caused by the point of operation itself, the power transmission apparatus, or other
moving parts.