Even the most elaborate safeguarding
system cannot offer effective protection unless the worker knows how to
use it and why. Specific and detailed training is therefore a crucial
part of any effort to provide safeguarding against machine-related
hazards. Thorough operator training should involve instruction or
hands-on training in the following:
• A description and identification of
the hazards associated with particular machines;
• The safeguards themselves, how they
provide protection, and the hazards for which they are intended;
• How to use the safeguards and why;
• How and under what circumstances
safeguards can be removed, and by whom (in most cases, repair or
maintenance personnel only); and
• When a lockout/tagout program is
required;
• What to do (e.g., contact the
supervisor) if a safeguard is damaged, missing, or unable to provide
adequate protection.
This kind of safety training is
necessary for new operators and maintenance or setup personnel, when any
new or altered safeguards are put in service, or when workers are
assigned to a new machine or operation.
While these aids do not give complete
protection from machine hazards, they may provide the operator with an
extra margin of safety. Sound judgment is needed in their application
and usage.
Examples of possible application
include the following:
• An awareness barrier serves as a
reminder to a person that he or she is approaching the danger area.
Although the barrier does not physically prevent a person from entering
the danger area, it calls 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.
Generally, awareness barriers are not
considered adequate when continual exposure to the hazard exists.
• Special hand tools may be used to
place or remove stock, particularly from or into the point of operation
of a machine. A typical use would be for reaching into the danger area
of a press or press brake. A push stick or block may be used when
feeding stock into a saw blade. When it becomes necessary for hands to
be in close proximity to the blade, the push stick or block may provide
a few inches of safety and prevent a severe injury.
Guard Construction
Today many builders of single-purpose
machines provide point-of-operation and power transmission safeguards as
standard equipment. However, not all machines in use have built-in
safeguards provided by the manufacturer. Guards designed and installed
by the builder offer two main advantages:
• They usually conform to the design
and function of the machine; and
• They can be designed to strengthen
the machine in some way or to serve some additional functional purposes.
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 may 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 even changing situations;
• They can be installed on individual
dies and feeding mechanisms; and
• Design and installation of machine
safeguards by plant personnel can help to promote safety consciousness
in the workplace.
User-built guards may not conform
well to the configuration and function of the machine. There is a risk
that user-built guards may be poorly designed or built.
Feeding and Ejection
Many feeding and ejection methods do
not require the operator to place his or her hands in the danger area.
In some cases, no operator involvement is necessary after the machine is
set up. In other situations, operators can manually feed the stock with
the assistance of a feeding mechanism. Properly designed ejection
methods do not require any operator involvement after the machine starts
to function.
Using these feeding and ejection
methods does not eliminate the need for guards and devices. Guards and
devices must be used wherever they are necessary and possible in order
to provide protection from exposure to hazards.
Types of feeding and ejection
methods:
Automatic Feed
• Stock is fed from rolls, indexed by
machine mechanism, etc.;
• Eliminates the need for operator
involvement in the danger area;
• Other guards are required for
operator protection, usually fixed barrier guards;
• Requires frequent maintenance; and
• May not be adaptable to stock
variation.
Semiautomatic Feed
• Stock is fed by chutes, movable
dies, dial feed, plungers, or sliding bolster.
Automatic Ejection
• Work pieces are ejected by air or
mechanical means;
• May create a hazard of blowing
chips or debris;
• Size of stock limits the use of
this method;
• Air ejection may present a noise
hazard.
Semiautomatic Ejection
• Work pieces are ejected by
mechanical means which are initiated by the operator;
• Operator does not have to enter
danger area to remove finished work;
• Other guards are required for
operator protection;
• May not be adaptable to stock
variation.
Machinery Maintenance and Repair
Good maintenance and repair
procedures contribute significantly to the safety of the maintenance
crew as well as that of machine operators. The variety and complexity of
machines to be serviced, the hazards associated with their power
sources, the special dangers that may be present during machine
breakdown, and the severe time constraints often placed on maintenance
personnel all make safe maintenance and repair work difficult.
If possible, machine design should
permit routine lubrication and adjustment without removal of
safeguards. But when safeguards must be removed, and the machine
serviced, the lockout procedure of 29 CFR 1910.147 must be adhered to.
The maintenance and repair crew must
never fail to replace the guards before the job is considered finished
and the machine released from lockout.
In order to prevent hazards while
servicing machines, each machine or piece of equipment should be
safeguarded during the conduct of servicing or maintenance by:
• Notifying all affected employees
(usually machine or equipment operators or users) that the machine or
equipment must be shut down to perform some maintenance or servicing;
• Stopping the machine;
• Isolating the machine or piece of
equipment from its energy source;
• Locking out or tagging out the
energy source;
• Relieving any stored or residual
energy; and
• Verifying that the machine or
equipment is isolated from the energy source.
Although this is the general rule,
there are exceptions when the servicing or maintenance is not hazardous
for an employee, when the servicing which is conducted is minor in
nature, done as an integral part of production, and the employer
utilizes alternative safeguards which provide effective protection as is
required by 29 CFR 1910.212 or other specific standards.
When the servicing or maintenance is
completed, there are specific steps that 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 safety devices are in
place and functional;
• Checking the area to ensure that
energization and start up of the machine or equipment will not endanger
employees;
• Removal of the lockout devices;
• Reenergization of the machine or
equipment; and
• Notification of affected employees
that the machine or equipment may be returned to service.
If it is necessary to oil machine
parts while the machine is running, special safeguarding equipment may
be needed solely to protect the oiler from exposure to hazardous moving
parts.
Maintenance personnel must know which
machines can be serviced while running and which can not. The danger of
accident or injury is greatly reduced by shutting off and locking out
all sources of energy.
For more on OSHA’s requirements for
machine guarding, go to
www.osha.gov/SLTC/etools/machineguarding/generalrequirements.html.
FSM