Safety Precautions to Consider When Using Hand or Power Tools
by Larry Westfall
HAZARD RECOGNITION
Tools are such a common part of our lives that it is difficult
to remember that they may pose hazards. All tools are
manufactured with safety in mind but, tragically, a serious
accident often occurs before steps are taken to search out and
avoid or eliminate tool-related hazards.workers mustlearn to recognize the hazards associated with the different types of tools and the safety precautions necessary to prevent
those hazards.
HAND TOOLS
Hand tools are non-powered. They include anything from axes to
wrenches. The greatest hazards posed by hand tools result from
misuse and improper maintenance.
Some examples: ·Using a screwdriver as a chisel may cause the
tip of the screwdriver to break and fly, hitting the user or
other employees. ·If a wooden handle on a tool such as a hammer
or an axe is loose, splintered, or cracked, the head of the tool
may fly off and strike the user or another worker. ·A wrench
must not be used if its jaws are sprung, because it might slip.
·Impact tools such as chisels, wedges, or drift pins are unsafe
if they have mushroomed heads. The heads might shatter on
impact, sending sharp fragments flying. The employer is
responsible for the safe condition of tools and equipment used
by employees but the employees have the responsibility for
properly using and maintaining tools.
Employers should caution employees that saw blades, knives, or
other tools be directed away from aisle areas and other
employees working in close proximity. Knives and scissors must
be sharp. Dull tools can be more hazardous than sharp ones.
Appropriate personal protective equipment, e.g., safety goggles,
gloves, etc., should be worn due to hazards that may be
encountered while using portable power tools and hand tools.
Safety requires that floors be kept as clean and dry as possible
to prevent accidental slips with or around dangerous hand tools.
Around flammable substances, sparks produced by iron and steel
hand tools can be a dangerous ignition source. Where this hazard
exists, spark-resistant tools made from brass, plastic,
aluminum, or wood will provide for safety.
POWER TOOL PRECAUTIONS
Power tools can be hazardous when improperly used. There are
several types of power tools, based on the power source they
use: electric, pneumatic, liquid fuel, hydraulic, and
powder-actuated.
Employees should be trained in the use of all tools - not just
power tools. They should understand the potential hazards as
well as the safety precautions to prevent those hazards from
occurring.
Power tool users should observe the following general
precautions: ·Never carry a tool by the cord or hose. ·Never
yank the cord or the hose to disconnect it from the receptacle.
·Keep cords and hoses away from heat, oil, and sharp edges.
·Disconnect tools when not in use, before servicing, and when
changing accessories such as blades, bits and cutters. ·All
observers should be kept at a safe distance away from the work
area. ·Secure work with clamps or a vise, freeing both hands to
operate the tool. ·Avoid accidental starting. The worker should
not hold a finger on the switch button while carrying a
plugged-in tool. ·Tools should be maintained with care. They
should be kept sharp and clean for the best performance. Follow
instructions in the user's manual for lubricating and changing
accessories. ·Be sure to keep good footing and maintain good
balance. ·The proper apparel should be worn. Loose clothing,
ties, or jewelry can become caught in moving parts. ·All
portable electric tools that are damaged shall be removed from
use and tagged "Do Not Use."
GUARDS
Hazardous moving parts of a power tool need to be safeguarded.
For example, belts, gears, shafts, pulleys, sprockets, spindles,
drums, fly wheels, chains, or other reciprocating, rotating, or
moving parts of equipment must be guarded if such parts are
exposed to contact by employees.
Guards, as necessary, should be provided to protect the operator
and others from the following: ·point of operation, ·in-running
nip points, ·rotating parts, and ·flying chips and sparks.
Safety guards must never be removed when a tool is being used.
For example, portable circular saws must be equipped with
guards. An upper guard must cover the entire blade of the saw. A
retractable lower guard must cover the teeth of the saw, except
when it makes contact with the work material. The lower guard
must automatically return to the covering position when the tool
is withdrawn from the work.
SAFETY SWITCHES
The following hand-held powered tools must be equipped with a
momentary contact "on-off" control switch: drills, tappers,
fastener drivers, horizontal, vertical and angle grinders with
wheels larger than 2 inches in diameter, disc and belt sanders,
reciprocating saws, saber saws, and other similar tools. These
tools also may be equipped with a lock-on control provided that
a single motion of the same finger or fingers that turn it on
can accomplish turnoff.
The following hand-held powered tools may be equipped with only
a positive "on-off" control switch: platen sanders, disc sanders
with discs 2 inches or less in diameter; grinders with wheels 2
inches or less in diameter; routers, planers, laminate trimmers,
nibblers, shears, scroll saws and jigsaws with blade shanks
<-inch wide or less.
Other hand-held powered tools such as circular saws having a
blade diameter greater than 2 inches, chain saws, and percussion
tools without positive accessory holding means must be equipped
with a constant pressure switch that will shut off the power
when the pressure is released.
ELECTRIC TOOLS
Employees using electric tools must be aware of several dangers;
the most serious is the possibility of electrocution.
Among the chief hazards of electric-powered tools are burns and
slight shocks which can lead to injuries or even heart failure.
Under certain conditions, even a small amount of current can
result in fibrillation of the heart and eventual death. A shock
also can cause the user to fall off a ladder or other elevated
work surface.
To protect the user from shock, tools must either have a
three-wire cord with ground and be grounded, be double
insulated, or be powered by a low-voltage isolation transformer.
Three-wire cords contain two current-carrying conductors and a
grounding conductor. One end of the grounding conductor connects
to the tool's metal housing. The other end is grounded through a
prong on the plug. Anytime an adapter is used to accommodate a
two-hole receptacle, the adapter wire must be attached to a
known ground. The third prong should never be removed from the
plug.
Double insulation is more convenient. The user and the tools are
protected in two ways: by normal insulation on the wires inside,
and by a housing that cannot conduct electricity to the operator
in the event of a malfunction.
These general practices should be followed when using electric
tools: ·Electric tools should be operated within their design
limitations. ·Gloves and safety footwear are recommended during
use of electric tools. ·When not in use, tools should be stored
in a dry place. ·Electric tools should not be used in damp or
wet locations. ·Work areas should be well lighted. POWERED
ABRASIVE WHEEL TOOLS
Powered abrasive grinding, cutting, polishing, and wire buffing
wheels create special safety problems because they may throw off
flying fragments.
Before an abrasive wheel is mounted, it should be inspected
closely and sound- or ring-tested to be sure that it is free
from cracks or defects. To test, wheels should be tapped gently
with a light non-metallic instrument. If they sound cracked or
dead, they could fly apart in operation and so must not be used.
A sound and undamaged wheel will give a clear metallic tone or
"ring."
To prevent the wheel from cracking, the user should be sure it
fits freely on the spindle. The spindle nut must be tightened
enough to hold the wheel in place, without distorting the
flange. Follow the manufacturer's recommendations. Care must be
taken to assure that the spindle wheel will not exceed the
abrasive wheel specifications.
Due to the possibility of a wheel disintegrating (exploding)
during start-up, the employee should never stand directly in
front of the wheel as it accelerates to full operating speed.
Portable grinding tools need to be equipped with safety guards
to protect workers not only from the moving wheel surface, but
also from flying fragments in case of breakage.
In addition, when using a powered grinder: ·Always use eye
protection. ·Turn off the power when not in use. ·Never clamp a
hand-held grinder in a vise.
PNEUMATIC TOOLS
Pneumatic tools are powered by compressed air and include
chippers, drills, hammers, and sanders.
There are several dangers encountered in the use of pneumatic
tools. The main one is the danger of getting hit by one of the
tool's attachments or by some kind of fastener the worker is
using with the tool.
Eye protection is required and face protection is recommended
for employees working with pneumatic tools.
Noise is another hazard. Working with noisy tools such as
jackhammers requires proper, effective use of hearing protection.
When using pneumatic tools, employees must check to see that
they are fastened securely to the hose to prevent them from
becoming disconnected. A short wire or positive locking device
attaching the air hose to the tool will serve as an added
safeguard.
A safety clip or retainer must be installed to prevent
attachments, such as chisels on a chipping hammer, from being
unintentionally shot from the barrel.
Screens must be set up to protect nearby workers from being
struck by flying fragments around chippers, riveting guns,
staplers, or air drills.
Compressed air guns should never be pointed toward anyone. Users
should never "dead-end" it against themselves or anyone else.
POWDER-ACTUATED TOOLS
Powder-actuated tools operate like a loaded gun and should be
treated with the same respect and precautions. In fact, they are
so dangerous that only specially trained employees must operate
them.
Safety precautions to remember include the following: ·These
tools should not be used in an explosive or flammable
atmosphere. ·Before using the tool, the worker should inspect it
to determine that it is clean, that all moving parts operate
freely, and that the barrel is free from obstructions. ·The tool
should never be pointed at anybody. ·The tool should not be
loaded unless it is to be used immediately. A loaded tool should
not be left unattended, especially where it would be available
to unauthorized persons. ·Hands should be kept clear of the
barrel end. To prevent the tool from firing accidentally, two
separate motions are required for firing: one to bring the tool
into position, and another to pull the trigger. The tools must
not be able to operate until they are pressed against the work
surface with a force of at least 5 pounds greater than the total
weight of the tool.
If a powder-actuated tool misfires, the employee should wait at
least 30 seconds, then try firing it again. If it still will not
fire, the user should wait another 30 seconds so that the faulty
cartridge is less likely to explode, than carefully remove the
load. The bad cartridge should be put in water.
Suitable eye and face protection are essential when using a
powder-actuated tool.
The muzzle end of the tool must have a protective shield or
guard centered perpendicularly on the barrel to confine any
flying fragments or particles that might otherwise create a
hazard when the tool is fired. The tool must be designed so that
it will not fire unless it has this kind of safety device.
All powder-actuated tools must be designed for varying powder
charges so that the user can select a powder level necessary to
do the work without excessive force.
If the tool develops a defect during use it should be tagged and
taken out of service immediately until it is properly repaired.
FASTENERS
When using powder-actuated tools to apply fasteners, there are
some precautions to consider. Fasteners must not be fired into
material that would let them pass through to the other side. The
fastener must not be driven into materials like brick or
concrete any closer than 3 inches to an edge or corner. In
steel, the fastener must not come any closer than one-half inch
from a corner or edge. Fasteners must not be driven into very
hard or brittle materials which might chip or splatter, or make
the fastener ricochet.
An alignment guide must be used when shooting a fastener into an
existing hole. A fastener must not be driven into a spalled area
caused by an unsatisfactory fastening.
HYDRAULIC POWER TOOLS
The fluid used in hydraulic power tools must be an approved
fire-resistant fluid and must retain its operating
characteristics at the most extreme temperatures to which it
will be exposed.
The manufacturer's recommended safe operating pressure for
hoses, valves, pipes, filters, and other fittings must not be
exceeded.
JACKS
All jacks - lever and ratchet jacks, screw jacks, and hydraulic
jacks - must have a device that stops them from jacking up too
high. Also, the manufacturer's load limit must be permanently
marked in a prominent place on the jack and should not be
exceeded.
A jack should never be used to support a lifted load. Once the
load has been lifted, it must immediately be blocked up.
Use wooden blocking under the base if necessary to make the jack
level and secure. If the lift surface is metal, place a
1-inch-thick hardwood block or equivalent between it and the
metal jack head to reduce the danger of slippage.
To set up a jack, make certain of the following: ·the base rests
on a firm level surface, ·the jack is correctly centered, ·the
jack head bears against a level surface, and ·the lift force is
applied evenly. Proper maintenance of jacks is essential for
safety. All jacks must be inspected before each use and
lubricated regularly. If a jack is subjected to an abnormal load
or shock, it should be thoroughly examined to make sure it has
not been damaged.
Hydraulic jacks exposed to freezing temperatures must be filled
with an adequate antifreeze liquid.
About the author:
Larry Westfall is the owner of www.AboutCarpentry.com
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