electric arc welder remains one of our most useful and timesaving
pieces of shop equipment. Almost every farm, ranch, and Vocational
Agriculture shop is equipped with one or more welders which
are used for fabrication, repair, and/or educational programs.
Most of these welders are typically AC/DC, 240 volt transformer
types using electricity as the energy source. Portable welders
are of the diesel/gasoline engine powered type. Properly installed
and used the arc welder is very safe, but if used improperly
the operator can be exposed to a number of hazards including
toxic fumes, dusts, burns, fires, explosions, electric shock,
radiation, noise, and heat stress. Any of these hazards can
cause injury or death. By following suggestions and guidelines
in this pamphlet the risks can be greatly minimized.
purchasing an arc welder you can be assured of design safety
if the unit complies with National Electric Manufacturers Association
(NEMA) standards or the safety standards for arc welders as
determined by the Underwriters Laboratories (UL). Be sure that
the welder you purchase carries the seal of approval of one
of these organizations.
Prior to installing the arc welder you should determine if your
present electrical system is adequate to handle the increased
load required by the welder. Your local power supplier or
a qualified electrician can assist you in determining this.
It is very important for your safety to install the welder in
compliance with State of Arizona, Occupational Safety and Health
Administration (AOSHA) regulations and the National Electric
Code (NEC) by a qualified electrician. Failure to do so could
cause fire, a ground fault, or equipment failure. The following
rules are not a complete list but are especially important guidelines which
should be adhered to:
frame or case of the welder shall be properly grounded.
safety-type disconnecting switch or controller shall be
located near the machine (See Figure 1).
welder or welders shall be protected by a properly sized
fuse or circuit breaker on an independent circuit.
welder should be located in an area with adequate ventilation.
In general, when welding is being done on metals not considered
hazardous, a ventilation system that will move a minimum of
2000 cubic feet per minute (CFM) of air per welder is satisfactory.
However, many materials are considered very hazardous and should
be welded only in adequately ventilated areas to prevent the
accumulation of toxic materials or to eliminate possible oxygen
deficiency not only to the operator but to others in the immediate
vicinity. Such ventilation should be supplied by an exhaust
system located as close to the work as possible (See Figure
2). When welding or cutting metals with hazardous coatings such
as galvanized metal the operator should use a supplied-air type
respirator or a respirator specially designed to filter the
specific metal fume. Materials included in the very hazardous
category are welding rod fluxes, coverings, or other materials
containing fluorine compounds, zinc, lead, beryllium, admium,
and mercury. Some cleaning and degreasing compounds as well
as the metals they were cleaned with are also hazardous. Always
follow the manufacturers precautions before welding or cutting
in the presence of these materials.
arc welder is capable of producing temperatures in excess of
10,000 degrees F.,therefore it is important that the workplace
be made firesafe. This can be accomplished by using metal sheets
or fire resistant curtains as fire barriers. The floor should
be concrete or another fire resistant material. Cracks in the
floor should be filled to prevent sparks and hot metal from
entering. When work cannot be moved to a firesafe area then
the area should be made safe by removing or protecting combustibles
from ignition sources. In certain welding situations it may
be necessary to ask someone to watch for fires that could go
undetected until the welder has finished the job.
fire extinguishing equipment such as buckets of sand or a
dry chemical extinguisher of the ABC type should be readily
available. The extinguisher should be large enough for the
situation with a 10# size adequate for most farm and school
It is essential that the operator and helpers be properly clothed
and protected because of the heat, ultra-violet rays, and sparks,
produced by the arc welder (See Figure 3). For body protection
a pair of fire retardant long sleeved coveralls without cuffs
is a good choice. Always avoid clothing with tears, snags, rips,
or worn spots as these are easily ignited by sparks. The sleeves
and collars should be kept buttoned. The hands should be protected
with leather gauntlet gloves. A pair o high top leather shoes,
preferably safety shoes, is good protection for the feet. If
low shoes are worn the ankles should be protected by fire resistant
leggings. Eyes should be protected by transparent goggles if
the person wears prescription glasses or safety glasses if not.
A welding helmet or hand shield with filter plate and cover
plate is mandatory for eye protection from the harmful rays
of the arc. The filter plate should be at least shade #10 for
general welding up to 200 amps. However, certain operations
such as carbon-arc welding and higher current welding operations
require darker shades. Never use a helmet if the filter plate
or cover lens is cracked or broken. A flame-proof skull cap
to protect the hair and head as well as hearing protection in
noisy situations is recommended.
disposable cigarette lighters are very dangerous around heat
and flame. It is very important that they not be carried in
the pockets while welding. Always provide protection to bystanders
or other workers by welding inside a properly screened area,
if possible. If unable to work inside a screened area then
protection to others should be provided by a portable screen
or shield, or by their wearing anti-flash goggles.
is important that anyone operating an arc welder be instructed
on its safe use by a qualified teacher or welder.
of their potentially explosive nature, we strongly recommend
that no welding, cutting, or hot work be attempted on used
drums, barrels, tanks, or other containers under any circumstances.
work to be welded should be placed on a firebrick surface
at a comfortable height. Welding should never be done directly
on a concrete floor. Heat from the arc can cause steam to
build-up in the floor which could cause an explosion. The
welder cables should be positioned so that sparks and molten
metal will not fall on them. They should also be kept free
of grease and oil and located where they will not be driven
welders can kill by electric shock. If the welding operation
must be done on steel or other conductive material an insulating
mat must be used under the operator. If the welding area is
wet or damp or the operator is actively perspiring then he/she
should wear rubber gloves under the welding gloves.
easier and safer to establish an arc on a clean surface than
a dirty or rusty one. Therefore, metal should always be thoroughly
cleaned by wire brushing or other method prior to welding.
When chipping slag or wire brushing the finished bead the
operator should always be sure to protect his eyes and body
from flying slag and chips. Unused electrodes and electrode
stubs should not be left on the floor as they create a slipping
hazard. Hot metal should be handled with metal tongs or pliers. When quenching hot metal in water it should be done carefully
to prevent painful burns from the escaping steam. Any metal
left to cool should be carefully marked "HOT" with a soapstone.
When welding is finished for the day or suspended for any
length of time electrodes should be removed from the holder.
The holder should be placed where no accidental contact could
occur, and the welder should be disconnected from the power
operate in an open well-ventilated area or vent the engine
exhaust directly outdoors.
fuel the engine while running or in the presence of an open
up spilled fuel immediately and wait for fumes to disperse
before starting the engine. *Never remove the radiator pressure
cap from liquid cooled engines while they are hot to prevent
the engine before performing any maintenance or trouble
shooting. The ignition system should be disabled to prevent
accidental start of the engine.
all guards and shields in place.
hands, hair, and clothing away from moving parts.
welding area should always be equipped with a fire blanket and
a well stocked first aid kit. It is desirable that one person
be trained in first aid to treat the minor injuries that may
occur. All injuries, no matter how minor they may seem can become
more serious if not properly treated by trained medical personnel.
sure the welder is properly installed and grounded.
weld without adequate ventilation.
proper precautions to prevent fires.
your entire body with fire retardant clothing, shoes, and
eye protection at all times.
only in a firesafe area.
do any welding, cutting, or hot work on used drums, barrels,
tanks, or other containers.
metal "HOT" with a soapstone.
a well stocked first aid kit handy.
Publication #: 8818
is apart of
a series from the Cooperative Extension, the University of
Arizona, Tucson, AZ 85719. Publication date: May 1989.
Fluegel, Safety Coordinator and Bradley Rein, Engineering
Specialist, the College of Agriculture, the University of
Arizona, Tucson AZ 85719.
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.