Download 1 Electrical hazards 2 Heat-related risks 3 Light-related risks

critical to maintaining your own safety.
Cylinders and structural building components such as I-beams should never
be made part of the electrical circuit. All
electrical connections, including ground
clamps and cables, should be tight, and
not worn or frayed.
2 Heat-related risks
Work pieces can be hot, and this may
not always be visually apparent. To reduce
the risk of burns, allow pieces that have
been welded or cut adequate time to cool.
Also, sparks from the welding process are
hot metal and can burn arms or exposed
skin, as well as eyes. Proper PPE, including closed-toe shoes, safety glasses with
side shields under a welding helmet, welding jackets and covering exposed skin, can
help the welder avoid burns.
3 Light-related risks
By KAREN GILGENBACH
B
eyond following the regulations mandated by OSHA and
your state, safety in welding
is largely based on understanding hazards
and awareness of your surroundings.
Welding hazards can be roughly broken
into seven risk categories:
1 Electrical hazards
Arc welding is based on the creation
of an electrical circuit, and a “break” in
the electrical circuit, where the electricity is forced to travel through a gas (that
becomes ionized in this process). The
resistance in gas (think about the difficulty electricity has traveling through air)
creates an “arc.” An arc is comprised of
electrical energy lost as heat and light, so
electrical hazards may be the most intuitively recognizable risk in arc welding.
Common electrical hazards include:
Improperly wired machines:
If a machine is not properly wired, the
metal outer shell of the welder may be
electrically hot, which represents a serious risk for electrical shock. Always use
a licensed electrician to wire machines.
Improper personal protective equipment (PPE): Damp or
wet clothing, or welding in a wet area,
increases the risk of completing the circuit. Clean, dry gloves and rubber-soled
boots provide insulation.
High frequency can change
the risks: Some welders, specifically gas
tungsten arc welders (GTAW), use a high frequency voltage superimposed upon the welding current to initiate an arc without making
electrical contact between the electrode and
the work piece. The welder should not put
himself or herself in the electrical circuit, even
if not actually making direct contact with the
electrically hot tungsten, and especially if
not wearing gloves. People with implanted
medical devices and pace makers should stay
away from welding equipment that utilizes
high frequency radiation.
Removing the cover of the
welder increases risks: Some
welders can store electrical energy even
when the input voltage is removed. Never
open up a welder to expose electrical components for repair unless properly trained.
Awareness of the electrical
circuit can mitigate risk: Being
aware of what is electrically hot is
Arc welding, plasma welding and cutting, and oxyfuel welding and cutting all
produce light. Eyes are best protected
from UV and visible light emission of arc
welding by means of a welding helmet.
Different shades of lenses are available as
appropriate for different welding processes and currents. Welding shades generally
vary between 8-12, although auto-darkening helmets can have variations between
7-14. If you are not sure what lens shade
you need, see your welding distributor.
Newer auto-darkening helmets utilize
lenses that protect from UV (ultraviolet)
and IR (infrared) light even when not
darkened. Other employees working near
a welder should also be protected with
welding screens. Oxyfuel welding should
use at least Shade 5 goggles.
Another risk related to the light from
arc welding is burns to the skin akin to
rapid sunburn. Use proper PPE to make
sure no skin is exposed.
Finally, many experienced welders
“tack,” or create small welds to hold pieces in place for welding — oftentimes this
is done without the use of their welding
helmet. An auto-darkening helmet, which
allows the end user to manipulate pieces
with the helmet down, is a great option to
consider for welders who ‘tack’.
4 Fire-related risks
Maintaining a workspace free of flammability hazards such as oily rags is one
of the best ways to reduce risk of fire.
Butane lighters should not be kept in the
welder’s pocket or on the welder’s person,
and oxygen should never be used to clean
the welder’s clothes or introduced into the
welding area. Even vapors from gasoline
or other chemicals can create flammability risk and should be kept away from the
area. Remember, sparks can fly from the
welding area into the surrounding area and
present a risk for anything flammable in
the nearby vicinity.
Welding or cutting a tank that once
contained something flammable or an
unknown chemical is not advised.
5 Asphyxiation risks
Asphyxiation robs your body of sufficient oxygen to live. If other gases displace
oxygen out of the area or decrease the
percentage of oxygen in the air, a welder
would still have “air” to breathe, but if this
air is depleted of oxygen, asphyxiation can
take place quickly and without warning.
Never weld in a confined space without supplied breathing air. Be aware that
cylinders left open or liquid cylinders
releasing pressure through a relief valve
can introduce gas into the area that can
displace oxygen and cause asphyxiation.
Allow for lateral airflow into the welding
through open doors and use of fans.
6 Fumes/respiratory risks
Some materials — for example, coated
materials and stainless steels — can create
toxic fumes. Know the base metal you are
welding and associated hazards. Remove
oils and other foreign chemicals that can be
vaporized when welding, prior to heating the
piece. Different filler metals and electrodes
can have their own unique risks. Some tungsten can contain thorium, which is a radioac-
tive element. This can present a hazard in
the grinding area where dust can be inhaled.
7 Gas use and storage
The risks associated with compressed
and liquefied gases vary and can include,
but are not limited to,
flammability, risk of explosion and risk
of accelerating combustion and temperature. Gases should be stored in a
way that complies with the National
Fire Protection Association (NFPA)
standards as well as all applicable CGA
(Compressed Gas Association) standards.
Karen Gilgenbach is a welding process specialist for Airgas, Inc. (www.
airgas.com). She can be reached at
(262) 613-3790 or Karen.Gilgenbach@
Airgas.com. MCM-306
Nine steps to welding safety: Consider your surroundings
1. Evaluate the electrical circuit
ÒAre I-beams, gas cylinders or anything inappropriate included in the welding circuit?
2. Evaluate the PPE being used
ÒIs it clean and dry?
ÒDoes it cover all of the welder’s skin to protect from sparks and light?
ÒDoes it provide insulation from electricity?
ÒAre both a welding helmet and safety glasses being used?
ÒIs the welding lens appropriate for the work
being done?
ÒIs it free from any flammable components?
3. Evaluate the work station
ÒIs it free of flammability risks?
ÒIs it clean and free of trip hazards?
ÒCan the piece parts be held in place safely
or should fixturing or positioning equipment be
utilized?
4. Evaluate the base material
ÒAre there respiratory risks in welding the
material?
ÒAre there coatings on it that could create
fumes?
ÒAre there foreign chemicals that could create fumes?
5. Evaluate the filler metal and electrode
ÒWhat are the respiratory risks?
6. Evaluate gas storage
ÒIs it in compliance with the NFPA & CGA?
ÒAre cylinders part of the welding circuit?
ÒHave cylinders had their integrity
compromised by arcs, etc.?
7. Evaluate equipment for safety
ÒHas it been properly wired by an
electrician?
ÒAre the correct regulators and hoses being
used?
ÒAre electrical connections tight and not
frayed?
ÒAre all welding power and ground cables
sized properly for the current required?
8. Evaluate the project
ÒAre there risks associated with the job?
For example, will the welder be welding or cutting
on a tank that once contained gas?
9. Evaluate air flow and respiratory risks
ÒIs there adequate airflow to the welder?
ÒIs fume extraction necessary?
Reprinted from Industrial Safety & Hygiene News
April 2011 ©2011 Industrial Safety & Hygiene News