Welding Safety
Copyright © 2012 American Safety Management Inc.
Definitions
Weld
• A localized fusion of metals
produced by heating to
suitable temperatures.
• Pressure and/or filler metal
may or may not be used.
• The filler material has a
melting point approximately
the same or below that of
the base metals, but always
above 800 °F.
Gas Metal-Arc (MIG) Welding (GMAW)
• Fusion is produced by
heating with an electric arc
between a consumable
metal electrode and the
work.
• Shielding from an inert gas
such as helium or argon.
• Electrode fed continuously
and deposited as weld
material in the intense heat
of the arc.
Gas Tungsten-Arc (TIG) Welding (GTAW)
• Fusion is produced by
heating with an electric
arc between a nonconsumable tungsten
electrode and the work.
• An inert gas forms
around the weld area to
prevent oxidation.
• A welding rod with no
flux is used.
Shielded Metal Arc Welding (SMAW)
• Most widely used type of arc welding
• Also known as manual metal arc (MMA) welding or informally
as stick welding.
• Uses a consumable electrode coated in flux to lay the weld.
Spot Welding
• Resistance welding process in which fusion is
produced by converting electrical energy to heat
energy and transferring it to the work pieces held
together under pressure by electrodes.
• Size and shape of the individually formed welds
are limited by the size and contour of the
electrodes.
Stud Welding
• Arc welding process in which fusion is produced by
heating with an electric arc drawn between a metal
stud and the other work piece.
• They are brought together under pressure.
General Safety Rules
• Study the Owners Manual.
• Pay particular attention to safety
information. Only qualified persons
should install, operate, maintain, and
repair welding units.
• MSDS – metals, consumables,
coatings.
• Wear approved safety glasses with
side shields under your welding
helmet. Welding, chipping, wire
brushing, and grinding cause sparks
and flying metal.
• Turn off equipment when not in use.
Electrical Safety
• Wear dry, hole-free insulating gloves and body
protection.
• Do not touch electrode with bare hand.
• Do not wear wet or damaged gloves.
• Do not touch live electrical parts.
Electrical Safety (Cont.)
• Protect yourself from electric shock by insulating
yourself from work and ground.
• Use non-flammable, dry insulating material such as
dry rubber mats, dry wood big enough to cover your
full area of contact with the work or ground.
Electrical Safety (Cont.)
• Disconnect input plug or power before working
on machine.
• Frequently inspect input power cord for damage
or bare wiring – repair or replace cord
immediately if damaged.
• Keep cords dry, free of oil and grease, and
protected from hot metal and sparks.
• Properly install and ground all equipment.
Respiratory Safety
• Keep your head out of the fumes. Do not breathe
the fumes.
• Refer to Material Safety Data Sheets (MSDSs) for
metals, consumables, and coatings.
Respiratory Safety (Cont.)
• Use local exhaust at the arc to remove the fumes
from your breathing area.
• Use a ventilating fan to remove fumes from the
breathing zone and welding area.
• If adequacy of ventilation or exhaust is uncertain,
have your exposure checked by an industrial
hygienist.
Fire Safety
• Flying sparks, hot work piece, and hot equipment can
cause fires and burns.
• Do not weld near flammable material or where the
atmosphere may contain flammable dust, gas, or
liquid vapors (such as gasoline).
• Watch for fire, and keep a fire extinguisher nearby.
Fire Safety (Cont.)
• A fire watch person shall be provided during and for
1-hour (UEI policy) past the completion of the
welding project when
– (a) appreciable combustible materials are closer than 35
feet to the point of operation or
– (b) appreciable combustibles are more than 35 feet away
but are easily ignited by sparks (OSHA rule.)
• At least one 10-lb. dry chemical fire extinguisher.
• Ensure area is free of sparks, glowing embers, and
flames.
Fire Safety (Cont.)
• Be alert that welding sparks
and hot materials from
welding can easily go through
small cracks and openings to
adjacent areas.
• Be aware that welding on a
ceiling, floor, bulkhead, or
partition can cause fire on the
hidden side.
Fire Safety (Cont.)
• Do not weld on drums, tanks,
or any closed containers
unless a qualified person has
tested it and declared it or
prepared it to be safe.
• Welding on closed containers,
such as tanks, drums, or
pipes, can cause them to
blow up.
Fire Safety (Cont.)
• Connect work cable to the work as close to the
welding area as practical to prevent welding current
from traveling long paths and causing electric shock
and fire hazards.
• Remove any combustibles, such as a butane lighter
or matches, from your person before doing any
welding.
• Remove stick electrode from holder or cut off
welding wire at contact tip when not in use.
PPE Safety
• Wear complete body protection. Wear oil-free
protective clothing such as leather gloves, heavy
shirt, cuff-less pants, and high boots.
• Wear clothing made from durable, flame-resistant
material (leather and wool) as a protection against
sparks and hot metal.
• Shirt should have full sleeves, no pockets and should
be worn outside the trousers with collar buttoned.
PPE Safety (Cont.)
• Arcs produce intense visible
and invisible rays that can
burn eyes and skin.
• Wear a welding helmet
fitted with a proper shade of
filter to protect your face
and eyes when welding or
watching.
• Should be an insulator for
heat and electricity.
PPE Safety (Cont.)
PPE Safety (Cont.)
• Do not touch hot welded or cut parts with bare
hand.
• If handling is needed, use proper tools and/or
wear heavy, insulated welding gloves to prevent
burns.
• Allow cooling period before handling parts or
working on equipment.
PPE Safety (Cont.)
• Wear welders cap and
safety glasses with side
shields.
• Use protective screens or
barriers to protect others
from flash and glare;
warn others not to watch
the arc.
• Where the work permits,
the welder should be
enclosed in an individual
booth.
Gas Cylinder Safety
• Shielding gas cylinders
contain gas under high
pressure.
• If damaged, a cylinder can
explode.
• Since gas cylinders are
normally part of the welding
process, be sure to treat
them carefully.
• What’s wrong with this
picture?
Gas Cylinder Safety (Cont.)
“A cylinder that leaks, is bulged, has defective
valves or safety devices, bears evidence of
physical abuse, fire or heat damage, or
detrimental rusting or corrosion, must not be
used unless it is properly repaired and
requalified.”
Gas Cylinder Safety (Cont.)
• Protect compressed gas cylinders from excessive
heat, mechanical shocks, slag, open flames, sparks,
and arcs.
• Secure cylinders in an upright position.
• Keep cylinders away from any electrical circuits.
• Never drape a welding torch over a gas cylinder.
• Never allow a welding electrode to touch any
cylinder.
• Never weld on a pressurized cylinder – explosion will
result.
Gas Cylinder Safety (Cont.)
• Before attaching the regulator,
remove the protective cap
from the cylinder.
• Turn face away from valve
outlet.
• “Crack” the valve slightly for an
instant, and then close it, to
clean the valve of dust and dirt
that can damage the regulator
and cause a fire or explosion.
• What’s wrong with this
picture?
Gas Cylinder Safety (Cont.)
• Unless cylinders are secured on a special truck, remove
regulators and install valve-protection caps before
moving.
• Close the valve and release the gas from the regulator
before removing it from the cylinder.
• Keep protective cap in place over valve except when
cylinder is in use or connected for use.
• Do not use valve protection caps for lifting cylinders.
• Cylinders can be heavy — use lifting device and proper
methods to injury to yourself or damage to the cylinder.
Gas Cylinder Safety (Cont.)
• Keep cylinders, valves, couplings, regulators, hose, and
apparatus free from oily or greasy substances.
• Use only correct shielding gas cylinders, regulators, hoses, and
fittings designed for the specific application; maintain them
and associated parts in good condition.
Confined Space Safety
• Spaces that can be entered
but not designed for
continuous human
occupancy and have
restricted means of entry
and exit such as tanks, pits,
attics, and crawl spaces.
• All normal arc welding and
cutting hazards are
amplified in confined
spaces.
Confined Space Safety (Cont.)
• Always open all covers, remove
any hazardous or toxic
materials and provide forced
ventilation.
• Have constant communication
with someone outside who can
quickly turn off power and gas,
is trained in rescue procedures,
and is able to pull you out in
case of emergency.
• Do not use AC weld output in
confined spaces.
EMF Safety
• Welding current creates an EMF
field around the welding circuit
and welding equipment.
• EMF fields may interfere with
some medical implants, e.g.
pacemakers.
• Protective measures for persons
wearing medical implants have to
be taken. For example, access
restrictions for passersby or
individual risk assessment for
welders.
EMF Safety (Cont.)
Use the following procedures in order
to minimize exposure to EMF fields
from the welding circuit:
• Keep cables close together by
twisting or taping them.
• Keep welding power source and
cables as far away from operator as
practical.
• Connect work clamp to work piece
as close to the weld as possible
Summary
• Wear dry, insulated gloves and other protective
clothing in good condition.
• Insulate yourself with rubber-soled shoes or
stand on a dry, insulated mat.
• Use fully insulated electrode holders.
• Do not touch an energized electrode with bare
hands.
Summary (Cont.)
• Inspect equipment and cables before each use
and repair or replace damaged parts.
• Avoid breathing the welding fumes.
• Treat gas cylinders with respect.
• Beware of fire hazards.
• Turn off equipment when not in use.