Impax IM-MMA140 Instruction Manual page 6

SAFETY INFORMATION
Checking the Equipment
Check that the equipment is suitable for the
operation and connected in accordance with the
manufacturer's recommendations. The welder is
responsible for checking the equipment (cable,
electrode holder and coupling devices) daily for
damage and defects. All external connections
should be clean and tight and checked each
time a reconnection is made. The welding return
clamp should be connected directly to the work
piece, as close as possible to the point of
welding or to the metal work bench on which
the work piece is placed. Any damaged or
defective parts must be replaced before
continuing the welding operation.
Fumes
The welding process vaporises metals, and
anything that is resting on the surface. This
gives rise to fumes, which is condensed fine
particulate material. The fume is mostly oxides
of the metals, including any alloying elements,
but it also contains gases produced in the arc,
such as ozone or oxides of nitrogen, and
decomposition products from any paint or
coating which was on the metal surface. The
nature and quantity of this fume depends
critically upon the welding process, the
materials and the welding parameters.
Severe discomfort, illness or death can result
from fumes, vapours, heat, or oxygen
enrichment or depletion that welding (or cutting)
may produce. Prevent them with adequate
ventilation. NEVER ventilate with oxygen. Lead-,
cadmium-, zinc-, mercury- and beryllium-,
bearing materials, when welded (or cut) may
produce harmful concentrations of toxic fumes.
Adequate local exhaust ventilation must be
used, or each person in the area as well as the
operator must wear an airsupplied respirator. For
beryllium, both must be used. Metals coated
with or containing materials that emit toxic
fumes should not be heated unless coating is
removed from the work surface, the area is well
ventilated, or the operator wears an air-supplied
respirator. Work in a confined space only while it
is being ventilated and, if necessary, while
wearing an air-supplied respirator. Vapours from
chlorinated solvents can be decomposed by the
heat of the arc (or flame) to form PHOSGENE, a
highly toxic gas, and other lung and eye
irritating products. The ultraviolet (radiant)
energy of the arc can also decompose
trichloroethylene and perchloroethylene vapours
to form phosgene. DO NOT WELD or cut where
solvent vapours can be drawn into the welding
or cutting atmosphere or where the radiant
energy can penetrate to atmospheres containing
even minute amounts of trichloroethylene or
perchloroethylene.
Noise
Welding environments are frequently noisy as
other operations such as grinding, etc. may also
be taking place. Some operations, such a de-
slagging may take the noise up to such a level
where it will damage hearing. In such cases
hearing protection must be used.
Optical Radiation
The welding process produces a large quantity
of visible light, ultraviolet and infrared. Exposure
to the radiation from an arc causes damage to
the eyes (Arc Eye). For this reason, welders need
to wear efficient eye protection, which is usually
supplied in the form of a protective shield.
The precise choice of the shade of glass filter in
these shields depends on the type of welding
operation, since they vary in their light output.
Hand Held and Head Shields
For most operations a hand-held or head shield
constructed of lightweight insulating and non-
reflecting material is used which conforms to
EN175. The shield is fitted with a protective filter
glass, sufficiently dark in colour and capable of
absorbing the harmful infrared and ultraviolet
rays. The filter glasses conform to the strict
requirements of EN169 and are graded
according to a shade number which specifies
the amount of visible light allowed to pass
through - the lower the number, the lighter the
filter. The correct shade number for ARC welding
must be used according to the welding current
level, for example:
• Shade 9 - up to 40A
• Shade 10 - 40 to 80A
• Shade 11 - 80 to 175A
• Shade 12 - 175 to 300A
• Shade 13 - 300 to 500A
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