
page
14
TtGARC
15QDC
MANUAL
Work
in
a confinedspace
only
while
it
is being ventilatedand,
if
necessary, while Wearing air-
supplied respirator.
Vapours from chlorinatedsolventscan be decomposed by the heatof the arc (orflame)
to
form
PHOSGENE,
ahighlytoxic gas,and
lung
andeye irritatingproducts. The ultra-violet(radiant)
energyof the arccan also decompose trichlorethylene and perchlorethylene vapors to form
phosgene.
Do
not weld or cut where solvent vaporscanbedrawn into
the
welding
or
cutting
atmosphere orwhere the radiant energycan penetrate
to
atmospheres containing even minute
amounts
of
trichlorethyleneor percholorethylene.
FIRE
AND
EXPLOSION PREVENTION.
Be
aware that flying sparks orfalling slag can pass through cracks,
along
pipes,through
windows or doors, and throughwatl orfloor openings,out of sight of the operator.Sparksand slag
cantravel upto
10
metresfrom the arc.
Keepequipment clean and operable, free
of
oil, grease,and (in electrical parts) of metallic
particlesthat cancauseshort circuits.
If
combustibles are presentinthe work area, do
NOT
weld or cut. Move thework
if
practicable,
to
an areafree of combustibles. Avoid paintspray rooms, diptanks, storageareas,ventilators.
If
the
work can not bemoved, movecombustiblesat least
10
metresaway out
of
reachof sparks andheat;
or protectagainst ignition with suitableand snug-fitting fire-resistantcovers or shields.
Walls
touchingcombustibleson oppositesides should not bewelded on orcut. Walls, ceilings,
andfloor near work should be protected
by
heat-resistantcoversor shields.
A
person acting
as
FireWatcher mustbe standingbywith suitable fire extinguishingequipment
durlngand for sometimeafter welding or cutting
if;
U
Combustibles(including building construction)arewithin
10
metres.
U
Combustiblesarefurtherthan
10
metresbutcan beignited
by
sparks.
U
Openings (concealed or visible)
in
floors or wallswithin
10
metres may expose
a
Combustibles adjacent
to
walls,ceilings,roofs,
or
metalpartitions can be ignited by
After work
is
done, checkthat area
is
free
of
sparks, glowingembers, and flames.
combustiblesto sparks.
radiant or conductedheat.
An
tank or drum which has contained combustibles can produce flammable vapors when
heated. Such a container must never be weldedonor cut,unless
it
has first been cleaned as
described
in
AS.1674-1974,
the
S.A.A.
Cutting and Welding Safety Code. This includes a thorough
steam
or
caustic cleaning(or asolvent or water washing,dependlng on thecombustible’ssolubility),
followed by purgingand inerting wlth nitrogen orcarbondioxide, and using protectiveequipment as
recommendedIn
AS.1674-1974.
Water-filling justbelow worktng levelmay substitute for inerting.
Hollow castings or containers must bevented before weldlng or cutting. They can explode.
Neverweld
or
cutwhere the air may containflammable dust,gas, orliquidvapours.
SHOCK
PREVENTION.
Exposedconductors or other baremetal
in
the welding circuit,or ungroundedelectrlcallyalive
equipmentcanfatallyshock a personwhose bodybecomesa conductor.Ensurethat the machine
is
correctly connected andearthed.
If
unsure havemachine installedbyaqualifiedelectricfan. On
mobile or portable equlpment, regularly inspect condition of traillng power teads and connecting
plugs. Repairor replacedamaged leads.
Fully insulated electrode holders shouldbe used.
Do
not use holders with protrudingscrews.
Fully insulated lock-typeconnectorsshould be usedto joinweldingcable lengths.
Terminals and other exposed parts of electrical unlts should have insulated knobs or covers
securedbefore operation.