Page 154 - CITS - Welder - Trade Theory

WELDER - CITS

MODULE 6 : GMAW

Lesson 49 - 60 : Safety precautions pertaining to GTAW

& GMAW

Objectives

Objectives: At the end of this lesson you shall be able to
• safety precautions in GTAW
• explain the welding environment safety rules
• explain the safety precaution in GMAW.

GTAW safety :
GTAW/TIG welding is a skill which may be performed safely with a minimum of risk if the welder used good
common sense and safety rules. It is recommended that you establish good safety habits as you work in this
industrial area. Check your equipment regularly and be sure that your environment is safe. Safety in TIG welding
covers the following major areas and includes

Electrical current: Primary current to the electrical powered welding machine is usually 220V A/C or more, and
this amount of voltage can cause extreme shock to the body and possible death. For this reason
a never install fuses higher than specified

b always ground/earth the welding machine properly
c install electrical components as per the codes given by the electricity boards
d ensure electrical connections are tight
e never open a welding machine when it is operating
f lock primary voltage switches, open and remove fuses when working on electrical components inside the
machine
g welding current supplied by the power supply has a maximum of 80 open circuit volts. At this low voltage, the
possibility of lethal shock is very small. However, it will still produce a good shock. To reduce the possibility of
this occurrence.
h keep the welding power supply dry

i keep the power cable, ground cable and torch dry
j do not weld in damp area. If you must, wear rubber boots and gloves
k make sure the ground clamp is securely attached to the power supply and the work piece
l high frequency components in some GTAW ma- chines produce a spark for starting the initial arc or maintenance
of the arc during the alternating current welding. The high frequency voltage is very high; however, the
amperage is very low. Since the ampere- age is so low, the high frequency voltage will not usually travel
through the body and is therefore not as dangerous as other currents
Inert gases:
Inert gases used in GTAW are produced and distributed to the user in two forms: high pressure gas and liquid.
All storage vessels used for inert gases are approved by the department of transportation and are so stamped on
the vessel name plate or the cylinder wall.
Most of the gases used in GTAW are inert, colorless and tasteless. Therefore, special precautions must be taken
when using them. Nitrogen, argon, and helium are non- toxic. However they can cause asphyxiation (suffocation)
in a confined or closed area that does not have adequate ventilation. Any atmosphere that does not contain at
least 18 % oxygen can cause dizziness, unconscious- ness or even death. The gases cannot be detected by the
human senses and will be inhaled like air. So ensure the welding area is well ventilated with good air circulation.

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