09-01-2014, 04:29 PM
ARC SAFETY
ARC WELDING.ppt (Size: 202.5 KB / Downloads: 45)
INTRODUCTION
Before starting actual arc welding the operator should be fully aware of the dangers involved. The high temperature arc and hot metal can cause severe burns. In addition the electric arc itself provides an additional safety hazard.
The electric arc emits large amounts of ultra violet and infra-red rays. Both types of rays are invisible to the naked eye just as the same type of rays emitted by the sun are invisible. However they both have the identical properties of causing sunburn on the human skin, except that the arc burns much more rapidly and deeply. Since these rays are produced very close to the operator they can cause very severe burns to the eyes in a short exposure time.
The welding operator needs to protect himself, by means of a helmet and other protective devices from the harmful rays of the arc and flying sparks. The filter plates in the welding helmet will remove 99% of the harmful rays if the proper shade lens is used.
Examples of Confined Spaces
• Small rooms • Unventilated • Degreasers
• Process vessels corners of a • Boilers
• Pits room • Compartments of
• Tunnels • Furnaces ships
• Vats • Storage tanks • Ventilation and
• Reactor vessels • Pipelines exhaust ducts
• Underground utili- • Sewers
ty vaults • Silos
Actions Required Before Approving Start of Work In A Confined Space
• Open all covers and secure them from closing.
• Test confined space atmosphere for
suitable oxygen content, no
combustibles or reactives, no toxics.
• Isolate lines by capping or double valving and venting, if feasible-keep vents open
and valves leak-free.
• Lock out all systems not required during welding, cutting, or heating.
• Provide means for readily turning off power, gas, and other supplies from outside
the confined space.
• Protect or remove any hazardous materials or materials which may become a
physical or health risk when heated or exposed to an arc.