TIG Welding

Shielding gases for TIG welding are in terms of health and safety, to all intents and purposes, inert.

Inert gases are not toxic, but will not support life.

Of the two main inert gases used in TIG welding helium is lighter than air but argon is heavier and can gather in low lying areas if the atmosphere is still and relatively undisturbed.

Arc welding produces electromagnetic radiation over a wide range of wavelengths. These wavelengths cover three distinct types of 'non-ionizing' radiation, namely, Ultraviolet (UV), Visible Light and Infrared (IR). TIG welding does not produce ionizing radiation.

Burns to the skin and eyes due to exposure to arc radiation may not become apparent until some time after welding has ceased.

Some points to bear in mind are:

- Radiation is only generated while the arc is generated and the amount emitted generally increases as the welding current increases.

- Burns can be avoided by wearing proper protective clothing and ensuring no areas of skin are left exposed.

Sources of heat include welded components, the electrode holder and hot or discarded electrodes, and any of these can cause burns to the skin.

A hot environment can cause the body to overheat, and this is known as Heat Stress.

However those working in welding shops can reduce the risk by adhering to the following recommendation:

Always assume all metal objects in a welding shop are hot.

Welding fume is an unavoidable by-product of TIG welding, although fume generation from the process is generally low. However, the welder should still be aware of what fume is likely to be generated while welding is taking place and the potential hazards of exposure to the welding fume.

Particulate fume is mostly formed from vapourisation of the welding consumable in processes where the consumable is transferred across an electric arc.

Welding processes with open arcs, such as TIG, are likely to promote the formation of gaseous fume as a result of the action of ultraviolet light and heat on atmospheric oxygen and nitrogen.

Whilst all components of welding fume may present a risk to health, given a high enough concentration, some present a greater hazard than do others. The potential effect of exposure to welding fume depends upon:

- The composition of the fume.

- The volume of fume produced.

The TIG welding processes, like all others, generates noise, although it tends to be the quietest of the major arc welding processes.

Back injuries are one of the most common industrial injuries suffered by workers. When moving and positioning welding equipment, be aware that these units are often heavy, including some of the so-called 'portable' units.

Any of the hazards associated with TIG welding will be exacerbated when welding is carried out in a confined space. When TIG welding in a confined space, there is also the potential additional hazard of a build-up of inert shielding gas to contend with.

Thorium is a radioactive alpha emitter, which means that it is a hazard if inhaled or swallowed. Some tungsten electrodes used in TIG welding are alloyed with thorium oxide, thoria, to improve arc striking and stability.

Flammable solvents may have been used to clean components prior to welding and may still be present around the welding area, presenting a fire or explosion hazard. Similarly chlorinated hydrocarbon degreasers, such as 1-1-1 Trichloro-ethane (Genklene), may have been used.

The welder should allow all traces of any solvents to disappear from component surfaces and ensure no containers of solvent are in close proximity before welding starts.

General workshop safety is really a matter of common sense and good housekeeping and the following actions may be used to avoid accidents:

The advice given above is general in nature but forms a good overview of the potential hazards associated with the process. There are, however, things that can be done to help reduce the possibility of problems occurring in the workplace:

There is a considerable amount of misinformation in the fabrication industry about the health hazards associated with welding. There is also a lack of understanding among welders as the how they can influence the type and severity of hazard. The main cause for this is often poor training and some welders appear to be unwilling to operate at welding conditions that will keep fume production to a minimum.

Simple routine maintenance and a formalised system of safety audits on welding equipment has been shown to help reduce the number of safety related incidents within the industry.

Welders should ensure that they wear appropriate clothing for the operation they are carrying out. Flame-retardant boiler suits, gloves or gauntlets, safety shoes, leather aprons, etc, should be in good condition and as free from oil, grease and moisture as is physically possible as these can reduce the effectiveness of the safety equipment.