In this toolbox we devote attention to the topic welding.
Welding is a method of joining two metals together. During the welding process, they are fused together. This requires a high temperature at the welding site. Auxiliary welding material is sometimes added as well.
We distinguish two methods of welding: electric and autogenous.
In electric welding, an electric arc is used that heats up the material locally to a very high temperature. In fact, electric welding is nothing more than a controlled short-circuit.
In autogenous welding, the heat comes from a gas flame reinforced by oxygen. The combustible gases are:
Non-flammable, but oxygen displacement gases are:
Fire and explosion hazard
A fire and explosion hazard can arise due to the unnoticed escape of gases and/or oxygen. The escape can be due to leaking hoses or improperly closed blowtorches or defective shutoff valves. This is why it is necessary to make use of a hose failure protection device. This device automatically shuts down the gas and/or oxygen supply in case of major leaks. An explosion hazard is particularly prevalent during autogenous welding performed on vessels that are closed or nearly closed. As the vessel heats up, the gases present in the vessel can ignite.
Exposure to harmful vapours
Harmful gases and vapours can be generated during autogenous welding (and cutting). These can be hazardous to health. For example, think of welding in confined spaces. The hazard can be created by:
The combustion of the acetylene or propane by the blowtorch will not only draw oxygen from the oxygen bottle, but from the surrounding air as well. When combustion is incomplete, this can create highly toxic carbon monoxide. Furthermore, in a poorly ventilated space the oxygen concentration in the air will drop due to the consumption of the oxygen by the welding flame.
In addition, the welding flame’s elevated temperature (approx. 3,000°C) causes nitrogen oxides to be formed by combining the nitrogen and oxygen present in the air. These are known as ‘nitric vapours’. These vapours are already highly toxic at low concentrations and can cause illness (pulmonary oedema).
Harmful noise
The process used, the type of voltage and the welder’s surroundings can result in harmful noise. Harmful noise is defined as noise where the sound pressure level exceeds 80 dB(A).
Harmful radiation
Excessive heat
Welder's flash
When, without protection, you come close to an area where welding is being done, you run the risk of burning your skin through UV radiation. Covering your entire skin, including your face/neck/arms/hands, is a must.
Clinical picture
Do not take welder's flash lightly and take measures to prevent it.
Fire and explosion hazard
Exposure to harmful vapours
Harmful noise
Welder's flash
What you can do:
Preventive measures