Welding and cutting smoke contains gases and a number of heavy metals which together can cause chronic bronchitis and cancer of the airways. Therefore, this smoke must always be removed effectively. Make sure you protect your skin from ultraviolet light and sparks. The light from welding can also cause permanent eye damage.
Materials with surface coatings
Grease, paint and other surface coatings must be removed before starting to weld. Clean mechanically as far as possible, and use only organic solvents if you are unable to get the surface clean in any other way. Always use relevant respiratory protection and make sure solvent residues are removed before welding.
Remove welding smoke and grinding dust using suitable ventilation and extraction facilities. Use a portable system if it is not possible to set up a central extractor. If this is not possible either, use suitable respiratory protection.
If it is not possible to set up effective process ventilation with extraction to the open air, it is necessary to decide on how to prevent spreading to others at the work site, and signs must be put up which state that working and moving around in the area are permitted only if suitable respiratory protection is used.
Metalworking such as cutting and grinding typically involve noise that could damage the hearing, and this noise must be countered by means of enclosure, noise damping or similar. It may be necessary to use suitable ear defenders. Other people must not be subjected to noise which is unnecessary or could be harmful to health. Areas in which ear defenders are to be worn must be cordoned off, and signs must be put up stating requirements for the use of ear defenders.
Special health and safety training is required to be able to carry out welding and thermal metal cutting and grinding work linked with the same. There are no special training requirements for other kinds of grinding. The same training requirements apply to operators of welding and cutting machines that may give off smoke.
This training must be approved by the Working Environment Authority and be offered in many locations.
Wear gloves when you will be welding. These will protect you from radiation or burns from the welding flame.
If you are welding in a kneeling position, you must use knee protectors/pads and suitable ankle cuffs and an apron to protect against sparks and glowing drops of metal.
Wear a welding helmet, manual visor or suitable goggles with side protection if you are going to weld or are working near to the welding site. Use the right type of filter glass in welding helmets, manual visors or suitable goggles. Using a fixed or moving visor where the density is the same as in the protective glass is even better.
Light from welding/photo-ophthalmia
Hypersensitivity to light, runny eyes, swollen eyelids and great pain in the eyes are typical symptoms of photo-ophthalmia.
If you experience these symptoms, you must seek medical attention promptly. The doctor can prescribe a prescription medicine which will help you, and at the same time tell you how to use this medicine.
Make a decision on the issue when the enterprise is to compile its APV, and if necessary seek the advice of an ophthalmologist – before starting work.
Risk of fire
Inflammable objects must be removed from the welding site. If you need to weld near to inflammable materials which cannot be removed, you should have both a guard and a fire extinguisher.
Check neighbouring rooms which are linked via pipes to the room where welding is taking place. Also check whether any fire would block escape routes. Always carry out a final inspection when you have finished welding.
Do not touch conductive objects which are often found between pipes, behind containers, etc. Damp soil may conduct electricity. Therefore, be particularly careful if you are wet because of rain or sweat.
When you are to carry out welding:
- Wear undamaged, dry welding gloves (any assistants must also do so). You must only touch the electrode with insulated gloves.
- Do not place the electrode between your arm and chest when swapping it.
- Do not place the welding cable across your neck or arm.
- Keep your working clothes dry and in one piece.
- Immediately replace any damaged welding equipment.
If there is any risk of your body coming into contact with conductive parts (e.g. in boilers or containers), the following requirements are laid down for the welding equipment:
- The open circuit voltage must be reduced to 12 V AC or converted to a maximum of 100 V DC within 0.2 seconds of the arc being switched off.
- There must be a monitoring device so that the protection can be checked.
Checklist for gas welding (oxyacetylene welding):
- Make sure that the steel bottles are safeguarded against shocks, blows, falling over and heat.
- Store them in such a way as to protect them from the sun and rain.
- Store full and empty bottles separately.
- The bottle valve on empty bottles must be closed and the protective cap must be on.
- Gas and oxygen hoses must be entire and have no joints.
- Bottle valves must not be lubricated or subject to violence.
- Bottles with defective valves must not be used.
- Bottles are transported with a suitable trolley.
- Check whether the bottles have undergone periodic inspection. The date of the next inspection will be stamped onto each individual bottle.
During MIG welding, ozone is formed in a sphere around the arc for a distance of up to 1 metre.
Ozone, which is hazardous to health, can only be captured effectively by means of low pressure extraction, which has a much greater catch zone than high pressure extraction.
Protect yourself from spatter and optical radiation by wearing a helmet with loose neck protection, as well as gloves and workwear to cover your body.
The helmet must be fitted with self-closing welding glass which automatically changes the density of the welding glass when the arc is struck. Self-closing welding glass reduced the risk of photo-ophthalmia as this prevents the effect that may arise if the helmet is closed too late once the arc is struck.
Also, set up screens to protect your colleagues from direct and reflected optical radiation.
At high current strengths and when welding aluminium, the ozone is formed so far away from the arc that low pressure extraction has problems capturing the ozone effectively. Therefore, in this situation low pressure extraction must be combined with the use of suitable respiratory protection to counter ozone.
Respiratory protection with a turbo unit (turbo mask) is accepted by the Working Environment Authority only if the low pressure extraction effectively captures all the smoke, otherwise respiratory protection with a fresh air supply must be used.
Oxygen bottles must be of a blue distinguishing colour with white shoulders. Bottles, pipes and devices must not come into contact with oil or other greases as this may cause spontaneous combustion.
Acetylene bottles must be of a red-brown distinguishing colour. Acetylene is highly explosive. Never use any bottle with an unsealed or defective valve.
The bottle should remain upright when in use. To prevent blowback in the acetylene bottle, you must fit a blowback safety valve at the pressure relief valve. Blowback or strong heating may cause the bottle to explode.
Soldering and flux
During heating, most fluxes give off unpleasant vapours (often acid vapours) which are harmful to health. These vapours must be removed by extraction before they reach your nose and mouth. Fluxes and solders must not contain more than 0.1% cadmium due to the risk of poisoning.