In recent months, new laser welding equipment has become very popular. Their advantages include ease of use and speed of operation, but little has been said about the occupational hazards of using a laser for welding. But very little has been said about the occupational hazards involved in using a laser for welding. What are the health risks involved in using a laser for welding or what are the regulations that apply are some of the topics where less information is given.
What type of laser is used for laser welding?
First of all, we have to define the laser used for welding: a laser welding machine is manufactured with the latest generation of continuous wave fibre lasers. Its wavelength is between 1030 and 1080 Nm and powers are usually from 1000W.
Its classification is class 4 being the highest and most dangerous level for human beings for both eyes and skin.
These lasers require any user or person in the vicinity to be protected from both the beam and the diffuse reflections of the laser beam.
It is therefore essential to wear the appropriate protection at all times, even if the worker does not come into direct contact with the laser beam.
How can I protect myself from the light produced during laser welding?
The risk assessment shall include both collective means of protection and individual means of protection for the operator.
Collective protection means
As both the beam and the diffuse reflections of the laser beam are hazardous to the eyes and skin, the laser welding area must first of all be delimited with approved partitions or booths to avoid possible harm to personnel in the vicinity of the welding station.
A laser system must be designed and installed in such a way that harmful radiation is not accessible in all circumstances. This means that the maximum permissible irradiance levels for eyes and skin must not be exceeded outside a laser protection booth or system.
It should be noted that, in addition, during a laser welding process, no other persons should be present without the appropriate and certified Personal Protective Equipment for such an activity.
It is possible to install windows with specific materials in order to be able to control the manufacturing processes from the outside. These windows must comply with and be certified according to EN 12254. Please consult Dacar for measurements.
Means of personal protection
For eye and face protection, there is currently no specific standard for welding helmets for laser protection. In the absence of this, a combination of a conventional welding helmet complying with EN175 (or ISO16321-2) together with laser safety goggles or a filter complying with EN207 should be chosen.
EN 207 is the European standard for laser safety eyewear. Any laser eye protection sold within the European Community must be certified and labelled with the CE mark. According to this standard, laser safety eyewear must not only absorb laser light of a given wavelength, but must also be able to withstand a direct laser impact without breaking or melting, both the filter and the frame.
The level of blockage is quantified by the Optical Density (OD) of the filter, but cannot be considered on its own. Blocked light absorption can cause damage to the filter material or frame.
The LB rating is on the same scale as OD, but takes precedence over it. The LB rating takes into account both the protection offered by the lens and that of the frame.
Therefore, according to the European standard EN207:2017, you should look at the LB rating, which ensures that a material should last at least 5 seconds for a continuous wave laser, or 50 pulses for a pulsed laser.
The EN207 standard establishes 10 levels of protection ranging from LB1 to LB10 with the level of protection ascending from 1 to 10. The higher the number, the greater the protection.
In the case of laser welding, taking into account the technical characteristics described above, according to EN207 the following minimum levels of protection can be established:
-For lasers up to 1500 W: LB5 and with an optical density (OD) of 7 or more.
-For lasers of more than 1500 W: LB6 and with an optical density (OD) of 8 or more
An example of marking according to EN207:2017 would read D 900-1100 LB6.
Here, the letter D indicates the working mode of the laser, in this case a continuous mode. The range 900-1100 indicates the wavelength range in nanometres. Finally, the scale number LB6 indicates a lower limit for the optical density, i.e. the transmittance within this wavelength range is less than 10-6.
Dacar offers you 2 options of laser safety goggles to wear under your welding helmet and depending on the laser power:
For lasers up to 1500 W: Model YHP-2 with a protection level LB5 and an optical density (OD) of 7.
For lasers above 1500 W: Model RTD-5 with a protection level LB6 and an optical density (OD) of 8+.
You can also choose to use a welding helmet with laser protection. At present, there is no specific standard for such a product, but you can find conventional welding helmets with an additional lens with EN207 certification. Our proposal: DC-4 LASER helmet.
The DC-4 LASER helmet incorporates the RTD-5 filter certified with LB6 protection level and an optical density (OD) of 8+, offering the same protection as the RTD-5 goggle but with additional facial protection against diffuse welding light.
In addition to wearing face and eye protection, the operator must also wear suitable clothing, gloves and footwear. Unfortunately, there are no specific standards for such clothing for laser welding tasks to date.
The most similar standards for protective clothing could be EN ISO 13688:2013/A1:2021 which specifies general requirements for protective clothing together with EN ISO 11611:2015 specific to protective clothing used during welding and allied processes.
As for gloves, similarly, in the absence of specific standards, the ones to be taken into account are EN 12477:2002/A1:2005 on protective gloves for welders. It should be noted that such clothing must not come into direct contact with the laser beam under any circumstances.
As a result of this observation, activities involving the use of such PPE, which is not designed for this purpose , should be restricted as much as possible.
It should be made clear that this clothing is not an optimal protective element for this type of risk, and that it would offer only relative and probably insufficient protection.
Dacar offers a wide range of garments that could be recommended.
The COMFORT leather jacket, for example, is one of the most important elements. Certified according to CE EN ISO 13688:2013/A1:2021 and EN ISO 11611:2015 level A1, class 2, the Comfort leather welding jacket meets the standards for protection against molten metal splashes, contact with a flame for short periods of time, radiant heat and minimises the possibility of a small electric shock or accidental contact with electrical conductors up to 100V DC under normal welding conditions.
As to gloves, Dacar offers the brand new G8CP_ model consisting of anti-cut welder’s gloves offering increased safety due to their thermal insulation and anti-cut Kevlar lining, without compromising comfort due to their great flexibility and feel.
Thanks to their anti-cut certification, these gloves may be used for welding but also for handling metal sheets or any metal part that may pose a cutting risk when handled.
G8CP_ welding gloves comply with EN 12477:2001+A1:2005 TYPE B, EN 407:2020 413X4X, EN 388:2016 + A1:2018 3X32D as well as EN ISO 21420:2020 Cat. II.
As far as suitable footwear is concerned, Dacar recommends consulting a specialist in this type of PPE, as these items are not available.
In conclusion, laser welding is certainly a technological breakthrough in the world of welding, but unfortunately it is not without risks. Very high risks indeed for workers. The lack of safety legislation for the handling of such equipment should be of concern to operators and they should take the utmost care in their use to avoid possible accidents with irreversible consequences. As long as there are no regulations that clearly define the risks and how to prevent accidents, it will be up to each individual to find the most effective solutions to minimise the risks as much as possible.
