Handheld laser welding equipment is a high-power Class 4 laser instrument.
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All persons using welding processes should already be aware of the necessary precautions, such as electrical, fumes and gases, fire or explosion, burn, arc rays, noise, and electric and magnetic fields (EMF). In addition to the above-listed arc welding hazards, users should understand that handheld laser welding equipment creates laser beam hazards.
In addition to the hazards associated with arc welding, direct, or reflected high-power laser beams are hazardous to view under any condition. In the U.S., handheld laser standards exist regarding the general safe use of lasers and the safe use of lasers in manufacturing environments (e.g., ANSI Z136.1 and ANSI Z136.9). High-power lasers typically emit multiple kilowatts of high-intensity visible or invisible (near-infrared) light.
Each organization or any sole operator outside an organization operating Class 3B or 4 lasers shall:
Operators and all persons in the LCA shall wear specified personal protective equipment (PPE), laser safety eyewear, including laser welding helmet, heat-resistant gloves, and flame-resistant clothing.
Class 4 high-power lasers present the most serious of all laser hazards.
The reflected beam hazard typically occurs momentarily before the laser-induced plasma initiates (emitting light similar to that from an arc). A hazardous laser beam reflected
forward of the torch can exist for a longer time period if the plasma is not immediately initiated. Precautions shall be taken to prevent incidental exposure to both direct and reflected beams.
Specular (mirror-like) laser beam reflections can inflict instantaneous and permanent severe eye and skin damage.
Exposure to laser light can inflict severe retina and/or cornea injuries, leading to permanent eye damage. Some laser light, including the welding, cutting, or cleaning beam (e.g. nm), is invisible. Laser safety eyewear is designed to protect against direct, reflected, scattered laser beams and radiation. Follow the equipment manufacturer’s recommendations for the appropriate wavelength and optical density (OD) of protective eyewear. Always inspect eyewear for damage or improper fit before use. Direct beams are the most hazardous. Depending on the power level of the laser beam, laser safety eyewear is designed only to protect from incidental (i.e., very brief) direct and reflected beams. Never look directly into a laser aperture, even if wearing full eye protection. Never point the torch at another person.
In addition to laser safety eyewear, the user shall wear a laser welding helmet. It is important to understand that standard safety eyewear and standard welding helmets do not provide adequate protection from laser beam hazards.
Exposure to infrared (IR) and ultraviolet (UV) light radiation, as well as heat and sparks, can cause injury to the skin. All persons in the LCA shall wear all appropriate PPE. Exposure to UV light and from the plasma (the bright light created during welding) can cause sunburn and increase a user’s risk of skin cancer and accelerated signs of skin aging.
Highly reflective metals can produce hazardous reflected beams by “specular” (mirror-like) — Fig. 1. The intensity of the reflection will vary based on the material type and surface finish. Also, very thermally conductive metals (e.g., aluminum and copper) can cause some portion of the laser beam energy to be reflected from the target weld site since the plasma ignition is delayed (Fig. 1). Once the plasma is initiated, specular reflection is minimized. The user needs to assess the work site prior to using the hand-held laser welding equipment to understand the surfaces where hazardous reflected beams can exist. This assessment shall include a complete review of the LCA.
The normal direction of the laser reflection from a metal surface can produce a hazardous beam reflected from one surface of the targeted weld site — Fig. 2, Detail A.
Additionally, the normal direction of the laser reflection can produce a hazardous beam reflected back from two surfaces oriented at an angle (termed a “retroreflection”) — Fig. 2, Detail B.
Specular reflections can present eye and skin hazards to the operator as a portion of the beam can be reflected from multiple surfaces.
Read and follow all labels and the equipment Owner’s Manual before installing, operating, or servicing handheld laser welding equipment. Follow all standards, individual facility or building regulations, and national, state, and local codes.
Have only qualified persons install, operate, maintain, and repair handheld laser welding equipment.
Users shall ensure handheld laser welding equipment incorporates important built-in safety features required for all Class 4 laser products as follows:
Users of handheld laser equipment should consider additional safety features as required in ISO -1, an international safety standard for handheld lasers, to protect operators and bystanders, including the following:
Provide an LCA for each point of use, including demonstrations. An LCA is a light-tight enclosure with laser-blocking panels, an access door with an interlock switch, and a “Laser On” warning sign. Any barriers or windows used in the welding area shall be made of a laser-safe material that can withstand direct and reflected beams.
Appropriate laser warning signs shall be posted throughout the controlled area, especially any entrances to and from the area.
Restrict access to the LCA only to those individuals who are trained in laser safety while operating a laser.
See OSHA, Technical Manual (OTM), Section III: Chapter 6, Laser Hazards (osha.gov).
Each organization shall have a qualified LSO who is responsible for the safety of operators and observers, which includes but is not limited to:
1. American Conference of Governmental Industrial Hygienists (ACGIH). TLVs and BEIs: Based on the Documentation of the Threshold Limit Values for Chemical Substances and Physical Agents & Biological Exposure Indices. (acgih.org).
Link to Yinglai
2. American Welding Society. ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes. (aws.org).
3. American National Standards Institute. ANSI Z87.1, Safe Practice for Occupational and Educational Eye and Face Protection. (ansi.org).
4. American National Standards Institute. ANSI Z136.1, Safe Use of Lasers. (ansi.org).
5. American National Standards Institute. ANSI Z136.9, Safe Use of Lasers in Manufacturing Environments. (ansi.org).
6. Canadian Standards Association. CSA W117.2, Safety in Welding, Cutting, and Allied Processes. (csagroup.org).
7. Henrichsen, M., Schwarz, B., Ritt, G., Azarian, A., and Eberle, B. . Laser safety assessments supported by analyses of reflections from metallic targets irradiated by high-power laser light. Applied Optics 60(22): F71–F87.
8. International Electrotechnical Commission. IEC -1, Safety of laser products – Part 1: Equipment classification and requirements. (webstore.iec.ch/publication/).
9. International Organization for Standardization. ISO -1, Safety of machinery — Laser processing machines. Part 1: Laser safety requirements (iso.org/standard/.html).
10. International Organization for Standardization. ISO -2, Safety of machinery — Laser processing machines. Part 2: Laser safety requirements for hand-held or hand-operated laser processing machines. (iso.org/standard/.html).
11. Laser Institute of America. Questions that an OSHA Inspector May Ask You about Laser Safety Fact Sheet. (assets.lia.org/s3fs-public/pdf/OSHAquestions_.pdf).
12. National Fire Protection Association. NFPA 51B, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work. (nfpa.org/codes-and-standards/nfpa-51b-standard-development/51b).
13. Occupational Safety and Health Administration. OSHA .177 Title 29, Subpart N, Part Subpart Q, and Part , Subpart J, Occupational Safety and Health Standards for General Industry, Occupational Safety and Health Administration, Code of Federal Regulations (CFR). (osha.gov).
14. Occupational Safety and Health Administration. OSHA .10 Title 21 Code of Federal Regulations (CFR) Chapter I, Subchapter J, Laser Products, Occupational Safety and Health Standards for Food and Drugs, Occupational Safety and Health Administration, Code of Federal Regulations (CFR). (osha.gov).
15. Occupational Safety and Health Administration. OSHA, Technical Manual (OTM), Section III: Chapter 6, Laser Hazards. (osha.gov).
How long will my glasses protect me?
There is no simple answer to this question. Some glasses are worn-out after only one year, while others look like new after four years. This depends on several factors such as careful treatment, proper care, and environmental factors. A pair of glasses that are treated with care, cleaned according to instructions and used in a laboratory setting will certainly outlast a pair of glasses that are treated carelessly and perhaps even worn by several different people in a rough production environment.
Glasses that show any damage whatsoever (e.g. a damaged or scratched filter, colour changes in the filter, damaged metal enforcement of the frames) should not be used. If you are in doubt, please contact our technical support for a safety inspection of your glasses.
Instructions for cleaning and disinfecting laservision laser safety eyewear to download
Can you repair laser safety glasses?
Of course laservision repairs its own frames and replaces damaged filters. Please contact laservision or one of our customer representatives by , fax or mail for details.
Why is the beam diameter so important for the calculation of the protection level?
This has to do with the resistance time the filter will withstand a direct hit. It is necessary to calculate the damage threshold – which is the highest value that the material can withstand. The unit is power or energy density, i.e. the power or energy per square metre. For this calculation the pulse energy or average power of the laser and the beam area is needed. Without the diameter it is neither possible to calculate the beam area nor the energy or power density. Therefore it is impossible to know what the filter has to withstand in case of a direct laser hit.
Can I see the laser beam with the glasses?
The laser beam itself cannot be seen; what might be seen by visible laser wavelength is mostly the spot where the laser beam hits an object or some scattered light from dust in the air. Laser safety eyewear is usually designed as full protection eyewear (EN 207). Such filters protect against laser radiation of the specified wavelength or wavelengths ranges and absorb or reflect the beam completely. So the beam spot even of visible laser radiation is not visible anymore. If it is still visible, this would mean that the protection level of the glasses is not high enough, or that secondary radiation (at a different wavelength) is generated. Please check carefully whether the marking of the lasersafety
eyewear matches the requirements of the laser.
The protection of carefully selected eyewear will remain stable when hit by the laser throughout a minimum period of 10 seconds and 100 pulses under standardised conditions. Nevertheless, it is under no circumstances advisable to look into the beam directly.
What can I do when I have to align my visible laser? Do I have to put down my glasses?
Never put down your laser safety glasses when working with lasers above class II. There are so called alignment glasses available for this purpose, (acc. to EN 208 for 400 – 700 nm only). These filters are suitable for aligning lasers which emit dangerous radiation in the visible spectral range. Alignment filters do not absorb or reflect the laser radiation completely. The radiation is only reduced to values below 1mW for continuous wave lasers (see laser class 2). It must be taken care, that the average power of the laser does not exceed the power (R – protection level) given on the glasses.
Can I look right into the laser beam with my laser safety glasses?
Laser safety glasses are designed to protect your eyes against an accidental direct hit of the laser beam. They are not designed for long-term or intra beam laser viewing conditions. A properly selected pair of glasses will protect you under standardised conditions against a direct look into the laser, but only for minimum 10 seconds/100 pulses.
You have quoted red filters. Can I have the glasses with a different colour?
The colour of absorption filters cannot be chosen at random, but depends on the wavelength the filters protect against. To protect against wavelengths in the UV-region or the lower visible (blue radiation), a yellow or orange filter is usually offered. A red filter is usually used to protect against wavelengths in the green region. Please take into consideration that you may not select glasses by the colour. Always make sure that the quoted or available pair of glasses matches the requirements of your laser.
Pure coated filters (interference structure on clear substrates), do not affect the colour recognition and possess a high daylight transmission additionally.
I have a pair of glasses (e.g. for a Nd:YAG Laser). Can I use them for my new laser as well?
Before this question can be answered you must determine the specific requirements of your new laser (wavelength, operational parameters, viewing conditions, etc) and calculate the protection level according to the EN 207/208 standard. When these parameters are known, verify that the marking on your existing pair of glasses matches these requirements. If you are not sure, please call us. We will carry out the calculation and check for you.
Please note: The thoughtless use of a pair of laser safety glasses for a different application (different wavelength or different power/energy than calculated before) may cause the loss of your eyesight.
Why is there no pair of glasses covering all my lasers?
The radiation that is visible to humans lies between 380–780 nm (the exact limits are different in each person). In order to cover all lasers you would need a material that does not transmit any radiation for visible radiation, which means it is completely black. When you block all visible radiation, the only wavelengths left are invisible to the human eye. If you have several lasers in this area, then it is necessary to use several pairs of glasses.
But even if you do not want to completely block all wavelengths or have ’just a few wavelengths‘ to cover, the glasses may be too dark. Usually the protection within a material slowly increases spectrally until it reaches the required protection level at a given wavelength. This means that it not only covers the required wavelength but also areas below and above it (with lower Optical Density). Therefore, if you want to cover several wavelengths in the visible spectrum the Optical Density curves will overlap resulting in dark filters or glasses.
Do you have laser safety glasses with “Class 4”?
If you are looking for more details, kindly visit Laser Vision Sensor for Special Welding Machine.