Overview of laser safety

Laser welders are a game changer for fabrication, but they do require extra safety measures compared with arc welding.  Laser welders use fiber laser at the Nd:YAG wavelength, which is dangerous for our eyes. Correct laser eyewear is  required for safe use. Most fiber lasers output high powered “near infrared” light, meaning our eyes take it in and treat it like visible light, but we cannot see it, and unprotected eyes can be damaged by it. This section explains the eyewear and safety measures required for safe use.

Hazards such as fire, electrical, asphyxiation and their respective control measures are also covered below.

Laser welders have zero or minimal spatter, so burns and fires from spatter are unlikely.  They also produce a smaller heat affected zone, so metal fume is less of a risk than arc processes such as MIG, TIG or stick welding. However a laser welder’s reflected rays can still be strong enough to start fires.

UV production is much less with a laser welder, only coming from the white hot metal being welded. However there is a risk of a reflected ray causing heat burns, particularly from welding aluminium or reflective metals. Gloves are also necessary.  A direct reflection hitting a finger at close range burns instantly, and hurts at least as much as a burn from arc welding.

Laser Safety Glossary – Terminology & Abbreviations

MPE or maximum permissible exposure.

This value represents the highest dose amount and duration of laser radiation to which a person may be exposed without hazardous effects to the eye or skin.

OD or optical density of laser eyewear

The numeric OD value must be marked on the lens or frame and represents the attenuation factor of the filter to the base of ten. For example, OD two attenuates the beam by ten to the power of two or 100, meaning one percent of the laser light is passed to the eye.

NOHZ or nominal ocular hazard zone.

This is the distance within which the direct, reflected, or scattered light is above the allowed intensity for eye safety. i.e. How far away you must be from the laser before laser glasses are not required. For a fiber laser welder this can be up to a few hundred yards. Note that the welding laser “beam” is a cone, not a parallel-sided beam, so it does diverge. This divergence across a long distance means the laser beam becomes weaker, following the inverse square law (double the distance means a quarter of the power).

IR or infra red

Laser welders are commonly fiber laser based and operate in the near infrared spectrum, meaning above red in the rainbow, but the emissions are unable to be seen.

Compliance

Safety is regulated by The American Compliance National Standard Institute with their standard ANSI Z136.1 and the Occupational Safety and Health Administration or OSHA. Laser products must also meet the US code of federal regulations or CFR, which is usually covered by the Food and Drug Adminstration or FDA. Other requirements may come from CE/IEC for Europe (increasingly accepted in the US for things such as laser eyewear EN207), CSA in Canada, and TUV or UL guidelines.

To ensure that you understand all the potential hazards on your particular system, refer to the safety section of the operator’s manual that shipped with your system.

Interlocks

Interlocks are a critcal part of the safety design of your laser welder.  We have two main interlocks:

  • Trigger interlock:  The laser cannot fire unless the head is in electrical contact with the red earth clamp.  This earth clamp is only for sensing the head contact.  NOTE:  If the head is rested or sat on the metal table or workpiece, this interlock is overcome, and the head can fire if the gun slides or falls, or the trigger is bumped.  This is dangerous, so take care to have a secure place to rest the gun, such as an insulated gun holder or place not on the work bench.
  • Door interlock:  Our laser welders have two wires which must be shorted to enable the welder.  These must be run to a switch on the door to the enclosure.  When the door starts to open, the switch opens and stops the laser from firing.  Most of our welders also have two wires which can power a sign which says “DANGER – LASER ON” when the laser system is turned on and therefore could be in use. See our flashing LED sign in the shop section.

Safety is regulated by The American Compliance National Standard Institute with their standard ANSI Z136.1 and the Occupational Safety and Health Administration or OSHA. Laser products must also meet the US code of federal regulations or CFR, which is usually covered by the Food and Drug Adminstration or FDA. Other requirements may come from CE/IEC for Europe (increasingly accepted in the US for things such as laser eyewear EN207), CSA in Canada, and TUV or UL guidelines.

To ensure that you understand all the potential hazards on your particular system, refer to the safety section of the operator’s manual that shipped with your system.

Light & Wavelengths of electromagnetic radiation

Light from the sun is comprised of many different wavelengths, from ultraviolet to infrared. Laser light is unique because all the light is at one wavelength (think of it as a colour) and it is very concentrated. Most lasers operate in the ultraviolet, visible or infrared spectrums. Ultraviolet or UV light consist of wavelengths between 100 and 400 nm (nanometers). Then we move into visible light, which consists of wavelengths in the region of 380 to 780 nm. Beyond visible light we have near infrared (IR) starting at 780 nm, and far infrared extending to a long wavelength of 1 mm.  Our laser welders operate in this near IR band, usually in the range 1064 to 1085nm.

Laser Classification

Lasers are classified as Class one to four, based on how dangerous they are. The main categories are

  1. Class i or 1 products represent no hazard during normal use.
  2. Class ii or 2 represents visible lasers up to 1mw of output power, such as red laser pointers. Our blink reflex is considered to close the eye if exposed to the laser, so 1mW won’t result in eye injury.
  3. Class iii or 3 represents visible lasers with a power range of 1 to five mW.
  4. Class iv or 4 lasers are the highest hazard level.  Eyes are damaged by direct exposure or reflections.   Fire hazard at close range.

Most are hazardous if the eye is exposed directly but diffuse reflections on matte surfaces are far less harmful, as the reflected light is partially absorbed, while the remainder is scattered and less intense.  Dark colours like black absorb the most laser radiation, in general, so back stops should be black and have no reflective surfaces such as bare aluminum or copper.

Note that any laser product can be classified as class one (totally safe) if an enclosure or room with a door interlock is used to reduce the output outside the room to class one levels. This allows a fiber laser to safely be used in a production facility

Red fibre laser glasses
Fibre laser glasses by Laser Welder Company

Eye Protection from lasers

Laser exposure for only a fraction of a second could cause permanent eye damage including blindness. The most dangerous wavelengths for eyes are the ones that are focused (read concentrated/multiplied) onto the retina in the same way as visible light. This “ocular” range includes both visible and near infrared light which is 400 to 1400 nm wavelength. Laser welders usually emit wavelengths in the range 1064 to 1085nm, so are in the dangerous category.

Know More

Laser Safety Glasses, Protective Eyewear & Clothing

Light from the sun is comprised of many different wavelengths, from ultraviolet to infrared. Laser light is unique because all the light is at one wavelength (think of it as a colour). Most lasers operate in the ultraviolet, visible or infrared spectrums. Ultraviolet or UV light consist of wavelengths between 100 and 400 nm (nanometers). Then we move into visible light, which consists of wavelengths in the region of 380 to 780 nm. Beyond visible light we have near infrared (IR) starting at 780 nm, and far infrared extending to a long wavelength of 1 mm.

Laser safety glasses and laser welding helmets

Laser safety glasses only protect you from the wavelength they are designed to block. There is no such thing as laser glasses that work for all lasers. They have to match the laser beam’s wavelength, and attenuate the incoming laser light by around a factor of one million (10^6, or OD6).  In the worst case of a direct reflection at close range they must also be resistant enough not to be burnt through or shatter.

All laser protection eyewear must be clearly labelled with the wavelength range they provide protection for.

ANSI vs CE eyewear standards

ANSI Z136.1 covers laser eyewear safety in the USA, while EN207 covers Europe or CE countries. Both standards are similar and should protect you well. These standards require that laser safety eyewear is marked with the wavelength/s they cover, and OD (optical density) or attenuation factor at that wavelength. There are also “direct hit” resistance requirements, to make sure they withstand several seconds of direct laser impingement without being penetrated. However your face is also sensitive to laser and in practice, a laser welding helmet is required.

Wear a laser welding helmet over your glasses

Laser-welder.net and most other authorities on laser welding safety (IPG, Weld Australia and laser-welder.com.au for example) recommend wearing laser glasses AND a welding helmet to provide full protection during laser welding. Part of the rationale is that even if you forget to flip your helmet down, or forget to put your glasses on, the other protective eyewear will have sufficient protection for most welding.

Laser welding helmets – what to look for

Left side of white laser welding helmet
Laser welding helmet LHS view

ARC welding helmets have inherent filtering of UV and IR light. Based on our testing with fiber lasers some filters are OK, and better than many laser glasses at filtering 1064 to 1085 nm. However, such helmet bodies are made from cheap black plastic with a low melting point. This is a bad combination, meaning they absorb a lot of IR, and are melted by it, As such they are not resistant to strong direct reflections. Rather than risking face burns or a damaged helmet, we recommend using a laser welding helmet rated for such strikes including the lens filter area, such as our new model (which must be worn with laser glasses in the same way as IPG’s welding helmet). 

Check out our new Mk2 laser welding helmet.

 
Know More

We have done extensive testing of many laser glasses, welding helmets and filters. In addition to the standard OD (attenuation) tests, this was done to the EN207 laser resistance standard, that results in an LB rating. The simplest way to explain this is: During LB testing the eyewear is exposed to the worst case impact (highest power and smallest beam size, meaning closest range when welding). In my opinion this is a very severe test, but by passing that we can sleep soundly knowing users are safe. The test time is 5 seconds, which is plently because it is difficult to keep the beam in one spot for that long when welding.  For some safety wear the impact results in a VERY bright glow at the impact site as the eyewear starts being penetrated.  This is bad for degradation, but good for warning, as the blink reflex kicks in as the eye’s self defence mechanism, and you would stop welding or move your head in less than 5 seconds.

The blink reflex is used in setting laser standards to account for a reduction in danger. It hasn’t been discussed with IR lasers because IR itself is invisible. However super bright flaring from a high intensity laser strike (on eyewear rated to block it) will definitely make you blink.  This certainly makes them safer than the standard would normally say, which adds two extra margins of safety in the real world (blinking and also releasing the trigger quickly). However, note that some filters shattered very quickly, going from offering reasonable protection to zero protection. This would be catastrophic for a user’s eyes, and is a strong reminder to only use properly developed and rated laser eyewear for your application. These shattering lenses were glass types.  Because of this, fixed shade arc welding glass filters are NOT to be used for laser welding.

Assistants must wear laser welding helmets too

All personnel working near welder or in the laser welding enclosure must also wear laser safety eyewear, a welding helmet, and protective clothing. This is especially true for anyone assisting the welder, or otherwise close to the welding and at risk of reflections.

A welding helmet can also protect the welder from sparks and spatter, although lasers produce much less of this than an MIG.

Man wearing laser glasses with arc welding helmet lifted up
Wearing laser glasses with arc welding helmet lifted up

Only buy laser PPE from reputable sellers

Laser-welder has purchased and tested dozens of laser glasses. We found a high percentage of the ones on Aliexpress, ebay and Amazon DO NOT block much, if any, and are NOT as advertised. Only purchase laser safety eyewear from reputable sellers in the USA, Europe and Australia that claim to suit your application.

1

Do not use IPL or surveying laser glasses

IPL glasses are for intense pulsed light, and do very little to attenuate fiber lasers. Likewise for surveying and similar “laser glasses”.

2

Do not use damaged laser glasses

Some laser glasses have coatings. If the coating is scratched or worn they will not protect you, so be sure to destroy and replace any with damage.

Green laser glasses with EN207 markings showing OD and LB ratings
EN207 fibre laser glasses markings for OD and LB

Always check the glasses have at least the correct optical density.  OSHA requires OD8 or numerically higher for fiber laser welders covering 1064 to 1085nm at least).

We recommend EN207 “D LB8” or higher, which is superior to OD8 because EN207 includes a penetration test. 

You need a system to avoid someone putting on the wrong glasses, such as sunglasses.  This requires clear colour coding or labelling together with an instruction. For this reason our laser glasses are RED and clearly rated.

If you have multiple lasers with different wavelengths (universities for example), you will need a system to make it clear which eyewear is for which laser.

Know More

Laser resistant clothing and gloves

White leather gloves are mandatory hand protection. White is the most reflective colour, so most of the energy won’t heat up the glove. At the very least one must be worn on the non-welding hand, as that will experience frequent reflections. Reflections are still quite hot through the leather, but your hand should not be burnt.

Clothing should be flameproof same as for any welding process, and we recommend heavyweight, tightly woven, 100% wool or cotton. White is also nice in theory, but not essential.  We have not experienced reflected rays affecting our clothes, but your welding and reflections may be different.  Copper for example.

Click to Know More!

Avoid reflective jewelry

Watches and jewelry can reflect laser beams and scatter them into unintended areas, risking eye or skin injury. Arc welders don’t wear these things for reasons of electrical safety. Follow the same principles, but for a different reason.

Chemical & Asphyxiation Hazards

Although it produces less than arc welding, laser welding can still cause hazardous particulate and gaseous by-products. Vaporized metal and coatings can create hazardous fumes and vapors that can lead to asphyxiation if in a closed environment. Shielding gases displace oxygen, so a large leak of shielding gas in an enclosed area can also be hazardous.

Good ventilation is required, similar to other welding processes.

Fire Hazards

The biggest risk of fire is from reflections striking flammable items nearby. Remove fuels and aerosol cans from the area. Back stops and barriers should be fire retardant, ideally concrete or metal.  Inspect for damage regularly. Keep a fire extinguishing device near the laser equipment.

Electrical Safety

Black metal plate and breaker to UL 50 and UL 1077
Breaker area to UL 50 and UL 1077
  • Your laser welder should be made up of CE/IEC and/or UL listed or UL registered (UR) components, particularly at touch points.
  • The breaker area should be designed in accordance with UL50 for the USA.
    Breakers in the laser welder should meet UL 1077 or UL489 for the USA. For CE the IEC standard number is IEC 60947 or 60898.
  • The power supply circuit in the factory’s fuse box should be protected by a UL489 circuit breaker and an industrial Ground Fault Circuit Interrupter or GFCI with less than 30mA trip threshold. This is now law in some countries.
  • Some Chinese laser sources are not electrically safe, such as Raycus and at least one other having the mains power connections directly under the cooling water connection which can leak. Our laser sources are designed to avoid such basic safety errors. Water and electricity don’t mix

Compressed shielding gas safety

Laser beams striking the shielding gas cylinder or regulator could cause rapid release of high pressure gases. Keep the cylinder clear of the welding area and direct reflections, or shield it.

Administrative Control Measures & Standard Operating Procedures

Some administrative control measures are required to conform to safety regulations. A laser safety officer or LSO understands and implements the risk management measures such as:

  • Assuring the availability of protective eyewear at the entrance to a laser area.
  • Installing warning signs
  • Installing laser windows so workers can be observed
  • Fitting a warning light on the door/s of laser rooms or enclosures
  • Writing standard operating procedures to include safety measures such as knocking on the door loudly
  • Periodic checking of safety features
  • Ensure there is good lighting.

Warning signs required for laser welding

Laser welders are Class IV and require several labels according to CFR 21 section 1040.10, including this FDA version label:

(FDA-DANGER-label-2kW-1075nm-CW)

Or labels in compliance with IEC 60825.1

If the welding room or enclosure does not have an interlock, it requires a label stating:
DANGER – Laser radiation when open. AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION.