Laser Safety

IPG Photonics supplies our unique line of fiber lasers and amplifiers to systems integrators as well as directly to end-users.  Because IPG provides products to a variety of end users, it is our desire to provide basic information on the topic of laser safety. 

This information is being provided as a service to both our existing customers and perspective customers.  Please see the links at the end of this section for additional sources of information concerning laser safety.

General

Lasers/amplified light sources produce light that does not exist in nature.  A stimulus such as high intensity light is input into a laser cavity and the result is laser emission or light output.  Although the output is light, the laser/ amplified light is much different that sunlight or a light bulb.  Therefore because laser/amplified light has special properties there are often hazards associated during operation and potentially during service. Lasers/amplified light sources produce highly intense monochromatic light which can be visible or invisible to the human eye.  Laser/amplified light is also coherent which means that all of the waves are in phase with each other.  Coherence makes this light much more dangerous than non-coherent light of the same wavelength and intensity.  Collimated beams or beams that do not diverge rapidly as they exit the device aperture have risks that are present even at long distances from the aperture.

Hazards

When considering laser hazards, the most common area of concern is usually the eye.  The information below will not only speak to hazards associated with the eye, but will also touch on other hazards that may be present with the use of a laser product. 

IPG’s diode lasers operate in the 980 nm range, Ytterbium lasers and amplifiers operate at around 1060 nm, Raman lasers and amplifiers operate at around 1400nm, Erbium lasers and amplifiers at around 1550 nm and Thulium lasers and amplifiers operate at around 2000nm.  IPG also provides laser sources below 980nm.

Eye Hazards

Ocular damage can occur from laser exposure. Lasers can damage the eye in different ways depending on the wavelength and output power that the user may become exposed to:

  • Visible (400 to 700nm) and Near-infrared (IR-A, 700 to 1400nm) beams can penetrate the eye and thus cause irreversible damage to the retina, optic nerve and central portions of the eye.  Typically the human eye can resolve light within the wavelength range of 400 to 700nm (violet to red). Unfortunately the eye will also allow wavelengths upwards of 1400nm to penetrate and still pose a significant threat for retinal and optic nerve damage.
  • Invisible beams of wavelengths other than Near-infrared can cause damage to the outer sections of the eye. UV radiation (180 to 400nm) can cause corneal damage as well as damage to the lens. Middle-infrared radiation (IR-B, 1400 to 3000nm) has the potential to penetrate the surface and cause cataracts.  Far-infrared (IR-C, 3000nm to 1mm) can damage the outer surface or cornea.
  • The user should expect the presence secondary beams at various angles. The secondary beams may be at or close to the work surface. These beams are specular reflections of the main beam from various surfaces. Although these secondary beams may be less powerful than the total power emitted from the laser, the intensity may be large enough to cause damage to the eye. This should be taken into consideration when installing laser systems.

Additional Hazards

  • Burns to skin are possible from laser systems. ; The damage potential and severity will very as a function of wavelength and power.
  • Some of the laser systems are components of heavy equipment and they should be operated with a high degree of care to the operator and others that are in the area of the laser.
  • Some lasers are powerful enough to burn clothing, paper or ignite solvents and other flammable substances. This must be considered when using laser systems.
  • Hot or molten pieces of metal may be present when using high power lasers. Exercise caution if debris is being generated in your application.

Electrical Hazards

  • The voltage (both AC and DC) used for laser products are often high.  All electrical cables and connections should be treated as if it were a harmful level. All parts of the electrical cable, connector or device housing should be considered dangerous.

Laser Classification.

In addition to the information provided above about safety, the following is a brief description of laser system classification.  Laser systems are classified by the wavelength and output power the end user may be exposed to during operation.  This could also be described as the hazard potential of the laser system.  The classification is determined by the emission wavelength(s), output power and beam characteristics.

Laser classes start at Class 1 and end at Class 4.  The higher the number in the classification, the greater hazard potential the laser system has.  These laser classifications are identified on the laser system and often Roman numerals are used to identify the class number.  The identification process is accomplished by affixing a label onto the product.  Along with text warnings, these labels include information pertaining to the wavelength, total output power and laser classification.

Class 1
Class 1 laser systems are intrinsically safe.  Under normal operating conditions, these lasers do not pose potential health hazards.  Special design considerations are used to prevent human access to laser radiation during operation.

Class 2
Class 2 laser systems are low power, visible lasers.  The eye’s natural blinking reflex caused by bright light aversion will protect the user.  There are some potential hazards if directly viewed for an extended period of time.  A CAUTION label is required for Class 2 lasers.

Class 3
Class 3a laser systems are also required to have a CAUTION label and on some cases require a DANGER label.  The light aversion reflex should protect the user if only viewed momentarily.  A hazard may be present if viewed with collecting optics such as during an optical alignment process.

Class 3b laser systems can produce a hazard if viewed directly or by viewing secondary beams.  Typically, these lasers will not produce hazardous reflections from a matte surface.  These systems have a DANGER label affixed and although the potential for eye damage is present, the risk for fire or skin hazards is low.  Laser safety eyewear is recommended while using these lasers

Class 4
Class 4 laser systems present hazards to both the eye and skin.  The hazards can be present from direct, secondary and diffuse reflections.  A DANGER label is affixed to all Class 4 laser systems.  Class 4 lasers can also damage materials in or around the laser area and ignite flammable substances.  Laser safety eyewear is required while using these lasers.

IPG Photonics supplies both Class 3b and Class 4 lasers and laser systems to our end-users.
The following list contains items that laser users or prospective users should consider when using laser systems.

  • Please take time to read and understand the User’s Guide and familiarize yourself with the operating and maintenance instructions that have provided before using the product.  If there are any questions or sections that are not understood, do not hesitate to contact the manufacturer.
  • All operators that are in the area must be wearing appropriate laser safety eyewear prior to enabling laser emission.  This would include operators that are not directly using the laser system.
  • Never look directly into the laser output port when the power is on.
  • Set up the laser and all optical components used with the laser away from eye level.
  • Do not install or terminate fibers or collimators when laser is active.
  • Always switch the laser off when working with the output such as mounting the fiber or collimator into a fixture, etc.  If necessary, align the output at low output power and then increase the output power gradually.
  • The interaction between the laser and the material being processes can also generate high intensity UV and visible radiation. Ensure that laser enclosures are in place to prevent eye damage from visible radiation.
  • Ensure that the work surface is properly vented.  The gases, sparks and debris that can be generated from interaction between the laser and the work surface can pose additional safety hazards.
  • Use the laser in a room with access controlled by door interlocks. Post warning signs. Limit access to the area to individuals who are trained in laser safety while operating the laser.
  • Avoid using the laser in a darkened environment.
  • Do not enable the laser without a coupling fiber or equivalent attached to the optical output connector.
  • The operator of the laser is responsible to notify of laser usage and control the laser area.

Protective Eyewear
Laser safety eyewear is labeled with both the optical density and the wavelength coverage range. The optical density, OD, is a parameter of great interest when selecting laser safety eyewear.  The formula for optical density is listed below.

Optical Density =   -1 (Light Transmission)

Tl = 10 -OD

Using the formula above you can see that there is a 10x increase in protection (10x decreases in laser transmission) for each increase in OD.  IPG Photonics recommends that the end user of laser systems review the particular application when assessing eyewear requirements.  It is important to understand the potential hazards associated with or as a result of the end use application.

IPG Photonics recommends that laser users investigate any local, state, federal or governmental requirements as well as facility or building requirements that may apply to installing or using a laser or laser system.

For additional information regarding Laser Safety please refer to the list below, which contains some available information:

Laser Institute of America (LIA)
13501 Ingenuity Drive, Suite 128
Orlando, Florida 32826
Phone: 407.380.1553, Fax: 407.380.5588
Toll Free: 1.800.34.LASER
http://www.laserinstitute.org/

American National Standards Institute
ANSI Z136.1 – 2000, American National Standard for the Safe Use of Lasers
(Available through LIA)

International Electro-technical Commission
IEC 60825-1, Edition 1.2, 2001-08
Safety of laser products –
Part 1: Equipment classification, requirements and user’s guide.
(Available through LIA)

Laser Safety Equipment
Laurin Publishing
Laser safety equipment and Buyer’s Guides
http://www.photonics.com/Directory/