All lasers should be classified according to the British Standard BS EN 60825-1:2014. If this isn't possible, it's sufficient to refer to a separate (i.e. ANSI Z136) or older (i.e. pre-2002) classification system when completing risk assessments, but individuals using lasers classified under a separate system must be suitably trained in the different classifications.
Lasers and laser products supplied by manufacturers from within the EU will be classified according to the British Standard BS EN 60825-1+A11:2021. Departments who make lasers or obtain lasers from non-EU suppliers must ensure they're properly classified and meet all relevant European Standards.
This is a complex matter and although the use of commercially available software can be used as an aid to classification (LaserBee software is available via the University Safety Office), departments may need to obtain external assistance to ensure the full requirements of BS EN 60825-1 and other standards are met.
Descriptions of all classes of lasers, according to BS EN 60825-1 |
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Class 1 |
Laser products, which are safe under reasonably foreseeable conditions of operation, either because of the low emission of the laser itself, or because of its engineering design such that it is totally enclosed and human access to higher levels is not possible under normal operation.
Note: If access panels of a totally enclosed system are removed for servicing etc. then the laser product is no longer Class 1 and the precautions applicable to the embedded laser must be applied until the panels are replaced. It is important that when such systems are installed in open areas, the potential for this should be considered prior to first installing the system. |
Class 1M |
Laser products emitting in the wavelength range 302.5 nm to 4000 nm, whose total output is in excess of that normally permitted in Class 1 laser products but because of their very low power density, large beam diameter, or high divergence does not pose a hazard in normal use. However, they may be hazardous to the eyes under certain conditions if gathering optics (e.g. binocular, telescope, and microscope lens) are used with them. |
Class 1C |
Any laser product which is designed explicitly for contact application to the skin or tissue, but the ocular hazard is prevented by engineering means (i.e. it must be in contact with the skin to enable the laser radiation to be emitted) and through following the instructions provided with the product. |
Class 2 |
Lasers that only emit visible radiation (i.e. 400 nm to 700nm) and whose output is such that they are safe for accidental viewing because a person’s natural aversion response (i.e. blink reflex, moving head) provides adequate protection under reasonably foreseeable conditions. |
Class 2M |
Lasers that only emit visible radiation (i.e. 400 nm to 700nm) and whose total output is in excess of that normally permitted in Class 2 laser products but because of their very low power density, beam diameter, or high divergence does not pose a hazard for accidental viewing due to the aversion response. |
Class 3R |
Lasers that emit in the wavelength range from 180 nm to 1 mm where direct intrabeam viewing is potentially hazardous but the risk is lower than for Class 3B lasers. |
Class 3B |
Lasers that are normally hazardous when direct intrabeam exposure occurs (i.e. within the Norminal Ocular Hazard Distance (NOHD), which is the distance within which the beam irradiance and radiant exposure will exceed the appropriate MPE). Viewing diffuse reflections is normally safe, but exposure to specular/mirror reflections could be a significant risk. |
Class 4 |
High power lasers that are not only a serious risk to the eyes, but may also cause skin injuries. Even diffuse reflections may be hazardous. They constitute a fire hazard and can cause hazardous fumes to be produced. |