All lasers should be classified according to the British Standard BS EN 60825-1:2014. If this is not possible, then it is sufficient to refer to a separate (i.e. ANZI 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 (Table 2). Departments who make lasers or obtain lasers from non-EU suppliers must ensure that they are 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 aide to classification (software is available via the University Safety Office), departments may need to obtain external assistance to ensure that the full requirements of BS EN 60825-1 and other standards are met.
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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. |
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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. |
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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 before, and only, when the laser is emitted). |
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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. |
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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. |
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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. |
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Class 3B |
Lasers that are normally hazardous when direct intrabeam exposure occurs (i.e. 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. |
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Class 4 |
High power lasers that do not meet the definition of other lower classes of laser are capable of producing hazardous diffuse reflections. They are not only a serious risk to the eyes, but they may also cause skin injuries. Finally, they constitute a fire hazard and can cause hazardous fumes to be produced. |
