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European & Australian / NZ Laser Safety Standards
An Overview of Laser Classification System in EN 60825-1, IEC 60825-1 and AS/NZS 2211.1:2004
In 2001 the standard governing the safety of laser products in Europe (EN) and Internationally (IEC), was substantially revised and the Classification system was overhauled. This resulted in the introduction of three new laser classes (1M, 2M and 3R) and the abolition of Class 3A. Below is a brief description of each of the current laser classes.
The 60825-1 standards apply equally to lasers and LEDs. In most places we have used the word "laser", but it can be replaced by "LED". Generally speaking LEDs would be in the lower Classes (1, 1M, 2, 2M, 3R), but very exceptionally may be Class 3B. At the time of writing we are not aware of any Class 4 LEDs*.
The phrase "eye-safe" is used below. Please note that "eye-safe" is applicable to the whole optical spectrum from 180nm to 1mm wavelength, not just in the retinal hazard range of 400nm to 1400nm. Outside the retinal hazard range there is potentially a hazard to the cornea. A wavelength outside the retinal hazard range is therefore not automatically eye-safe!
Class 1
Lasers that are safe under reasonably foreseeable conditions of operation, including the use of optical instruments for intrabeam viewing. laser safety glasses are not required for this Class.
Class 1M
Lasers emitting in the wavelength range from 302.5nm to 4,000nm which are safe under reasonably foreseable conditions of operation, but may be hazardous if the user employs optics within the beam. Two conditions apply:
a) for diverging beams if the user places optical components within 100mm from the source to concentrate (collimate) the beam; or
b) for a collimated beam with a diameter larger than the diameter specified in table 10 for the measurements of irradiance and radiant exposure.
Classes 1M and 2M broadly replace the old class 3A under IEC and EN classification. Prior to the 2001 amendment there were also lasers which were Class 3B but were eye-safe when viewed without optical instruments. These lasers are Class 1M or 2M under the current Classification system.
In general laser safety glasses are not required to be worn for Class 1M lasers although in some circumstances it may be recommended.
Class 2:
Lasers that emit visible radiation in the wavelength range from 400nm to 700nm where eye protection is normally afforded by the 0.25s blink reflex. This reaction may be expected to provide adequate protection under reasonably foreseable conditions of operation including the use of optical instruments for intrabeam viewing. (NOTE: Outside the wavelength range from 400nm to 700nm, any additional emissions of Class 2 lasers are required to be below the AEL of Class 1).
Laser safety glasses are not required to be worn with Class 2 lasers.
Class 2M:
Lasers that emit visible radiation in the wavelength range from 400nm to 700nm where eye protection is normally afforded by aversion responses including the 0.25s blink reflex. However, viewing of the output may be more hazardous if the user employs optics within the beam. Two conditions apply:
a) for diverging beams if the user places optical components within 100mm from the source to concentrate (collimate) the beam; or
b) for a collimated beam with a diameter larger than the diameter specified in table 10 for the measurements of irradiance and radiant exposure.
(NOTE: Outside the wavelength range from 400nm to 700nm, any additional emissions of Class 2 lasers are required to be below the AEL of Class 1).
In general laser safety glasses are not required to be worn for Class 2M lasers although in some circumstances it may be recommended.
Classes 1M and 2M broadly replace the old class 3A under IEC and EN classification. Prior to the 2001 amendment there were also lasers which were Class 3B but were eye-safe when viewed without optical instruments. These lasers are Class 1M or 2M under the current Classification system.
Class 3R:
Lasers that emit in the wavelength range from 302.5nm to 10mm where direct intrabeam viewing is potentially hazardous but the risk is lower than for Class 3B lasers, and fewer manufacturing requirements and control measures for the user apply than for Class 3B lasers. The accessible emission limit is within five times the AEL of Class 2 in the wavelength from 400nm to 700nm and within five times the AEL of Class 1 for other wavelengths.
Radiation in this class is considered low risk, but potentially hazardous. The class limit for 3R is 5x the applicable class limit for Class 1 (for invisible radiation) or class 2 (for visible radiation). Hence CW visible lasers emitting between 1 and 5 mW are normally Class 3R. Visible class 3R is similar to class IIIA in the US regulations.
It is recommended that laser safety glasses should be worn for Class 3R lasers.
Class 3B:
Lasers that are normally hazardous when direct intrabeam exposure occurs (i.e. within NOHD).
Radiation in this class is very likely to be dangerous. For a continuous wave laser the maximum output into the eye must not exceed 500mW. The radiation can be a hazard to the eye or skin. However, viewing of the diffuse reflection is safe.
Laser safety glasses are required to be worn for Class 3B lasers.
Class 4:
Lasers that are also capible of producing hazaedous diffuse reflections. They may cause skin injuries and could also constitute a fire hazard. Their use requires extreme caution.
Laser safety glasses are required to be worn for Class 4 lasers.
Any laser product of a given Class may contain 'embedded' lasers which are greater than the Class assigned to the product, but in these cases engineering controls (protective housings and interlocks) ensure that human access to radiation in excess of product Class is not possible. Notable examples of this are CD and DVD players which are Class 1 laser products while containing Class 3R or Class 3B lasers and laser printers which are Class 1 laser products but contain Class 4 embedded lasers.
Note:- for a product to be classified correctly, it must be tested at the maximum output accessible under reasonably foreseeable single-fault conditions (eg in the drive circuitry). A non-M class product must pass both Condition 1 and Condition 2 of Table 10 in IEC/EN 60825-1, and an M-class product (which by definition has failed either Condition 1 or 2) must pass the irradiance condition in the same table.
* Generally speaking lasers are point sources while LEDs are extended sources. Extended sources have higher power limits than point sources for a given laser Class. Therefore a visible LED emitting 10 mW may be Class 2, while a visible laser pointer of the same power would be Class 3B. NB Laser pointers above Class 2 are banned for sale to the public by trading standards.
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