Laser Safety Europe, Australia & NZ

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 glassesare 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 glassesare 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.

Below is a table showing the meaning of the different Classes of Lasers and LEDs according to the current to the version of EN 60825-1 and IEC 60825-1. Class 1 Safe. Class 1M Safe provided optical instruments are not used. Class 2 Visible lasers. Safe for accidental exposure (< 0.25 s). Class 2M Visible lasers. Safe for accidental exposure (< 0.25 s) providing optical instruments* are not used. Class 3R Not safe. Low risk. Class 3B Hazardous. Viewing of diffuse reflection** is safe. Class 4 Hazardous. Viewing of diffuse reflection is also hazardous. Fire risk. Glossary CW Continuous Wave - i.e. not pulsed Diffuse reflection the reflection of radiation from a matt surface such as a wall Extended source having an apparent source size with angular subtense of greater than 1.5 mradian Optical instruments binoculars, telescopes, microscopes, magnifying glasses (but not prescription glasses) Point source having an apparent source size with angular subtense of less than 1.5 mradian