CDRH 21 CFR §1040.10

Class I

Class I laser product means any laser product that does not permit access during the operation to levels of laser radiation in excess of the accessible emission limits contained in table I of CDRH 21 CFR §1040.10 page 614.
Remark:
Class I levels of laser radiation are not considered to be hazardous.

Class IIa

Class IIa laser product means any laser product that permits human access during operation to levels of visible laser radiation in excess of the accessible emission limits contained in table I, but does not permit human access during operation to levels of laser radiation in excess of the accessible emission limits contained in table II–A of CDRH 21 CFR §1040.10 page 615.
Remark:
Class IIa levels of laser radiation are not considered to be hazardous if viewed for any period of time less than or equal to 1000 seconds but are considered to be a chronic viewing hazard for any period of time greater than 1000 seconds.

Class II

Class II laser product means any laser product that permits human access during operation to levels of visible laser radiation in excess of the accessible emission limits contained in
table II–A, but does not permit human access during operation to levels of laser radiation in excess of the accessible accessible emission limits contained in table II of CDRH 21 CFR §1040.10 page 615.
Remark:
Class II levels of laser radiation are considered to be a chronic viewing hazard.

Class IIIa

Class IIIa laser product means any laser product that permits human access during operation to levels of visible laser radiation in excess of the accessible emission limits contained in table II, but does not permit human access during operation to levels of laser radiation in excess of the accessible emission limits contained in table III–A of CDRH 21 CFR §1040.10 page 616.
Remark:
Class IIIa levels of laser radiation are considered to be, depending upon the irradiance, either an acute intrabeam viewing hazard or chronic viewing hazard, and an acute viewinghazard if viewed directly with optical instruments.

Class IIIb

Class IIIb laser product means any laser product that permits human access during operation to levels of laser radiation in excess of the accessible emission limits of table III–A, but does not permit human access during operation to levels of laser radiation in excess of the accessible emission limits contained in table III–B of CDRH 21 CFR §1040.10 page 616.
Remark:
Class IIIb levels of laser radiation are considered to be an acute hazard to the skin and eyes from direct radiation.

Class III

Class III laser product means anyClass IIIa or Class IIIb laser product.

Class IV

Class IV laser product means anylaser that permits human access during operation to levels of laser radiation inexcess of the accessible emission limits contained in table III–B .
Remark:
Class IV levels of laser radiation are consideredto be an acute hazard to the skin and eyes from direct and scattered radiation.

IEC & EN

Class 1

The accessible laser beam poses no danger under reasonable foreseeable conditions.
Please note:
“Reasonable foreseeable conditions” are maintained during proper use. It is not possible to rule out dazzling, impairment of vision and irritation, for example, with Class 1 laser equipment in the upper power range.

Class 1M

The accessible laser beam has a wavelength of between 302.5 nm and 4000 nm. The accessible laser beam poses no danger for the eyes as long as the beam cross-section is not reduced by light-collecting optical instruments, e.g. magnifying glasses, lenses, telescope, etc.
Please note:
As long as no optical instruments are used that reduce beam cross-section, laser equipment in Class 1M poses a comparable risk to Class 1 laser devices. Risks comparable to Class 3R or 3B may occur if light-collecting instruments are used.

Class 2

The accessible laser beam is in the visible portion of the spectrum (400 nm to 700 nm). It, too, poses no danger for the eyes over short periods of exposure (up to 0.25 s). Any secondary beam components outside the range of wavelengths from 400 nm to 700 nm fulfill the requirements for Class 1.
Please note:
Class 2 laser equipment does not pose any risk to the eyes if randomly exposed to the laser beam for very short periods, i.e. exposures lasting up to 0.25 s. Class 2 laser equipment can therefore be used without auxiliary protective measures if it is guaranteed that use requires neither intentional looking into the light for periods longer than 0.25 s, nor repeated looking into the laser beam or its mirrored reflection. As a rule, it cannot be assumed that the blink reflex to protect the eyes is actually present. Therefore one should deliberately shut one’s eyes or immediately turn away if a Class 2 laser beam hits the eyes.

Class 2M

The accessible laser beam is in the visible portion of the spectrum (400 nm to 700 nm). It poses no danger for the eyes over short periods of exposure (up to 0.25 s), as long as the beam cross-section is not reduced by optical instruments, e.g. magnifying glasses, lenses, telescope, etc. Any secondary beam components outside the range of wavelengths from 400 nm to 700 nm fulfill the requirements for Class 1M.
Please note:
As long as no optical instruments are used that reduce beam cross-section, laser equipment in Class 2M poses a comparable risk to Class 2 laser devices. Risks comparable to Class 3R or 3B may occur if light-collecting instruments are used.

Class 3A

The accessible laser beam has a wavelength of between 302.5 nm and 106nm and is dangerous for eyes. The power or energy has a value at most five times the limit value of the accessible beam in Class 2 between wavelengths of 400 nm and 700 nm, and five times the limit value of Class 1 for other wavelengths.
Please note:
Class 3R laser devices are potentially as dangerous for the eyes as Class 3B laser equipment. The risk of damage to the eyes is reduced by limiting the Accessible Emissions Limit (AEL) in the visible spectrum to five times the Class 2 AEL, and those of the other wavelength ranges to five times the Class 1 AEL.

Class 3R

The accessible laser beam has a wavelength of between 302.5 nm and 106nm and is dangerous for eyes. The power or energy has a value at most five times the limit value of the accessible beam in Class 2 between wavelengths of 400 nm and 700 nm, and five times the limit value of Class 1 for other wavelengths.
Please note:
Class 3R laser devices are potentially as dangerous for the eyes as Class 3B laser equipment. The risk of damage to the eyes is reduced by limiting the Accessible Emissions Limit (AEL) in the visible spectrum to five times the Class 2 AEL, and those of the other wavelength ranges to five times the Class 1 AEL.

Class 3B

The accessible laser beam is dangerous for the eyes and frequently for the skin, too.
Please note:
Looking directly into the beam of Class 3B lasers is dangerous. The accessible laser beams of Class 3B laser devices pose a hazard to the skin if the value of the Maximum Permissible Exposure (MPE) is exceeded.

Class 4

The accessible laser beam is very dangerous for the eyes and dangerous for the skin. Even diffuse emissions can be dangerous. The laser beam can potentially cause fires and explosions.
Please note:
Class 4 laser devices are high-power lasers whose exit powers or energies exceed the Class 3B AEL. The laser beam of Class 4 laser equipment is so intensive that any type of exposure is liable to cause damage to the eyes or skin. Moreover, when Class 4 laser equipment is used it is always necessary to check whether sufficient measures have been taken to prevent the risk of fire and explosions.