Laser Classifications

The American National Standards Institute (ANSI) has established a laser hazard classification system in publication ANSI Z136.1-2014, Safe Use of Lasers. Certified laser manufactures are required to label their products as to the class type. Information regarding appropriate eyewear for a specific laser may be obtained from the manufacturer at time of purchase. The following table summarizes this laser classification scheme and the hazard capabilities associated with each class of laser:

Class Hazards
1 Eye safe lasers; may not produce hazardous radiation
2 Continuous intrabeam viewing can cause eye damage; momentary intrabeam exposure (< 0.25 sec) is not damaging to the eye; visible radiation only
2a Continuous intrabeam viewing can cause eye damage; the accessible radiation shall not exceed Class 1 accessible emission limit (AEL) for an exposure duration of 1000 seconds
3R Invisible lasers having an output power < 5x the Class 1 AEL or visible laser having an output power < 5 mW; capable of causing damage through intrabeam viewing, with optical instruments or through viewing a specular reflection for < 0.25 sec
3B Invisible lasers having output power <500 mW; as with 3R lasers, 3B lasers can cause injury through intrabeam viewing, viewing with optical instruments, or through viewing a specular reflection
4 Beam power > 500 mW; intrabeam exposure, exposure to specular- and diffuse reflections capable of causing eye- and skin damage; fire hazard due o their power density