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Section III

Laser Classification

Lasers and laser systems are classified based on their capability of injuring personnel.

  1. Lasers manufactured after August 1, 1976 are classified and labeled by the manufacturer. The Principal Investigator shall classify lasers and laser systems that are constructed or modified in the laboratory.
  2. There are five laser hazard classes:
    • Class 1 lasers and laser systems cannot emit accessible levels of radiation that are capable of causing eye injury under normal operating condition. (A more hazardous laser may be embedded in a Class 1 product that is not accessible during normal operating conditions, but may be accessible during service and maintenance.)
    • Class 1M lasers and laser systems refer to lasers with a large diameter or highly divergent beam.  Class 1M lasers cannot emit accessible levels of laser radiation that are capable of causing injury under normal operating conditions, but may be a hazard if viewed through magnifying optics, such as a microscope, eye-loupe or telescope.
    • Class 2 lasers and laser systems are visible lasers with an accessible output ≤ 1 mW. Class 2 lasers and laser systems are incapable of causing eye injury unless intentionally viewed directly for an extended period. The normal aversion response to bright light (blinking) protects the eye from a momentary exposure.
    • Class 2M laser or laser systems refer to lasers with a large diameter or highly divergent visible beam with an accessible output < 1mW.  However, Class 2M is potentially hazardous if viewed with collecting optics such as a microscope, eye-loupe or telescope. 
    • Class 3R (formally 3A) lasers and laser systems have an accessible output between 1-5 mW and do not pose a serious eye hazard unless viewed through optical instruments.
    • Class 3b lasers and laser systems have an accessible output between 5-500 mW for continuous wave lasers and < 0.125 J within 0.25 second for a pulsed laser. Class 3b lasers and laser systems pose a serious eye hazard from viewing the direct beam or specular reflections.
    • Class 4 lasers and laser systems have an accessible output > 500 mW for a continuous wave laser and > 0.125 J within 0.25 second for a pulsed laser. Class 4 lasers and laser systems pose a serious eye hazard from viewing the direct beam, specular reflections and diffuse reflections. Class 4 lasers and laser systems also pose skin and fire hazards.

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