The hazard class of a laser is very important to determine what appropriate controls are needed to make the laser safe. The LSO must assure that all UC Berkeley lasers are properly designated as to their appropriate hazard class. All commercially- manufactured lasers come marked with the hazard class as required under the FDA Center for Devices and Radiological Health regulations. Lasers modified at UC Berkeley must be evaluated by the LSO and appropriately classed. It is the responsibility of the PI to assist the LSO by supplying the appropriate radiometric parameters of the laser system. The campus laser safety program is designed for the oversight of Class 3B and Class 4 lasers only. The most common classes of lasers are as follows:
Class 1 - Exempt
- Output a few microwatts; and
- Beam fully enclosed; incapable of causing eye or skin injury due to enclosure. They may contain a higher class laser embedded within the unit that cannot be accessed in normal operations; and
- Exempt from additional control measures
Example: Laser printers
Class 1M
- Large diameter or divergent beams
- Same as Class 1 except they may be hazardous to view with the aid of optical instruments
Examples: LEDs and bare laser diodes
Class 2 – Low Power Visible
- Output < 1 mW in the visible portion of the spectrum (400-700 nm), and
- Eye protection is normally afforded by the aversion response
Example: Supermarket style bar-code scanner.
Class 2M - medium power visible
These are visible lasers. Same as Class 2 but may be hazardous if viewed with the aid of optical instruments
Class 3R - medium power visible (used to be called Class 3A)
- Output 1-5mW visible range far-infrared and UV; and
- Only a hazard if viewed through optics or for long-duration
- This laser will not pose either a fire hazard or diffuse-reflection hazard
Examples: Laser pointers See Appendix C for Laser Pointer Safety Guidelines
Class 3B - Intermediate Power Continuous Wave or Pulsed - Requires Laser Use Authorization (LUA)
- Output 5-500 mW visible and invisible range; pulsed or continuous wave, and
- May be hazardous under direct and specular reflection viewing conditions, but normally not a diffuse reflection or fire hazard; and
- It is a hazard to the eye or skin from the direct beam and eye protection is required, as well as barriers
Example: Diode pump solid-state lasers used for spectroscopy
Class 4 - High Power Laser - Requires LUA
- Output > 500 mW; and
- A hazard to the eye or skin from the direct beam; it may also pose a diffuse reflection and fire hazard. Eye protection is required, as well as other barriers
- It may also produce laser-generated air contaminants and hazardous plasma radiation
Example: ND:YAG laser used to pump a Ti-Sapphire laser