Laser Safey Classification
In 2001, the Safety of Laser Products standard was revised.The revision to the laser classification system has resulted in the introduction of three new laser classifications –
1M, 2M and 3R – and the abolition of Class 3A.
The 2001 revised standard included a letter appended to a number of the laser classifications. The laser classification scheme only deals with the laser beam hazard.
The letter ‘M’ in Class 1M and Class 2M is derived from ‘magnifying’: optical viewing instruments.
The letter ‘R’ in Class 3R, is derived from ‘reduced’ or ‘relaxed’ requirements. The ‘R’ requirement relates to certain equipment and user specifics e.g. manufacturer: no key switch and interlock connector required; user: no eye protection is usually required.
The letter ‘B’ in Class 3B is historical.
Laser safety class |
Laser type |
Potential eye or skin hazard |
|---|---|---|
Class 1(embedded) |
Laser completely enclosed |
Generally safe during use. Hazards according to power of enclosed laser when interlocks are overridden. |
Class 1 |
Very low power level |
Emitted power generally safe for long-term intrabeam viewing, even with optical instruments such as magnifying glasses. |
Class 1M |
Low power level. Collimated large beam diameter or divergent |
Safe for long-term intrabeam viewing, but potentially hazardous with magnifiers (divergent beams) or binoculars (large diameter collimated beams). |
Class 2 |
Low power level Visible wavelengths only |
Safe for brief (accidental) direct exposure with naked eye and optical instruments. Prolonged staring may injure eye, especially blue wavelengths. |
Class 2M |
Low power visible Collimated large beam diameter or divergent |
Safe for brief exposure with the naked eye, but potentially hazardous when exposure occurs with magnifiers (divergent beams) or binoculars (large diameter collimated beams). |
Class 3R(visible) |
Low power Typically alignment lasers |
Accidental exposure usually not hazardous, but eye injury possible for intentional intrabeam viewing |
Class 3R(non-visible) |
Low power |
Accidental exposure usually not hazardous, but eye injury possible for intentional intrabeam viewing. |
Class 3B |
Medium power |
Exposure (including brief accidental exposure) of the eye to the direct beam and close viewing of diffuse reflections may lead to serious eye injuries. May cause serious skin hazard. Presents fire hazard. |
Class 4 |
High power |
Exposure (including brief accidental exposure) of the eye to the direct beam and close viewing of diffuse reflections may lead to serious eye injuries. May cause serious skin hazard. Presents fire hazard. |
The Q-Switch Solid State Nd: YAG Lasers are classified as – CLASS 4
Class 4 lasers may cause skin injury and represent a potential fire hazard. The operation of Class 4 lasers requires the entire beam path be controlled. The laser shall be operated in designated areas where safety interlocks may be used to prevent unexpected entry into the controlled area. Access shall be limited to persons wearing laser protection eyewear.
Class 4 lasers include all lasers with power levels greater than 500 mW cw or greater than 10 J/cm2 for a 1/4-second pulsed system. They pose eye hazards, skin hazards, and fire hazards. Viewing the beam, specular reflections, or exposure to diffuse reflections can cause eye and skin injuries.
