Laser Safety Manual - Appendices and Resources

The template illustrated in the Sample Laser Standard Operating Procedure is to be followed when preparing written laser safety operating procedures (LSOP). A written procedure is to include all lasers in a laser system, including alignment lasers. This LSOP must be reviewed and approved by the LSO.

Title

Laser Safety Manual - Appendices and Resources

Table of Contents

1. Appendix A: Sample Laser Standard Operating Procedure
2. Appendix B: Associated Hazards
   1. Electrical
   2. Chemical
   3. Collateral Radiation
   4. UV and Visible Radiation
   5. Fire
   6. Explosion
3. Glossary
4. References

Appendix A: Sample Laser Standard Operating Procedure

The template illustrated in the Sample Laser Standard Operating Procedure is to be followed when preparing written laser safety operating procedures (LSOP). A written procedure is to include all lasers in a laser system, including alignment lasers. This LSOP must be reviewed and approved by the LSO.

Appendix B: Associated Hazards

Electrical

Accidental electrocution while working with high voltage sections of laser systems can be lethal. Electrical hazards are not normally present during laser operation, but great care should always be exercised during installation, maintenance, or servicing. Laser users must ensure that high voltage electrodes are not exposed and that capacitors are correctly discharged. Some laser systems incorporate the use of a water cooling system. The combination of water and electrical hazards of course increase the risk of serious injury.

Chemical

Many dyes used as lasing media are toxic, carcinogenic, corrosive or pose a fire hazard. A Safety Data Sheet (SDS) (formerly known as the MSDS) should accompany any chemical handled in the laser laboratory. The SDS (formerly known as MSDS) will supply appropriate information pertaining to the toxicity, personal protective equipment and storage of chemicals.

Collateral Radiation

Radiation other than that associated with the primary laser beam is called collateral radiation. Examples are x-rays, UV, plasma, radio frequency emissions, and ionizing radiation. X-rays could be produced from two main sources in the laser laboratories: electric-discharge lasers and high-voltage vacuum tubes of laser power supplies, such as rectifiers and thyratrons. A power supply, which requires more than 15 kilovolts (kV), may produce enough x-rays to be a health hazard.

UV and Visible Radiation

Laser discharge tubes and pump lamps may generate ultraviolet and visible radiation. The levels produced may exceed safe limits and, thus cause skin and eye damage.

Fire

Class 4 lasers represent a fire hazard. Depending on the construction material, beam enclosures, barriers, stops and wiring are potentially flammable if exposed to high beam irradiance for more than a few seconds.

Explosion

High-pressure arc lamps, filament lamps, and capacitors may explode violently if they fail during operation. These components are to be enclosed in a housing, which will withstand the maximum explosive force that may be produced. Laser targets and some optical components also may shatter if heat cannot be dissipated quickly enough. Consequently, care must be used to provide adequate mechanical shielding when exposing brittle materials to high-intensity lasers.

Glossary

• Aversion Response: Closure of the eyelid, or movement of the head to avoid exposure to a bright light. The average response to an exposure from a bright laser source is assumed to occur within 0.25s, including the blink reflex time.
• Controlled Area: An area where the occupancy and activity of those within is subject to control and supervision for the purpose of protection from radiation hazards. Examples of controlled area boundaries include: doors, curtains, and partitions.
• Diffuse Reflection: Change of the spatial distribution of a beam of radiation when it is reflected in many directions by a surface or by a medium.
• Maximum Permissible Exposure (MPE): The level of laser radiation to which a person may be exposed without hazardous effect or adverse biological changes in the eye or skin.
• Nominal Hazard Zone (NHZ): The space within which the level of the direct, reflected, or scattered radiation during normal operation exceeds the applicable MPE. Exposure levels beyond the boundary of the NHZ are below the appropriate MPE level.
• Laser: A device that emits a collimated (pencil-like) beam of either visible or invisible electromagnetic radiation (light). The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation.
• Laser System: An assembly of electrical, mechanical, and optical components which includes a laser.
• Intrabeam Viewing: The viewing condition whereby the eye is exposed to all or part of a laser beam.
• Specular Reflection: A mirror-like reflection.

References

1. The American National Standard for the Safe Use of Lasers [ANSI Z136.1 – 2000].
2. David Sliney, and Myron Wolbarsht, 1980, “Safety with Lasers and Other Optical Sources,” Plenum Press, New York.

Back to Chapter Eleven