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Laser FAQs
Q. What does "LASER" stand for?
A. Light Amplification by Stimulated Emission of Radiation
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Q. Do I need to let someone know about my laser?
A. Only if you have Class 3b and Class 4 lasers.  The EH&S Radiation Safety Office maintains an inventory of all Class 3b and Class 4 lasers, and can provide help to you in setting up your safety program.
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Q. If my laser is not a class 3b or class 4 laser, what should I do to make sure I use it safely?
A. Class 1 lasers should not be disassembled.   A class 1 laser may contain a powerful embedded laser capable of causing severe injury.   Maintenance of a class 1 laser should be performed only by trained technicians.   Class 2 and class 3a lasers are not capable of causing eye injuries when used properly.   You should avoid staring into the laser light.
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Q. What room postings are required for my laser?
A. For Class 3b and Class 4 lasers ANSI X136.1-2000 "Safe User of Lasers" addresses the posting of warning signs.  All signs shall be conspicuously displayed in locations where they best will serve to warn onlookers.  An area which contains a Class 3b or Class 4 laser or laser system shall be posted with the appropriate Laser Warning Sign.
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Q. What should be considered for a laser hazard evaluation?

A. 1) The laser system's capability of injuring personnel or interfering with task performance.  2) The environment in which the laser is used.  3) The personnel who may use the laser or be exposed to radiation. <FAQ Top> <Return to FAQ Index>
Q. What is the Nominal Hazard Zone?
A. The space within which the level of direct, reflected or scattered laser radiation during normal operation exceeds the applicable maximum permissible exposure, or MPE, which is the level of laser radiation to which a person may be exposed without hazardous effects or biological changes in the eye.
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Q. Who may operate a Class 3b or Class 4 laser?
A. Class 3b and Class 4 laser systems shall be operated at all times under the direct supervision or control of an experienced, trained operator who shall maintain visual surveillance of conditions for safe use and terminate laser emission in the event of equipment malfunction or any other condition of unsafe use.
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Q. Is eye protection required?
A. Eye protection devices which are specifically designed for protection against laser radiation from Class 4 laser systems shall be administratively required and their use enforced when engineering or other procedural and administrative controls are inadequate to eliminate potential exposure in excess of the applicable MPE.
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Q. How do I choose the appropriate eyewear?
A. Many factors shall be considered to determine the appropriate eyewear, i.e., laser power, wavelength, exposure time, comfort, etc.   For more information, contact the laser manufacturer or the Radiation Safety Office at 314-362-3476.
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Q. Does my lab need laser protective barriers and curtains?
A. A blocking barrier, screen, or curtain which can block or filter the laser beam at the entryway should be used inside the controlled area to prevent the laser light from exiting the area at levels above the applicable MPE level.
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Q. Do laser users need training?
A. Yes.  Laser safety training programs shall be provided to the users of Class 3b and Class 4 laser systems.  In general, this training is provided by the principal investigator overseeing the laser system.   Please contact Radiation Safety at 314-362-3476 for more information
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