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06 September 2008

Answer to Question #6810 Submitted to "Ask the Experts"

Category: Industrial Radiation — Industrial Exposures

The following question was answered by an expert in the appropriate field:

My research is focused on optical wireless communication in the ultraviolet-C (UVC) spectral range (100-280 nm). Although we consider this very low power, I worry that it may raise some issues because, as far as I know, present-day medical studies cannot demonstrate that there is a safe level of UVC exposure. Could you please let me know if there are any standards concerning UVC radiation?

You can order a copy of ANSI/ASSE Z87.1-2003, "Occupational and Educational Personal Eye and Face Protection Devices," from the American National Standards Institute Standards Web store.

You can look at "UV Safety Goggles" which claim to meet the ANSI Z87.1 requirements at several Web sites, i.e, UV Safety Goggles - Edmund Scientific.

You should also refer to the American Conference of Governmental Industrial Hygienists' (ACGIH) recommendations for the threshold limit value (TLV) for ultraviolet radiation (UVR). The TLV is 3 mJ/cm² (0.1 μW/cm² for all-day exposure), based on preventing photokeratitis in the cornea. (This is the primary effect to protect against and it is a safe exposure level.) Go to the ACGIH Web store and search on "ultraviolet" for the TLV references. If the source is low power, ordinary glasses will protect the eye because glass and most plastics will absorb UVR < 320 nm. However, UVC will also cause skin erythema at exposure levels about 10 times higher than the threshold for photokeratitis. Thus, skin exposure may also be hazardous.

Also, if you are using a laser rather than a broad-band source, there could be other issues. You could refer to the American National Standard for Safe Use of Lasers, ANSI Z136.1-2007.

John P. Hageman, MS, CHP

Answer posted on 18 September 2007. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.