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11 October 2008

Answer to Question #5912 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment/Shielding — Shielding

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

As one of the alternative shielding materials, what is the lead equivalence of tiles?

In order to determine the lead equivalency of any material, you must first know the density. There is a table of information for commercial building materials in Report No. 49 from the National Council on Radiation Protection and Measurements (NCRP 1976); however, the value for tile is given as a range, so you will need to know the actual density for your particular tile. Turner provides discussion regarding calculation of tile thickness compared to concrete (Turner 1986).

In addition, remember that if tile is used, there must be grout with similar density filling up all seam/joint areas, or there must be overlap of the tiles to provide adequate shielding.

Ken "Duke" Lovins, CHP

References

National Council on Radiation Protection and Measurements. Structural shielding design and evaluation for medical use of x-rays and gamma rays of energies up to 10 MeV. Washington, DC; NCRP; NCRP Report No. 49; 1976.
Turner, JE. Atoms, radiation, and radiation protection. Pergamon Press; 1986.

Answer posted on 13 February 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.