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Memo to All Drywall Installers & Suppliers * May 2005 The following material regarding the installation of lead drywall is offered for your information. A recent change in wording from the "NCRP" ( National Congress on Radiation Protection ) in their "Report #147" has indicated that lead tabs or discs no longer are necessary to cover the wall penetrations. The exact wording is as follows:
PGH 2.3.1.1 Sheet Lead "............for typical shielding applications, a lead sheet is glued to a sheet of gypsum wallboard and installed lead inward with nails or screws on wooden or metal studs. X-Ray images of wall segments show that insertion of the nails or screws does not result in significant radiation leaks. In fact, the steel nails or screws generally attenuate radiation equally, or more effectively, than the lead displaced by the nails. Therefore, steel nails or screws used to secure lead barriers need not be covered with lead discs or supplementary lead. However, where of two lead sheets meet, the continuity of shielding shall be ensured at the joints (SEC. 2.4.2)....." This should be good news to all installers and finishers. Since it may take some time for everyone to accept this change, a-fabco will be pleased to provide you or you customer with copies of this article or lead discs for the really stubborn ones. Remember, a-fabco is the one that delivers the "clean" board. |
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