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A case study on radiation shielding in a hospital
When radiation shielding was needed for a new addition to the Lahey Hospital and Medical Center (LHMC) in Burlington, MA, heavyweight concrete-also known as high-density concrete-proved to be the obvious solution. But how does a contractor procure materials for such a concrete mixture? While some concrete producers and contractors may have experience in working with high-density aggregates, few can provide concrete with a unit weight of 325 lb/ft3 (density of 5200 kg/m3). That's more than double the density of normalweight portland cement concrete mixtures and about two-thirds the density of steel!
Liberty Construction Services, LLC (LCS) was faced with this challenge in April 2015, when Suffolk Construction retained the company to provide concrete forming and placement for the LHMC project. The contract called for LCS to place a series of concrete columns and a large concrete slab totaling about 400 yd3 (305 m3) of heavyweight concrete (Fig. 1) for a new emergency department located above a shell space that will eventually house a new radiation oncology department. The shell space will house equipment using radiation sources that will require shielding protection for the personnel and patients within the new emergency department. The heavyweight concrete slab had to be carefully designed to provide the necessary protection and fit within the space allotted. Once the requirement for a 325 lb/ft3 (5200 kg/m3) heavyweight concrete was confirmed, LCS went to work to identify the right company to assist them.
Nuclear Shielding Supplies & Service (NSS) in Tucson, AZ, turned out to have a product that was "just what the doctor ordered." Their extensive experience with heavyweight concrete (DenseCRETE®) spans over five decades of service to the nuclear, medical, and industrial radiation shielding industries, including projects at McMaster University, Hamilton, ON, Canada; Centre hospitalier de l'Université de Montréal, Montreal, QC, Canada; and McGill University, Montreal, QC, Canada. This history showed that NSS could meet the requirements for the LHMC project and provide assistance along the way to help LCS place the material without any glitches.
Project Challenges
Limited space
The plans for the future radiation oncology department include up to three treatment rooms, each with a linear accelerator. In addition to a base level of shielding on the walls...