Summary of Building Protection Factor Studies for External Exposure to Ionizing Radiation

Radiation dose assessments are used to help inform decisions to minimize health risks in the event of an atmospheric release of radioactivity including, for example, from a Radiological Dispersal Device, an Improvised Nuclear Device detonation, or a Nuclear Power Plant accident. During these incidents, radiation dose assessments for both indoor and outdoor populations are needed to make informed decisions. These dose assessments inform emergency plans and decisions including, for example, identifying areas in which people should be sheltered and determining when controlled population evacuations should be made.

US dose assessment methodologies allow consideration of the protection, and therefore dose reduction, that buildings provide their occupants. However, these methodologies require an understanding of the protection provided by various building types that is currently lacking. To help address this need, Lawrence Livermore National Laboratory, in cooperation with Sandia National Laboratories and the Nuclear Regulatory Commission, was tasked with (a) identifying prior building protection studies, (b) extracting results relevant to US building construction, and (c) summarizing building protection by building type. This report focuses primarily on the protection against radiation from outdoor fallout particles (external gamma radiation).

This study identified and summarized the results of approximately 400 building analyses in 26 previously published studies. This study’s results were consistent with, and extend, prior studies of building protection by building type. The protection values, and a brief discussion on their use, provided in this report will be used to improve dose predictions and assessments generated by US Federal centers. As such, this work will potentially benefit government agencies nationwide that use these centers’ dose assessments during emergencies, drills, and exercises.