Turk B H, Harrison J, Prill R J, Sextro R G
Applied Science Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
Health Phys. 1990 Oct;59(4):405-19. doi: 10.1097/00004032-199010000-00003.
Research-based procedures for characterizing the causes of elevated indoor 222Rn levels and guiding the selection of an appropriate control technique were evaluated at seven New Jersey houses. Procedures such as thorough visual inspections, blower door air leakage tests, pressure field mapping, subsurface vacuum extension tests, sampling of 222Rn concentrations throughout the substructure, and measurements of the additional depressurization caused by various appliances all were found to furnish important information to the mitigation contractor or researcher. An analysis of data from these and other diagnostic techniques performed at the seven houses also indicated: (1) regions of very high permeability existed directly adjacent to the exterior of substructure walls and floors; (2) the additional substructure depressurization caused by operation of forced-air furnaces and attic exhaust fans could exceed 1 Pascal; (3) 222Rn concentrations below basement slabs and slabs-on-grade adjoining below grade basement walls were approximately seven times higher than those within block wall cavities; and (4) air leakage areas of crawlspace and basement ceilings were quite large, ranging up to 0.15 m2. The pressure field mapping tests identified the areas surrounding the substructure that were well coupled to the indoors. Using flow, pressure difference, and 222Rn concentration data, indices of soil gas entry potential and 222Rn entry potential were developed to indicate the areas of the substructure that may have high entry rates of soil gas and 222Rn, respectively. These indices could be helpful for quantifying the relative resistance to soil gas movement of substructure surfaces and surrounding soils and for determining the placement of 222Rn control systems.
在新泽西州的七所房屋中，对基于研究的程序进行了评估，这些程序用于确定室内222Rn水平升高的原因，并指导选择合适的控制技术。诸如全面的目视检查、鼓风门漏气测试、压力场测绘、地下真空扩展测试、整个下部结构的222Rn浓度采样以及各种电器引起的额外减压测量等程序，都被发现能为缓解承包商或研究人员提供重要信息。对在这七所房屋中进行的这些及其他诊断技术的数据进行分析后还表明：(1) 在下部结构墙壁和地板外部直接相邻的区域存在渗透率非常高的区域；(2) 强制热风炉和阁楼排气扇运行引起的下部结构额外减压可能超过1帕斯卡；(3) 地下室楼板下方以及与地下室下部墙壁相邻的地面楼板下方的222Rn浓度大约是砌块墙腔内浓度的七倍；(4) 爬行空间和地下室天花板的漏气面积相当大，范围可达0.15平方米。压力场测绘测试确定了与室内耦合良好的下部结构周围区域。利用流量、压差和222Rn浓度数据，开发了土壤气体进入潜力指数和222Rn进入潜力指数，分别指示下部结构中可能具有高土壤气体进入率和222Rn进入率的区域。这些指数有助于量化下部结构表面和周围土壤对土壤气体运动的相对阻力，并有助于确定222Rn控制系统的放置位置。
