Many vapor intrusion (VI) mitigation systems involve some form of gas extraction from below the concrete floor slab of a building to create a static vacuum below the slab that meets or exceeds a value specified in a guidance document or standard. This also results in some degree of ventilation below the floor slab, which reduces vapor concentrations and achieves some level of mass removal of target chemicals. The relative contribution of vacuum and ventilation to protecting building occupants is generally not quantified. Recent research completed under ESTCP Project ER-201322 yields some new insights using new lines of evidence. The results warrant changes in the guidance documents and standards of practice to promote and enable VI mitigation system designs that vary according to the transmissivity of the material below the floor slab and the rate of vertical leakance of indoor air across the floor slab and incorporate additional lines of evidence including the mass removal rate.

中文翻译：

---

地下平板减压与地下平板通风：最新研究的真知灼见

许多蒸气入侵（VI）缓解系统涉及从建筑物的混凝土楼板下方抽出某种形式的气体，以在楼板下方产生达到或超过指导文件或标准中指定值的静态真空。这也导致地板下方一定程度的通风，从而降低了蒸汽浓度并实现了一定程度的目标化学物质质量去除。真空和通风对保护建筑居民的相对贡献通常无法量化。ESTCP项目ER-201322下完成的最新研究使用新的证据线得出了一些新见解。