Vapor intrusion mitigation: Road map to successful sub‐slab depressurization at sites with shallow water tables

Abstract

A common practice to prevent intrusion of contaminated vapor from the subsurface to overlying buildings is to install a sub‐slab depressurization system (SSDS) that creates lower pressure beneath the lowest level floor slabs, thereby preventing contaminated vapor from entering buildings. However, this standard approach cannot be implemented in the presence of a high groundwater table that is close to or in contact with lowest level building floor slabs. Therefore, for sites with a high groundwater table that require vapor intrusion mitigation, a unique “double slab” design has been developed. This alternate double slab design has been implemented and proven effective at new construction sites in New York City with sensitive receptors. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1758–1761, 2018