SSD is a strategy used to prevent vapors from entering a structure through its foundation. Historically depressurization systems have been an effective strategy for preventing radon gas from entering homes and commercial buildings.
Indoor air quality is increasingly scrutinized and low concentrations of volatile organic compounds (VOC’s) are a serious concern. This is especially true in newer energy efficient structures with minimal air exchange. Indoor air can be contaminated by existing sources of VOC’s present in the soil below, or adjacent to a building which enter through cracks in the foundation. SSD systems can improve indoor air quality by preventing vapor intrusion into living spaces.
SSD systems operate on the same principle as soil vapor extraction, but typically for longer duration and at lower flow. The focus of SSD systems is usually to prevent vapor migration rather than remediation of the source.
Usually VOC or CVOC vapors extracted from SSD systems are low in concentration and are vented directly to the atmosphere. When direct discharge is not permitted, low concentrations can be absorbed by activated carbon (GAC). If concentrations are higher, it may be cost effective to destroy them with a FALCO electric catalytic oxidizer. The FALCO 100 (without VCV) is well suited to treat low flow VOC sources economically and continuously.
