What is the main difference between an active and a passive soil depressurization system?

The distinction between active and passive soil depressurization systems primarily hinges on the presence of a fan in active systems. An active system incorporates a fan or blower that actively reduces the pressure in the soil beneath a building, thus preventing radon gas from entering the living spaces. The fan continuously removes air from the soil, creating a negative pressure that effectively keeps radon from infiltrating the home. This mechanism allows for a more controlled and efficient means of radon mitigation, especially in conditions where passive systems may struggle to maintain adequate pressure differentials.

In contrast, passive systems rely on natural airflow and pressure differences to facilitate the movement of radon gas away from the building without the assistance of a mechanical fan. While they can be effective in certain circumstances, they often depend on wind and temperature variations to work, and their performance is generally less reliable compared to active systems, particularly in homes where radon levels are significantly high.

Understanding this fundamental difference is crucial for effective radon mitigation strategies and addressing radon exposure risks in residential environments.