What allows the rough-in of a radon control system to be activated into an Active Soil Depressurization system?

The activation of a rough-in radon control system into an Active Soil Depressurization (ASD) system primarily relies on the inclusion of a fan. An Active Soil Depressurization system functions by employing a fan that actively pulls radon gas from beneath the foundation of a building and exhausts it safely outside, thus lowering the concentration of radon in the occupied spaces.

This fan is crucial for creating the negative pressure necessary to effectively draw radon-laden air from the soil. Without the fan, the rough-in system would remain passive and would not be able to control the radon levels effectively. Although humidity control measures, manual suction methods, and secondary vent systems can play a role in radon mitigation practices, they do not directly convert the rough-in to an active system in the way that a fan does. The fan is the key component that enables the transition to an active system, making it essential for controlling radon levels in a home or building.