How Sub-Slab Depressurization Works

An ASD system consists of four main components:

1. Suction pit(s): One or more holes drilled through the concrete slab to access the aggregate layer beneath

2. Piping: PVC pipe routed from the suction pit(s) through the building and to the exterior

3. Fan: A continuously operating fan that maintains negative pressure beneath the slab

4. Discharge point: The pipe terminates above the roofline or to the side of the building, away from windows and air intakes