D06 · Block-wall and sub-slab radon system

ALT TEXT
Labeled basement diagram combining hollow block-wall suction and sub-slab suction into an active radon vent system.

LONG DESCRIPTION
A basement cross-section shows two conceptual collection paths: a hollow block-wall path and a suction point beneath the slab. The branches join a vent riser and fan for outdoor discharge. The figure illustrates a combined system family but does not prescribe wall openings, structural alterations, firestopping, or pressure-field diagnostics.

Source basis: U.S. EPA Consumer’s Guide to Radon Reduction (2025), block-wall suction and mixed-foundation guidance.
