D05 · Crawlspace submembrane radon system

ALT TEXT
Labeled crawlspace diagram with a sealed ground membrane, submembrane suction pipe, fan, pressure indicator, and outdoor discharge.

LONG DESCRIPTION
A house cross-section shows a crawlspace soil-gas-retarder membrane sealed conceptually over the exposed soil. A suction connection beneath the membrane joins a vent riser and fan that discharge outdoors. A separate radon test is shown in occupied space. Membrane thickness, seam construction, anchorage, drainage, and access details are not specified.

Source basis: U.S. EPA Consumer’s Guide to Radon Reduction (2025), crawlspace submembrane suction description and typical-reduction table.
