sub-slab depressurization 3

https://remote-wiki.win/index.php/Why_Your_Radon_Vent_Pipe_Matters_for_a_Safer_Home_in_St._Louis

Sub-slab depressurization is a method used to prevent soil gases like radon from entering a building by creating a vacuum beneath the concrete floor slab. A fan system pulls air from the ground, exhausting it safely outdoors. It's a quiet, permanent solution that doesn't disrupt living spaces.