Vertical pipes behind house

What are this pipes for?

Vertical pipes coming out of the ground behind a 2007 multi family on slab. You can see in the picture the unfinished house of similar construction also has them

WAG: Radon vents under slab. :thinking:

That is what I was thinking but they appear to have caps on them. :flushed:

Larry, I don’t think they are caps.

Yeah no caps. Didn’t think of it being radon. Kind of an unusual passive system maybe? The other house is unfinished, looks like it has sat like that for quite a while, and has even more of these pipes. Thanks for the replies!

Thanks, Joseph. I appreciate the help. :smile:

That’s a foundation also, not a slab.

Those look like corrugated PE or HDPE drainage pipes. Tied into perimeter drains?

Wonder if it is connected to the perforated under drain and using it for passive radon at the same time with pipe under the slab at the interior.

15ADS 3000 TRIPLEWALL PIPESEPTIC STACkADDITIONAL INFORMATION AVAILABLE1. arc - asTM Pipe specification F4052. gravel-less - asTM Pipe specification F6673. smoothwall - asTM Pipe specification F8104. asTM installation specification F481ads 3000 tripleWall® pipeUsing state-of-the-art extrusion technology, this three-layer HDPE pipe has unprecedented beam strength, far exceeding the stiffness requirements of ASTM F810 . A co-extruded smooth inner wall and corrugated center section is covered by an extrusion-laminated white outer wall . A deep bell coupling is spun-welded to the pipe and is designed to fit all standard 3" (75 mm) and 4" (100 mm) sewer and drain fittings . TripleWall pipe’s exceptional stiffness permits assembly on work stands and its light weight allows for one-man installation . It is produced in 3" (75 mm) and 4" (100 mm) diameters in 10’ (3 m) lengths, either solid or with standard 5/8" perforations set 120° apart