Source for Oval PVC Pipe?

[Brian Tymchak]

Hey all, I'm thinking about having a radon system installed just to make the basement air where my shop is a little more healthy. I'm within the recommended guidelines for radon but the levels are not as low as they could be.

The upshot to all this is that I don't want to run an ugly pvc vent pipe up the outside of my house. I want to run it up an interior wall to the attic and then through the roof as it would typically be for new construction and the wall I want to run it through is a 2x4 construction. No closets or any other options available to hide it in. Was wandering thru Home Depot and saw oval metal HVAC duct designed to run in walls. I can't use that because the joints all have to be glued. But, I got to wondering if the same thing might exist in PVC, or maybe a rectangular pipe. Googling around, I only find something like what I'm thinking available on Alibaba (https://www.google.com/search?q=oval+pvc+pipe&espv=2&biw=1106&bih=736&tbm=isch&imgil=XSPTqy78uYcY8M%253A%253B64460lC7C_CLFM%253Bh ttp%25253A%25252F%25252Fwww.alibaba.com%25252Fprod uct-detail%25252Foval-pvc-plastic-pipe_60089470759.html&source=iu&pf=m&fir=XSPTqy78uYcY8M%253A%252C64460lC7C_CLFM%252C_&usg=__2NpaxQxy-zbbfxaQpXTYke98nzc%3D&dpr=1&ved=0ahUKEwj2k7zA4-PLAhVGqx4KHccoBmcQyjcINQ&ei=l1j5VrbsI8bWesfRmLgG#imgrc=XSPTqy78uYcY8M%3A) from companies in China at very large quantities. I'm assuming that there are fittings to convert circle<->oval as well...

So, my questions to the ever-wise collective is: does anyone know if this stuff is offered domestically? and if so, can someone point me to a supplier? Are there other alternatives I'm not aware of?

One alternative that I've considered would be to fur out that wall to be a 2x6 so a 4" circular pipe would fit. But I would have to move an interior door and a window (stucco siding) over to accommodate. A lot more work than I would want to put into this project.

Appreciate any help!
Thanks!

[Doug Garson]

Don't know about oval PVC pipe but how about running two 3" pipes rather than one 4" pipe? Two 3" pipes would give you slightly more flow area than one 4".

[Chris Padilla]

4" is about 12.5 in^2 and two 3" is about 14 in^2.

If you really need to use 4", you could heat it and reform it but I like Doug's idea a lot better.

[Anthony Whitesell]

I added half of a stud to the inside of an interior closet wall in order to fit a 4" PVC pipe through it.

[roger wiegand]

Why not use a pipe like this (http://www.homedepot.com/p/Speedi-Products-8-in-x-60-in-30-Gauge-Galvanized-Oval-Pipe-SM-3060GO-08/202907171?cm_mmc=Shopping%7CTHD%7CG%7C0%7CG-BASE-PLA-D26P-AirCirculation%7C&gclid=CjwKEAjwrOO3BRCX55-L9_WojHoSJAAPxcSPZPecFIKMiKWy1MdOyl1kuWVMxTQlOOX2x cBsMbIbvRoCnMXw_wcB&gclsrc=aw.ds)? (oval galvanized in 5 ft sections) You can seal the joints with mastic or a urethane caulk, there won't be very many of them unless you have a really tall house.

You can also use aluminum flex pipe like you would use for a dryer, it is nominally 4" but can easily be squeezed into an oval to fit inside a wall cavity. The rough surface will cut down air flow relative to a smooth walled tube.

Or use a 3"x4" aluminum downspout (http://www.homedepot.com/p/Amerimax-Home-Products-3-in-x-4-in-x-10-ft-Aluminum-Downspout-Brown-4401119120/100520846), which comes in 10 ft lengths.

[Brian Tymchak]

Thanks for the replies guys. I meant to get back to the thread last night but got busy after work.

Doug, the 2 3" runs is an interesting idea. Thanks for that. I wonder if they make "manifold" style fittings for such an arrangement. Something to check into at lunchtime today.

Anthony, the work to fur out the wall to fit the 4" pipe would cause too much other collateral work (move door frame, window, electric, etc)

Roger, I'm assuming that galv pipe is not recommended for radon mitigation since it is more difficult to get a completely sealed run vs glued PVC. But I haven't talked yet to a contractor or my local building code dept. And there is the possibility of water of collecting in the venting since radon vents should not have a rain cap of any type on them. Otherwise I agree that would be the quick solution to this.

[Doug Garson]

I doubt you'll find a manifold fitting but PVC fittings are pretty cheap, depending on your space available there's probably several combinations of tees, elbows and bushings that will work. If your local big box store doesn't have what you need try an industrial plumbing supply place - better pricing also. I use Andrew Sheret up here in Vancouver for my pond piping and fittings, not sure if they are also south of the border.

[Chris Padilla]

Doug, the 2 3" runs is an interesting idea. Thanks for that. I wonder if they make "manifold" style fittings for such an arrangement. Something to check into at lunchtime today.


I really doubt there is a 'nice' manifold set-up for such things but you can easily make your own up with the various DWV fittings available.

Home Depot (http://www.homedepot.com/b/Plumbing-Pipes-Fittings-ABS-DWV-Pipe-Fittings/3%22/N-5yc1vZbqogZ1z0u2l0) has a wye, a street 45 and a street 90 on this page and AL-LA-KAZAM, there is your manifold for 2 pipes. :)

[Brad Adams]

Hate to bust you guys bubble, but radon systems are typically installed with three inch PVC pipe.
Three inch sch. 35 pipe will fit in a 2x4 wall but it isn't easy to find anymore. It was used a lot in the seventies.

[Doug Garson]

Not a piping expert just a retired mechanical engineer but why would pipe schedule matter in a venting system? Lot's of 3" Sched 40 pipe available even at the big box stores. There's no significant pressure in a vent system so the only reason to select a given pipe thickness would be corrosion(not an issue with plastic pipe) and mechanical strength and sched 40 is heavier wall than sched 35.

[Brian Tymchak]

Hate to bust you guys bubble, but radon systems are typically installed with three inch PVC pipe.
Three inch sch. 35 pipe will fit in a 2x4 wall but it isn't easy to find anymore. It was used a lot in the seventies.

Thanks Brad. All the radon fans I've looked at online have inlet/outlet of 4" (or greater) so I assumed that was minimal vent size. It's probably time to get someone in that does this stuff for a living and stop guessing. Was just trying to learn some things before I engage the contractors so that I didn't settle for something that I was ultimately not going to like.

[Al Launier]

You could simply place the length 4" PVC between a couple of 2x4s & clamping everything together. Then heat the length with a heat gun, or even a propane torch (not held too closely), & tightening the clamps as you progress down the length of PVC to form the oval shape you are looking for. Keep the 2x4s clamped until the PVC is totally cooled. You could leave a section of PVC extended beyond the 2x4s to keep the 4" dia. or flare at each end if needed for connection outside the wall. Obviously, you'll need a long enough section for the height of the wall & to extend beyond as needed. The thinner schedule 40 will deform much easier than the schedule 80. I've done similar things with PVC including making archery bows from PVC. Give it a shot, you'll be surprised.

[George Bokros]

According to what I was told when I had my radon mitigation system installed you cannot use metal pipe any longer, it must be pvc. The fans seem to all have inlet and outlets that are larger than 4" but it is acceptable to reduce down to 4" for inlet and outlet but no smaller. It also must terminate above the roof line. Also you cannot put any kind of rain cap on it any longer.

[Chris Padilla]

Keep the thread updated with what you find out, Bryan.

[Brian Tymchak]

Yep! will do.

[Tom Hartranft]

Another option ... end the exhaust pipe at ground level. I added a basement 4" radon exhaust pipe about a year ago and stressed over having to add a vertical outside pipe up to roof level ... didn't want to look at a 2-story PVC pipe on the outside of my house. After some investigation such as yours for piping the exhaust up inside an interior wall, I just said screw it and ended my radon exhaust pipe right outside the 4" hole I cut in the house outside wall right behind my house A/C unit. I know that the 'experts' say one has to pipe the exhaust up to roof-top level, but it works fine and the routine winds here in Illinois amply disperse the exhausting air quite well. My indoor Radon readings have run 1.0 to 1.4 steadily so the exhaust system has done well for us in our basement. Here's a photo of the 4" PVC exhaust pipe on the outside of my house ... I ended the pipe with a 90* ell that directs the discharged air a bit downward. I installed a wooden orifice inside the ell to cut back on the exhaust airflow a bit while still abating radon levels in the basement.

Tom

[Tom Hartranft]

Wanted to follow up and offer critique of my own previous response which was a bit disdainful of legal mitigation requirements.

Upon revisiting my own radon research of a couple of years ago, I am reminded that my approach violates two Illinois environmental radon mitigation requirements: 1) vent pipe must rise at least 2 ft above roof line and 2) exhaust fan must be outside dwelling. Both of these requirements are for safety in avoiding any possibility of back flow of vented gas from re-entering one's home. So, let's say that I have a 'proof-of-concept' system installed ... that is, my current quick solution does reduce my basement radon levels well below the mandated level of 4.0. Sometime in the future I'll have to finish off my system to meet Illinois environmental installation requirements 1 and 2 above. As with the OP, I too don't want an ugly PVC pipe rising 2 stories on the outside of my house.

Tom

[Brian Tymchak]

Hi Tom,

My first thoughts about this were exactly the way you did it. It would be so simple to do. Then I figured that at some point I might be selling the house so I wanted to make sure I was doing it right the first time instead of dealing with a big mess trying to get a deal closed.

Thanks, Brian