Height of Radon Vent Pipe

So that the wind doesn't carry the radon back into the upper, living, areas of the house.

Yes, I agree that's the reason. If the discharge was located on a side of the house where it's far away from any window or door, then the problem of it coming back into the house is essentially eliminated. Although if there are soffit vents, some of the air could still make it's way into the attic. Then you still have the problem of people standing near it outside. I don't know how you can say for sure where people will or won't congregate. Just vent it where there is no chance of any of it getting back in and be done with it.

FWIW, mine was installed using aluminum rain gutter downspout pipe, instead of PVC, from the fan to roof line. Not quite so obvious, and easily painted same color as siding.

One thing I've wondered about. Why no rain cap, does the fan have a rain diverter built-in ??

I have a neighbor who has a radon vent without a cap and it fills with debris. She isn't too happy!!!

so the stuff don't blow back in the window. Some think it's dangerous.

Has she bought the cap yet? If not, she deserves having a PITA.

Having a cap does not guarantee no water or debris. Water can easily condense as the temperature changes. So, the fan needs to handle water regardless and to return to the original question, maybe the pipe should be higher to avoid debris from trees.

Yes, about 75 ft high should avoid most trees. Any more practical tips?

You just said what I was thinking.

The outlet is on the outside of the foundation wall, behind a heavy hedge of evergreens. No one ever goes there except to pick up accumulated wind-blown trash every once in a while (three times a year maybe). So, I don'tt think anyone is going to get contaminated unless they are homeless and set up a tiny tent behind the hedges so that no one can see them.

One doesn't need to avoid "most" trees. One only needs to avoid the trees in your particular installation. My vent is above the roof line per code and that happens to be above the nearby small trees. If it was at the roof line, it would not be. The OP asked why the vent needed to be higher. I gave one *possible* reason. My main point was why it is not necessary to keep rain water out.

Obviously the concept of a simple rain/debris cap escapes you

I think that they do know about those ideas and wondered why the usual radon remediation exhaust looks like this:

That's fine for new construction, but a retrofit on an older home usually looks like this:

The point is that if the issue is that you need to avoid having debris like leaves falling into the pipe, that can be solved with a simple screen or cap. A simple screen cover could even be in the diagram you provided, just not shown. It's just a simple wire screen.

So, yeah, I'd say someone who instead proposes extending the pipe up above the height of the trees is probably a hippie.

All systems must account for water, condensation or rain. It's real dum to put an open pipe sticking up. It's also real dum to use a large diameter pipe. It does not depend on fan size, it's all about how much flow you get. I put up a pipe with a bend above roof. I have a water collection system for condensation. It's easy to clog. I only have to run the system in the colder months, and a bug screen is necessary. My 120 cfm German fan is pulling about 20-30 cfm, at 1 inch pull. My radon is 1.5 in the summer without fan. In winter it could jump to 20 times that without fan.

Greg

On Mon, 25 Jun 2012 18:24:22 +0000 (UTC), gregz wrote Re Re: Height of Radon Vent Pipe:

What's really dumb is spelling "dumb" as "dum".

I figured somebody would say that.

Greg

I think the old work version in your image is basically the new work version mounted on the outside. They install around here them just like your image shows.