Rain Caps and Radon Mitigation
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- čas přidán 9. 03. 2022
- People often ask, "Why don't you put rain caps on your exhaust pipes?" Leaving a pipe open to rain and snow might sound a little concerning, but radon mitigation systems are designed to deal with the amount of moisture that we experience in Minnesota. In this video, we explain why rain caps aren't necessary and discuss how different fittings affect airflow and exhaust trajectory.
We recommend checking the ANSI/AARST standards for the most accurate, up-to-date information.
standards.aarst.org/
Standards for exhaust discharge as of March 2022
ANSI/AARST SGM-SF-2017 with 12/2020 REVISIONS
standards.aarst.org/SGM-SF-20...
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I cannot express how grateful I am for this video. When we tested for Radon results came back at 40 pCi/L. That is not a typo. I picked up an EcoQube radon detector for monitoring and saw peeks as high as over 60 pCi/L. I installed a mitigation system using 4" pipe and a strong suction fan. The system reduced the Radon considerably, but we were still averaging around 6 pCi/L. I was trying to figure out what next steps I would take when I stumbled across this video. I had put a half sphere rain cap on my system to prevent rain from going down the vent. After watching this video I jumped up on the roof and pulled the cap. The levels came down and I've not seen them go above 2.1 pCi/L since pulling the cap and average around 1.2 pCi/L. Amazing what just a little resistance to the air flow can do. Thanks for the great demonstration and all your other videos that have helped me so much to get a great working system!
Thank you for your comment, Kevin. I'm glad the video helped you make your home safer.
This can't be correct. This was just a coincidence. As you can see in the video, he says the CFM is the same open or with the cap, the only difference is it blows the radon downwards which is not allowed and not good for open windows
How long after did you test after installation? Could take some time to lower levels.
Very informative video. Had the first vent for a long time not even thinking that it's just blowing it in a 360 degree area and we do have a window not too far from it. Installed a new fan recently and just left the end pipe open but did end up putting on a 45 degree cap since it's "allowed" so as to flow it even more away from the house and the window area.
Thanks, glad you found it helpful!
Muchas Gracias por la información!
De nada!
We recently had a storm here in Florida that dumped a whole lot of rain (48 hours of non-stop rain). Our radon contractor used a cap (4 way exhaust cap) on our radon system. I'm wondering why? A bit more info, the suction point is about 40' away from the exhaust point in the garage. In addition, at the point of suction, the pipe runs up an additional 10' inside a vaulted ceiling closet. The majority of the pipe run is horizontal through our attic. Do you think that has anything to do with our cap and having water not move through all the pipe run?
Does capping the exhaust really matter if 1) the exhaust is placed at the appropriate distance from windows and 2) if our radon levels have dropped dramatically. We're currently averaging .6 pci/l in the last month. Down from an average of 5 pci/l in a multi family townhouse building (our unit located in the middle).
It's probably not that big of an issue in your climate. Here in Minnesota, it would likely be a place for ice to form on the cap and possibly the surrounding area that the air is blowing on.
First off, your videos are top notch ! Very informative and well done! If doing a roof exhaust, is it best to have the fan closer to the end of the pipe so it has max pushing power out the end of the pipe to prevent freeze, or can it be down a bit further like 7-8 ft without issue of freezing as long as my attic pipe is wrapped with insulation? I could put the fan in the basement, but then it has a run of about 20ft until it hits the attic, so I assume the closer to the exhaust the better? Whats the longest run of pipe recommended if I wanted to go across my attic and out the gable instead of a vertical exit?
Thank you.
1. I've been told it doesn't matter where the fan is within the piping run. The fan doesn't care whether it's pushing or pulling air.
2. If you're in the USA, the standards don't allow a radon fan to be in a conditioned space. We only install them in unconditioned attics or outside.
3. The exhaust discharge has several requirements. I'd go through the roof.
Check out the standards before getting started. They are easy to navigate and are super helpful. standards.aarst.org/SGM-SF-2023/4/index.html
if you want to vent out a wall, and across, with a bit of a downward slope is that OK. If radon is heavier than air, how does it get all the way out the roof?
I'd point you to section 6.4 of the radon mitigation standard. That section talks about the exhaust discharge requirements. standards.aarst.org/SGM-SF-2017/23/index.html
Very informative video! Thanks a lot! Thinking outloud however here: I have had some water issues in my downstairs bathroom since about the time I had a radon system installed. I have always had a sump pump and it continues to work. Got a new one installed when I got the radon system installed. The water in the bathroom seems to come from below....just moisture seeping up between the vinyl tiles and appears if we have had a heavy rain. I know you don't recommend a cover for the top of the radon pipe.....but I'm really starting to think that I might be getting excess water coming down the pipe during those heavy rains and then some is seeping up through the bathroom floor was it works it way toward to the sump hole? Is that possible? Thinking the T connection on top might prevent that possible issue. Again....not sure that is what is happening or not.
I'd be shocked if you could get a significant amount of rain down a three-or four-inch radon exhaust pipe. If so, I imagine your sump pump would catch it. You could try it and see if it makes a difference.
I have a house built on a sand hill overlooking a lake with drip tubes around both outside and inside the wall perimeter footings. The slab is over sand with a plastic barrier. The outside end in a outlet tube down the hill toward the lake. The inside tubes end in the sump basin. The basin in the ten years since the house was built has never had water and the pump had not had to run. The cover has a open slot where the pump exit pipe comes up out of the pit and exits the house on the side. My radon meter reads 4.67 in this room. Can I just put a sealed cover over the pit or should I add a vent pipe and fan to draw air from the drip pipes to the outside? Is this sufficient? The lower level design is open concept finished areas all glass looking toward the lake, and the readings in this open area are below 4.
I would install a system similar to the one in this video. czcams.com/video/h0g_UY5-Zew/video.htmlsi=6VOfawVCJqlTuvIe
My GFCI tripped on radon fan after high rain. I took the fan apart and seems there was water on the inside causing GFCI to trip. I think a 90 degree bend on the top will fix that problem.
They have a bypass offset rain drain coupler
Thank you for the video. How long of a pipe would you recommend if the roof ridge is far away or if it is close and we get a lot of snow,15 inches and more.
I was thinking about the 45 and direct the air away from windows on one side. This will be better with snow and rain. Do you know how far away you can breathe in radon if it is a lot? I mean, how fast does it delude in air to not be an issue if we have air coming down due to pressure?
Check out the exhaust discharge requirements here: standards.aarst.org/SGM-SF-2023/24/index.html#zoom=z
@@AmericanRadonMitigation We don't have requirements and regulations where I am from. We can do basically anything we want and we are in the middle of the woods.
So what would be the best solution to both prevent snow/condensation of the cap and also make sure we don't get radon air backwards. Is the 90 degree an ok solution? Why did you say " but not preferred". How is the 90 less efficient thatn the Tee, can't see much of a difference? Thank you!
We had a Radon mitigation system installed in 2006 in Wisconsin. This summer we noticed mold growing on the pipe running up through our garage. The fan is still working properly based on the gauge reading in our basement.Can you do a video that addresses this issue? Thanks.
Yes, we can. Would you be able to send us some photos of the issue so we can add them to the video?
That's not a bad idea. How do you suggest I set this up so you can see the results?
Great video. I am in Florida and we can get some major rain. I just had a mitigation system installed and noted there was no cap on the exhaust pipe on the roof. Although I read it is not necessary, the thought of that much rain going into the system, through the fan, and back into the foundation caused me some real anxiety (I heard termites like a moist foundation). So I put a cap on it. Got it from Amazon (RadonAway 76001 Vent Cap for 4" Schedule 40 - I have 3" pipe so I had to use a connector to fit my exhaust). I noticed recently that the radon levels in my house spiked, but only at night (from .05 to 9.43). It then comes down during the day. I thought the cap may have been the reason, but the first several days with the cap I saw no increases. I guess I can get up there and remove the cap to see if that makes a difference, but it sure feels like it is still moving the same amount of air. Before I try to remove the cap, I wanted to know if you or anyone else has had any experience with this cap causing issues. Maybe remove the "critter guard" screen to increase flow? We do not have "critter" issues. Your thoughts?
Boy, I'm not sure what would cause that. Could you be getting re-entrainment with the discharge air being pushed in a horizontal direction? Perhaps the winds are calm at night allowing the radon from the exhaust to enter your home.
I know your are inclined to locate fans inside rather than outside. But if your home does not have an attic, and you are not allowed to put it in a garage with living space above, you are forced to put it outside. Have you utilized any low profile encased fans for exterior mounting? I have seen the fantech RNSL as well as the "RadonAway" encased low profile sold at home depot
I have used each of the low-profile fans you are talking about. They are the equivalent of a midrange radon fan. I prefer the mounting method used by the Fantech RNSL over the RadonAway SF180. However, the SF180 gets points for looking cleaner.
Check out out what the standards say about rain caps. Also, check out the next page for more on rain caps and icing. standards.aarst.org/SGM-SF-2017-1220/26/index.html
I have a new house that is pre-plumbed for Radon mitigation but do not have a Radon mitigation system. Just a pipe going from my SEALED crawlspace to the roof. Shouldn't there be a cap on the roof pipe to prevent rain from getting into the crawlspace? I should add that I cannot see daylight while looking up from the crawlspace but that might be due to elbows installed between the floors somewhere. I am getting rain water in crawlspace after a heavy rain. And there's no chance I'm getting on the roof to look (way too high for me).
I'm just an inquisitive homeowner. Not a professional. Wondering if the pipe in your crawlspace penetrates below a vapor barrier. Is the pipe continuous (no breaks)? Does it go up through the living space, through the attic to the exterior roof or does it exit the crawlspace horizontally and then continue up above the roof line? The system installed at the time of build may be a complete passive system or the builder wasn't required to complete the system but gave you "the starter pack" which at least alleviates the need for a more expensive retrofit.
I'm starting a radon mitigation company in East TN and will be taking the Kansas State courses in 2 weeks. Did you take their courses? I've learned alot from your videos. Very informative! ...Off topic, what toy you got under that cover?
Thank you.
Congratulations! I didn't take their entry-level courses since the University of Minnesota still offered them at the time. I have taken and helped teach some other courses Kansas State University offers, though. They have a fantastic radon training program.
The toy is a 70’s Chev, my dad restored.
What about snow and ice blocking the pipe? Not worried about rain getting in.
The open vent at the beginning of the video is the best way to prevent an ice blockage. Attic routes that include insulation on the piping, rather than external systems, rarely have freeze-up issues.
@@AmericanRadonMitigation what do you do if it has to be mounted on the side of the house?
We offer our customers a deicing system to help ensure the system doesn't freeze-up. You can also purchase our deicing kit here: americanradonmitigation.com/product-category/radon-system-de-icing/
wait wouldn't the preferred "open" method allow rainfall and critters to just fall straight down the tube? Why is this preferred?
You can read all about exhaust discharge requirements in section 6.4 of the radon mitigation standard. standards.aarst.org/SGM-SF-2023/24/index.html#zoom=z
My basement is dirt with bricks on top, and a long dirt crawl space. The walls are round boulders with bricks at top that our house sits on. How on earth do I have something like this installed. Maybe just vent the whole basement ?
It might be cheaper to use dynamite and start over. 😂
All joking aside, it sounds like a ton of work. You will have to make an airtight barrier between the soil below the bricks and the basement air. I'd look at removing the brick installing a drain tile system to draw from, a vapor barrier, and a new concrete floor. While you're at it, you could encapsulate the walls and crawlspace.
There are many ways to go about it, but that's the one I'd choose if it were my house.
Good luck, my friend.
Why does it matter if it goes down. Its on the roof. Mine comes out the center of the roof. It would have to move many feet, down and then find a window or door which is unlikely. Do you ever see smoke from a chimney come back in a house? Makes no sense.
This is covered in Section 6.4.9 Angled Trajectories in the 2023 Soil Gas Mitigation Standards for Existing Homes. Here's a link standards.aarst.org/SGM-SF-2023/26/index.html#zoom=z
I didn't have a cap and a chipmunk ended up inside, killing the fan. I put a radonaway t vent cap when I replaced my fan.
You may want to check to see if your radon system still complies with the mitigation standards since adding a rain cap.
See section 6.4.12.2 standards.aarst.org/SGM-SF-2017/26/index.html
Since that screen cap freezes up I'm going to get creative and just drill a few holes around my open pipe and run some 3" screws Into it. Close enough together to keep the squirrels out and far enough apart they won't freeze together.
That's an interesting idea.
@@AmericanRadonMitigation Hahahaha...I guess it isn't listed yet on "not allowed".
How is okay to vent carbon monoxide from my furnace using that cap but not okay for radon? If it was blowing bad air back into the house then people would be dropping dead from carbon monoxide poisoning. Certainly the highly diluted air from the radon system is not nearly as dangerous as we’re being led to believe. Once it’s mixed with outside air, it immediately becomes even more diluted. I don’t argue that radon is dangerous and needs to be removed from our homes but some of the installation guidelines feel a bit over blown.
I wouldn't want rain and snow coming down the b vent and onto my water heater. However, rain or snow in a radon system doesn't hurt anything. Radon systems remove a substantial amount of moisture below the home and are designed to handle water.
Keep in mind we don't write the standards. However, we do have to follow them, even the ones we may disagree with.
Here's a link to the standards for your reference. standards.aarst.org/
I appreciate that you want to follow best practices, but unless I am misunderstanding (always a possibility), these "standards" are recommendations from a private organization and no-one is under any obligation to follow them, except, perhaps, members of said organization.@@AmericanRadonMitigation