Radon and Pellet Stove Basement Intake Question?

[drizler]

Here is one for you scientific types in the building industry.
BACKGROUND: New keyed concrete poured foundation 1995. Ground consists of one great big shale that this sits directly on, clearance 0" . Basically concrete poured on the shale and yes we feel every little earthquake very well. Not a lot of surveyed radon in the area but some hot spots found by govt survey at one time or another. I did a radon test a few months after construction and it came in at around 2.00 ( if I recall th calibration correctly). At any rate it was well below any concern. Basement was sealed up pretty tight during the test period and it was winter so the boiler cycled regularly drawing its air from that area say 20' from trap. This summer I decide to test again which is advised by the experts. This time its 3.2, again below needing corrective action of any sort. This test was in summer 48 hour duration as indicated but basement was tightly closed off, nothing open. This time boiler shut down completely except for a couple cycles to heat up some DHW to shower. Like most things I like to do my tests "worst case scenario" so its not usually that closed up anyways, in fact I leave the cellar door open much of the time and at least one of the casement windows open for ventilation.
OK enough baloney. I draw the air for my pellet / corn stove from the living room and have without problems for 2 seasons. I would like to put an elbow or T in the intake and draw my air from the cooler, damper air in the basement which should warm it some in the winter and draw down on the moisture content. Someone on a bulletin board did this and had these results. To do this all I have to do is drill and cut a 3" hole in the floor and drop my intake pipe. Is this something that I should back off on considering the somewhat elevated radon levels in the basement and leave it down there rather than bringing it upstairs? Plan "B": just leave well enough alone and keep the intake in the living room. What do you enlightened types say?

 

[HarryBack]

Yea, your Radon numbers are low....Radon is usually emitted from Granite, not shale.

I dont see any problems whatsoever in what you plan to do....all intake air is eventually pushed outside anyways.

 

[Sandor]

I like your idea Driz.

Pellet Stove, Wood Stove, Clothes Dryer, bathroom fans, etc will create a negative pressure environment within the home envelope. That make up air comes from somewhere, usually leaks around doors, windows, electric outlets, attic accesses, etc.

By drawing air from the basement, that make up air should come from somewhere upstairs, IF your basement is sealed tight. And you will have a limited heating and dehumidification going on in the basement as the combustion air is drawn from the warm and dry upstairs. Thinking about it, it should decrease radon levels upstairs, as well as the basement, as the fresh air comes from outside (ABOVE GROUND) and makes it way to the basement to the pellet stove intake.

The only caveat I will give you is make sure your basement is sealed as tight as possible from outside ground level to the bottom. Make sure you caulk the seam between the floor and basement wall. There should be an expansion joint in there and this is where radon can creep in. Also, seal any plumbing penetrations, etc. It would also be a good idea to seal the concrete walls and floor. There are speciality products for this. The reason you want to do all of this is to minimize drawing more radon into the basement.

I say go for it !!

 

[elkimmeg]

Is there any other combustion appliances in the basement? If so you may create a nevagive effect. By adding another outlet used for combustion. Is there a clothes dryer there? All these things have to be considered before adding more demand to your basement enviorment. For every 1000 BTUS out of the appliances 50 cu ft of air is needed for proper combustion so find your air vollume add up your total BTU and factor the BTU requirement of the pellet stove and see if it can be done. Dryers figure 150 cfms Gas dryer even more criticle as combustion air is also needed for that appliance.

If you create a negative effect and draw in exhast gases from draft hoods or other chimneys. You could create a situation far worse than worring about radon You just created a carbon Monoxide issue

 

[drizler]

Wow I got enough reasponses quick enough. All I have is the boiler and gas dryer in the 28 bu 50 basement. Truth is The boiler doesn't run much any more due to the corn stove crankin away. Even the dryer only runs after I hang the stuff for a day or so. I have my faithful digital CO detector so am not worried about that much really. My big desire here it to dry up that basement as the guy described it in his article. If I can swing it I plan on having an elbow with a manual damper in it so I can bring it in from where ever I choose. In reality probably all of it should come in from below. One of these days as Pa Kettle said, I gotta spot me that hole and I am betting there is a floor joice right where I need to drill. Like I said one of these days, too much other busted stuff outside to play with it now. Thanks for the advice all.................

 

[elkimmeg]

Driz its not like it can't be done I just wanted to point out there are other factors to consider

 

[Dr_rox]

A couple of comments about radon that may add to the discussion:

Granite is not the only rock type that can pose a radon problem. The statement made by a previous poster that shale does not emitt radon is simply incorrect. The rocks just need to have elevated concentrations of uranium which produces radon by radioactive decay. Organic rich black shales frequently have elevated uranium. The Ohio Shale in central Ohio and the Marcellus Shale in central New York are a good examples of shales with well documented radon issues.

Short term radon tests (2-7 day, typical activated charcoal canister type) are not very precise. Probably not much better than 20% (1 standard deviation, thats 67% of the results fall within that 20% range) but it depends on the device and exposure time. Humidity, drafts, and temperature, can all affect the accuracy of the test results. Radon concentrations in basements vary naturally with ventilaton but also with surrounding soil/rock conditions. Normal short term variations in basements can be on the order of 50-70 %. A good rain storm can effect radon concentrations dramatically in some cases (without ever putting water in your basement).

I would not make too much of the difference between two tests that are 2.0 and 3.2 pCi/L The differences in the numbers are barely significant assuming normal errors for this type of test procedure. Given the seasonal difference in the tests they fall within normal variations. At this point I would not interpret the two analyses as "things are geting worse through time". You would need alot more data to determine that. They are also low concentrations and generally not considered a problem. Long term tests (90 days - 1 year, using an alpha track detector) are much more accurate. It is typically recommended to do a long term test if short term tests indicate a concentrations near the 4 pCi/L EPA action level - particularly if you are concerned about it.

Average indoor air (first floor living space) is about 1.3 pCi/L. Average ambient outdoor air is about 0.4 pCi/L. This means you will never be able reach a zero radon concentration. Radon is naturally occuring in air and is just one of those things we all have to live with. 4 pCi/L is the EPA "action level" for radon although they do "suggest" remediation between 2 and 4 pCi/L.

Anytime you lower the air pressure in the basement you increase the potential for radon to be drawn in from the surrounding soil/rock. EPA does not recommend sealing basement as the sole remedy for radon abatement. In most cases sealing only marginally improves radon conditions. If there is a real radon problem, it only takes one small area where the seal is not complete for radon to continue to leak in. Basically radon can pool under the slab and find that one little spot/crack to get in. Radon is aso significantly heavier than other elements that make up normal air and therefore it tends to like to stay in the basement. If you draft your stove from the basement ceiling you create a negative pressure in the basement that will draw in air from the surrounding soil/rock. Radon in that air will not necessarily "all draft out" as one poster said becasue it is heavier than other elements it tends to sink to the floor to a greater extent and stay in the basement.

All this being said, I don't think you have a significant enough radon problem to worry about it. I would still do another radon test after you start drafting the basement air -- just in case. Good luck.

 

[elkimmeg]

Dr-rox thanks for the info. Are there any wood stove related issues you want to discuss?
BTW welcome aboard

 

[velvetfoot]

I re-routed the dryer exhaust a couple of days ago so that it would exhaust out the side right through an exterior wall. Anyway, while testing, it was an eyeopener to me how much air is exhausted - quite impressive. The dryer manual mentions outside air for mobile home installations, but who the heck would know how to install that? Everything needs another hole in the wall.

We opened the window this summer in the basement because my wife was concerned about radon (it was around 12 down there if I recall). Although that brought it down, it also brought in a lot of moisture which caused a lot of condensation on all cold surfaces. I closed the window and put a 15 watt fan on a pipe that was already there for the purpose, and it knocked it down to 1.7, with no caulking. It's now .6 upstairs, down from 1.x.

I found that a dehumidifier makes a big difference too for moisture, but as I said, closing the window down there was major.

I would think that your radon level upstairs (where you live?) is a lot less than it is downstairs.

We bought a couple of electric detectors for a 100 bucks each.

 

[drizler]

Thank you Dr Rox. I can tell by the post that you do know the subject matter and I thank you very much. I don't worry about many things, hell I don't even wear my bullet proof vest at work but radiation is another matter. That stuff can just eat you alive and you won't have the slightest idea. That bothers me especially as time goes on they keep finding ( more like discolosing) how lower and lower levels do more damage ect. I just find it better to stay away from the stuff. Hell I won't even work other than occasionally around the big industrial x ray machine we use to scan trucks for drugs, terrorists, bombs, ect. The good old US Govt says you don't need radiation badges its so safe yet they park that source right next to the office where its run which has standard glass and aluminum sides. I was there and watched them build it. Strange how every one I have ever talked to in the industry who works around this stuff can hardly believe it. Ah yes, trust your government, they never lied to us before. Anyways, I digress here so thanks again for the very insiteful info on radon. Let me finish this off by telling everyone. GET A RADON TEST ITS $15 AND LIKELY WILL ONLY HAVE TO DO IT ONCE. Radon causes LUNG CANCER and its the second leading cause after smoking. It might just save your kids lives someday. Radon can be in any house, the only way to tell is to test!
When I get brave enough to drill a 3" hole in the floor and check it out I will let you guys know how it works out.

 

[Sandor]

Thank you Dr Rox. I can tell by the post that you do know the subject matter and I thank you very much. I don't worry about many things, hell I don't even wear my bullet proof vest at work but radiation is another matter. That stuff can just eat you alive and you won't have the slightest idea. That bothers me especially as time goes on they keep finding ( more like discolosing) how lower and lower levels do more damage ect. I just find it better to stay away from the stuff. Hell I won't even work other than occasionally around the big industrial x ray machine we use to scan trucks for drugs, terrorists, bombs, ect. The good old US Govt says you don't need radiation badges its so safe yet they park that source right next to the office where its run which has standard glass and aluminum sides. I was there and watched them build it. Strange how every one I have ever talked to in the industry who works around this stuff can hardly believe it. Ah yes, trust your government, they never lied to us before. Anyways, I digress here so thanks again for the very insiteful info on radon. Let me finish this off by telling everyone. GET A RADON TEST ITS $15 AND LIKELY WILL ONLY HAVE TO DO IT ONCE. Radon causes LUNG CANCER and its the second leading cause after smoking. It might just save your kids lives someday. Radon can be in any house, the only way to tell is to test!
When I get brave enough to drill a 3" hole in the floor and check it out I will let you guys know how it works out.

Come on Driz, get busy. Drill a small pilot hole first, like an 1/8 inch. Go down below to make sure the 3 inch hole has room without hitting a floor joist, and complete the bore.

 

[drizler]

Problem is I did me some cyperin last season and I think I am gonna hit that floor joist. Secondly the stove is locaded smack between 2 french doors that comprise most of the entire outside wall. How do you spell LOAD BEARING. With that squarely in mind whatever I cut oout will have to be made up for somewhere. Its just one of those little things that is so easily put off. While I am at it, does anyone know how to best go about cutting a 3" hole through 1/4" ceramic tile bonded to a piece of plywood?

 

[Sandor]

Problem is I did me some cyperin last season and I think I am gonna hit that floor joist. Secondly the stove is locaded smack between 2 french doors that comprise most of the entire outside wall. How do you spell LOAD BEARING. With that squarely in mind whatever I cut oout will have to be made up for somewhere. Its just one of those little things that is so easily put off. While I am at it, does anyone know how to best go about cutting a 3" hole through 1/4" ceramic tile bonded to a piece of plywood?

Uh, whats "cyperin"?

Anyway, your floor joist are running perpendicular from the french doors. Meaning, your joists are most likely 19-24 inches on center, so you should be able to find room to bore the hole between the doors somewhere, without hitting a joist.

If you have a spare tile, (you do, don't you?) beat out the tile with a hammer, and replace it with a new tile once the new pipe is in place. Will have to be in two pieces, obviously.

It would not be easy for me to put off doing knowing that I was inhaling radioactive gas.

 

[drizler]

Cypern is what Jed Clampett referred to as arithmatic. My joists are 16" OC and the stove sits fully occupying the area between the doors. Thats it thats all there is 32" to work with and the stove takes up 29". In order to get some measure of utility the stove has to sit almost to the wall so there is a mere 6" back there to squeeze in "T" or elbow. There is room for everything but just barely and thats all there is. I can't very well go in there and wiggle or angle stuff. That part of the outer wall is so thick with studs that I had to ream hell out of one of em to get the required 3" of clearance from the outer pipe. Not much to work with there as you can see. Thats why me gotta approach this so carefully. I can move the stove out a tad if needed but thats all to be done. Personally I wanted the thing more centrally located as recommended but the wife is adamant against it and the cost of the pipe and going up through the vaulted ceiling and roof is a real costly pain. I was very surprised how well that stove heats the entire houe including the bedrooms after making a couple of turns with a hallway using just one small 10" fan sitting on the hallway floor.