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jonr
Senior Member
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| 12 May 2010 03:50 PM |
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I expect that the size of fan needed to depressurize underneath a slab varies greatly with how well the slab is sealed. And that the replacement air is coming from the interior, so this sealing is important from an energy standpoint. Underslab flow should be minimized.
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Clark
Basic Member
Posts:248
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| 12 May 2010 04:56 PM |
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Posted By jonr on 12 May 2010 03:50 PM
I expect that the size of fan needed to depressurize underneath a slab varies greatly with how well the slab is sealed. And that the replacement air is coming from the interior, so this sealing is important from an energy standpoint. Underslab flow should be minimized.
I think that little air is pulled from the interior as compared to air through the window well drains and the sump vent. Air can also be drawn in through the space between the ICF foam and the dimpled water shield. My radon level is continuing to drop (0.8 pCi/L was the latest reading) so I'm going to take the suggestion of putting the fan on a timer to reduce the duty cycle. The fan also works with a motor speed control, but that's probably more expensive. |
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Clark
Basic Member
Posts:248
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| 14 May 2010 08:47 PM |
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This is intesting: Radon Pathways into Our Homes
Apparently, radon can diffuse through concrete. Since I used only dimple membrane to waterproof my ICF foundation (Platon), I didn't get the radon sealing benefit of a bituminous seal coat. That might explain my high radon levels as compared to my next door neighbor's. |
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robinnc
Advanced Member
Posts:586
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| 14 May 2010 10:19 PM |
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That is very interesting....I never would have thought it could come thru concrete!!
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Clark
Basic Member
Posts:248
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| 30 Nov 2010 10:36 AM |
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Over the summer I've experimented with my radon pump and found that I can keep the radon level well under 4 pCi/L running at a 75% duty cycle. Using an 81 watt pump (fan) and avoiding the afternoon peak electrical demand period (I'm using time-based metering), it costs me about 10 cents a day. In retrosect, I wish I had paid more attention to radon sealing during construction. |
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John Clem
New Member
Posts:38
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| 30 Nov 2010 09:09 PM |
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Thought I might add some info to this discussion. It is my understanding that radon presence in a home is a hit or mis situation, purely dependent on the spot where the home is built. Of course you have to live where radon present in the soil. Unfortunately you can’t know until a house is built if it will have a radon buildup issue.
I live in ICF house in an area where radon is present in the ground. I have tested our home, twice just to make sure. The levels are below 1.5pCi/L, so no remediation measures are needed.
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Home Design<br>
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Clark
Basic Member
Posts:248
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| 01 Dec 2010 10:37 AM |
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Posted By John Clem on 30 Nov 2010 09:09 PM
Thought I might add some info to this discussion. It is my understanding that radon presence in a home is a hit or mis situation, purely dependent on the spot where the home is built. Of course you have to live where radon present in the soil. Unfortunately you can’t know until a house is built if it will have a radon buildup issue.
I live in ICF house in an area where radon is present in the ground. I have tested our home, twice just to make sure. The levels are below 1.5pCi/L, so no remediation measures are needed.
John, how did you go about testing for radon? I've found that my radon levels vary from place to place and from one seaon to another. Also, did you incorporate radon barriers/sealing into your foundation design? --Clark |
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John Clem
New Member
Posts:38
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| 01 Dec 2010 10:54 PM |
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I used off the shelf test kits, different types. Need to have all the windows and doors closed for time of the test, so tested in late spring. Testers need to be in a location where they will not be disturbed and where there is no air movement, so I used 2 different closets. I think the test period was 2 or 3 days on each kit.
No special measures for radon sealing. Traditional slab floor with 6mil plastic and 2 inches of foam over 8" of gravel. I did incorporate a 3" radon stack going from the gravel out to the roof. Planed to add a fan later if needed. |
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Home Design<br>
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judas
New Member
Posts:23
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| 17 Dec 2010 06:13 PM |
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well radon as well as arsnic in the wells is defonately a problem in maine as its all granite just under the top soil almost everywhere.
call me silly but would not a "simple" air/heat exchanger ..that exchanges heat from vent air to incoming air change enough air to mitigate radon? from the floor since it is the heaviest gas or a cold air return like back in the day .. a grate on the floor near the door/ in the mud room allowing the heavy gas in the room .. and cold air to sink . having a exhaust from the basement floor area and exchange the heat to 'fresh' air on the first or second level. this should allow radon to travel to the lowest point of your home and exhaust .. or am i missing something??
as for hard wood floors they should be in your home unboxed to acclimate to local conditions |
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Clark
Basic Member
Posts:248
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| 17 Dec 2010 06:52 PM |
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Posted By judas on 17 Dec 2010 06:13 PM
well radon as well as arsnic in the wells is defonately a problem in maine as its all granite just under the top soil almost everywhere.
call me silly but would not a "simple" air/heat exchanger ..that exchanges heat from vent air to incoming air change enough air to mitigate radon? from the floor since it is the heaviest gas or a cold air return like back in the day .. a grate on the floor near the door/ in the mud room allowing the heavy gas in the room .. and cold air to sink . having a exhaust from the basement floor area and exchange the heat to 'fresh' air on the first or second level. this should allow radon to travel to the lowest point of your home and exhaust .. or am i missing something??
as for hard wood floors they should be in your home unboxed to acclimate to local conditions Any method of removing the radon from the interior of the house is good, but, if I understand the radon mitigation recommendations of the EPA, the goal is to prevent the radon from entering the house in the first place by either sealing the foundation, or, if that is not effective, evacuating radon-laced air from under the basement floor to a point above the eaves of the house. Also, most basements have ventilation supply and return vents placed in the ceiling making it hard to expel the radon, which, as you mentioned, is heavier than air and settles in low areas. |
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greencleaning
New Member
Posts:50
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| 19 Dec 2010 09:48 PM |
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Where air bricks are recommended as the means of dispersing radon from beneath beam and block floors they should be installed where possible on all sides of the building, and should be placed at intervals at lease as frequent as would be normal for an ordinary suspended floor. Typically this means that vents should be positioned at 2m maximum centres along the external walls and not more than 450mm from corners.
This type of subfloor ventilation has been in use for a number of years with the only drawback that the landscaping, paths and driveways must not compromise the subfloor ventilation.
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Here's to you, your health and the health of your family. <a href="http://www.cleaningcleaner.com">Eco friendly cleaning</a>
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Dave Spencer
New Member
Posts:2
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| 10 Mar 2011 03:10 PM |
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I have a net zero, very tight new home experiencing very high radon levels (over 8.5 pCi). The basement walls are foam-insulated pressure treated wood and under the concrete slab we placed rigid insulation, poly sheeting and gravel, running the poly up the inside walls to the level of the concrete slab. The initial readings 3 months ago were high so I ran the HRV for a month and trhe levels went down but not below the "recommended" maximum. I am in Western Canada and soils are silty clay but no bedrock other than sandstone here and there and nobody seems to have any concerns in the past, so this is exrtrraordinary. We did install an underslab perimeter collection pipe just in case so I will now have to duct outside with a fan to depressurize under the slab. There is a sump as well so I will be sealing off the cap. Just goes to show you can construct to avoid issues and with the goal of superior air quality but radon was not considered a high risk. |
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BrucePolycrete
Advanced Member
Posts:524
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| 10 Mar 2011 03:38 PM |
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There's no real evidence that radon is anything other than a revenue generating opportunity for a real-estate related industry created during the recession of the early 1980's. http://fumento.com/cancer/radonscare.html |
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jonr
Senior Member
Posts:5341
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| 10 Mar 2011 05:31 PM |
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That study may have flaws, but others don't:
http://www.epa.gov/radon/pubs/physic.html#HealthRisk
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Dave Spencer
New Member
Posts:2
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| 10 Mar 2011 05:48 PM |
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The evidence seems to be compelling, if not conclusive. In any case for a couple of hundred dollars I will not be taking any risks
www.echohaven.ca
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Dana1
Senior Member
Posts:6991
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| 11 Mar 2011 12:40 PM |
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Posted By jonr on 10 Mar 2011 05:31 PM
That study may have flaws, but others don't:
http://www.epa.gov/radon/pubs/physic.html#HealthRisk
You'd take the consensus of health & enviro-science professionals over that of a self-promoting book-selling political gadfly with a non-technical B.A. degree!!?  It's fun to throw darts and stir up stuff, sometimes it's even profitable. And it's a lot easier than doing actual science. Best of luck to Fumento, but I won't be buying his books. His "review of the scientific literature" isn't the same as a peer-review by multiple somebodies who actually know stuff. He pretends to expertise well beyond what's credible, and an authority on very little (if anything.) His value (if any) is as a critic of how popular media misconstrues/misreads and politicizes the science, but technically he's a real lightweight IMHO. |
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BrucePolycrete
Advanced Member
Posts:524
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| 11 Mar 2011 01:19 PM |
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Enjoy your Kool Aide |
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Eric Anderson
Basic Member
Posts:441
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| 11 Mar 2011 01:52 PM |
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Is that you Jim Jones?
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| Think Energy CT, LLC Comprehensive Home Performance Energy Auditing |
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BrucePolycrete
Advanced Member
Posts:524
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| 11 Mar 2011 02:35 PM |
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No, he was reincarnated and works for the EPA |
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ICFHybrid
Veteran Member
Posts:3039
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| 11 Mar 2011 02:59 PM |
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Well, I certainly wouldn't want to argue with a guy who has embedded with SEALs and the 101st Airborne.
And, if you think about it, the only real evidence that radon exists in the first place comes from electronic gadgets and chemical magic; all of which is made or formulated by folks who have been to universities and the like.
Need I point out the opportunities for mass brain-washing there? |
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