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Thread: Granite....radon

  1. #46
    Master Plumber master plumber mark's Avatar
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    Talking Mold is the big scare now.....

    Quote Originally Posted by hj View Post
    I guess when the class action lawyers start advertising for clients, that is the time to wonder whether this is the new "asbestos" scare. They didn't get much business the first time around with Radon, so maybe this time is the charm.

    Why worry about something as silly as Radon..emitting from
    a granite kitchen top....

    Poor people with expensive 40k granite kitchens
    I really, really feel for them.....



    Radon was the big scare back in the early 90s....
    and Mold is the big, big money maker now...


    people have literally been scared to death when they see any of it.
    and if you inadvertanly pour a gallon of water out on their basement floors and they go nuts..........


    Perhaps the new scam and money maker will be to somehow "seal the granite"
    in your home so it wont emit radon....

    I should look into starting a franchise.




    What about all the other chemicals that emit from the carpets, walls,
    floors, and other building materials in a normal modern home???





    something is going to kill you........ someday......







    How about going back to living like this??

  2. #47
    Radon Contractor and Water Treatment 99k's Avatar
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    The average granite out there is under 20 uR/hr gamma, or around .2 or .3 mR/hr if you count all radiation. If you look at it in terms of background radiation, the "safe" granite will double, triple or quadruple your radiation that you get from natural sources all around you. As a granite fabricator, we have a limit of 25 uR/hr gamma, mainly out of concern for our workers.
    Al:

    Radiation exposure is related to the distance from the material. Are these numbers being reported with the geiger counter directly on the granite ... the levels drop substanially since the levels are inversely related to the distance squared. A radiation level 3" from the rock is only about 10% of what it was 1" from the rock.

    Do you monitor the radon levels in your plant? You want to install a heat recovery ventilator if your radon levels are high and the source is determined to be from the materials you handle.

    In the several homes I have measured for radiation, I found the ceramic tile floor gave off the same background levels as the granite countertop (about 3X what is was in other parts of the homes and that was 1" from the material ... practically nothing).

  3. #48
    Plumber jimbo's Avatar
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    Default Thank you, Al G.

    I appreciate getting some input from someone with a lot of experience on the topic.

    It is still a gray area to me. We did get the safety siren machine, and have been running it for a week at a time in various rooms in the house. Set right on top of the granite, it averaged about 2.6 pico/Ci over a week. And similar readings are obtained at most rooms in the house, including the garage which has me wondering if they are in fact on a ground area which is the problem, more so than the granite!

    I did run it for a week in my house, and the readings ran about 0.24

    I realize that this machine, and the over-the-counter lab test she did are all non-scientific in approach. SO what does a person do? They say over 2 is a concern, but what?

    We are thinking of just installing a temporary exhaust fan and see if that does anything for the average level in the house. We are somewhat reluctant to put in an "official" radon system, as that may "poison" the future sale-ability of the house!


    When I was in the Navy, I think the maximum permitted exposure was given as 250 milliRad per quarter ( 3 months ). Obviously the granite gamma numbers in micro Rem would not be a problem, but the airborne dose of granite dust or radon........maybe.

  4. #49
    Retired Defense Industry Engineer jadnashua's Avatar
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    Radon is a gas, so it can diffuse throughout the house. The higher it is at the source and the tighter the house, the higher the ultimate level could reach. The draftier the house, the less the problems. You can get it from your well-water, too. This is probably the worst possible situation since you often are in a closed space (shower) where you could be breathing it in deep. The hot water and the spray disperses it out of solution right at you. NH is nicknamed the granite state, and radon can be problematic here. Not a bad idea when purchasing a house to check for it both in the water (many places rely on wells), and in the air.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #50
    Radon Contractor and Water Treatment 99k's Avatar
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    It is still a gray area to me. We did get the safety siren machine, and have been running it for a week at a time in various rooms in the house. Set right on top of the granite, it averaged about 2.6 pico/Ci over a week. And similar readings are obtained at most rooms in the house, including the garage which has me wondering if they are in fact on a ground area which is the problem, more so than the granite!
    Directly on the granite is an invalid test ... should be at least 20" away from it. Also, test invalid when placed in the kitchen due to high moisture (doesn't affect safety siren but skewed by the radon in water). Retest this room or put in adjacent room. The source of the radon is not from the granite, otherwise the numbers on the counter would have been substanially higher.

    I did run it for a week in my house, and the readings ran about 0.24
    Those are unusually low numbers since the outside air is typically .4 pCi/l.
    I realize that this machine, and the over-the-counter lab test she did are all non-scientific in approach. SO what does a person do?
    The safety Siren is an accurate piece of equipment. Many over the counter tests are very accurate ... I would not be so quick to discount them.

    They say over 2 is a concern, but what?
    You should be less than 4 pCi/L ... and ideally less than 2 pCi/L if you are going to fix it. However, some homes are difficult/not practical to reduce to less than 2 pCi/L.

    We are thinking of just installing a temporary exhaust fan and see if that does anything for the average level in the house. We are somewhat reluctant to put in an "official" radon system, as that may "poison" the future sale-ability of the house!
    A temporary exhaust may reduce numbers short term, but they will return to original levels within hours. A radon system will not hurt your resale value and can actually help resale by reducing radon, moisture, and possible mold problems.

  6. #51
    Plumber jimbo's Avatar
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    Thank you 99 for your input as well.

    When I say non-scientific, what I meant was the testing was not done in a really controlled manner. Life went on, so no particular attention was paid to opening and closing of doors, etc. I do appreciate knowing the the equipment is reliable.

    The house is insulated, heated, and air conditioned. There are no particular problems with humidity, etc. The drawback of the ventilation fan.....I was proposing running something like 12 to 18 hours per day....is that it would just be directly exhausting conditioned ( heated or cooled) air to the outside. But I still want her to do it for a month or so to see if it makes a difference.

  7. #52
    Retired Defense Industry Engineer jadnashua's Avatar
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    Jimbo, if you are going to address this, put in a heat-recovery ventillation system. Panasonic and others have some that are pretty good about recovering the energy you paid for. This also will keep the pressure more constant...just exhausting means drawing air in through any crack or leak in the house...managing it is a much better plan.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  8. #53
    DIY Hillbilly Southern Man's Avatar
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    Quote Originally Posted by jadnashua View Post
    Jimbo, if you are going to address this, put in a heat-recovery ventillation system. Panasonic and others have some that are pretty good about recovering the energy you paid for. This also will keep the pressure more constant...just exhausting means drawing air in through any crack or leak in the house...managing it is a much better plan.
    Yup- plus putting your house under a vacuum means you could be pumping radon into it from the foundation.

    Radon removal involves putting the foundation under a vacuum.

  9. #54
    Plumber jimbo's Avatar
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    Good point....I'll tell her to look into that.

  10. #55
    Radon Contractor and Water Treatment 99k's Avatar
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    Quote Originally Posted by jimbo View Post
    Thank you 99 for your input as well.

    When I say non-scientific, what I meant was the testing was not done in a really controlled manner. Life went on, so no particular attention was paid to opening and closing of doors, etc. I do appreciate knowing the the equipment is reliable.

    The house is insulated, heated, and air conditioned. There are no particular problems with humidity, etc. The drawback of the ventilation fan.....I was proposing running something like 12 to 18 hours per day....is that it would just be directly exhausting conditioned ( heated or cooled) air to the outside. But I still want her to do it for a month or so to see if it makes a difference.
    Jim:

    As a radon contractor, many of things you are suggesting do not make sense. I suggest you get a pro to look at your daughter's house because you can actually make the situation worse. I handle Connecticut, otherwise take a look at this link.
    http://www.radongas.org/radon_mitigation_service.shtml

  11. #56

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    99K,

    Close on the radiation range info, were a granite countertop a point source, your info would be correct. But a plane surface is not a point source, so the radiation reaches much further than you can imagine.

    There is a lot of misinformation out there on this topic, take Beta radiation and the distance it can travel. Once we were told the Beta can travel a few inches in dry air, now we are told, oh, that was for Beta sources found in a nuclear plant. It turns out that Beta from some of the decay products can go over 5 meV, with 1 meV allowing ten feet of travel.

    We have done range tests with a sensitive pancake probe using hot granite slabs, up to six feet away, radiation levels are at three times background. Six inches will be about half of what it was on contact.

    Currently we are contducting dosimeter studies using a mannequin with badge dosimeters, and our Radon room has passed the intial tests (up to 30 pCi/L from 36 square feet of granite). Next is to start varying ventilation levels and tracking what happens.

    If you are finding granite at 3 x background, while there is a small risk, it isn't something I personally would be concerned about unless it was one of those few stones that put out large amounts of radon despite being low level. One stone studied in Mn was at 7 uR/hr (background was 6 uR/hr) but it pumped out some serious Radon according to the scientist that reported it.

    Jimbo,
    thanks, but there isn't anyone with a lot of experience, even the scientists are still learning. This has been a quite humbling experience for me, I had know idea on how little I knew on this topic.

    The Safety Siren will slightly over respond sitting on the granite. When we run E-Perm tests, we use two meters, one sealed under a 3 liter bowl sitting on the granite, the other sealed under a 3 liter bowl sitting on a PVC sheet that is sitting on the granite. That gives us a reading on the air that is trapped inside the bowl before it was sealed and the radiaton coming from the granite that will affect the test.

    In our Radon room, we keep the CRM's and Electrets about three feet away from any granite. We do accumulator tests as well, following the proper protocol that accounts for the varibles.

    2.6 pCi/L just sitting on a slab does show some concern. Under a bowl, it would jump to hundreds of pCi/L. If you do a test under a bowl with a known volume, a known time, a known background radiation, send me the data, I have an Excel templete set up by a Radon researcher (Dr. Kotrappa) that will tell you the pCi/SF/hr coming off the spot being tested. Or I can send you a formula if you are good at algebra.

    Radon levels at any level carry risk. The annual death rate for Radon is 21,000 according to the EPA, but that is based on 1.3 pCi/L, the national average for homes. So 2 will kill you just as 4 will. Get it as low as possible if you can, but as others have said, sometimes below 2 isn't practical.

    The annual radiation levels allowed are high if there is a public benefit and the person knows about the risk, accepts it, and the workers exposures are carefully tracked. Like a medical x ray, there is an excellent reason for the exposure. Not so with a hot granite countertop. The NRC holds the states to cleaning up contaminated areas to less than 25 mrem per year exposure to the inhabitants. Even the stone industry has agreed that is a target to shoot for, no more than 25 mrem per year. That means that a dose from a granite top has to be less than 17 uR/hr, about three times background here in Oklahoma.

    And Jim is so right, Radon in water is a problem too. Just imagine if that shower was lined with granite walls, granite tile floors, and granite countertops on the vanity.

    There is some great info on Radon mitigating posted in this thread. Excellent advice from all.

    There has been a lot happening since I last ran across this site. Three committees looking into the controversy, AARST (Radon scientists), CRCPD (State radiation protection officials), and ASME. I sit on the ASME committee, recently set up a panel dicussion for AARST for the September conference (it still has to be approved, but they came to me to ask it be done), and my email group has many of the other two committee members as members, so I get a front row seat. The stone industry came out with another "study" but the scientists reviewing it are tearing it apart, calling it unreliable. Would you believe they didn't calibrate their instruments before doing the tests? Some of the stones in the study were studied by independent researchers, finding 20 times the Radon that the stone industry found. No surprise there, eh?

    We have a forum ( forum.solidsurfacealliance.org ) where I post what information I can, although not alot of the really good info can be used until my email group members publish their papers in journals. The first paper will come out in April, Health Physicist Journal. DR. Steck at St Johns univesity is rushing to publish his work, Dr. Llope has conducted his gamma spectrometery studies and is working with a couple of cancer doctors to put the data into direct organ dose rates so that the cancer rates from the hottest stones can be given.

    Great forum, intelligent posters that post some solid info. Usually one of these discussions turns into a battle from little informed egos or a granite guy wacking away at the truth.

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