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jimbo
08-21-2008, 08:30 PM
Has anyone been reading about this issue? My daughter decided to buy one of those test kits, and sent in to the lab for results. It came back with 3 pico-curies. The lab danced, and basically said that is not high enough to panic and too high to just ignore. But doesn't say WHAT to do.

We are in an area where naturally occuring radon from the ground is basically not existent, so we assume these numbers are the off-gassing from the granite.


There seems to be a ton of info on this on the internet, but I have not come across an authoritative source which will say whether this off-gassing from the granite is something which is worrisome, like the stuff that comes up from under the house.

statjunk
08-22-2008, 04:42 AM
Nowadays everything will kill you. You can't even eat a damn chicken anymore.

Tom

Cass
08-22-2008, 04:58 AM
My dad is fairly well versed in this...I will ask him later today and report back.

99k
08-22-2008, 05:03 AM
Has anyone been reading about this issue? My daughter decided to buy one of those test kits, and sent in to the lab for results. It came back with 3 pico-curies. The lab danced, and basically said that is not high enough to panic and too high to just ignore. But doesn't say WHAT to do.

We are in an area where naturally occuring radon from the ground is basically not existent, so we assume these numbers are the off-gassing from the granite.


There seems to be a ton of info on this on the internet, but I have not come across an authoritative source which will say whether this off-gassing from the granite is something which is worrisome, like the stuff that comes up from under the house.


I am very familar with this problem. I just tested someones house yesterday ... their well water, basement air, upstairs air, and geiger counter of the granite. Tests have determined that an average countertop will contribute about .13 pCi/L to a house average when the threshold action level is set at 4 pCi/L. Does she have a basement or does she live on a slab? Does she have city water or well?

Cass
08-22-2008, 05:22 AM
jimbo, how many days long was the test, what room was the sample taken from, the house windows should have been closed, AC being on may cause it (the reading) to be lower. With max of 4 pci/l if it was a 1 day test that could be a false negative or positive. 1 day tests are not good and conditions in the home should simulate winter conditions during testing...every thing being closed up.

Does any one in the home smoke in the house? Smoking exacerbates radon.

The test should be done in the room where they spend most of their time which is normally where the TV is.

99k
08-22-2008, 05:27 AM
jimbo, how many days long was the test, what room was the sample taken from, the house windows should have been closed, AC being on may cause it (the reading) to be lower. With max of 4 pci/l if it was a 1 day test that could be a false negative or positive. 1 day tests are not good and conditions in the home should simulate winter conditions during testing...every thing being closed up.

Does any one in the home smoke in the house? Smoking and radon together is worse than either one alone.

Having the A/C on is perfectly fine as long as you are recirculating the air and not introducing new air. As far as the location, please confirm the kit WAS NOT ON THE GRANITE. Should be 20" off floor, 3' from an outside door or window, and 12" from an outside, 4" from other objects.

hj
08-22-2008, 06:38 AM
radon testing is like going to the optometrist. According to them EVERYONE needs glasses and everyone has a Radon problem.

99k
08-22-2008, 06:45 AM
radon testing is like going to the optometrist. According to them EVERYONE needs glasses and everyone has a Radon problem.

The only problem I have with that statement is that approximately 22,000 die each year from radon induced lung cancer ... when I loose my reading glasses I just need to stretch my arms:D

jimbo
08-22-2008, 07:10 AM
The house is on a slab, cith water. According to any maps I have found on the internet, this is a "low" area for natural radon.

She bought a kit which had 3 cannisters. She did all three in the "great room" which is kitchen/dining/family combo. But none right on the granite. A/C recirculates, but 2 little girls who hate to close the doors allow a lot of outside air in!

I was thinking of buying one of those machines ( geiger counter ??) which allow you to do repeated tests, and accumulate short term ( few days ) and longer term results. About $120. Looks like another toy I need!

99k
08-22-2008, 01:38 PM
The house is on a slab, cith water. According to any maps I have found on the internet, this is a "low" area for natural radon.

She bought a kit which had 3 cannisters. She did all three in the "great room" which is kitchen/dining/family combo. But none right on the granite. A/C recirculates, but 2 little girls who hate to close the doors allow a lot of outside air in!

I was thinking of buying one of those machines ( geiger counter ??) which allow you to do repeated tests, and accumulate short term ( few days ) and longer term results. About $120. Looks like another toy I need!

Well, I don't see anything that would indicate these tests are invalid as long as she followed the protocol of heights and distances that I listed before. Also, you don't want to take measurements directly in the kitchen. Understand high radon is in every state and in every country ... don't read too much into local maps.

You do not need a geiger counter because a good one will cost you $600. A Continuous radon monitor runs anywhere from $600 to 10K. I have a continuous radon monitor and have found good correlation to a device called a Safety Siron. This device looks just like a plug-in CO detector. You can buy them on e-bay for ~$100.

Anymore q's, fireaway because radon contracting is my business.

Bob NH
08-22-2008, 02:50 PM
Radon comes from decomposition of radium, which is often present in granite.

If there is graninte under the slab or basement floor, the gas is trapped and tries to escape through the floor, which almost always has some cracks or joints. It is practically impossible to make the floor gas-tight.

I helped my son install a mitigation system in the basement of his home in Vermont. The level was about 8 before installation and about 1 when we tested after we finished.

The principle of the systems is to use a blower to create a vacuum under the slab or floor so the pressure under the slab is lower than the pressure in the basement or room. The connection is made with PVC pipe sealed into a hole (or holes) in the floor, run to the blower in an attic or other convenient place, with the exhaust through the roof. You can run it out the side of the house if it is not near a window.

Effectiveness depends on having a porous layer (gravel or coarse sand) under the concrete so the gas and air can pass under the slab to the collection point(s).

The cracks and other openings in the floor should be sealed as well as possible so the blower size can be minimized. That is because power consumption can be significant. A 100 watt blower uses about 72 kW per month which can add $10 per month to the electric bill.

We caulked all around the edge of the basement floor, around the toilet in the basement, and around a drain penetration.

With the level that you have it would be worth investing in the continuous radon detector. I suspect that radon will be down in the summer with all of the inside/outside traffic and ventilation, and you could shut off the system to save power.

jimbo
08-22-2008, 02:58 PM
Yes. The Safety Siren is the one I was looking at.

Problem with this issue is getting a straight answer! Some sites ( probably related to the granite industry!) suggest not to worry about localized readings off the granite....it is just the whole house number which matters. Who knows! Granite kitchens have been around a long time, and I have never heard that they have connected any cancers to that....but who knows!

I am not paranoid about the issue...not a stranger to radioactivity. As a whippersnapper, I have slept within inches of a nuclear tipped subroc rocket. The made us sleep at the rocket motor end, not up at the warhead end! Also breathed enough CO, CO2, and R12 that a few stinking picocuries of something won't phase me!

99k
08-22-2008, 07:44 PM
It is good advice not to worry about the granite and concentrate on the total radon levels. As I said, the average granite top is adding .13pCi/L which is pretty low.

99k
08-22-2008, 07:53 PM
It is good advice not to worry about the granite and concentrate on the total radon levels. As I said, the average granite top is adding .13pCi/L which is pretty low.


Radon comes from decomposition of radium, which is often present in granite.

If there is graninte under the slab or basement floor, the gas is trapped and tries to escape through the floor, which almost always has some cracks or joints. It is practically impossible to make the floor gas-tight.

I helped my son install a mitigation system in the basement of his home in Vermont. The level was about 8 before installation and about 1 when we tested after we finished.

The principle of the systems is to use a blower to create a vacuum under the slab or floor so the pressure under the slab is lower than the pressure in the basement or room. The connection is made with PVC pipe sealed into a hole (or holes) in the floor, run to the blower in an attic or other convenient place, with the exhaust through the roof. You can run it out the side of the house if it is not near a window.

Effectiveness depends on having a porous layer (gravel or coarse sand) under the concrete so the gas and air can pass under the slab to the collection point(s).

You can effectively remediate a building without having porous material if proper techniques and equipment is used

The cracks and other openings in the floor should be sealed as well as possible so the blower size can be minimized. That is because power consumption can be significant. A 100 watt blower uses about 72 kW per month which can add $10 per month to the electric bill.

This is not necessary in most instances ... especially is a home that is finished and on a slab

We caulked all around the edge of the basement floor, around the toilet in the basement, and around a drain penetration.

With the level that you have it would be worth investing in the continuous radon detector. I suspect that radon will be down in the summer with all of the inside/outside traffic and ventilation, and you could shut off the system to save power.

You should never shut down a system. The radon level will be back to were it was within hours. Not only does a system remove radon, but can mine out as much as gallons a day of moisture. Many of my clients have seen the dehumidifier run much less and the musty smell is gone

hj
08-23-2008, 03:10 PM
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.

Bob NH
08-23-2008, 10:10 PM
You should never shut down a system. The radon level will be back to were it was within hours. Not only does a system remove radon, but can mine out as much as gallons a day of moisture. Many of my clients have seen the dehumidifier run much less and the musty smell is gone

99k;
I would be grateful if, when you are quoting a post that I have made, you don't embed your comments within the quote of my posting. What you have done is very misleading and wrongly represents my position in a manner that makes it appear that I have contradicted myself.

I would be further grateful if you would edit your post to remove your comments from within your quote of my post, and leave an editing note so that other readers will realize the basis for this post.

If that is too difficult, then please delete the quote altogether from your post and leave an editing note that will explain the basis for this message.

There are ways to split up a quoted posting so that you can insert comments relative to each part of it. I suggest that you learn how to do that so that others you choose to quote are not misrepresented.

jimbo
08-24-2008, 06:38 AM
for 99k> What I do when I wish to make a few comments regarding a longish post like bobs.....I put my comments in either caps/bold, or change the font color to red. That way, there is no confusion as to who said what.

The way you did it, we can't tell reading that what was your comment versus what was the orignal poster.

Alectrician
08-24-2008, 09:20 AM
Smoking exacerbates radon.

Anyone who smokes really shouldn't be concerned over other health hazards.


Smoking exacerbates death.


Radon is the new mold IMHO.

jimbo
08-24-2008, 10:51 AM
Radon is the new mold IMHO.
Funny how things work! Mold was the new asbestos!

99k
08-24-2008, 03:01 PM
99k;
I would be grateful if, when you are quoting a post that I have made, you don't embed your comments within the quote of my posting. What you have done is very misleading and wrongly represents my position in a manner that makes it appear that I have contradicted myself.

I would be further grateful if you would edit your post to remove your comments from within your quote of my post, and leave an editing note so that other readers will realize the basis for this post.

If that is too difficult, then please delete the quote altogether from your post and leave an editing note that will explain the basis for this message.

There are ways to split up a quoted posting so that you can insert comments relative to each part of it. I suggest that you learn how to do that so that others you choose to quote are not misrepresented.

Sorry Bob:

I was trying to comment at certain points in your message ... I have never be able to figure out how to do this. Once it was posted I figured no one would pick up on my comments.

99k
08-24-2008, 03:21 PM
Let me undo my mess. These are all my comments ...

"You can effectively remediate a building without having porous material if proper techniques and equipment is used"

"Filling cracks is not necessary in most instances ... especially is a home that is finished and on a slab"

"You should never shut down a system. The radon level will be back to were it was within hours. Not only does a system remove radon, but can mine out as much as gallons a day of moisture. Many of my clients have seen the dehumidifier run much less and the musty smell is gone"

Anyone want to instruct me hown to multiquote?

Thanks,

Alectrician
08-24-2008, 04:25 PM
Anyone want to instruct me hown to multiquote?

In the reply box, paste and highlight the portion you want to quote and hit the quote icon.

If you want to quote the whole comment but comment on individual sentences just paste the whole thing, highlight the individual portions and leave space between them for your replies.


You can preview reply to test.

jimbo
08-24-2008, 05:13 PM
Sorry Bob:

I was trying to comment at certain points in your message Here is how I insert comments ... I have never be able to figure out how to do this. Once it was posted within a quote I figured no one would pick up on my comments.

You do have to put a little something down here, else you get a "short reply" error. But it can literally be just :,,,,,,,,

99k
08-24-2008, 08:22 PM
In the reply box, paste and highlight the portion you want to quote and hit the quote icon.

If you want to quote the whole comment but comment on individual sentences just paste the whole thing, highlight the individual portions and leave space between them for your replies.


You can preview reply to test.


I cannot figure it out??:mad:

Alectrician
08-25-2008, 12:55 PM
Don't use the quote function in the post. That will quote the whole post.

Copy what you want and paste it in your reply. Split it appart if you like.

Highlight the part you want to appear as a quote and click the quote icon above the reply box (it's yellow and looks like text in a cartoon like thingy).

Redwood
08-25-2008, 04:33 PM
If I was quoting you this would be at the start of the quote [QUOTE=99k;153209] The 153209 is the message number being quoted.

Redwood
08-25-2008, 04:33 PM
And this would be at the end of the quote... [/QUOTE]

99k
08-25-2008, 05:51 PM
Don't use the quote function in the post. That will quote the whole post.

Copy what you want and paste it in your reply. Split it appart if you like.

Highlight the part you want to appear as a quote and click the quote icon above the reply box (it's yellow and looks like text in a cartoon like thingy).
Don't use the quote function in the post. That will quote the whole post.

Let's see if this works.

99k
08-25-2008, 05:53 PM
I must be brain dead from smelling all that PVC glue:rolleyes: I have been using computers forever, but I can't get this silly thing down. It isn't very intuitive.

99k
08-25-2008, 05:55 PM
Don't use the quote function in the post. That will quote the whole post.

Copy what you want and paste it in your reply. Split it appart if you like.

Highlight the part you want to appear as a quote and click the quote icon above the reply box (it's yellow and looks like text in a cartoon like thingy).


Copy what you want and paste it in your reply. Split it appart if you like.

I may have it this time.

99k
08-25-2008, 05:58 PM
Thank you Alectrician! I finally figured out what that "cartooney" thing was that you referenced.:D

Alectrician
08-25-2008, 07:26 PM
Thank you Alectrician!

Glad to help



I finally figured out what that "cartooney" thing was that you referenced.

Now try the picture thingy next to it.


My cabin ROCKS!

http://i8.photobucket.com/albums/a8/JohnC1952/DSC01867.jpg

99k
08-26-2008, 06:40 PM
Your cabin does rock. What state is it in? Those are million dollar views.

Alectrician
08-27-2008, 04:19 PM
It is in Prescott AZ about 2 hours North of Phoenix.

Storm watching is awesome there.

Video link

http://s8.photobucket.com/albums/a8/JohnC1952/?action=view&current=MOV01786.flv

Southern Man
08-27-2008, 07:05 PM
I built a new mountain cabin three years ago with a basement and granite in the kitchen and upstairs baths, then discovered 30 units of radon in it a year later. So I put a vacuum system in the basement and knocked it down to 2 using a plug-in detector (in the basement, of course).

Then read this damn thread!! So I reset the detector, plugged it into a kitchen outlet, tucked back way in the corner just above the counter, then waited three days to get a new reading of 1.

Phew.

jadnashua
08-28-2008, 06:25 AM
Not all granites are the same - just look at the vast quantity of colors and textures available from around the world. So, your result is not unexpected. Too much of anything is bad for you.

Southern Man
08-28-2008, 06:39 PM
Not all granites are the same - just look at the vast quantity of colors and textures available from around the world. So, your result is not unexpected. Too much of anything is bad for you.
No kidding. Anyone know if there is a cheap hand held detector that gives instant results? It would be nice to know if the slab that you selected is "hot" before you pay to have it installed.

jimbo
08-28-2008, 07:54 PM
An actual geiger counter to measure radiation is probably quite expensive, and the radiation level in millirem per hour is probably quite low...below any problem level, and probably below detection level. But what we are concerned about in this case is not the RADIATION, but the CONTAMINATION....that is the breakdown product of the unranium and other isotopes....which decompose to radon gas. Since radon is radioactive, with a half life of 432 years, it is NOT GOOD to breath it in.

When we are around nuclear reactors and nuclear weapons, there is some exposure of the body to RADIATION. But there are well known and studied limits of exposure, based on level and time, which are considered safe. In those environments, personnel wear long term and short term dosimiters, which are monitored appropriately. Exposure is limited by limiting time in the area, and of course by shielding with water, polyethylene, and lead. Any escape of radioactive material into the environment...surface or airborne....that is an extremely serious situation and requires immediate emergency measures.

SO, it is not the radiation from the granite which is so much of a problem. It is that it releases a gas which can be ingested and absorbed into the body.

Bob NH
08-28-2008, 08:41 PM
The hazard from radon is that the radioactive gas gets into your lungs which absorb the radiation directly. That is why it is considered particularly bad to combine radon with smoking.

The radiation from radon and its daughter products is alpha (a helium nucleus) and beta (an electron) (See list at second link). Both of those have low range penetration so they have little effect if OUTSIDE the body.

http://energy.cr.usgs.gov/radon/georadon/2.html

http://www.blackcatsystems.com/GM/experiments/ex1.html

99k
08-30-2008, 08:10 PM
Since radon is radioactive, with a half life of 432 years, it is NOT GOOD to breath it in.

The half life of radon is actually 3.8 days.

99k
08-30-2008, 08:20 PM
The radiation from radon and its daughter products is alpha (a helium nucleus) and beta (an electron) (See list at second link). Both of those have low range penetration so they have little effect if OUTSIDE the body.
It's important to realize that radon gas can cross over from your lungs and enter into your bloodstream (like oxygen). The radon in your bloodstream can then decay back to radioactive solids and become trapped in your body, such as the brain. This is not good. There was a study showing a strong correlation to alzheimers and parkinson's and radon decay products, although, not sure how conclusive the study was. Bottom line, get the radon out.

jimbo
08-31-2008, 06:29 AM
I bought the Safety Siren monitor. It has been running in my house for about 5 days, and shows an average of 0.3 pCI/L. From what I read, 0 to 2.0 picocuries is considered normal background.

I will take it over to daughters house this weekend and see what kind of readings we get. Although they suggest not using in the kitchen, I plan to plunk it right on top of the countertop and let it go for 5 days, just to see. Then we will place it in other rooms in the house, and get some avearage readings. Depending on what comes up, THEN we wil panic!

Al Gerhart
10-04-2008, 07:50 PM
Hello,

I am pretty deep into this subject, and can answer a lot of questions on the subject if anyone has any. Keep in mind that I am helping many of the researchers looking into this, so I have some stuff available that isn't published yet.

There are studies out there on the Radon emanation from granite, ranges from nothing to thousands of pCi per square foot per hour. The record was Stan Liebert's find in the Sugarman home in up state NY, the case used for the NY Times story. As to research papers, well, even the Marble Institute's study done by Dr. Chyi found a .27 pCi/L increase in a homes level if a small amount (13 linear feet) of Crema Bordeaux is used in a 2,000 square foot home. Now, there were many problems with that study, as it was paid for by the MIA, it was expected to support their position, but it shattered their previous claims of no Radon from granite, or immeasurable amounts.

At the AARST conference (American Association of Radon Scientists and Technologists), there were two studies specifically on granite countertop radtiation and Radon, and two discussion sessions on what to do about the problem.

One study, by Bill Brodhead, showed over 500 pCi/sf/hr of Radon coming from one of the samples I provided. Bill calculated that in the right circumstances, a small tight home, a small countertop, the Radon levels could hit 4 pCi/L. Now most granites aren't his bad, they range from very little, say 8 pCi/sf/hr and up. But no one is concerned about the safer granites, it is the hot ones that need taken off the market.

Another study was by Dr. Mike Kitto, who showed several startling discoveries. Mike had accepted a grant from Sensa, a natural stone company (also owned by Silestone, or C & C North America to be precise), and studied thirty or forty stone samples and some of the quartz products as well. The study was set for peer review after the conference, but then something happened.

Back in May, I had shipped a sample of Niagara gold granite, from a remnant purchased from one of my competitors. At 220 uR/hr, it was pretty hot but I had no way to test for granite. So I sent a large section to Brodhead for testing, who cut it in half, sending half to Dr. Kitto at the NY state Health Dept. Broken in shipment, half was tested, the other half appreared in the NY Times story and on the CBS Morning show a bit later.

That Niagara Gold sample hit over 500 pCi/SF/hr, which convineced the researchers to keep looking. Later I sent more samples to both Brodhead and Kitto, as well as other scientists leading the effort. So Kitto stopped the peer review, reopened the study to include samples other than what he was provided with initially by the stone company.

Another amazing result from Kitto's study was that one could put a high Radon producing granite slab under a low Radon producing slab and the Radon from the lower would penetrate the upper slab easily. What we think as "solid rock" is anything but. As a fabricator, I can tell you that water soaks right through, so I guess it shouldn't have been a surprise.

On the radiation issue, well the hottest found to date was around 17 mR/hr, with one hot spot cored out (2.5" diameter core) that hit 1.080 mR/hr. One hundred hours of contact, or less than 30 minutes a day for a year, would put you over the 100 mR per year additional radiation dose recommended by the experts.

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.

Sensa has used this as a marketing tool, 300 cpm or around 53 uR/hr gamma is their limits for fabrication and sale.

Sorry for the long post, but I felt the info needed to be out there. Let me know if I missed anything. I'll end my saying that many of the granites out there are perfectly safe, but the problem is that we don't know which ones are dangerous.

For more info, solidsurfacealliance.org solidsurfacealliance.org/blog

Thanks,
Al

K2
10-04-2008, 08:36 PM
man no wonder people in my hometown are so messed up...

I grew up in Rockport, which is known for it's natural granite resources...

town is like a bowl of granola, if it's not fruits and nuts, it's flakes.

Cass
10-05-2008, 03:43 AM
The fabracators just need to supply every sale with one of these

https://www.bsu.edu/radiationsafety/media/72327/radiation_safety_logo.jpg

And with one of these...for when the home owner wants to cut up some onions.

http://www.wolfhazmat.de/a2000/sunghan_04.jpg

master plumber mark
10-05-2008, 05:29 AM
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......







http://www.fotosearch.com/thumb/SBY/SBY839/E004209.jpg How about going back to living like this??

99k
10-05-2008, 06:35 AM
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).

jimbo
10-05-2008, 07:42 AM
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.

jadnashua
10-05-2008, 02:51 PM
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.

99k
10-05-2008, 06:55 PM
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.

jimbo
10-06-2008, 05:46 AM
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.

jadnashua
10-06-2008, 12:01 PM
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.

Southern Man
10-06-2008, 12:37 PM
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.

jimbo
10-06-2008, 05:45 PM
Good point....I'll tell her to look into that.

99k
10-06-2008, 08:17 PM
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

Al Gerhart
02-21-2009, 07:12 PM
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.