Hey Guys it looks like this is more truth than fiction.
Recent imports from Brazil have been shown to give much high levels that thought. Check out the NY Times article
I will be testing a home on Saturday that has granite from this location. Ill report back when I get the results.
Check Mark Services
Home Inspection and Environmental Testing Services
Lots and lots of supposed data flying around. If we think about this logically and without bias we can come to some conclusions relatively easily.
1. Granite is not radioactive to a degree that is harmful to the public. Think about it. If it was this would have become an issue long before now.
2. Radon can be a health risk. some granite emits radon. no surprise here for an informed person, radon is emitted by well water and soil to varying degrees in different parts of the country. Occasionally, in some parts of the country like here in MN the soil emits enough radon that radon abatement (essentially additional fresh air) is required.
3. radon is a gas. any radon that might be emitted by granite or soil is mixed with (and greatly diluted by) the ambient air inside a structure. A significant factor in the possible risk from radon in a structure is how much and how frequently fresh air is introduced into the structure. The radon mitigation systems already in use simply preheat outside air and introduce it into the household.
4. Any assessment of risk associated with radon emissions from granite (or any other source) must do the following:
a. measure, in some repeatable, verifiable fashion, the actual amount of radon emitted over some period of time from a specified mass of source material.
b. assumptions must be made about the ambient air volume which the radon emission will be mixed with.
c. assumptions must be made about the percentage of the ambient air volume which will be replaced per unit of time.
5. anyone that presents data which does not address the factors cited in #4 above is simply throwing meaningless data around in an attempt to further some agenda not connected with accurately informing the consumer.
6. I believe when all the huffing and puffing is over this will go the way of the brain cancer/cellphone and breast implant scares. Lots of consumer angst created by self serving unscrupulous individuals out to make a buck. Can the tort lawyers be far behind?
Now we all know smoking is bad..or is it? some live to 100 that have smoked for years and some die fast. Right? Now what is great about America is if one feels for any reason something would better protect their family they have the right. The EPA now is switching sides on this issue why? Fact any amount of Radiation is unsafe. Why live with high reading of a Granite slab when a choice of a background slab could be installed ?
So sit in the the room with smokers or leave, its your choice.
oh and yes I do Radiation testing for Granite slabs in the Seattle area :) some low and some high. One thing is for sure is the buyers of this $150sf Granite are happy when the reading is 7 uR/hr !
Radon is usually found in underground basements, houses that have the lower floor beneath ground level at the rear, etc.
Granit tile should not be emitting Radon. Gases expand to fill the room by volume. The miniscule amount of Radon that may have been in the tile at the point of excavation has probably been totally emitted before it arrived at the quary or where it was polished.
There are Radon testing kits you can obtain from a variety of suppliers that cater to Home Inspection Professionals.
I don't think you need to worry about Radon from Granite Tile. Is the house beneath ground level? That would be your source.:)
Hey if it was radio-active, maybe that's what Ralph Kramden of the Honeymooners meant when he said he had a new invention: Glow in the dark Pizza.
If everything else fails list the house as "energy efficient" LOL
I just wanted to point out that it is not the element radon itself that is a potential health hazard, but radon progeny or daughters that emit alpha and beta particles as they decay. Alpha particles can injure cells in the alveoli, when these progeny are inhaled and decay inside the lungs, by damaging DNA strands. However, an alpha particle does not have enough energy to penetrate clothing or skin. That means radon progeny have to be inhaled to cause injury. That also means one can test radon levels in the air to gauge whether the EPA action level of 4 pC/l is exceeded. That's more useful to know than the radon content of the stone, which is hard to measure and relate to levels in the air.
Well its time to report back... after several months of testing radon levels in homes with granite materials I have not found one location (out of several dozen) that had elevated levels of radon in the air that could not be traced back to elevated basement levels. I took samples near granite, on granite, on granite with covers, Etc. No appreciable differences were found from samples taken in other locations on the same levels.
I am not saying that I measured counter tops for radiation levels. I did not. All of my "experiments" were strictly to find if I could create a condition where I got a higher level of radon in air in areas that had granite installations.
All of the elevated (4.0 pCi/L or higher)results in areas with granite were mitigated with standard sub-slab depressurizing techniques in the basements. There was high communication between the areas in these instances such as large open stairways. Areas that had elevated readings fell in proportion to the basement air samples.
My assessment, and I am sure most professional testers will agree, is that there is little if any hard evidence that Granite installation in residential applications is contributing to radon in air levels that would be considered problematic.
I can not comment (I'm not a Physicist or Geologist)on what levels of Radiation exposure may be harmful or as to their sources. Clearly, Granite from different locations emit different levels of radiation due to different levels of Uranium concentration. How much is too much? I don't know.
What I can and do advise my clients is to test their homes for radon in air (and water in some cases) as we know for sure that this can truly be harmful!
Just because you tested a number of granite installation doesn't mean you tested correctly or that you tested a granite of concern. No one knows if you tested the hot spots on the granite, not likely since you said you didn't measure for radioactivity first.
Most inexpensive granites, most not all, are fairly low level Radon emanation. The problem has always lay with the exceptions to that rule and the exotic granites.
If this was a non issue, neither the CRCPD (state radiation officials) nor AARST (radon scientists) would have committees seting maximum allowable radiation/radon levels for stones and measurement protocols. ANSI and ASME are also looking into the controversy for their organizations.
On the radon issue, we have a full scale radon test going currently, over 10 pCi/L so far from only 18square feet of granite in a 96 square foot room. That is like smoking 1 1/2 packs a day,
We have a lot of info on the topics available.
What is underneath your test room? What are you floors and walls made of? Didn't seem to show any CO2 data in that thread, but perhaps I misread, thread is quite confusing.