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Old 04-30-2009, 09:30 PM   #61
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The polyester resins will be inert "IF" the product is properly steam cured immeadiately after pouring. I explain this process to customers by using the example of baking a cake. If the oven is at the right temperature and the cake is cooked for the required amount of time, the cake will be cooked perfectly. Polyester resins require much the same care when manufacturing. If done properly, the individual ingredients link up into polymers, one molecule becomeing one new molecule, and the bond can't be broken even by the original solvents.

Some major screw ups have happened with companies trying to pour their own polyester solid surface without having proper curing equipment. I would check that granite transformations has curing ovens if you are worried about any VOCs. I've seen chinsese polyester solid surfaces that changed texture after installation and one local company was near bankrupted because of their polyester products changing color, warping, and breaking due to problems that lead back to manufacturing defects caused by lack of proper equipment.

Keep an eye out on those cement based recylced countertop materials. We looked at a few to fabricate, but the fly ash content put us off. Fly ash has a lot of heavy metals content and can have radio nucleides present. Granite transformations reported that one of two of their colors has elevated radon emissions (.4 pCi/L if I remember right), likely caused by fly ash content or the aggregrate being slightly radioactive.

Have you considered the amount of VOCs and pollution generated by working more hours to pay for a higher cost countertop? And wouldn't a local product be more "green" sometimes?


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Old 04-30-2009, 09:48 PM   #62
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Good info...thanks very much!! We're really just starting our research on this whole thing, so I'm trying to get as much info as possible so that we choose something we like and that is environmentally-friendly, all things considered. There are sooooo many options, and each one says it's "greener" than the next, so it takes some research and comparison. A local product probably would be more green, all things being equal. The GT rep told me the recycled glass product is manufactured in Florida and fabricated here. I'll definitely check into the curing oven if GT makes our short list of options. Good to know about the flyash in the cement-based recycled countertops. We were looking into Vetrazzo which I think is cement-based, so that info is helpful. That would also require ripping out the old counters, which we'd rather not do...unless we can donate them or something.
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Old 04-30-2009, 10:25 PM   #63
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The information discussed about radionuclides (not radio nucleides) is misleading. Radon emissions are not measured in pC/l, that is a measure of the airborne concentration of radon gas. Radioactive emissions from a source would be measured in curies or becquerels. The actual concentration of radon in the air would be a function of the size of the room and the air exchange rate as well as the size of the source and the concentration of uranium in the source.

Radon gas is a product of the breakdown of uranium, which occurs naturally in rock. Certain rock types have naturally higher concentrations of uranium than others, and granite in particular is well known for having relatively higher concentrations of uranium than most sedimentary rocks. Therefore, any product that uses granite, either in the form of slabs or chips, is going to emit radon gas, generally at a very low level. This means that the granite countertop in my house emits radon gas, and any granite transformation product made in part from granite chips would also be a radioactive source. As would the concrete in your foundation, and just about anything else in your house.

The amount of radioactivity in most products is so low as to be inconsequential. Radon in your house may be a problem if you are on well water that has elevated radon levels, or you have radon in your basement due to the underlying bedrock. But I would not lose any sleep over radioactivity from a concrete countertop, granite countertop, or granite transformation countertop emitting radon.
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Old 04-30-2009, 10:29 PM   #64
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You lost me at radionuclides
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Old 05-01-2009, 11:15 PM   #65
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We are lucky Daniel is an engineer and not a radiation enthusiast


You don't know much about radon research. It is the custom here in the U.S. to use pCi/SF/hr instead of Bq/SM/hr like the rest of the world does. Same thing with radiation units, they use standard units and we stick with our old rad, rem, and roetgen. Or you are one of those hair splitters that love to dazzle others with your precise use of terms. For public discussions, one is better off keeping as much jargon as possible out, especially when talking about radon or radiation where it glazes peoples eyes over on the first paragraph. The use of two sets of units would be ridiculous.

Here is a link that explains the dual use, look for table 2, units.

Here is another example, note the use of pCi/L then they put the standard unit in parasenthesis.

Here are some more errors in your post. You wrote:
"Therefore, any product that uses granite, either in the form of slabs or chips, is going to emit radon gas, generally at a very low level."

Congratulations, you made four mistakes in one sentence. Not all granite produces radon. Some stones have little to no uranium present, the radiation comes from potassium (only 13% gamma) or thorium (produces thoron gas, not radon gas, no one really knows what the thoron risk from granite is). You also are ignorant about the chips used in other products, most is quartz chips, not granite. Granite has a lot of feldspar, mica, and other softer chemically unstable minerals so no one is using "granite" chips in engineered products like quartz slabs.

The quartz manufactures had their products tested for radiation and radon and I sent three full sample boxes out of our showroom to two different researchers for testing. No radon, no radiation present. Were I you, I would check the facts before sounding off on a subject you know very, very, little of.

Lastly, saying that stone generally emits at low levels without knowing the facts is quite irresponsible. Most are low, it is looking like 5% of all stones are going to be the problem materials but too few slabs of too few granite types have been studied. Just when we think one stone is safe, we find a kitchen with elevated radon due to the granite countertop. More important, it is illrelevant that most are safe, it is the unsafe ones that we should be concerned about.

You also wrote:

"But I would not lose any sleep over radioactivity from a concrete countertop, granite countertop, or granite transformation countertop emitting radon."

Again ignorance is at play. Last years AARST convention had three papers presented that covered concrete radon, and three that covered granite countertop radon/radiation issues, and another that set a protocol for measuring granite countertops using E-Perms. Here is last years list of papers presented. Look for Bill Brodhead's paper on granite and concrete and you will find my name mentioned as one of the providers of samples for the study.

Furthermore, at that joint AARST/CRCPD convention, there was an hour long panel discussion on the granite controversy on Tuesday, and on Wendsday both CRCPD and AARST (state radiaton protection officials organization and radon scientists organization) produced committees that are setting testing protocols and maximum allowed limits for radiation/radon from granite countertop materials. Apparently this group of leading experts were losing sleep over radon from building materials.

I would advise that you read the entire thread before making claims that others have posted misleading information. Follow the discusssion and some of the links before you criticise others. As for pointing out spelling or typos, typical anal retentive personality. Most of us don't proof read simple posts. Get a life.


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