Green Building Discussion

 

Topic: Radon From Slate Flooring

Discussion Participants:

• The Minkels wonder about radon from slate
• Alan Wickstrom lists some info sources
• Norbert Senf recommends some tools
• Bion Howard says masonry is not radioactive
• Norbert Senf responds
• Dave Saum thinks slate is not a problem

All postings are the opinion of the writer, and BuildingGreen can take no responsibility for their accuracy or appropriateness.

The Minkels wonder about radon from slate

From: Don Minkel
Sent: Friday, September 27, 1996 11:20 AM

Greetings greenbuilders, I live near several slate quarries and am considering putting slate floors in a significant portion of my as yet unbuilt solar house. A friend in the enviro-remediation biz tells me that some slates are very high in radon. Calls to information hotlines etc. have produced no info. Does anyone out there have knowlege/experience w/this?

Annie
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Alan Wickstrom lists some info sources

From: BuildingOnline: Alan Wickstrom
Sent: Thursday, September 26, 1996 7:33 PM

William Levy, Senior radon consultant for Associated Radon Services, knows the most about Radon of anyone I have ever met in this business and he can be reached at: http://www.vero.com/web/radon.htm or eMail: radon@metrolink.net

Or you can drop in on a manufacturer of slate flooring and roofing, the Virgina Slate company online at: http://members.aol.com/vaslates/home.html or eMail: VASlates@aol.com

Alan Wickstrom ~ webhead@BuildingOnline.com

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Norbert Senf recommends some tools

From: Norbert Senf
Sent: Friday, September 27, 1996 3:35 PM

Any masonry material can be radioactive, including drywall. Best bet is to check it yourself. You can get an extremely sensitive detector for alpha, beta, gamma and X-rays for about $150.00 from:

Aware Electronics PO box 4299 Wilmington DE 19807 phone/fax 302/655 3800 -------------------------------------------------------- Norbert Senf mheat@hookup.net Masonry Stove Builders Shawville, Quebec http://mha-net.org/msb
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Bion Howard says masonry is not radioactive

From: Bion Howard
Sent: Friday, September 27, 1996 8:02 PM

Well folks, I was going to lay low awhile after today, but I just could not resist commenting on this. --->

Years of research and testing, summarized in numerous EPA and contractors reports does NOT show "masonry materials" are radioactive. Much of the so-called information showing block, brick and concrete emit quantities of radon has come from findings of specific tests on masonry materials that were either intentionally (to dump radioactive tailings) or inadvertently contaminated via aggregate materials with elevated Rn emissions levels. There were a couple of widely publicized cases -- one in Grand Junction, CO and another near Oak Ridge, TN -- where hot aggregate entered the masonry production process and wound up in buildings. These situations I believe were remidied and the subject of investigation and litigation in the mid- to late-1980's.

I have not seen, however, data on gypsum wall board products and would love to review actual emissions testing results. Also, field testing carries massive uncertainty: 1.) the age of the material, 2.) the ventilation rate during the test versus typical ventilation in the affected space, 3.) whether the material was painted, coated, or not since paints will seal the paper facings of GWB and may alter the amplitude and duration of emissions of Rn or other pollutants.

If anything, there are too many "authorities" on radon and much has been written, said and predicted about its dire consequences. But one thing is fairly well known: much more radon and daughters contamination enters homes through construction defects in slabs, foundation walls and crawl spaces due to pressure differences, as well as through indoor water releases, than is emitted from "masonry" surfaces. To this end, I hope the real Radon experts like Dave Saum (you might want to look at the AARST web-site) and the folks at the EPA Radon Division, continue to accurately portray the relationship of surface emissions from building products versus other more serious sources. Implicating "masonry" -- and I am not sure the gypsum folks would agree with this category -- as a significant source of radon is just not accurate without the rest of the story. ---------------------------------------------------------- Mr. Bion D. Howard bhoward2@sprynet.com (business) Building Environmental ZowWatt@aol.com (fall-back) Science & Technology Voice:(301)627-2780 FAX:(301)627-4735

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Norbert Senf responds

From: Norbert Senf
Sent: Friday, September 27, 1996 7:38 PM

Masonry material in general are no doubt not radioactive. However, it would be nice to know that the PARTICULAR materials you will be using in your own house are clean. Up here on the Precambrian Shield, for example, local variations in background radiation are detectible with low cost equipment. Whether it means anything or not is a different matter.

On page 175 of the current issue (Sep 96) of Scientific American, is an ad for some impressive sounding, low cost, equipment that plugs into the serial port of a PC. Among the interesting claims made by the advertiser are:

- palm sized unit detects alpha, beta, gamma and x-rays - displays 1000 times the resolution of survery geiger counters - track radon gas - find sources - check food, water and ceramic coffee mugs for contamination - plot muon showers - Plot nuclear fleas, ceramics, plane ride, cosmic rays, BUILDING MATERIALS, etc.

Sure sounds like it might be a fun toy, and at $150, perhaps either a path to some first hand knowledge, or cheap insurance.

Personally, I'd be most concerned about drywall. It can contain gypsum made from the gunk that you get by scrubbing sulphur in the smoke stacks of coal-burning power plants with lime (calcium sulphate). -------------------------------------------------------- Norbert Senf mheat@hookup.net Masonry Stove Builders Shawville, Quebec http://mha-net.org/msb

Dave Saum thinks slate is not a problem

From: Dave Saum
Sent: Friday, September 27, 1996 9:03 PM

Like Bion, I have not run across any situations in my 10+ years of radon mitigation research where large hunks of rock, like you would find in walls, chimneys, fireplaces and floors, has been found to be a significant source of radon in houses. No mitigators that I know even bother too look at what the house is made of in making radon mitigation decisions.

I guess the surface to volume ratio is too low. How are radon atoms and decay products going to get out of the rocks? Only a very thin surface layer can emanate. It is only when you get fine material that has a high surface to volume ratio that you get significant radon emanation.

...Dave Saum Infiltec, Air Infiltration Measurement and Control Technologies Web: http://www.nmaa.org/member/infiltec/