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Green Building Discussion
Topic: EMF's and Electric Radiant Heat
Discussion Participants:
- Darrin Thorn asks of EMF's from electric slab
- Marc Rosenbaum is skeptical
- Bill Christensen offers some resources
- Bruce Sullivan discusses some measurements
- Rob Tom explains the radon theory
- Nadav Malin brings up some other issues
- John Bunzick recommends story in Tech Review
- Nadav Malin on relative fuel efficiencies
- Marilyn asks about hydrogen fuel
- John Alderman on life in a submarine
- Terry Brennan with some insight
All postings are the opinion of the writer, and BuildingGreen can take no responsibility
for their accuracy or appropriateness.
Darrin Thorn asks of EMF's from electric slab
From: DARRIN THORNTON
Sent: Friday, December 06, 1996 1:51 PM
Anyone have any info. about electro-magnetic fields and the health issues. We have been contacted by a radiant floor heating firm that use's the electric "mats" placed under your floor covering and then is wired into your house. Controlled by either wall switch and/or thermostat. I would be concerned about the EMF's and as someone mentioned before about the EMF's they may not cause cancer but they attract radon gasses? Any comments??? Thanks again,
Darrin Thornton @ Polysteel Alternative Building Systems, Inc. 664 Hillandale Circle Eagle Point, Oregon 97524 Fax 541-830-FORM (3676) EMAIL: epsform@cdsnet.net
Top of fileMarc Rosenbaum is skeptical
From: Marc J. Rosenbaum
Sent: Saturday, December 07, 1996 8:23 AM
Darrin - I don't know about the absolute health effects of EMFs (I'm skeptical anyone really does). But as to your specific application: it would seem that the electric mats could be constructed so that the fields from adjacent wires mostly cancelled each other out. Perhaps you could get an EMF meter and check out the proposed product, and if the fields are high then you might get the company to rethink their layout of wires in the mats.
As to EM fields "attracting" any kind of gases, that's a new one on me. Assuming that the gas molecules aren't charged, how would this occur - what's the physical explanation?
Marc
Bill Christensen offers some resources
From: greenbuilding Conference @ txinfinet.com
Sent: Saturday, December 07, 1996 3:15 PM
I agree, probably the best solution would be to get a meter and test an actual installation.
You may want to read the admittedly brief overview in the Sustainable Building Sourcebook on EMFs at http://www.greenbuilder.com/sourcebook/emf.html. At the end of the Resources section, you'll find a link to a site that started out from one neighborhood's opposition to the installation of some 500KV lines, and has grown into a strong set of resources and information on the subject, including a bibliograpy list of over 1000 resources.
Bill Christensen billc@txinfinet.com Sustainable Building Calendar at http://www.greenbuilder.com
Bruce Sullivan discusses some measurements
From: Bruce Sullivan
Sent: Saturday, December 07, 1996 6:33 PM
Nuheat claims to do just that with their mat product. In the last issue of Energy Source Builder we covered electric radiant floor heat. The next issue will list measurements. I'd share the data with everyone now, but it's in a FedEx package winging it's way to the ESB editor, Charlie Wardell. I do have the Nuheat contact info from REDI:
Nuheat PO Box 8110-217 Blaine, WA 98231-8110 tel: 604-599-4052 tel: 800-778-9276 fax: 604-599-6092
Several other companies are listed under Electric Mat and Cables heaters and Electric Radiant Panel Heaters.
Bruce Bruce Sullivan Tel: 541-484-9353 Iris Communications, Inc. Fax: 541-484-1645 Web: http://oikos.com/ E-mail: iris@oikos.com
Rob Tom explains the radon theory
From: Robert W. Tom
Sent: Sunday, December 08, 1996 8:52 PM
> As to EM fields "attracting" any kind of gases, that's a new > one on me. Assuming that the gas molecules aren't charged, > how would this occur - what's the physical explanation?
Okay. I confess. I'm the clown who put that notion into Darrin's head.
That hearsay about EMF's *possibly* causing high concentrations of Radon Daughters (and hence the cancer that some say is associated with EMFs) ...was tossed out in the hopes that some Bright Light on this List would illuminate us as to the validity of this fairly recent hypothesis.
I too, snorted derisively when I first heard it. On fourth thought, it doesn't seem that silly after all.
As for the physical explanation, as I understand it (which I *don't* very well), radioactive nuclei, for which Z > 82, alpha decay requires that:
a a-4 4 Parent Nuclei --> Daughter Nuclei + Alpha Particle b b-2 2
... where a & b give the electric charge and nucleon numbers respectively. From the above which was copied from an old physics text (which after all these years I am immune to), it certainly looks to me like the Radon Daughters *would* be charged and if so, probably could be easily coerced by an EMF to gang up and look for trouble to get into.
You will note that I have cc'd this post to Our Friend in the Field of Nuclear Engineering for comment on the above. -- Rob Tom be417@FreeNet.Carleton.ca Kanata, Ontario, Canada
Nadav Malin brings up some other issues
From: Nadav Malin
Sent: Monday, December 09, 1996 4:51 AM
Don't forget to consider the cost implications, both in dollars and in environmental impact, of choosing to rely on electric resistance heat! In most cases, much cheaper fuels are available to generate heat, and at higher efficiencies (when you take the conversion efficiency of generating the electricity into account). There are many other factors to consider, though, including distribution efficiency and total heating load. For very, very small loads, electric resistance may be appropriate due to it's low installation cost. Of course, concern about EMFs is another matter...
Nadav
John Bunzick recommends story in Tech Review
From: JBunzick
Sent: Monday, December 09, 1996 8:36 AM
A recent issue of "Technology Review" (published by MIT in Cambridge, MA) had a survey of the worldwide research on whether EMF fields, as produced by our electric power distribution systems, were hazardous. Nearly all of the studies (numbering in the dozens if I recollect) could find no effects whatsoever. There _were_ a small number of studies that found a correlation between lukemia (I think it was) and proximity to high tension transmission lines. However, because the other studies found no link to EMF fields, it could not be concluded that it was the electric fields coming from these lines that caused the lukemia. (It occurs to me that maybe its from herbicides used under these lines or something like that.) In any case, there were no studies done showing any correlations between in-house wiring and health hazards. These were not all power-industry sponsored studies, I might add. I think that this is a case where the media event is bigger than issue itself. I urge everyone with an interest in this to check out this story. Unfortunately, I don't have the magazine around to advise which month the story was in. They may have it posted on their web site, however I don't have that address either. (Sorry! my internet web connection is down this week.)
John Bunzick, CCS, CCCA Dean Packard Rafuse, Inc.
Nadav Malin on relative fuel efficiencies
From: Nadav Malin
Sent: Monday, December 09, 1996 4:15 PM
Mike O'Brien wrote:
>Say, don't you think there is a compelling topic for an article--the >relative environmental impacts and efficiencies of fuels?
Check out Environmental Building News Vol. 3, No. 6: "Heating Fuel Choices: Weighing the Alternatives." Alex did a pretty good job dealing with the complexities of this topic, though there is certainly more that could be said.
Oops! It was Vol. 2, No. 6. Sorry. Nadav
Nadav
Marilyn asks about hydrogen fuel
From: marilynz@mail.westonia.com
Sent: Monday, December 09, 1996 3:26 PM
Mike and everybody:
Have been doing a little bit of reading on hydrogen fuel. Not being technically trained, I would love it if some one, or several someones could address where this fits into the energy picture. Apparently it is already being installed in some buildings, and pretty much ready for use in converted autos.
What do you all think??
Marilyn
John Alderman on life in a submarine
From: John H. Alderman III
Sent: Monday, December 09, 1996 10:25 PM
Re:EMF In several trade magazines I have read there is no bad affect from Electrical Transmission Lines. In my own experience I lived for 9 years in Submarines as a Nuke Super (MM1SS). The Navy was very thorough in protecting us as we were scarse and very expensive to train. I lived with MegaWatts flowing near me. Our only concern was some areas forward near the Reactor at high bells for Radiation. We got less than our familys who stayed home. I can document further but the Emf is a not to worry topic. Someone said that if the wires lie side by side they counter. I believe if you scope it you will see a witches brew of adding, subtracting, and harmonics. If electrostatics are so generated I would like to see it. Especially submerged in a dielectric. John Alderman http://www.randomc.com/~mountain/
Terry Brennan with some insight
From: TBren46501@aol.com
Sent: Tuesday, December 10, 1996 1:03 PM
Hi,
I've kept up with the literature on EMF's pretty good since 1976. One health effect from an electro-magnetic field is cooking the tissue. Yep, just like in the micro-wave oven, a high enough field will raise tissue temperature. I've met vet's who used to keep warm while on guard duty on the DEW line by stnading in front of the radar dishes. It is nearly impossible to find fields that strong in any ordinary situation.
Evidence for a second health effect has emerged from a number of epidemiological studies, the earliest of which were the Leper and Wirthheimer studies done in Colorado. Overall, these studies and others that followed them found a correlation between slightly elevated magnetic fields and some cancers, particularly leukemia. Since then, other epidemiological studies have found similar evidence. However, laboratory studies have produced contradictory results. The American Physical Society took the postition a few years ago that the health effects found in the epi studies are probably not directly related to the fields. The most complete reference to the health effects are reported in "Biological Effects of Electric and Magnetic Fields" vols. 1 and 2 edited by David Carpenter SUNY, Albany. I judge that it is likely the epi studies have picked up a real effect because of the number of times the results have been reproduced and the quality of the studies. I can think of two possible explanations: 1) there is am unknown factor which contributes to leukemia that is frequently present near electric devices and lines. (Probably not herbacides because most of the epi work was done in urban residential settings, not near powerline corridors). Or 2) There is an as yet unknown physiological effect which results directly or indirectly from exposure to magnetic fields of relatively low strength. The risk is great enough I keep my eyes on the literature, and I do simple things to avoid exposures, but I don't make myself crazy over it. Many manufacturers of electrical devices have responded to this possibility by oragnizing the geometry of the components to cancel out the fields. This does greatly reduce the overall field strength.
Laslty, radon daughters are ions and are attracted to surfaces with a static electric charge (check the screen of your TV set or computer or even synthetic countertops, fabrics or wall coverings with a microR or Geiger sometime and you'll find radiation elevated above the background). If the current is AC they'll be attracted and repelled 60 times a secomd. If it's DC current they'll be attracted. I'd consider this a benefit because the radon decay products account for the bulk of the radiation the lungs receive and you won't be breathing them if they're stuck to the ceiling or floor. Radon itself is inert and could care less if a surface is charged or not.
-Terry-
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