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The Electrical Apocalypse: Can we avoid it?

Discussion in 'Hypersensitivity and Intolerance' started by Womble, Nov 18, 2013.

  1. Helen

    Helen Senior Member

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    I am really sorry for you in this difficult situation. My, and others experience is that you should take these symptoms seriously so they don´t get worse as they sometime do all of a sudden. And then there is a long way back. I don´t want to make it more difficult for you by saying this but when the body is shouting with symptoms as a warning... take care.

    Cardiologists at the university hospital close to me know that EMF might give high blood pressure and heart disturbances. They have patients coming and going with these reactions. Patients get better when they get into their ER that is shielded but they still often get medicated.

    The only thing I could recommend is to get a better place to stay at as soon as possible. Without knowing what kind of EMF that are emitted from the AC it is impossible to try shielding. The EMF´s should be recorded first or I think you should look for another website/commumity where people are discussing these issues more thourough. I have heard of problems with AC´s but as they are not so common where I live I don´t remember what kind of EMF and/or radiation it causes. All the best to you!
     
  2. Hanna

    Hanna Senior Member

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    Jerusalem, Israel
    Thank you for caring and trying finding some solutions , Womble and Helen !
    I wrote to some people here in israel (engineer + docs) who ran a forum which dealt with EMF from AC. But they didn't offer any solution... just beeing at a safe distance.
    It seems that only the AC unit of one neighbour here is causing BIG issue for me. I am surrounded by other units, and though it is not optimal,it is far from causing serious harm. As it is an old one, there is chance that it is linked to this.

    Here, people make an intensive use of AC, for cooling of course but also to warm. What is somewhat strange, is that the problem arises only when the neighbours are running the "warming" option. A technician said that it could be fixed when adding a special filter to the internal unit.( Very sensitive people may suffer from big fluctuations in the gas pressure he said...) . We will see. I HOPE so much that it will be the solution. I'll keep you informed. Thank U once again.
     
  3. Womble

    Womble

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    I ordered a grounding sheet on amazon.com, but it was so over-loaded with chemicals
    that I was not able to use it.

    Tried washing it, and also aired it out but the chemicals were strong enough to fill our house
    even from the outside patio.

    Probably going to return it Monday... can't even off-gas it.

    Any suggestions?
     
  4. Helen

    Helen Senior Member

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    Did you wash in 60 degrees Celsius ? If not, the flame retardant will not get washed away. That is all I can tell. So sorry you have to have trouble with this - too.
     
  5. Womble

    Womble

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    I washed it on warm temperature, as they suggested. Not sure what else to do.

    Most products I buy are probably going to make me too sick chemically.

    My new idea then is to buy a tent and line it with aluminum foil.

    Do you think this will work? :)
     
  6. Womble

    Womble

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  7. Womble

    Womble

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    I ordered some Mylar, and it made me sick.

    Now considering just wrapping a tent in aluminum foil, does anyone think this will work?
     
  8. biophile

    biophile Places I'd rather be.

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    Mylar plastic is a good insulator.

    Metalized mylar is still a relatively poor conductor. So I doubt it would be a particularly useful EMI shield.

    The aluminum foil tent should work better, just be sure to minimize any gaps between the foil without suffocating!
     
  9. Helen

    Helen Senior Member

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    @Womble and @biophile
    I have heard from people who tried to shield with aluminium foil that it might make things worse. The explanation should be that aluminium foil is shielding by reflecting radiation. The shielding paint absorbes the radiation.

    In the first case the shielding sometimes cause measureable "points" in the room with much higher radiation than in other areas. Without a device that measures the levels of radiation it is impossible to evaluate the shielding. And to make it even more complicated, the EMF devices all have their limits too.
     
  10. biophile

    biophile Places I'd rather be.

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    There is indeed a difference between reflection and absorption, and it is true that reflection is the primary mechanism for EMI shielding with aluminum foil, but absorption also tends to increase at higher frequencies due to the skin effect, so it may not be accurate to simply contrast aluminum as a pure reflector and shielding paints as primarily absorbing.

    Reflection losses are those which are reflected from the external side of the shielding material. Absorption losses are those which are absorbed inside the shielding material itself. Internal reflection losses also occur inside the shielding material itself. Highly conductive materials should generally be good for frequencies between AM radio and UHF microwaves.

    Last time I looked into shielding paints, one seller claimed that carbon is a good absorber of RF and that 10% of the shielding effect was due to absorption, which does not sound like much to me, but I guess it would be better than nothing if EMI bouncing around inside the shielded room and concentrating in certain areas is a problem.

    As far as I know (I am certainly no expert on the issue), there is nothing really special about carbon-based shielding paints, other than being more convenient and aesthetic than metal foil. Although conductivity is related to reflective characteristics, shielding does not necessarily have to be a very good conductor to work at all. On the other hand, the relatively high resistance of some of these carbon-based paints and metalized plastics might limit their effectiveness.

    I would be interested in any studies done on comparisons between carbon-based shielding and common metal shielding, but I would be surprised if thin coats of carbon-based paints were actually better than copper sheets or even aluminum foil.

    Different materials demonstrate differences in their shielding properties, which are also frequency dependent, so the best shielding for the job also depends on which frequencies are causing the most problem. I think I mentioned in an earlier post that a reliable broad-spectrum shield for EMI sensitivity would be complicated and/or expensive.

    Regarding problems with EMI bouncing around inside a shield constructed of aluminum foil. Although there would still be some greatly attenuated EMI which managed to get through the shielding and would then be reflected inside the shielded room, it sounds like the main problem (I could be wrong) is external EMI getting in through gaps and seams in the shielding.

    A distance of 1/20th the wavelength of the EMF is a commonly used guideline for engineers to determine the maximum size of any apertures in the EMI shielding to maintain at least -20db attenuation through those apertures. So for example, the wavelength of 2.4GHz transmissions is about 12cm, so any gaps and seams approaching roughly a centimeter or more in size could be increasingly problematic, particularly for areas closer to the breach. The aluminum foil would also reflect internal sources of EMI, but that does not seem to be what you are talking about.

    If materials with free electrons can make good EMI reflectors, and materials with electric and/or magnetic dipoles can make good EMI absorbers, perhaps magnetic metals i.e. those with high permeability should be good at "absorbing" EMI (but more expensive), and are used for shielding low frequency magnetic radiation too, a weakspot for the metals commonly used for EMI shielding. I read about conductive polymers showing future promise for absorption because of their dielectric properties.

    I do not have a problem with EMI sensitivity so it is not something I have had to spend much time looking into. It seems difficult to find much good information on the internet, so it might be worth consulting EE text books. Purchasing personal shielding for EMI-S sort of reminds me of purchasing health supplements: I would be weary of taking any anecdotes and manufacturer claims of superiority at face value without further research and experimentation with quality EMF meters.
     
    Last edited: Feb 9, 2014
  11. Womble

    Womble

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    Someone told me that just regular plain polyester is a good EMF and RF shield... this is similar to what they sell as "Swiss Daylite", except that I suppose its regular polyester without any silver or copper in it.

    Is there any truth to that?

    I'm also wondering if putting a layer of aluminum foil, then a layer of polyester, then another layer of aluminum foil might work... Or vice versa.

    I'm just trying to be creative here! It appears so far that my chemical sensitivity is going to react with every retail product on the web, so I need to think OUTSIDE THE BOX!
     
  12. Martial

    Martial Senior Member

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    Ventura, CA
    I use earthing mats at home and keep all electronics out of my bedroom, keep all sockets unplugged and when my cellphone is in my pocket it is in airplane mode.
     
  13. biophile

    biophile Places I'd rather be.

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    I doubt ordinary polyester is an effective EMI shield, that is why metals or carbons are added to increase conductivity. Unless you are thinking of low-charge materials which resist electrostatic buildup, although they are not EMI shields either.

    Adding polyester between layers of aluminum foil may help because of the separate layers of aluminum foil. However, I do not recall whether there needs to be more space between layers for this to make much difference. Using a thick layer of aluminum foil should be OK on its own, multiple alternating layers sounds like too much work. On the other hand, multiple layers of just aluminum foil on its own will increase the thickness and therefore be better at lower frequencies.

    Do not forget about the importance of limiting gaps and seams to 1/20th of the EMF wavelength. This tolerance is why it is possible to put small holes in the microwave oven window and look through it without being cooked when it is operating.
     
    Last edited: Feb 10, 2014
  14. Womble

    Womble

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    I'm not sure what you mean by "limiting gaps and seams to 1/20th of the EMF wavelength".

    I'm not an expert in wavelengths, or what frequencies are involved here, or what gaps to leave.

    Can you explain?
     
  15. biophile

    biophile Places I'd rather be.

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    The wavelength is inversely proportional to its frequency.

    So, for example, this is the wavelength of 2.4GHz electromagnetic radiation:

    wavelength = speed / frequency

    wavelength = 3*10^8 m/s i.e. 300,000,000 meters per second / 2.4*10^9 Hz i.e. 2,400,000,000 cycles per second

    wavelength = 0.125 meters or 12.5cm (when using the exact speed of light it is about 12.49cm).

    Large gaps in the shield let EMI leak in but gaps smaller than 1/2 of the wavelength of the EMI begin to attenuate that leakage. There are general engineering guidelines such as 1/10th, 1/20th, 1/50th, 1/100th etc, but basically the smaller the gap the better, particularly when you want a broad spectrum shield and are uncertain what the highest frequency to shield against is.

    Hope that helps.
     
    Last edited: Feb 15, 2014
  16. Womble

    Womble

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    Still a bit confused.

    Why should there be any gap at all?

    Isn't the idea to layer the enclosed area with shielding material so that nothing gets through?
     
  17. biophile

    biophile Places I'd rather be.

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    Yes, no gap at all is ideal, but not always practical. You have to breathe for instance.

    Entry points or a doorway is a common weakness of shielding.

    Fine mesh should handle the ventilation issue.
     
  18. sharlene

    sharlene

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    If you don't own an acoustimeter, you should. Prob. the number one thing to have to get a true read on the level of RF that you are exposed to.
    Unplug routers, unplug xbox, turn off ipad, ipod, cell phones.....
    walk around barefoot....google antenna search...if you are within 500 m of a tower that sends signals, move
     
    melamine and Wayne like this.
  19. sharlene

    sharlene

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    Most importantly, write your state representatives and implore them to "do due diligence" and read about non-ionizing microwave radiation....
     
    Wayne likes this.

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