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Safety of mounting AP near people (Radiation)

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  • 1.  Safety of mounting AP near people (Radiation)

    Posted Jul 12, 2021 01:59 PM
    In mounting an AP, are there any concerns, rules or FCC regulations about mounting them lower than normal and/or near to a person, than when mounting it on the ceiling? (Of course, mounting low means considering obstacles/materials that would attenuate the signal, but the question is more about safety and the effect on nearby people.) I found in the AP installation guide that it should be no less than 20cm from a person, which I would think is when the AP is at normal/full power, but it doesn't elaborate, i.e., would that 20cm be less if AP power is reduced? Or is Aruba stating that it's 20cm and no less, regardless of power?  Thank you.

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    Aaron Abitia
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  • 2.  RE: Safety of mounting AP near people (Radiation)

    Posted Jul 15, 2021 04:05 AM
    Disclaimer: This may be a 'slippery slope' as there are people with strong opinions on this, and if you search on the health effects of any RF technology you may find a lot of conflicting scientific and non-scientific information. In many countries around the world, there is active movements against for example 5G, but in some countries even to WiFi in schools.

    I think for US, this appears to be an extensive explanation and answers to many questions. In other parts of the world, the theory behind it would not be different as all are based on the same worldwide scientific research.

    Note that your smartphone for cellular will emit magnitudes more power than WiFi, and many people carry those on their bodies and hold it to their head (ear). For WiFi, the used powers are much lower, but still, it is hard to scientifically prove there is absolutely no possible effect, and the most wide-spread consensus is that heat development in the body by absorption of the energy is the most prevalent effect of RF of frequencies used in WiFi. In the linked article there is also a reference to radiation as ionizing, like X-Ray, which is known to be capable of changing cell structures above certain limits, and non-ionizing, where the waves are magnitudes larger than the cells and there is no observed risk of cell structure changes. I prefer radiation and RF-field for the two, instead of putting everything under radiation, which sounds scary.

    I believe the 20cm comes from something called 'near-field / far-field' where in antenna technology the electromagetic waves behave different close to the antenna versus further away. Most of the research done, is based on observation at distance (far field), because that is most relevant, so much of the recommendations may not be valid in the near-field.

    Given that in order to increase the body temperature it takes time to absorb the energy, it also depends on how long a person is in the RF field. That 20cm should be considered a 'safe limit'/recommendation, closer to the AP there is just less knowledge but given the wavelength is the same, no reason for the WiFi scenario. And as mentioned, the client device may be more relevant to look at versus the AP (with the note that an AP, in general, can have higher power, and the radios have a higher transmit duty-cycle which means it is transmitting more of the time).

    One more remark is that in general, the limits (like SAR / Specific Absorption Rate) for wireless devices are set to a big margin below the value where an effect is measured in a lab. There should be enough headroom, but I don't know why you would put an AP at 20cm from a person as you did not explain.

    If I have the choice in a bedroom to place the AP near the pillow, or at the other side of the room, I would pick the latter. Also because an AP will warm up during operations and it is good to have proper airflow around it and it may be uncomfortable to feel the direct heat from the AP.

    Maybe best to discuss your use case with your local Aruba partner, or Aruba team.

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    Herman Robers
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    If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
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  • 3.  RE: Safety of mounting AP near people (Radiation)

    Posted Jul 15, 2021 02:40 PM
    Thank you Herman for your detailed response, very helpful, and I realize that there are so many factors here.  The reason for asking this question, and the situation at hand, is many common areas that we have, where wallplates are mounted low in the room, approximately 2-3 ft or 1 meter.  If we were to mount the APs atop the wallplate, this would mean that furniture could potentially be close, and thus people.  I know that it's vastly preferable to have the APs mounted higher up, and even better, mounted on the ceiling in the center of the room, but it's an issue of our Techs being able to get wire there.  I've expressed that the APs should be mounted higher, either on the wall or in the ceiling, but it's a matter of what the Techs can/will do; they've asked why can't we mount them on the wallplate, to which the answer is, it can be done, but attenuation/signal propogation will be a problem, and possible even human exposure.  Human exposure starts to get into health/safety realm, so that's why I've asked the question, and of course we know that cellphone radiation is much worse than WiFi radiation. Thank you!

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    Aaron Abitia
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  • 4.  RE: Safety of mounting AP near people (Radiation)

    Posted Jul 16, 2021 03:29 AM
    One option might be to mount a small dome (20-30cm) over the AP to prevent people getting inside that 20cm radius.

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    Herman Robers
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    If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.

    In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
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