[Bldg-sim] radiation through glazing
Joe Huang
yjhuang at whiteboxtechnologies.com
Tue Mar 4 11:17:08 PST 2014
Larry,
I'm not ready to dismiss this effect totally. When I look at a plot of Low-E
transmissivity, it's shown to block anything from 800 nanometers on up, although the plot
stops at 2400 (see
http://www.leyboldoptics.com/cms/upload/downloads/S_Low_E_Coating_Apollon.pdf page 2).
Out of curiosity, I did a Google Search for "Low-E windows block cell phone signals" and
found this question raised in various web pages. Expanding on what I had said previously,
I do know of a building in Beijing (China Academy of Building Research) that did a facade
retrofit a few years back, after which the staff reported they could no longer get cell
phone signals. I think I'll send my colleagues an e-mail to ask for more details.
Joe
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
On 3/4/2014 7:26 AM, ldegelman at suddenlink.net wrote:
> I don't see how there could be any effect at all. The wavelengths are totally
> incompatible. Low-e coatings block the near-infrared radiation at wavelengths of 700 to
> 2400 nanometers. Even at the ultraviolet end, the wavelengths are around 100 to 400
> nanometers. The 3G and 4G networks that cell phones use are way off from this.
> Typically, cell phone wavelengths (at 0.8 to 2.4 Ghz, the RF portion of the spectrum)
> are about one foot long (or around 300 million nanometers) - not even in the same ball
> park.
>
> \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
> Larry O. Degelman, PE, FIBPSA, ASHRAE
> Professor Emeritus of Architecture
> Texas A&M University
> //////////////////////////////////////////////////////////////
> -----Original Message----- From: Russell Richman
> Sent: Monday, March 03, 2014 10:00 PM
> To: leen peeters
> Cc: BldgSim Mailing List
> Subject: Re: [Bldg-sim] radiation through glazing
>
> these types of glazing systems will help reduce EMF's from the exterior. As such, they
> 'may' reduce cell phone wave lengths as well. I have not come across any studies, but
> the physics says it is possible.
> -russell
>
> On 2014-03-03, at 6:47 PM, leen peeters wrote:
>
>> Dear all,
>>
>> is there anyone aware of a negative impact of triple glazing or foils used in triple
>> glazing on the transmittance of mobile phone signals?
>>
>>
>> Any input is welcome ...
>>
>> leen
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