[Bldg-sim] radiation through glazing

[Laouadi, Aziz]

Dear all,

My colleague, expert in low-e coating, told me that silver-based low-e coatings (most of the soft low-e coatings use Silver) will reflect most of the radio frequency waves. Indeed,  almost all of the radio power is reflected within the first few atoms of the metal material.



Best regards!

Abdelaziz (Aziz) Laouadi, Ph.D., MASHRAE  
Research Officer | Agent de recherche 
Construction
National Research Council Canada | Conseil national de recherches du Canada
1200 chemin de Montréal Road, Ottawa, ON K1A 0R6 
Tel: 613-990-6868 | Fax: 613-954-3733
Email: Aziz.Laouadi at nrc-cnrc.gc.ca 
http://archive.nrc-cnrc.gc.ca/eng/projects/irc/optical-characteristics.html
http://www.nrc-cnrc.gc.ca/eng/index.html


-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Joe Huang
Sent: March-04-14 2:17 PM
To: ldegelman at suddenlink.net
Cc: BldgSim Mailing List
Subject: Re: [Bldg-sim] radiation through glazing

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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