Poor Cell Phone Service in LEED buildings

5 replies [Last post]
Sustainability Director Boston University Jan 03 2012 Guest
36 Thumbs Up
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All,

I have heard that the low-ELow-E or Low-Emissivity Coating: Very thin metallic coating on glass or plastic window glazing that reduces heat loss and heat gain through the window; the coating emits less radiant energy (heat radiation), which makes it, in effect, reflective to that heat. In that way it boosts a window's R-value and reduces its U-factor. coatings on windows has been found to block cellular phone singals and make many LEED certified buildings "dead zones" for wireless service. Has anyone encountered this problem? If so, what are ways to prevent or fix this problem. Are there window coatings which do not block the signals?

Any help would be greatly appreciated.

Thank you,

IJ

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Francis Chua Project Architect NK Architects
Jan 03 2012
Guest
97 Thumbs Up

Is it really the windows?

Dennis:

I have experienced weak cell phone signal in a brand new 4-story 180-bed long term care facility. But I'm not sure if it is due to the low-eLow-E or Low-Emissivity Coating: Very thin metallic coating on glass or plastic window glazing that reduces heat loss and heat gain through the window; the coating emits less radiant energy (heat radiation), which makes it, in effect, reflective to that heat. In that way it boosts a window's R-value and reduces its U-factor. glazing. There are so many other factors that contribute to bad cell phone signal. The building is in a rural area, and it's quite possible that the distance to the nearest cell tower is too far. It may also be due to all the metal in the building, such as the metal deck holding the concrete floor slabs, the rebar in the concrete, the steel framing, the metal studs in the walls, or the sheet metal in the ductwork. As you probably already know, metal reflects radio waves.

To answer your question about the low-e glazing, I don't know of a viable alternative at this point in time. Low-e in itself is metallic. Window films that go on the inside face of the glass are also metallic based. (Window films by themselves without Low-E is not recommended, by the way). If you are that concerned about cell-phone signal, it may be worth looking into a signal repeating system, involving an external antenna and internal antennas spread throughout the building.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jan 18 2012 LEEDuser Moderator

I have heard this is a problem for a variety of reasons—wall construction, glazing type... anything that attenuates radio frequencies. In some buildings with high revenue potential, cell phone companies may be willing to install an in-building repeater to strengthen the signal. Or maybe someone will invent a hard-wired phone system?

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Alexander Maslakov Jan 04 2013 Guest 9 Thumbs Up

Low-ELow-E or Low-Emissivity Coating: Very thin metallic coating on glass or plastic window glazing that reduces heat loss and heat gain through the window; the coating emits less radiant energy (heat radiation), which makes it, in effect, reflective to that heat. In that way it boosts a window's R-value and reduces its U-factor. Glass does block cellular and radio signal. To overcome this, buildings install a distributed antenna signal and connect it to cellular service providers.

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Bill Swanson PE, LEED AP, Integrated Architecture Mar 06 2013 LEEDuser Expert 14551 Thumbs Up

Any modern steel frame building with the columns properly grounded will have cell phone signal problems. And the metal deck on each poured floor and roof adds to the problem. Either don't use steel or add a repeating antenna.

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Travis Reed CellAntenna Jan 06 2014 Guest 5 Thumbs Up

Regarding Francis' comment, it depends on the signal strength outside the building. The only way to know if a building's composition is affecting the signal is to test its strength in the area beyond the building confines. I work for a company that designs and installs cell phone signal boosters and Distributed Antenna Systems for business, government and home users, and we perform a considerable amount of work on LEED buildings. These materials absolutely affect cell phone signals, and we recommend that developers understand and address the imposition in the planning stages. As long as signal is delivered in the region, it's an absolutely fixable problem.

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