LEED Initiative Impairs In Building Cell Coverage

LEED Initiative Impairs In Building Cell Coverage

LEED Initiative Impairs In Building Cell Coverage

by Will Washburn
published 11.21.17

The green building initiative has taken hold and it is estimated that 48% of Non –Residential buildings constructed are green. LEED is a national certification system developed by the U.S. Green Building Council (USGBC) to encourage the construction of energy and resource-efficient buildings that are healthy to live in. LEED stands for Leadership in Energy and Environmental Design. Between 2015 and 2018, LEED-certified buildings in the United States are estimated to have $1.2 billion in energy savings, $149.5 million in water savings, $715.2 million in maintenance savings and $54.2 million in waste savings. As of October 2017, more than 19.3 billion square feet of building space is LEED-certified worldwide and an approximately 2.2 million square feet achieves LEED certification each day.

One of the unintended consequences of this trend is the impact on RF signal. LEED certified glass is Low-E. Low-E glass has a microscopically thin, transparent coating that reflects long-wave infrared energy (or heat). Some Low-E’s also reflect significant amounts of short-wave solar infrared energy. When the interior heat energy tries to escape to the colder outside during the winter, the low-e coating reflects the heat back to the inside, reducing the radiant heat loss through the glass. Since low-e glass is comprised of extremely thin layers of silver or other low emissivity materials, the same theory applies. The silver Low-E coating reflects the interior temperatures back inside, keeping the room warm or cold. Because of the metals and composite of the Low-E film, cellular transmission is interrupted. This is a major problem and is only going to get worse as more buildings are striving to be compliant with the LEED initiative.

The simple solution is to install a Distributed Antenna System “DAS”, to propagate in building coverage of cellular. A neutral host DAS system, installed in a building can provide seamless coverage to its tenants. The infrastructure of antennas strategically located within the building aggregate to the head-end equipment. The carriers bring signal to the head end equipment and backhaul it to the central office by means of fiber or Ethernet. The neutral host is available to all carriers who choose to participate.

Public Safety Systems are another concern. The NFPA requires buildings to conform to their code as well as local code, to allow for the propagation of their signal in building for first responders. NFPA 72 requires the use of a public safety distributed antenna system (DAS) for use by first responders. Public Safety DAS is installed to enable first responders within the building to communicate during an emergency. It must cover the entire building, including basements and stairwells. Public safety DAS must also have battery backup system in case of a fire or outage. These systems must accommodate the AHJ and their transmission frequency. This frequency can be analog or digital. Although there are technologies that can combine cellular DAS and Public Safety DAS, some AHJ’s require the PS system to be standalone.

As our nations buildings strive to be more energy efficient, we need to have a in-building RF distribution plan to accompany this trend. Today’s mobile workforce and consumer, rely on their handsets as their primary source of communication. All of the stakeholders need to band together to accommodate this shift, and provide the infrastructure to propagate cellular coverage in-building.

Will Washburn, is the COO of Combined Operations for Digitechx Inc. a global provider of wireless services to the carrier and enterprise markets.

 

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