Optimizing for Mobile in a LEED Design

The ultimate goal of a workspace design is to make the space not only functional, but aesthetically pleasing as well. Effective use of form and function promote employee health and happiness, which in turn promotes productivity.

And positively impacting employee health is part of the core values driving LEED (Leadership in Energy and Environmental Design) building standards today.

Working within the LEED framework means using copious amounts of natural light filtered through “low-E” (low emissive) glass, which allows the transmission of visible light while controlling the amount of solar heat allowed to enter the building. The use of natural light and heat has the combined benefit of reduced building operating costs and increasing employee comfort.

Unfortunately, the low-E glass can have a negative effect on employee productivity in our increasingly connected, and information driven workplace given that low-E glass is an effective barrier in the transmission of cellular and wireless communications signals.

A low-E glass window is actually a composite of panes of glass, inert gasses, and metal or metallic film coatings. The combination of glass, gas, and metal forms a window that has light and heat transmission properties appropriate for the building’s climate.

In an era where over half of all cellular phone calls are initiated within a building, the metal coating used temper the light and heat penetration has the negative effect of blocking a significant portion of the cellular signal available from neighboring antennas.USGBC does not take into account the frustration over another dropped call, or the inability to download a image to an tablet computer into its LEED point system.

One cure for the weak cellular signal is to bring the wireless antenna into the building through a Distributed Antenna System, better known by its acronym: DAS. By deploying a DAS infrastructure, the coveted “five bars” of service can be obtained in nearly every space within the building.

The proliferation of hand-held and mobile computing devices makes a DAS installation a near necessity in any new construction or significant renovation. By placing a full power signal within confines of the building, the wireless devices use less power to connect with the cellular network, which is always available. For the office worker, not only is the frustration of poor signal and dropped calls alleviated, their device lasts longer on a single charge.

Design Impacts

Physically speaking, a DAS system is visibly unobtrusive, since the antennas range in size from those with a footprint similar to a smoke detector, to ones the size of a small cereal box.

And within a conventional office space — even one with modest ceiling heights — the smaller antennas are more than sufficient to provide seamless coverage. In a larger atrium, conference hall, or auditorium setting, a slightly larger antenna would need to be installed on order to properly cover the open space.  In each case, the antenna would be placed according to user density and physical obstacles. Wireless signal does not travel well through dense materials, so concrete elevator shafts and firewalls play a significant part in antenna placement.

Given the relatively small footprint, and the generic electrical colorings, the antennas blend in seamlessly with the typical ceiling mounted building systems, such as security cameras, access control sensors, smoke and fire detectors, environmental sensors.

Installation Details

Depending on the system manufacturer, the antenna receives its data through a coax or fiber optic cable, which is placed either by the same low voltage contractor who is installing the conventional, hard-wired, voice and data network; or by a specialty DAS contractor.

The electronics required by DAS are often wall mounted in the telecomm closet. The cellular service is brought into the building either by a underground fiber connection running parallel to the conventional voice and data service cable, or by an rooftop mounted antenna connected to the head-end electronics via a fiber optic cable routed through the telecomm riser.

As with any system, there is an installed cost that must be considered. DAS systems are most cost-effective as the building reaches and exceeds 100,000 square feet.

• For a single tenant in a smaller office space, a DAS system is not a cost-effective option. But for the building owner, who leases to multiple tenants, a building wide deployment can be profitable.

• From a public safety standpoint, the DAS can be configured to work with police and fire radios, allowing public safety personnel to operate within the building on their service radios.

• For a large building or a campus setting where there is a dedicated security and building maintenance staff, their radios can also be operated over the DAS, providing better communications between support personnel, and a faster response to tenant requests for service.

Increasingly, DAS is an amenity to be considered when choosing lease space, and a full functioning DAS can command a premium on the lease rate.

Often, from a technology standpoint, the workspace design centers around the placement of the telephone, computer and monitor on the work surface; and the placement of  peripheral devices such as plotters, scanners, fax machines and copiers around the communal work area. As our increasingly transient workforce becomes less tethered to their desk, and the technology to work  remotely continues to evolve, the need for a wireless communications network within the building becomes even more vital to the productivity of the worker.

In a building constructed with  LEED goals in mind, a DAS system brings the outside communications infrastructure inside with the worker, who is always glad to operate with “five bars” of service.

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Article written by Ted Steeble, Network Consultant at Accu-Tech, and first appeared on Workspace Design magazine.