APPA

A s a follow up to the first Technology & Trends column on two-way radios, in this column I discuss how facilities management (FM) must also understand the importance of distributed antenna systems (DAS). Even among some professionals, incorrect terminology and questions abound about DAS. e topic mainly comes up during initial scope discussions for qualifications and proposals for new construction or major renovation projects, but it may be revisited at any time during a project—and hopefully before construction begins! ere are really two distinct purposes for DAS, although they are often mistakenly linked in discussions. One is for cell phones, and the other is for public safety communications, such as police, fire, and emergency medical services (EMS). ese first responders use licensed-frequency radios that are in many cases similar to radios used by FM, campus security, housekeeping, and engineering professionals. A DAS may or may not be needed in a building, depending on the radio frequency (RF) conditions of the built environment of the facility and surrounding areas. Per the National Fire Protection Association (NFPA) and International Fire Code (IFC), public safety radio reception is an absolute requirement. While cell service is not required by code, it is always expected by all occupants and visitors. Traditionally, the default approach to both radio reception and cell service has been to simply build the building and "see what happens." is approach can work in some areas where there are emergency responder antennas as well as cell towers in close proximity to the facility, in which case you might expect these services to sufficiently penetrate the building. But with the increase in steel structures and low-emissivity (Low-E) glass envelopes (which reflect many higher radio frequencies), waiting to see what happens results in continued disappointment. If the building has subgrade levels, parking garages, or utilized high-efficiency Low-E glass, you likely will require a DAS. PUBLIC SAFETY DAS • Also commonly referred to as first responder DAS, emergency responder DAS, or emergency responder radio communications system (ERRCS). • Supports first responder VHF and UHF frequencies. • Required by NFPA and IFC with stringent signal strength and floor-area coverage requirements. Occasionally there are additional requirements beyond the NFPA and IFC that many authorities having jurisdiction (AHJs) require. Many jurisdictions have a public safety DAS specification, guide, or document clearly outlining the additional performance, documentation, commissioning, and verification requirements for their jurisdiction. • Public safety DAS is similar to a cellular DAS passive system, except for some additional fire-rated components, National Electrical Manufacturers Association (NEMA) enclosures, emergency power requirements, acceptance test procedures, etc. Depending on the jurisdiction and floor plans, certain components of the two systems may even be combined, except in larger buildings and those with high occupancies per square foot. CELLULAR DAS—PASSIVE SYSTEM • Typically used in smaller, less complex stand- alone buildings. Beyond Code Requirements: How Distributed Antenna Systems are Critical to Building Operations By David K. Glenn, RCDD, CTS-D, LEED AP BD+C technology + trends 36 NOVEMBER/DECEMBER 2019 FACILITIES MANAGER John Cook is the editor of our new Technology and Trends column. John is vice president at Sextant Group/ NV5 Engineering & Technology, and his genuine passion and knowledge about leading-edge technology and environments will help make this column a great success. Please send suggestions for future columns directly to him at JCook@ TheSextantGroup.com.

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