Issue link: https://www.e-digitaleditions.com/i/1255991
July/August/September 2020 I 51 compliance is optional in many regions, such as counties within Florida, California, and Nevada, but AHJs' nation- wide demand for UL-2524-compliant wireless networking equipment continues to grow as the importance of bet- ter public safety communications takes center stage. To advocate and proactively propose new fire codes and standards, the Safer Buildings Coalition (SBC) was cre- ated in 2012 to foster constructive collaboration among wireless industry stakeholders, such as AHJs, wireless car- riers, manufactures and others, to further the mission of making buildings safer. 14 Many original equipment manufacturers (OEMs) are members of this organization. IMPLEMENTING IN-BUILDING TECHNOLOGIES Many schools have become near-impenetrable to natural disasters and perhaps intruders, including those that are built and used as evacuation centers. However, improve- ments in building construction have affected the rein- forcement layers that have altered how two-way radio sys- tems can be implemented within a school. Many school administrators assume they have a poor signal based on the approximate distance from a cell tower. However, the school's surrounding obstacles and structures can attenuate the signal. This challenge, combined with the increase in public response technologies such as E911, creates a need for adequate wireless infrastructure now more than ever. A typical cellular phone signal operates with a fre- quency ranging from >-70 dBm (full bars) to -120 dBm (no signal), and building materials and outdoor obstruc- tions are known to cause a subtraction in decibel (dB) readings. Schools are fortifying their walls with metal roofs, heavier glass and more rebar meant to strengthen concrete under tension. Most notorious for causing disrup- tions are metal (-32 to -50 dB), wood (-5 to -12 dB), plaster (-8 to -16 dB) and concrete (-32 to -50 dB). As schools also focus on becoming more energy efficient, denser materials and low-emission energy saving windows can disrupt a signal anywhere between -24 to -40 dB. Adding trees and architectural structures meant to break up open spaces can also negatively impact the 90-99% signal strength required by the NFPA and IFC codes for communication systems. 15 Tall trees and other vegetation can form natural barriers to cellular signal waves, attenuating the signal anywhere from -7 dB to -20 dB. Denser materials and low-emission energy saving windows can disrupt a sig nal anywhere between -24 to -40 dB. Get real-time, real-world learning with BICSI Virtual Classroom Training. bicsi.org/vct