Keep Your In-Building Network Coverage
Up to Code and Your Building Ready for Anything
Reliable, in-building coverage is important for employees and guests, but is even more critical during times of emergency for first responders. In order to ensure coverage for emergency personnel, the National Fire Protection Association (NFPA) established codes and standards for Emergency Communications Systems. While adherence to specific NFPA requirements varies based on jurisdiction, they can be a great resource when you are designing a new network or upgrading an existing system.
In designing a network solution, areas that are most frequently used are typically paid the most attention. During an emergency, personnel often find themselves in less-used areas, such as stairwells or basements, and in need of communications. The NFPA guidelines require 99 percent coverage in areas identified as critical by local fire departments, and 90 percent coverage in general use areas. That means, while a design will obviously ensure coverage in the lobby or offices, it is important to identify areas in the basement, elevators, parking structures and stairwells that are not well served. Completing a survey of the signal strengths in different areas of your building will allow you to identify weak spots in your network and implement enhancements to meet coverage requirements. When designing a new network, addressing weak coverage areas now will eliminate the need for more updates in the future. Additionally, frequencies often used by emergency personnel (VHF, UHF, 700 and 800 MHz) must be supported.
Determining the right equipment and designing for total coverage is only the beginning. In the event of a disaster, the equipment must be capable of withstanding adverse conditions. This is especially important in the event of a fire, when the equipment may be inundated with water. The NFPA requires that all equipment serving a network should be housed in NEMA-4* compliant, water- and weather-proof enclosures. Testing of these enclosures is rigorous and will ensure your equipment is protected from water pressure of least 65 gallons per minute from a distance of less than 10 feet. Implementing these safeguards initially will not only keep your network in line with the best practices for safety, it will prevent costly damage to your equipment.
Seamless coverage is important for your public safety network and the NFPA specifies minimum signal strengths that must be maintained. Within your coverage area, the minimum signal strength should be 95dB regardless of frequency. You will need to consider the coverage area, signal strength, and the various frequencies that might be used when designing your network. Antenna isolation of 15dB higher than the gain of the amplifier is the generally accepted specification. Your network may require multiple antennas to meet coverage requirements, so you will need to pay close attention to isolation. A directional antenna may be the optimal solution in some locations to meet requirements for coverage, signal strength, and isolation.
A comprehensive network, with well protected equipment, is only useful when it has power. That's why the NFPA regulations also require systems to include battery backups and real-time monitoring alarms to alert to any failures and malfunctions. All systems should include alarms that monitor and notify of power or battery failures, antenna malfunctions, and low battery capacity is at 70 percent or less. All equipment must also be supported by a battery backup that will keep the system running from 8 to 24 hours, depending on local regulations. Additional considerations include how to centralize the monitoring point and how to ensure power coverage for requirements that could range from 120/240 volts AC to -48 volts DC.
Finally, your network should be flexible so modifications can be made to address future public safety technology. Currently, a network may need to support VHF, UHF, 700 MHz, and 800 MHz based on local regulations, but with the constant advancement of wireless technology, new frequencies could be required in the near future. By looking ahead in your design and future-proofing your system, you will be ready to adapt and advance with the latest technology.
A reliable network can do more than provide connectivity in public spaces for employees and guests. A well-designed Public Safety network can protect your building and provide the peace of mind that comes with preparation.
NFPA=National Fire Protection Association
NEMA = National Electrical Manufacturers Association
* NEMA Type 4 Enclosures are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); and that will be undamaged by the external formation of ice on the enclosure.