Why Every New Building Should Have a Public Safety DAS

Posted by Bram Vandertuin on Aug 26, 2015 11:30:00 AM
Bram Vandertuin
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When an emergency occurs, reaction time and the ability to communicate effectively are vital. However, what happens if those inside a building do not have enough cellular coverage to call 911? Additionally, what if first responders cannot communicate on their two-way radios once they enter a building? Without reliable in-building communications systems, emergency situations can escalate, putting those inside at a much greater risk. 

When fire fighters enter a high rise building, point-to-point communications between those on scene and those on the ground can become severed. This is a result of structural materials such as steel and concrete that prevent or limit radio frequencies (RF).

Solutions exist to improve public safety communications and cellular coverage. Distributed antenna systems (DAS), specifically public safety DAS, can support Land Mobile Radio (LMR) as well as the multiple frequency bands used by first responders, such as VHF/UHF and 700/800MHz. Additionally, cellular DAS solutions enhance the multiple LTE frequencies used by Verizon, AT&T, T-Mobile and Sprint.

With fire and building codes for public safety communications becoming increasingly more prevalent, property owners and building managers need to stay up-to-date with the necessary requirements. Most notably, the International Fire Code (IFC) now mandates that there be a minimum of 95% general building coverage for public safety. The National Fire Protection Association (NFPA) requires 90% general building coverage as well as 99% coverage in all critical areas. In addition to these two major in-building fire codes, below are six other stipulations to be aware of when an in-building public safety DAS is required. 

Six Things to Keep in Mind

1. System Coverage
Critical areas can include control rooms, pump rooms, stairwells, lower exit stairs, exit passageways, elevator lobbies and standpipe cabinet locations. As mentioned, the IFC mandates a minimum of 95% general building coverage, while the NFPA mandates 90% general coverage and 99% critical area coverage.  

2. Radio Coverage

Buildings and structures which cannot support the required level of radio coverage shall be equipped with a radiating cable system, a distributed antenna system with Federal Communications Commission (FCC)-certified signal boosters, or other system approved by the fire code official in order to achieve the required adequate radio coverage.

3. New Buildings
All new buildings shall have approved radio coverage for emergency responders based upon existing coverage levels of the public safety communication systems. This does not require improvements to the existing public safety communications systems.

4. Emergency Back-Up
In an emergency situation such as a fire, a building will most likely lose its main source of power, and a secondary power source will be required. The NFPA requires 12 hours of emergency power batter back-up, while the IFC requires 24 hours. If Fiber-DAS is used, an optical-to-RF converter rack maybe required to assure uninterrupted service. 

5. System Monitoring
The NFPA Annex O requires an automatic monitoring system with a dedicated panel in the emergency command center of the building. The system must signal an alarm in the event of an antenna malfunction or signal booster failure. A separate alarm for oscillating amplifiers is desirable. Power supply systems must, at a minimum, signal an alarm when AC power is lost, when the battery charger fails and when the battery has a low charge (defined as 70% of capacity). 

6. Maintenance
The NFPA Annex O requires that the building owner have a service contract for emergency repair. The response time shall be no less than two hours.

For first responders who put their lives on the line everyday, two-way radios are a lifeline. Similarly, the importance of having reliable in-building cellular coverage continues to grow, especially as first responders adopt LTE handset technology. DAS has proven itself to be a comprehensive solution for providing reliable in-building communication. With the ability to support both LMR/VHF/UHF and LTE frequencies, DAS will be around for years to come.

Topics: Public Safety DAS

How to meet NFPA and IFC Public Safety Building Code