Distributed antenna systems (DAS) and Bi-Directional Amplifiers (BDAs or repeaters) are great in-building wireless solutions for enhancing your business infrastructure and making it easier for employees and customers to get the most out of their mobile devices—but they can be so much more than that. DAS and BDAs are critical components of public safety, providing critical wireless coverage to ensure connectivity for first responders. Public safety BDAs and DAS allow these emergency workers to properly and safety communicate during any emergency situation.
Regulations for in-building wireless coverage are being adopted by jurisdictions across the country. Most of these regulations take the form of standards set out by the National Fire Protection Association (NFPA) and/or the International Fire Code (IFC). Both of these organizations provide building standards and code recommendations for use by municipalities. The codes cover everything from existing structures to new construction.
Because of their expertise, quality, thoroughness, and effectiveness, most jurisdictions have chosen to adopt and adapt these standards in lieu of recreating their own. This is why it is important that all building professionals and owners understand these codes when considering the wireless coverage within their facilities. More and more municipalities are adopting these standards, so getting a good understanding of these codes and planning for compliance now will save you time and cost in the future.
NFPA Codes and Standards for Emergency Communications Systems
Here is a selection of relevant passages from the NFPA codes and standards relating to in-building wireless systems for handling emergency communication.
24.5.2.2 Radio Coverage. Radio coverage shall be provided throughout the building as a percentage of floor area as specified in 24.5.2.2.1 through 24.5.2.2.3.
24.5.2.2.1 Critical Areas. Critical areas, such as the fire command center(s), the fire pump room(s), exit stairs, exit passageways, elevator lobbies, standpipe cabinets, sprinkler sectional valve locations, and other areas deemed critical by the authority having jurisdiction, shall be provided with 99 percent floor and radio coverage.
24.5.2.2.2 General Building Areas. General building areas shall be provided with 90 percent floor area radio coverage.
24.5.2.2.3 Amplification Components. Buildings and structures that cannot support the required level of radio coverage shall be equipped with a radiating cable system or a distributed antenna system (DAS) with FCC-certified signal boosters, or both, or with a system that is otherwise approved, in order to achieve the required adequate radio coverage.
IFC Codes and Standards for Emergency Communications Systems
Here is a selection of relevant passages from the IFC codes and standards relating to in-building wireless systems for handling emergency communication. For the full codes and standards, be sure to read the codes directly from IFC.
510.1 Emergency responder radio coverage in new buildings. All new buildings shall have approved radio coverage for emergency responders within the building based upon the existing coverage levels of the public safety communication systems of the jurisdiction at the exterior of the building. This section shall not require the improvement of the existing public safety communication systems.
510.4.2.1 Amplification systems allowed. 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.
DAS for Public Safety: Integrated or Separate Systems?
There are two options when it comes to deploying a public safety system. Whether you are designing a new system or incorporating into an existing in-building DAS:
1. Integrate public safety coverage and capacity into the same infrastructure layer as the cellular wireless carrier network
2. Implement a separate overlay for the public safety network
Because of the high reliability standards of the NFPA and IFC codes, public safety DAS and BDA infrastructure must be extremely well-protected, including waterproofing measures (NEMA enclosures), alarm notifications, battery backup, and pathway survivability. They also need to extend coverage beyond where a typical cellular network would need to reach, such as stair wells and elevator shafts. Cellular DAS systems do not need to meet these extensive code requirements. Integrating the two systems will raise the overall cost of the system.
There are also differences in the goals of public safety DAS versus cellular coverage DAS. Public safety professionals believe critical areas are stairwells and building electrical areas, where wireless carriers believe critical areas are where their customers work. A DAS that is deployed primarily for cell coverage needs to provide enough data capacity for smartphones, but only in high public-use areas. A public safety DAS must be able to provide full-building coverage.
The International Wireless Communications Expo has a comprehensive article detailing the right structure for public-safety DAS on their blog. For a more complete discussion of which is the right approach, we recommend continuing with this resource.
DAS plays an increasingly important role in protecting life safety. As emergency communications codes and regulations are adopted by more jurisdictions, the demand for properly performing wireless coverage grows.