In an emergency, first responders must communicate effectively to take action. To do this, they depend on radio signals.
For this reason, the National Fire Protection Association (NFPA) requires 99% radio coverage in critical areas of all commercial buildings, such as basements, stairwells, and garages, in addition to 90% coverage in general use areas such as offices and conference rooms.
Public safety distributed antenna systems (DAS) help ensure that coverage.
Public Safety DAS: What Is It and Why Is It Important?
A public safety DAS is a network of antennas that enhances and extends wireless coverage for public safety communications inside buildings and other structures. It is designed to ensure reliable communication for first responders such as police, firefighters, and emergency medical personnel in critical situations.
A public safety DAS typically operates on dedicated frequencies reserved exclusively for public safety use, ensuring priority access and reliable communication for emergency services. It consists of a network of strategically placed antennas, coaxial cables, and signal amplifiers to distribute the enhanced signal throughout the building.
This uninterrupted connectivity is essential for providing the most rapid and effective first aid services possible—even in the most isolated parts of a building, particularly stairwells and basements. It helps to overcome the challenges of weak or blocked signals caused by the materials used in building construction, such as concrete, steel, and low-emissivity glass.
While many buildings already have a cellular DAS, updated infrastructure can be integrated into existing building systems to accommodate public safety requirements. This integration includes adherence to NFPA and International Fire Code (IFC) standards, the default standards for DAS installation across the country. These standards ensure the reliability of these systems by enforcing waterproofing requirements as well as alarm notifications, battery backup, and pathway survivability.
Introduction to Public Safety DAS Building Requirements
Many companies are required to install a public safety DAS system by their local jurisdiction for public safety reasons. Every jurisdiction has slightly different requirements, but most draw on language in IFC and NFPA codes instead of developing their own.
NFPA 72 covers the need for radio signal connectivity across critical areas such as exit stairs, elevator lobbies, and fire command centers, as well as requiring minimum inbound and outbound signal strengths to ensure uninterrupted communication for first responders. NFPA 70 requires public safety DAS installation in buildings with determined “dead zones” where radio signals are weak or nonexistent.
Dig Deeper
How to Meet Building Code Requirements With DAS
Learn more about the standards for the installation, maintenance, and use of public safety DAS. Learn More →
Is Your Facility Meeting Public Safety DAS Requirements?
While many facilities already have a public safety DAS, regular yearly inspections ensure commercial buildings still meet authority having jurisdiction (AHJ) requirements. These annual inspections cover equipment functionality, track current coverage and provide recommendations for any potential issues. A properly installed and well-maintained public safety DAS can save lives and facilitate first responders’ jobs in an emergency and are an essential part of any building’s security infrastructure.
Editor's Note: This post was originally published on August 24, 2020, and has been updated for accuracy and current best practices.
