If emergency responders can’t get a radio signal inside your building, that’s not just a small issue, it’s a code violation. And in some cases, it can cost lives.
That’s why more cities now require buildings to have a system that helps radio signals reach every corner, especially areas like stairwells, elevators, and basements. This is where a BDA system, or Bi-Directional Amplifier, comes in. At Maximum Communications, we help building owners and contractors prepare for these exact challenges with expert guidance and reliable installation.
Here’s a straight-up look at what it takes to get one installed, from start to finish.
Start with a Building Survey
Before anything else, someone has to come out and check how your building handles emergency radio signals. It doesn’t matter if you have great cell coverage, this is about whether public safety radios work inside.
A trained technician walks the property with test gear. They check multiple floors, rooms, and trouble spots. They’re looking to see if your building meets the minimum signal strength, usually -95 dBm or better.
If too many areas fall below that number, a BDA system is required. No guesswork here, it’s just how the code works in most places.
Talk to the Fire Department Early
Every city’s different. Some will want to review your signal test results. Others will have their own testing guidelines.
It’s smart to loop in the Authority Having Jurisdiction (AHJ) right after the survey. That might be the fire marshal or someone from the building department.
If you skip this, you might end up redoing work later. Worse, your system might not get signed off.
Design the System
Once it’s confirmed that you need a BDA, the system gets designed. This plan shows where the antennas will go, how the signal will be distributed, and where the main amplifier and power supply will live.
The design also includes how the BDA system ties into your fire alarm panel, which is required in most jurisdictions. If the BDA loses power or fails, the fire panel has to alert your monitoring company or on-site team right away.
The system should meet the UL 2524 standard, and follow whatever version of IFC 510 or NFPA 1225 your local code enforces.
Submit Plans and Get Permits
You can’t install the system until the plans are reviewed and approved. That usually means submitting the design to your local fire prevention office or building department.
If you’re in a jurisdiction that’s strict about BDA rules, the AHJ may ask for extra documents, like product specs, labels, or a backup power plan.
Permits get issued once everything checks out.
Install the Equipment
Once you’ve got permits in hand, the real work begins. The contractor installs coaxial cable, mounts antennas, places the amplifier, and connects the power supply. They also tie it into the fire panel.
This step isn’t just about getting everything in place, it’s about making sure it’s installed to spec. If the wrong cable is used or an antenna is installed in the wrong spot, the system might not work as intended.
Commission the System
After installation, the whole thing needs to be tested. This is called commissioning, and it confirms that the system boosts the radio signal correctly, reports any faults, and meets the design specs.
Another grid test is usually done, similar to the first one, to prove that the signal now covers the entire building. Areas that failed earlier should now pass.
The BDA should also show up as “supervised” on your fire alarm system. If it goes offline, the panel must alert you.
Final Inspection
Once commissioning is done, the fire marshal (or AHJ) schedules a final walk-through. They’ll want to see the test results, confirm backup battery life, and check that alerts are working.
You’ll also need to show them documentation, labels, floor plans, equipment manuals, etc. If everything’s good, they’ll give you the green light.
If not, you’ll get a list of things to fix before they sign off.
Maintenance After Approval
Getting approved doesn’t mean you’re finished. BDA systems need to be tested at least once a year. Batteries should be checked, signal levels should be verified, and alarms should be tested.
Also, if you renovate, add metal shelving, or make layout changes, the radio signal may be affected. A retest is often required when that happens.
Some teams choose to log monthly or quarterly checks to stay ahead of issues, especially in large buildings.
Final Thought
BDA systems aren’t just about checking a box. They’re about making sure firefighters and paramedics can stay in touch when seconds matter. If they can’t call for backup or get instructions inside the building, the risk goes way up.
Going through the BDA process step by step helps keep things on track. It also ensures your building meets code, and more importantly, it helps keep people safe.
