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Understanding Bi-Directional Amplifiers (BDA) in Construction
Construction Posted on

Understanding Bi-Directional Amplifiers (BDA) in Construction

by Brad Hoffman, Project Manager

 

Emergency Responder Radio Coverage Systems, more commonly referred to as BDAs, are critical components in modern building infrastructure, particularly for ensuring reliable communication in emergency situations. As the construction industry increasingly prioritizes safety and compliance, understanding the requirements for BDAs in new and existing structures is essential.

Building codes are updated frequently and staying up to date on those that could directly impact your project’s budget or schedule is not always clear cut or easy to decipher. Although BDA’s are not new, there are many people still unfamiliar with these systems or the process to follow if and when your building meets the criteria. We recently finished a project and were surprised to find out during our final building inspections that our project not only required the survey but also the installation of a new BDA system. Every project is different and, in some cases, the (AHJ) Authority Having Jurisdiction’s requirements may vary making it crucial to know the specifics during the preconstruction stages to set your project up for success.

What is a Bi-Directional Amplifier?

A Bi-Directional Amplifier is a device designed to improve communication signals within a building. It amplifies both incoming and outgoing radio frequencies, ensuring that signals can penetrate areas that would otherwise be dead zones. This is particularly important for first responders who rely on consistent and clear communication during emergencies.

Here is a link to the technical bulletin issued by The City of Raleigh’s Office of the Fire Marshal in January 2019 and revised on 12/02/2021 that provides additional information. https://cityofraleigh0drupal.blob.core.usgovcloudapi.net/drupal-prod/COR18/TB-17_Emergency_Responder_Radio_Coverage.pdf

As of the issuance of these bulletins, a survey will be required for any new commercial buildings and even some renovations based on size and jurisdiction. A code summary sheet and floor plans for your building must be provided to the company you hire to perform the survey. With this they will overlay the building floor plan with a 20’x20’ grid and test each square in the grid.

The survey is a Pass / Fail document reading the transmission of radio signals on the frequencies used by emergency response teams. Critical areas (elevator lobby, stair tower, mechanical room) will require 99% coverage and General areas will require 95% coverage in order to pass. The Fire Marshall or AHJ will ask for the survey at the final inspection. If the survey fails, a BDA system will be required.

To get ahead of the surprise at the end, it’s best to get the survey done when the building’s interior walls are in place and your building exterior is complete or roughly around 80%. If your building fails the test, you should still have time to file for the permit, order equipment and plan for the installation before running into costly delays at the end of your project.

Considerations in addition to a new BDA system are many. Here are a few:

  • Have pricing and submittals completed during your pre-con
  • A separate permit is required – have the permit application completed and ready before your survey is done
  • Shop drawings and submittals are to be submitted along with your permit application
  • Plan for space in the electrical room for the added equipment
  • A dedicated circuit is required for the BDA equipment and control panel
  • Conduit from the panel’s proposed location to the roof top antenna will be required * this can be done regardless and is way less involved if performed during the rough-in stage
  • Have your electrician install the required breaker and conduit with anticipation of a non-passing survey
  • There will be at least 5 or more monitored points added to your Fire Alarm panel – does it have capacity?
  • Get your Electrician, Fire Alarm, Roofing and BDA contractor’s on board early so you don’t incur added cost for remobilization and after hours or weekend rates

Conclusion

BDAs are vital for ensuring effective emergency communication within buildings, making them a critical component of all construction projects. By adhering to regulatory requirements, focusing on performance standards, and integrating proper design and maintenance practices, construction professionals can ensure that their buildings provide safe and reliable communication capabilities for emergency responders and occupants alike. As technology and regulations evolve, staying informed about the latest developments in BDA requirements will be essential for the construction industry.