BDA Systems

Emergency Responder Radio Coverage Required in Chelmsford for New Construction and Level 3 Renovations

The Chelmsford Fire Department enforces the Emergency Responder Radio Coverage code as found in the Massachusetts State Building Code, 780 CMR 915, 9th ed. This section mandates that in new buildings and buildings undergoing substantial (Level 3) renovations, downstream and upstream radio signals for public safety radios must meet certain thresholds for radio signal strength. The Chelmsford Fire Department requires testing and if necessary, Emergency Responder Radio Coverage in all existing buildings undergoing Level 3 Renovations.

As construction methods and materials have evolved over the recent years, firefighters and police officers experience increased difficulty in transmitting and receiving radio signals inside a building because of the shielding properties of modern construction materials. Low-E glass, concrete, and steel have a huge impact on radio signals.

Did you know that triple pane glass or low-E glass blocks almost all radio transmission in or out of a building? You may have noticed this signal degredation when you try to make that cell phone call in certain buildings.

Firefighters and Police Officers have been injured or killed in the line of duty because of communication failures.

The solution is a network of interconnected antennas (Distributed Antenna System, or DAS) attached to a signal booster (BiDirectional Amplifier System, or BDA).

Contractors and building developers must present the fire prevention office with a satisfactory radio survey prior to a final inspection being scheduled


So are you saying that fire department and police department radios are substandard?

No, not at all. Quite the opposite is true. The Chelmsford Fire Department and Chelmsford Police Department provide all members with top-notch radio equipment. In fact the Town of Chelmsford recently invested almost $2,000,000 in radio equipment to improve the quality and reliability of radio transmissions. 

The biggest problems in radio communications today lie with the buildings themselves. Modern construction materials wreak havoc on  radio signals. Perhaps you may have noticed that in some buildings, your cellphone does not get an adequate signal. The same holds true for fire and police radios. We can’t increase the signal strength of our radio system. Our handheld radios already transmit at approximately 3W, which is on the higher end of portable radios. Our repeater system transmits at 45W which is the maximum amount allowed by our FCC license at this time. 

As you can see by the picture, as a radio signal travels through a building, it loses strength. It becomes hard to understand the person on the other end of the radio. Good communication is quite often the difference between life and death in public safety operations.

So, how do we fix this coverage problem?

The solution is installing a complete BDA system installed by a licensed and certified contractor. A BDA system receives a radio transmission through the donor antenna on the roof. The signal travels down a cable to an amplifier. The amplifier sends the signal out to a network of antennas, the DAS. We are literally bringing the signal closer to the firefighter or police officer by decreasing the amount of building that signal has to travel through over the air to get to and from a firefighter or police officer’s radio. BDA systems have to be UL 2524 certified, and must be compliant with NFPA 72 and NFPA 1221, as well as compliant with the Massachusetts State Building Code. 


A BDA sounds like a great idea. Can I install one in my commercial building even though it’s not required?

Absolutely! BDA systems not only keep first responders safe, they also keep the public safe by allowing public safety providers to complete their jobs safely.

Where can I get more information on what the Chelmsford Fire Department requires?

Download the CFD ERRC guide here! If you have further questions, contact Captain Koutsoufis in the fire prevention office.