Monitoring and supervision
How a BDA system is monitored, and what to do when it alarms
A BDA system watches itself. When its power, battery, antenna or amplifier fails, it has to tell the fire alarm system, and somebody has to act. Here is what it reports, how long it must run on battery, and a plain response plan for the building.
Signals the system must send
NFPA 1225 (2022) lists what the BDA system must report to the fire alarm system (18.14.1.2). The model fire code's list is close to the same (IFC 510.4.2.5).
| Signal | Type | NFPA 1225 | IFC 510.4.2.5 | What it usually means for you |
|---|---|---|---|---|
| Loss of normal AC power | Power supply supervisory | 18.14.1.2(3)(a) | Item 1 | The system is on battery and the clock is running |
| Battery charger failure | Power supply supervisory | 18.14.1.2(3)(b) | Item 2 | The battery will not recharge after an outage |
| Low battery capacity (70% of 12 hours used) | System supervisory | 18.14.1.2(2)(c) | Item 5 | Less than about a third of the runtime is left |
| Donor antenna or signal source malfunction | System supervisory | 18.14.1.2(2)(a) | Item 3 | The link to the outside radio network is lost |
| Active RF-emitting device failure | System supervisory | 18.14.1.2(2)(b) | Item 4 | An amplifier or remote unit has failed |
| Active system component failure | System supervisory | 18.14.1.2(2)(d) | Item 6 | Another powered part has failed |
| Oscillation detected | Supervisory | 18.3.2.1 | Item 8 | Feedback between antennas; gain is being cut or the unit may shut down |
| Fire alarm to BDA link failure | Integrity monitoring | 18.14.1.2(4) | Item 7 | The fire alarm can no longer see the BDA at all |
Where the AHJ approves, all of these may come in on a single supervisory input to the fire alarm (NFPA 1225 18.14.1.2(5)). Ask your fire alarm contractor what your panel shows.
The annunciator panel
NFPA 1225 also requires a dedicated annunciator in the fire command center showing, for each component and RF device: normal AC power, loss of AC power, battery charger failure, low battery capacity, signal source malfunction, active RF device malfunction and active component malfunction (18.14.2.1, 18.14.2.2).
Local rules can be more specific. Miami-Dade requires a dedicated panel "similar to what is used for generators," labeled exactly: Normal A/C Power, Signal booster trouble, Loss of normal AC power, Failure of battery charger, Low battery capacity, Donor antenna failure. It also requires each alarm to show on its own rather than combined with another, and a separate alarm for oscillating amplifiers.
Train front desk and security staff to recognize this panel. A trouble light that nobody understands is the same as no monitoring.
Battery and power rules
| Rule | NFPA 1225 (2022) | IFC 510 |
|---|---|---|
| Primary power | Dedicated branch circuit, permanently connected, NFPA 72 compliant, protected from overvoltage (18.13.1) | Not detailed in section 510 |
| Backup option 1 | Dedicated battery, 12 hours at 100% capacity (18.13.2(1)) | Dedicated standby batteries, 12 hours at 100% capacity (510.4.2.3) |
| Backup option 2 | Another power source approved by the AHJ, 12 hours at 100% (18.13.2(2)) | Not listed |
| Backup option 3 | 2-hour battery plus building generator that can carry the full load for 12 hours (18.13.2(3)) | 2-hour batteries plus the facility generator (510.4.2.3) |
| Battery cabinet | NEMA 3R or higher (18.3.1.1) | NEMA 3R or higher (510.4.2.4) |
| Annual battery test | Part of the annual system test (20.3.10) | Under load for 1 hour, extended if the battery shows failure (510.6.1) |
Who gets the signal
The codes say the signal must reach the fire alarm. Who answers it is often local. Miami-Dade, for example, requires systems to send all supervisory and trouble signals "to a central station or to the radio service provider contracted to provide the runner service," with the central station calling the radio service provider immediately, and a runner on site within four hours who restores the system (Miami-Dade County Code Sec. 14-69(B), (C), quoted in the MDFR guideline). If the runner cannot restore it, the building may face limits "including fire watch requirements" until it works again (Sec. 14-69(C)(3)).
Ask your fire marshal whether your county has a rule like this, and check that your monitoring contract covers BDA signals, not only fire alarms.
A response plan for the building
Put this next to the annunciator and in your front desk binder.
- Note the time and the signal. Write down exactly which light or message is showing.
- Call the BDA service vendor the same day. Give them the signal name. Loss of AC power with a working battery buys hours, not days.
- Low battery or donor antenna failure is urgent. The system may already be down or close to it.
- Check for a cause you can see. A tripped breaker, roof work near the donor antenna, or a power outage in the building.
- Ask your fire marshal how they want to be told about an extended outage. Some, like Miami-Dade, can require a fire watch while the system is down.
- Log the event and the repair. Date, signal, vendor, what was fixed. Keep it with your BDA records; it is useful evidence at the next annual test.
Confirm local monitoring rules with your fire marshal (AHJ).
Questions people ask
Does the BDA have to be connected to our fire alarm?
Under NFPA 1225, yes. Malfunctions must be sent as supervisory signals "annunciated by the fire alarm system in accordance with NFPA 72" (18.14.1.1). The model fire code allows one alternative where the fire code official approves it, an audible signal at a constantly attended location on site (IFC 510.4.2.5).
How long must the battery last?
12 hours at 100 percent system operation under both NFPA 1225 (18.13.2) and IFC 510.4.2.3. A 2-hour battery is allowed only when the system is also on the building generator and the generator can carry it for 12 hours.
When does the low-battery alarm go off?
When 70 percent of the 12-hour operating capacity has been used (NFPA 1225 18.14.1.2(2)(c)). That leaves less than four hours of runtime, so treat it as urgent.
Where does the NFPA 72 fire alarm code come in?
NFPA 1225 sends the BDA's signals through the fire alarm "in accordance with NFPA 72" and requires integrity monitoring under Chapter 10 of NFPA 72 (18.14.1.2(1)). Miami-Dade's checklist also cites NFPA 72 section 24.9 for the final fire inspection. We have not reproduced NFPA 72 text here; ask your fire alarm contractor how your panel is programmed.
Sources
Primary documents we read for this page. Rules change; confirm with your fire marshal (AHJ).
- NFPA 1225, Standard for Emergency Services Communications, 2022 Edition: Chapter 18 and section 20.3.10, Georgia Office of Insurance and Safety Fire Commissioner (reproducing NFPA text)
- International Fire Code Section 510, Emergency Responder Communication Coverage, City of Eaton, Ohio (reproducing ICC model code text; edition not stated in the document)
- General Guidelines for the Deployment of Two-Way Radio Communication Enhancement System (BDAs), Miami-Dade County Fire Prevention Division
- Two-Way Radio Communications Enhancement Systems: BDA Installation and Testing, Miami-Dade Fire Rescue
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