Fire Alarm Battery Calculator
Static · formula-only · worked example computed when this page was built · no live data
The Fire Alarm Battery Calculator sizes the standby battery (Ah) for a fire alarm panel from its device load, standby hours, and alarm time. Example: for a 24 V panel with 40 smoke + 10 heat detectors, 6 pull stations, 12 horn/strobes, and 24 h standby, with 5 minutes in alarm, Selected battery = 4.5 Ah, Required capacity = 3.67 Ah, Standby period = 24 h (per NFPA 72:2022).
How it works
Computed from your inputs per NFPA 72:2022. Anything the worked example does not state uses this calculator's standard default; the interactive version shows every input and lets you change it.
Worked example (Fire Protection)
Inputs: a 24 V panel with 40 smoke + 10 heat detectors, 6 pull stations, 12 horn/strobes, and 24 h standby, with 5 minutes in alarm.
| Result | Value |
|---|---|
| Selected battery | 4.5 Ah |
| Required capacity | 3.67 Ah |
| Standby period | 24 h |
Computed by WorkHive's calculation engine when this page was built; standard: NFPA 72:2022.
How to use this calculator
- Read the worked example. It uses a 24 V panel with 40 smoke + 10 heat detectors, 6 pull stations, 12 horn/strobes, and 24 h standby, with 5 minutes in alarm and shows every number in the method.
- Follow the formula with your own figures: it returns Selected battery, Required, Standby, computed per NFPA 72:2022.
- To compute interactively, open the Fire Alarm Battery Calculator inside WorkHive's free Engineering Design suite (link below). It runs the same method with your inputs.
FAQ
What is a fire alarm battery standby calculator NFPA 72?
The Fire Alarm Battery Calculator is a free online tool that sizes the standby battery (Ah) for a fire alarm panel from its device load, standby hours, and alarm time. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following NFPA 72:2022. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive is free: this worked example is open to everyone, and the interactive calculator runs inside the free Engineering Design suite after a free sign-up (your work is saved to your account). WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive Fire Alarm Battery Calculator in WorkHive. Free, and a free sign-up saves your calculations, BOMs and scope-of-works to your account.