Fire Alarm Battery Calculator
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, Selected battery = 4.5 Ah, Required = 3.67 Ah, Standby = 24 h (per NFPA 72:2022).
How it works
Computed from your inputs per NFPA 72:2022.
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.
| Result | Value |
|---|---|
| Selected battery | 4.5 Ah |
| Required | 3.67 Ah |
| Standby | 24 h |
Computed live by WorkHive's calculation engine; standard: NFPA 72:2022.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a 24 V panel with 40 smoke + 10 heat detectors, 6 pull stations, 12 horn/strobes, and 24 h standby.
- The calculator returns Selected battery, Required, Standby, computed per NFPA 72:2022.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a fire alarm battery standby calculator NFPA 72?
The Fire Alarm Battery Calculator is a free online tool that computes 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's engineering calculators are free to use, no sign-up needed for the tools. 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, no sign-up needed for the calculators.