Fire Alarm Battery Backup Calculator
Calculate standby Ah, alarm Ah, derating, spare margin, and recommended battery size.
Open ToolFire Alarm Loop Load Calculator
A fire alarm loop planning tool for address count, device current, loop capacity, and spare allowance. Includes formulas, sample data, warnings, related.
Inputs
Forms are empty on load. Use sample data to preview the workflow or enter your own project values.
Learn more
Formula logic, use cases, assumptions, and limits for this tool.
How this tool helps
Use this to avoid overloading fire alarm loops or using too many addresses without spare capacity.
Assumptions and limits
This tool provides a planning-level result. It does not replace detailed engineering design, approved software, manufacturer data, authority requirements, or project specifications.
Typical use cases
- Early estimation and tender support.
- BOQ sanity checking and technical review.
- Site discussion before final engineering verification.
- Comparison of alternatives using consistent assumptions.
Result interpretation
Read the recommendation, warning, and confidence sections together. A result without warnings is still not an approval; it only means the entered values did not trigger built-in planning alerts.
Input definitions and typical values
These notes explain what each input means and which values usually produce a more reliable planning result.
Detectors devices
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Modules / MCPs devices
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Loop powered sounders devices
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Detector current mA
Electrical current or battery input. Use measured standby/alarm current or manufacturer datasheet values for better results.
Module current mA
Electrical current or battery input. Use measured standby/alarm current or manufacturer datasheet values for better results.
Sounder current mA
Electrical current or battery input. Use measured standby/alarm current or manufacturer datasheet values for better results.
Loop current capacity mA
Electrical current or battery input. Use measured standby/alarm current or manufacturer datasheet values for better results.
Address limit addresses
Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.
Practical verification checklist
- Confirm the selected standard profile is suitable for the project location and authority.
- Replace sample values with project drawings, schedules, equipment data, or measured site values.
- Review warnings, methodology, and PDF report before using the result outside early planning.
- Verify final decisions against official standards, manufacturer data, consultant specifications, and local approvals.
Related tools
Other tools in Fire Alarm.
Fire Alarm DIP Switch Calculator
Convert fire alarm device addresses into DIP switch ON/OFF positions and binary value checks.
Open ToolCalculation methodology
Loop usage is calculated from device counts, per-device current, loop current limit, and address capacity.
Inputs are treated as planning assumptions. The calculator shows warnings when entered values fall outside practical thresholds or selected standard-profile limits.
Version history
- v1.3.6-prelaunch: Added methodology, standard profile support, version notes, and direct PDF report download.
- v1.3.5: Calculator page added with sample data, warnings, and print-ready report layout.
Stage 2 roadmap: optional saved projects, dashboards, and shared calculation history without forcing login for free use.
Trust and verification
Every result includes assumptions, warning logic, and a downloadable report. Final engineering decisions still need qualified review, local authority approval, manufacturer data, and project specifications.
Worked example
Use the sample data button to load a realistic scenario, then download the PDF report to review inputs, results, methodology, warnings, and disclaimers in one place.