Free Tool — Fire Alarm / NICET
Fire Alarm Battery Capacity Worksheet
Work through standby and alarm amp-hours, then apply the 1.25 aging correction shown in NFPA's public Fire Alarm Basics example. Use project-specific values for real equipment decisions.
Duration example
Choose an NFPA public-guide example or enter the durations required by your adopted code, project documents, manufacturer instructions, and AHJ.
Total panel + devices in standby mode
Panel + all notification appliances firing
Use the duration required for the specific system and project
Use the duration required for the specific system and project
Battery Calculation Results
Standby Load
8.40
Ah
Alarm Load
0.21
Ah
Raw Required
8.61
Ah
Required after 1.25 aging correction
Raw amp-hours × 1.25, matching the current NFPA public-guide example
10.76 Ah
Example listed capacity: 12 Ah
Smallest displayed example ≥ 10.76 Ah. Shown capacities: 12 Ah, 18 Ah, 26 Ah. Verify the listed battery type, capacity, configuration, enclosure, and charger compatibility for the actual control unit.
Calculation breakdown
Standby: (350 mA × 24 h) ÷ 1,000 = 8.400 Ah
Alarm: (2500 mA × 5 min ÷ 60) ÷ 1,000 = 0.208 Ah
Total: 8.400 + 0.208 = 8.608 Ah
With 1.25 aging correction: 10.760 Ah
For exam practice and estimation only — not a substitute for engineered design, manufacturer data, current codes, or a licensed professional's judgment. Verify all values before relying on them.
How the worksheet works
NFPA's public Fire Alarm Basics guide shows a protected-premises example with 24 hours of standby followed by 5 minutes of alarm. Its EVACS example uses the same standby duration followed by 15 minutes of alarm. Other system arrangements can require different inputs, so the worksheet also supports custom durations.
Add the standby and alarm amp-hour results, then multiply that raw capacity by 1.25. This is the aging correction used in NFPA's public worked example. The arithmetic result is only one input to equipment selection; it does not establish compatibility, listing, enclosure capacity, temperature correction, or approval for a particular project.
For study, focus on the transparent sequence: (1) total standby current, (2) total alarm current, (3) convert each duration to amp-hours, (4) add the results, and (5) apply the stated correction factor. Do not infer NICET item frequency from this tool; use the current NICET outline and reference list to bound exam preparation.
Duration examples used by this worksheet
These two quick-fill values come from NFPA's public Fire Alarm Basics guide. They are examples, not a complete code table.
| Example | Standby | Alarm |
|---|---|---|
| Protected-premises example | 24 hours | 5 minutes |
| Emergency voice/alarm communications system (EVACS) | 24 hours | 15 minutes |
Use Custom for any other value. Verify the adopted code, project documents, manufacturer instructions, and AHJ requirements.
Frequently Asked Questions
Which standby and alarm durations does this worksheet include?
The two quick-fill examples mirror NFPA's public Fire Alarm Basics guide: 24 hours of standby followed by 5 minutes of alarm for its protected-premises example, or 15 minutes of alarm for an emergency voice/alarm communications system (EVACS). Use Custom when the adopted code, project documents, manufacturer instructions, or AHJ require different inputs.
Why does the worksheet multiply the raw capacity by 1.25?
NFPA's public Fire Alarm Basics example applies a 1.25 aging correction after adding standby and alarm amp-hours. This worksheet shows that arithmetic explicitly. Project specifications, battery technology, temperature, listing instructions, and the adopted code can require additional checks.
Is this a source-aligned NICET Level I practice item?
No. NICET's public Level I outline names Installation, Maintenance, and Submittal Preparation/System Layout, but it does not publish a battery-calculation item frequency. This standalone worksheet is not part of VoltExam's three-task reviewed FAS Level I navigation set and does not predict exam coverage or results.
What does standby current vs. alarm current mean for a fire alarm system?
Standby current is the quiescent (idle) current drawn by the panel and all connected devices when the system is in normal monitoring mode — no alarm active. This is typically a fraction of the alarm current. Alarm current is the total load when all notification appliances (horns, strobes, horn-strobes) are simultaneously activated. For battery sizing, both states must be accounted for separately because the system must survive the full standby period before the alarm period can begin.
Does the displayed amp-hour size specify a battery for my panel?
No. The displayed capacities are examples that help you see the next size above the arithmetic result. Verify the battery type, listed capacity, configuration, enclosure, charger compatibility, and any extra correction factors against the control-unit manufacturer, project documents, adopted code, and AHJ.
Can I use any battery in a fire alarm system?
No. A worksheet result is not an equipment approval. Use only a battery type and configuration permitted by the control-unit manufacturer's current instructions and the requirements that govern the project, and confirm uncertain choices with the AHJ or responsible design professional.
Also try: OSHA Fall Clearance Calculator
Required anchor height for shock-absorbing lanyards and SRLs — OSHA 1926.502
Want to continue into the credential-aware study path? Choose FAS or ITFAS →
Try it now — no account, no download
Practice 5 mixed supplemental Fire Alarm questions
These legacy prompts are not source-aligned to a NICET credential or level. Use them only as supplemental practice.
Fire Alarm mixed practice · Question 1 of 5
What is the primary difference between a conventional and an addressable fire alarm system?
Pick an answer to see the explanation + an instant AI breakdown.