Field Notes
Fire-alarm booster power supply battery and load-voltage records before final fire inspection
A useful fire final packet ties each booster supply, battery date code, battery calculation, NAC load, end-of-line voltage, trouble condition, correction, and release boundary together.
Direct answer
Before final fire inspection, a fire alarm booster power supply battery date-code and load-voltage record should identify the project, permit, protected area, fire alarm control unit, booster or remote power supply tag, manufacturer, model, serial number where required, AC branch circuit, battery cabinet, battery manufacturer, amp-hour rating, battery date code or manufacture date, installation date, battery calculation, standby and alarm load basis, NAC or auxiliary circuit numbers, notification appliance load, synchronization setting, trigger input, trouble supervision, charger status, battery voltage before test, battery voltage under alarm load where required, end-of-line or worst-case appliance voltage where required, failed condition, correction, retest, technician, witness, AHJ exception, and final release boundary.
Do not send a fire final packet with only a panel normal photo. That does not prove the remote power supply batteries are dated, sized, connected, supervised, charged, accepted by the listed equipment instructions, able to hold voltage under the required load, or matched to the approved notification appliance circuit calculations.
Use this field note as documentation guidance only. The adopted fire code, building code, electrical code, NFPA 72 edition, approved drawings, battery and voltage-drop calculations, fire alarm equipment listing, manufacturer instructions, fire marshal, AHJ, fire alarm contractor, electrical contractor, commissioning plan, and site safety plan control the actual installation, test method, acceptance, and final fire inspection release.
Fire final is when weak booster records fail
A booster power supply can look quiet on the wall and still be a weak closeout item. The cabinet is locked, the green LED is on, and the notification appliances may sound during a quick test. The final fire inspection asks a sharper question: can the record prove that this specific power supply, with these batteries and these circuits, supports the approved fire alarm design?
The record has to connect equipment identity to field performance. That means the booster supply tag, approved riser, NAC schedule, battery calculation, installed batteries, battery date code, measured voltage, observed troubles, and retest evidence all need to point to the same installed device.
NFPA public guidance, ICC fire alarm sections, UL standard pages, manufacturer manuals, and AHJ checklists reviewed for this package all reinforce the same practical idea: fire alarm power and notification records need to preserve both the design basis and the field condition found at test.
Tie the booster to the approved drawings
Start with identity before measuring anything. Record the booster power supply label, room, wall location, panel or riser reference, serving FACP, initiating trigger input, output circuit numbers, synchronization mode, and the exact approved drawing sheet or calculation page that lists the unit.
A final inspector should not have to guess whether BPS-2 feeds NAC-3 and NAC-4 on Level 2, the elevator lobby strobes, a shell corridor, or a tenant improvement add-on. The record should make the connection visible.
If the installed booster, connected load, battery size, device count, wire length, or circuit naming does not match the approved submittal, write that discrepancy into the record. Do not hide a design mismatch behind a normal panel status.
Battery date codes matter because batteries age quietly
Fire alarm secondary power records should not treat batteries as anonymous parts. Record each battery location, manufacturer, model, nominal voltage, amp-hour rating, date code or manufacture date, installation date where known, quantity, terminal condition, cabinet condition, charger status, and whether the battery matches the approved calculation and listed equipment instructions.
A date code is useful because batteries can sit in inventory, be swapped during troubleshooting, or be installed in different cabinets than the calculation assumed. A final record that says new batteries installed without the date code leaves a gap that the owner inherits.
If the date code is missing, unreadable, inconsistent, expired by the owner standard, older than expected, or different between paired batteries, state the condition and get direction from the responsible fire alarm contractor, owner, manufacturer, or AHJ. The record should show the question instead of smoothing it over.
Load voltage is a field fact, not a drawing assumption
Voltage-drop calculations are design evidence. Load-voltage readings are field evidence. The final inspection packet is strongest when it keeps both: the approved calculation showing expected circuit performance and the measured voltage at the defined test point under the required alarm or battery condition.
Record which circuit was measured, where the reading was taken, whether the system was on normal power or secondary power, whether appliances were active, what meter was used if the project requires it, and what the acceptance basis was.
Do not mix readings from different states. A no-load reading at the booster output, a normal-power reading at the cabinet, and an alarm-load reading at the end of the line answer different questions. Label the condition so a later reviewer can trust the number.
Test the condition the inspection asks for
Some AHJ checklists ask for proof of secondary power operation, battery testing, NAC voltage-drop evidence, or final acceptance documents. Some manufacturer manuals provide battery calculation worksheets and remote power supply current tables. The field record should state which required condition was tested.
If the test is a battery standby and alarm-load observation, write that. If it is a NAC end-of-line voltage reading during alarm, write that. If it is a charger, AC-fail, battery-fail, ground-fault, or supervision check, write that separately.
A clean record prevents one successful test from being stretched into another. Passing an appliance audibility or visibility walk does not automatically prove secondary power capacity. Passing a battery voltage check does not automatically prove every notification circuit met the voltage-drop basis.
Record troubles, supervision, and recovery
The booster supply should be documented before, during, and after the test. Record normal status, AC power status, battery status, charger status, ground-fault status, NAC trouble status, input trigger status, sync status, and any FACP or remote annunciator trouble tied to the booster.
Trouble signals are part of the evidence trail. If AC fail, battery missing, low battery, charger trouble, ground fault, NAC open, NAC short, sync trouble, communication trouble, or a disabled output appears during the work, record when it appeared, who corrected it, and how it was retested.
Return-to-normal is also part of the test. The final record should state that the system was restored, troubles cleared, monitoring notifications handled, bypasses or disables removed, occupants or building management notified as required, and the cabinet left locked or sealed as the project requires.
Keep booster scope separate from whole-system approval
A booster power supply record is not the whole fire alarm acceptance record. It supports a slice of the fire alarm system: remote power, batteries, connected notification circuits, auxiliary outputs where applicable, and supervision of that equipment.
The packet should say what it covers and what it does not. Voice evacuation amplifiers, smoke control interfaces, releasing systems, elevator recall, monitoring transmission, duct detectors, sprinkler waterflow, tamper switches, two-way communication systems, and other fire protection interfaces may need separate records.
If the booster feeds only part of a floor, a tenant area, a phased release, or a shell-and-core scope, state that boundary clearly. A partial pass should not become a building-wide fire alarm approval by implication.
Use a booster power supply test log
Use the AHJ form, NFPA 72 record of completion, fire alarm inspection form, manufacturer worksheet, commissioning form, or owner test sheet first. Add this table where the required form does not clearly connect the booster supply, batteries, calculations, measurements, corrections, and release boundary.
| Record item | Field detail | Why it matters |
|---|---|---|
| Booster identity | Tag, location, manufacturer, model, serial, FACP reference, riser sheet | Connects the record to the installed power supply |
| Power source | AC branch circuit, breaker label, disconnect lockout note, charger status | Shows primary power and charger context |
| Battery identity | Manufacturer, model, date code, install date, voltage, amp-hour rating, quantity | Proves the installed batteries match the record |
| Calculation basis | Battery calculation, standby load, alarm load, NAC voltage-drop calculation, approved revision | Keeps field readings tied to approved design evidence |
| Connected circuits | NAC number, auxiliary output, appliance count, circuit class, sync mode, end-of-line location | Prevents one circuit reading from being applied to another |
| Test condition | Normal power, secondary power, alarm mode, standby mode, charger test, trouble test | Labels the state under which the value was observed |
| Load voltage | Measurement point, reading, meter ID if required, appliances active, pass or fail basis | Captures field performance under the tested condition |
| Trouble supervision | AC fail, battery fail, charger, ground fault, NAC open or short, FACP indication | Shows that problems are reported instead of hidden |
| Correction and retest | Battery replaced, wiring corrected, circuit split, appliance changed, recalculation, retest | Preserves the repair chain |
| Release boundary | Final fire inspection ready, held circuit, held floor, phased area, AHJ review, owner exception | Prevents a partial record from becoming full approval |
Before final fire inspection checklist
Run this check before representing a fire alarm booster power supply as ready for final fire inspection.
- Confirm the adopted code edition, AHJ checklist, approved drawings, battery calculation, voltage-drop calculation, manufacturer instructions, and test form that control the inspection.
- List every booster or remote power supply in the inspection scope.
- Record each booster tag, location, FACP relationship, AC branch circuit, breaker label, output circuits, and connected notification appliance areas.
- Photograph the cabinet, nameplate, circuit labels, battery set, date codes, and final normal status where permitted.
- Confirm battery manufacturer, model, amp-hour rating, nominal voltage, quantity, date code, and installation date against the approved calculation.
- Record charger status, AC status, battery status, ground-fault status, NAC status, and FACP trouble status before testing.
- Verify the approved standby and alarm load basis for the booster and each connected output.
- Record NAC or auxiliary circuit load-voltage readings at the required point and condition.
- Label each voltage reading as normal power, secondary power, alarm-load, standby, output terminal, end-of-line, or worst-case appliance.
- Record AC-fail, battery-fail, charger, ground-fault, NAC open, NAC short, and other trouble supervision checks required by the project.
- Record failed conditions before correction, then add correction and retest evidence.
- Confirm that bypasses, disables, test modes, monitoring notifications, and temporary jumpers are removed or restored as required.
- State the release boundary: booster accepted, circuit held, floor held, phased area released, AHJ review required, or reinspection needed.
Weak and strong notes
Weak note: Booster panel normal. Batteries good.
That note does not identify the booster, batteries, date codes, calculation revision, NAC load, load-voltage readings, test condition, trouble supervision, corrections, retest, witness, or final inspection boundary.
Stronger note: Fire alarm booster supply BPS-2 final inspection record completed on 2026-06-09 for Level 3 east tenant area served by FACP FA-1. BPS-2 is Honeywell HPF24S8, tag BPS-2, located in Electrical Room 3E, fed from panel EM3 circuit 18. Approved riser FA-3.2 revision 4 and calculation package FA-CALC-3.2 list NAC-3E-1 through NAC-3E-4 and two 12 V 18 Ah batteries. Installed batteries are PowerSafe PS-12180, date codes 2026-02 and 2026-02, installed 2026-06-08. Cabinet photo BPS2-01 shows date codes and final labels. Pretest status showed AC normal, battery normal, charger normal, no ground fault, no NAC trouble. Secondary-power alarm-load test started at 13:20 after monitoring notification. NAC-3E-4 far-end strobe at Room 318 measured 21.1 VDC under alarm load at 13:26 using meter M-14; calculation predicted 21.4 VDC at that point. NAC-3E-2 initially reported open trouble after device removal; EOL resistor was corrected, trouble cleared, and NAC-3E-2 retested in photo set BPS2-07 through BPS2-09. System returned to normal at 13:42, monitoring restored, cabinet locked, and BPS-2 released for Level 3 east tenant fire final only. Level 3 west booster BPS-3 remains under separate reinspection.
The stronger note works because it ties the booster, batteries, calculation, measured circuit, failed condition, correction, retest, and release boundary together.
Common mistakes
The first mistake is treating a normal status LED as evidence of battery capacity or NAC voltage performance.
The second mistake is recording battery voltage without battery date codes, amp-hour rating, quantity, or calculation reference.
The third mistake is using a no-load cabinet voltage reading where the inspection question asks for an alarm-load or end-of-line condition.
The fourth mistake is failing to identify which NAC or auxiliary output was measured.
The fifth mistake is correcting a trouble condition without preserving the before condition and retest result.
The sixth mistake is letting a booster power supply pass imply that the entire fire alarm system, monitoring path, smoke control interface, or voice evacuation scope is accepted.
Questions that come up
Is a battery date code required on every final inspection? The AHJ, adopted NFPA 72 edition, project documents, owner standard, manufacturer instructions, and accepted forms control the requirement. A date-code record is still useful because it proves what was installed.
Is load voltage the same as voltage-drop calculation? No. The calculation is design evidence. The load-voltage reading is field evidence taken under a defined condition.
Can the fire alarm contractor use manufacturer battery worksheets? Usually the project expects manufacturer or approved calculation worksheets where applicable, but the AHJ and approved submittal define what is acceptable.
Should every NAC be measured? The AHJ checklist, commissioning plan, approved drawings, and test procedure decide whether every circuit or a worst-case sample is required. The record should state what was measured and what was not.
What if the battery date code is unreadable? Record it as unreadable and get direction. Do not invent a date from memory or from a purchase order unless the AHJ and owner accept that evidence.
Who can sign the record? Licensing rules, the contract, AHJ, fire alarm contractor, engineer, commissioning plan, and owner standard decide who can test, witness, certify, or accept the fire alarm record.
Compliance and safety limits
This field note is not a fire alarm design, electrical design, NFPA 72 interpretation, fire-code interpretation, battery calculation, voltage-drop calculation, manufacturer instruction, live-work procedure, impairment procedure, monitoring procedure, final inspection approval, or AHJ approval. The adopted fire code, building code, electrical code, NFPA 72 edition, approved drawings, calculations, listed equipment instructions, fire marshal, AHJ, fire alarm contractor, electrical contractor, commissioning plan, and site safety plan control the work.
Do not use this checklist to bypass permits, inspection holds, qualified-worker requirements, listing instructions, lockout/tagout, energized-work controls, arc-flash controls, battery safety, short-circuit protection, monitoring notifications, fire watch, impairment procedures, evacuation rules, occupant notification, ladder safety, cabinet access rules, or owner acceptance procedures. The packet preserves the fire alarm booster power supply battery date-code and load-voltage record. It does not authorize unsafe testing or final fire inspection approval.
Sources checked
- NFPA, Guide to Fire Alarm Basics: Power SuppliesUsed for public NFPA context on primary and secondary power supplies, batteries, and battery calculations.
- NFPA, Fire Alarm Systems and Loss of PowerUsed for public NFPA context on fire alarm system operation after loss of primary power.
- NFPA, Guide to Fire Alarm Basics: NotificationUsed for public NFPA context on notification appliances and notification system function.
- NFPA, NFPA 72 National Fire Alarm and Signaling Code Standard DevelopmentUsed for NFPA 72 context without reproducing or interpreting code text.
- ICC Digital Codes, 2021 IBC Chapter 9 Fire Protection and Life Safety SystemsUsed for building-code fire alarm and life-safety system context.
- ICC Digital Codes, 2021 IFC Section 907 Fire Alarm and Detection SystemsUsed for fire-code fire alarm and detection system context.
- ICC Digital Codes, 2021 IFC Chapter 9 Fire Protection and Life Safety SystemsUsed for fire-code inspection, testing, and maintenance context around fire protection systems.
- UL Standards and Engagement, UL 864 Control Units and Accessories for Fire Alarm SystemsUsed for product-standard scope covering fire alarm control units and commercial fixed power supplies for fire-protective signaling systems.
- UL Standards and Engagement, UL 1481 Power Supplies for Fire-Protective Signaling SystemsUsed for fire-protective signaling power supply standard context.
- Intertek, UL 1711 and UL 1481 Power Supplies for Fire-Protective Signaling SystemsUsed for NRTL context on fire-protective signaling amplifiers and power supply standard transition into UL 864.
- Honeywell, HPF24S6 and HPF24S8 Installation GuideUsed for manufacturer context on remotely mounted power supplies, battery chargers, NACs, supervision, and power supply calculations.
- Honeywell Silent Knight, Model 5499 Distributed Power Module Installation ManualUsed for manufacturer context on distributed power modules, filtered 24 volt output, battery charging, and battery calculation worksheets.
- Potter Electric Signal, PSN-1000 Installation ManualUsed for manufacturer context on notification power expander installation, battery calculations, and standby battery sizing.
- North Carolina Department of Administration, Fire Alarm System Check ListUsed for AHJ-style final inspection checks involving battery power and NAC voltage-drop verification.
- Everett Fire Department, Fire Alarm System Acceptance Test ChecklistUsed for municipal acceptance-test context around NFPA 72 record of completion and secondary power proof.
- Illinois Department of Public Health, NFPA 72 Fire Alarm System Record of Completion FormUsed for public record-of-completion fields covering battery calculations and battery date-of-manufacture marking.
- Town of Brunswick, Fire Alarm Inspection and Testing ReportUsed for public inspection form context around secondary power, battery condition, load voltage, charger test, and remote panel batteries.
- City of Long Beach, Fire Alarm Systems Plan Review ChecklistUsed for municipal plan-review context around battery calculations and NAC voltage-drop calculations.