3RZHU6XSSO\&DOFXODWLRQV &DOFXODWLQJWKH%DWWHU\6L]H
8QLPRGH31&
5.4 Calculating the Battery SizeUse Table 5.4 to calculate the total Standby and Alarm load in ampere hours (AH). This
total load determines the battery size (in AH), required to support the control panel under
the loss of AC power. Complete Table 5.4 as follows:
1. Enter the totals from Table 5.3 on page 129, Calculation Columns 2 and 3 where
shown
2. Enter the NFPA Standby and Alarm times (refer to ‘NFPA Requirements’ below)
3. Calculate the ampere hours for Standby and Alarm, then sum the Standby and
Alarm ampere hours
4. Multiply the sum by the derating factor of 1.2 to calculate the proper battery size (in
AH)
5. Write the ampere hour requirements on the Protected Premises label located inside
the cabinet door
5.4.1 NFPA Battery Requirements
• NFPA 72 Local and Proprietary Fire Alarm Systems require 24 hours of standby
power followed by 5 minutes in alarm
• NFPA 72 Central, Auxiliary and Remote Station Fire Alarm Systems require 60
hours of standby followed by 5 minutes in alarm. Batteries installed in a system
powered by a generator need to provide at least 4 hours of standby power
• NFPA requires 24 hours of standby plus 15 minutes activation for audio systems.
The total ampere hours required cannot exceed 25 AH with an internal charger
5.4.2 Selecting and Locating Batteries
Select batteries that meet or exceed the total ampere hours calculated in Table 5.4 . The
control panel can charge batteries in the 7 AH to 25 AH range. The control panel cabinet
is capable of housing batteries up to 18 AH. Batteries larger than 18 AH require the BB-
55F or other UL listed external battery cabinet.
Table 5.4 Total Secondary Power Requirements at 24 VDC
6HFRQGDU\6WDQGE\/RDG
WRWDOIURP7DEOH&DOFXODWLRQ
&ROXPQ
>@
5HTXLUHG6WDQGE\7LPH
RUKRXUV
;>@ $+
3ULPDU\$ODUP/RDG
WRWDOIURP7DEOH&DOFXODWLRQ
&ROXPQ
>@
5HTXLUHG$ODUP7LPH
IRUPLQHQWHU
IRUPLQHQWHU
;>@ $+
6XPRI6WDQGE\DQG$ODUP$PSHUH+RXUV $+
0XOWLSO\E\WKH'HUDWLQJ)DFWRU ;
%DWWHU\6L]H7RWDO$PSHUH+RXUV5HTXLUHG $+