HPF24S Series Power Supplies —
P/N 52751:D3 5/11/2010
41
Calculating the Battery Size
Power Supply Requirements
5. Write the ampere hour requirements on the Protected Premises label located inside the cabinet
door.
6.4.1 NFPA Battery Requirements
NFPA 72 Local and Proprietary Fire Alarm Systems require 24 hours of standby power followed by
5 minutes in alarm
6.4.2 Selecting and Locating Batteries
Select batteries that meet or exceed the total ampere hours calculated in Table 6.4 . The power
supply can charge batteries in the 7 AH to 18 AH range. The power supply cabinet is capable of
housing batteries up to 7 AH. Batteries larger than 7 AH require the BB-17 or other UL listed
external battery cabinet.
Secondary Standby Load
(total from Table 6.3
Calculation Column 3)
[ ]
Required Standby Time
(24 or 60 hours)
X [ ]
=
AH
Primary Alarm Load
(total from Table 6.3
Calculation Column 2)
[ ]
Required Alarm Time
(for 5 min., enter 0.084,
for 10 min., enter 0.168)
X [
=
AH
Sum of Standby and Alarm Ampere Hours
=
AH
For
nonULC
applications, multiply by the Derating Factor
*
For
ULC
applications, multiply by the Derating Factor
* Multiply by
only one
of the Derating Factors, depending on whether the power
supply is being used for a ULC (Canadian) application or nonULC application.
X 1.2
X 2.5
Battery Size, Total Ampere Hours Required
=
AH
Table 6.4 Total Secondary Power Requirements at 24 VDC
