Table of Contents
Advertisement
Power Supply Calculations
A.3 Calculating the Battery Requirements
A.3.1 Calculating the Battery Capacity
Use this table to determine the battery capacity needed for the system:
Current (amps)
Secondary Non-Fire Alarm Current
(from column 3 in Table A.2)
(see Note 8)
________________
APS-6R
Standby Load Current
________________
Secondary Fire Alarm Load
(from Table A.3)
(see Note 8)
________________
Sum Column for Total Secondary Amp Hours calculated
Multiply by the derating factor x 1.2 (see Note 7)
Battery Size – Total Secondary Amp Hours Required
1.
NFPA 72 Local, Proprietary, and Central Station systems requires 24 hours of standby power followed by
5 minutes in alarm.
2.
NFPA 72 Auxiliary and Remote Station Systems require 24 hours of standby power followed by 5 minutes
in alarm.
3.
Batteries installed in a system powered by an automatic starting engine generator need to provide at
least 4 hours of standby power.
4.
Factory Mutual requires 90 hours of standby for deluge-preaction systems.
5.
Emergency voice/alarm communications systems require 2 hours of operation in the alarm condition.
Due to the sporadic nature of voice operation, however, NFPA 72 permits 15 minutes of operation at a
maximum connected load to equal 2 hours of normal use.
6.
If the total exceeds 26 AH, the system requires a separate NFS-LBB, BB-100 or BB-200 battery
enclosure for two larger capacity batteries.
7.
The following battery derating factors must be used for Canadian installations using NFS-320C charger:
• For a 26 AH battery, use derating factor of 1.5
• For a 55 AH battery, use derating factor of 1.8
• For a 100 AH battery, use derating factor of 2.5
• For a 200 AH battery, use derating factor of 2.5
8.
For 26 AH batteries: maximum standby current cannot exceed 0.65A; maximum alarm current cannot
exceed 6.75A
56
X
Time (hours)
Required Secondary Non-Fire Alarm
Standby Time (24 or 60 hours)
X
________________
Required Secondary Non-Fire Alarm
Standby Time (24 or 60 hours)
X
________________
Required Fire Alarm Standby Time:
(for 5 minutes, enter 0.084; for 15
minutes, enter 0.25)
X
________________
Table A.4 Secondary Power Standby and Fire Alarm Load
Calculating the Battery Requirements
NFS-320/E/C Installation Manual — P/N 52745:M2 7/1/14
=
AH
=
_________AH
=
_________AH
=
_________AH
=
_________AH
=
_________AH
=
_________AH
Hide quick links:
Advertisement
Table of Contents
