2-38
AFP-400 Installation
PN
50253
:
A2 03/12/96
Calculating the
Secondary Power
Battery charger amp-hour
range: 12-55AH
Secondary Non-Fire
Alarm (current from last
column in Table 2-2)
X
Required Secondary Non-Fire Alarm
Standby Time (24 or 60 hours)
=
Non-Fire Alarm
Secondary Amp
Hours
Secondary Fire Alarm
Load (from Table 2-3)
X
Required Fire Alarm Standby Time
(for 5 minutes, enter 0.084; for
15 minutes, enter 0.25)
=
Secondary Fire
Alarm Amp Hour
Requirement
Sum Column for Total Secondary Amp Hours calculated =
Multiply by the derating factor x 1.2 =
Total Secondary Amp Hours Required
AH
Table 2-4 Secondary Power Standby and Fire Alarm Load
Table 2-5 sums the standby and alarm loads to determine the battery size, in
amp-hours , needed to support the system. Select batteries that meet or
exceed the Total Amp-Hours calculated and that are within the acceptable
charger range. Write the amp-hours requirements on the Protected Pre-
mises label located on the AFP-400.
Calculating the Battery
Size
Notes:
1) NFPA 72 Local, Proprietary, and Central Station systems require 24
hours of standby power followed by 5 minutes in alarm.
2) NFPA Auxiliary and Remote Station Systems require 60 hours of standby
power followed by 5 minutes in alarm.
3) Batteries installed in a system powered by a 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, however, due to the sporadic nature of
voice operation, NFPA 72 permits 15 minutes of operation at maximum
connected load to be considered the equivalent of 2 hours of normal
use.
6) If the total exceeds 25 AH, the system requires a BB-55. If the total
exceeds 55 AH, an Uninterruptable Power Supply with sufficient amp-
hour capacity is needed. The Uninterruptable Power Supply must be
listed for Fire-Protective Signaling.
Battery
Size
Voltage Rating Number
Required
Part
Number
Cabinet
Size
12 AH
12 volts
two
PS-12120
CAB-A3, B3, C3, D3
25AH
12 volts
two
PS-12250
CAB-A3, B3, C3, D3
55AH
12 volts
two
PS-12550
BB-55
Table 2-5 Selecting the Battery Size
