Calculations B
Shield Fire, Safety and Security Ltd.
Shield A-XT Releasing Fire Control Panel - Installation and Operation Manual SEXTCP-OM
Revision E01.00
78 of 127
This section describes current-loading and the process for determining the standby-battery rating, the NAC wiring
length and the releasing-circuit wiring length.
Current loading calculations do not include the combined IDC currents of the Shield A-XT Releasing Fire
Control Panel. These combined IDC currents are negligible in comparison to fire control panel, ancillary device and
NAC currents of the Shield A-XT Releasing Fire Control Panel and are therefore excluded from the current
loading calculation.
Determining the Amp-Hour Rating
Installers must identify the load current for each device connected to the fire control panel. The sum of this current
must be below the operating limits of the fire control panel and within the load capacity of the standby-batteries.
To determine the load rating of the fire control circuit:
Total standby-current of these loads must draw less than 236 mA to maintain continuous standby operation for
twenty-four hours followed by five minutes of alarm.
1 Record the standby and alarm currents of the Shield A-XT Releasing Fire Control Panel.
2 Record the standby and alarm currents of the Status Units.
3 Record the standby and alarm currents of the Ancillary Boards.
4 Record the standby and alarm currents of Auxiliary Devices.
5 Record the alarm currents of NAC Devices.
6 Record the alarm currents of the Releasing Solenoids.
7 Total the standby and alarm currents of the Shield A-XT Releasing Fire Control Panel, Status Units,
Ancillary Boards, Auxiliary Devices, NAC Devices and the Releasing Solenoid.
8 Calculate the Total Standby Amp Hours.
9 Calculate the Total Alarm Amp Hours.
10 Determine Total Amp-Hours by adding the Total Standby Amp Hours to the Total Alarm Amp Hours.
11 Determine the minimum Amp Hour rating for the battery by multiplying the Total Amp-Hours to the
Derating Factor (1.20).
12 Verify that the rating determined from the Load Capacity Worksheet does not exceed the 7 AH capacity of the
Standby-Batteries specified for operating the Shield A-XT Releasing Fire Control Panel.
Appendix B
Calculations
To Next Page
Loading...