BATTERY CALCULATION METHOD EXPLAINED
The basis of a FireCAD battery calculation is the standby and alarm current values of the components powered by the panel's power supply.
In the example below, four components are included in the ES-200x FACP:
COMPONENT STANDBY CURRENT ALARM CURRENT
- ES-200X MAIN BOARD .141 AMPS .257 AMPS
- PWRMOD24 0 AMPS 0 AMPS
- SD365 w/B300-6 BASE .0002 AMPS .0045 AMPS
- PC2RL HORN STROBE 0 AMPS .165 AMPS
The battery standby calculation uses these values in a formula to generate the required amp hour capacity of the batteries needed for a selected standby and alarm time period.
SETTING THE STANDBY AND ALARM TIME PERIODS
These time periods are set in the FireCAD Options Editor as shown below.
HOW THE STANDBY AND ALARM CURRENT VALUES ARE DETERMINED FROM THE MANUFACTURER'S DATA
The programmers of the Cadgen Master Database from which local project files (.atp files) are created use values from the manufacturers' data sheets and/or installation manuals to populate the data.
If changes are needed because of a FireCAD user's or an AHJ preference, the values can be edited by the FireCAD user. We will explain that later in this article.
THE INITIAL VALUES ARE SET BY REFERRING TO THE MANUFACTURER'S DATA
Below are portions of the data sheet for the SD365 detector.
We show the standby and alarm current values highlighted in yellow.
Below are portions of the data sheet for the PC2RL HornStrobe.
We show the alarm current values highlighted in yellow. Since this is a notification device there is 0 standby current.
HOW THE ALARM AND STANDBY CURRENT VALUES ARE ADDED TO THE CADGEN MASTER DATABASE/ LOCAL .ATP (PROJECT) FILE.
The FireCAD Project Device Editor or the Cadgen Database Utility is used to show or edit the values.
Values are entered in one of two locations:
The Device table is used where a device does not have multiple settings (such as a notification appliance with multiple selectable candela settings)
Notice the highlighted row in the device table below. The required standby and alarm current values are entered in the appropriate columns.
The Device Circuit Templates (Input) is used for devices with multiple settings. Notice the highlighted 95 candela row in the template group window below.
The required alarm current values are entered in the appropriate columns corresponding with the candela setting.
VOLTAGE DROP CALCULATION METHOD EXPLAINED
The basis of a FireCAD voltage drop calculation is the standby and alarm current values of the components powered by the panel's power supply.
Notice that these values we entered in the project device editor are used in the reports for notification appliance circuit voltage drop and battery calculations.
FACTORS USED IN THE VOLTAGE DROP CALCULATION
- Resistance From Previous (Ω) = Wire Resistance (Ω/Ft) x 2 x Dist. From Previous (Ft)
- Voltage Drop From Previous = Resistance From Previous (Ω) x Remaining Current (A)
BATTERY CALCULATION AS SHOWN ABOVE (FOR REFERENCE)
CHANGING THE VALUES USED IN THESE CALCULATIONS
The Project Device Editor permits a FireCAD user to modify the default values entered into the .atp file. Changing these values will cause subsequently generated reports to reflect the changed values.