Calculate Signaling Line Circuit device loading capacity per NFPA 72 for addressable fire alarm systems.
Input Parameters
Results
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Total Devices
devices
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SLC Load
%
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Remaining Capacity
devices
--
Status
Note: NFPA 72 requires that SLC loops not exceed manufacturer-rated device counts. The 80% rule is industry best practice for future expansion headroom.
Reference
SLC Load % = (Total Devices / Max Capacity) x 100
NFPA 72 recommends keeping SLC loading at or below 80% of rated capacity to allow for future expansion.
Remaining = Max Capacity - Total Devices