🔄 NFPA 72 SLC Loops (Class A Style 6/7 vs Class B Style 4, Max 50Ω Resistance)

Fire Alarm SLC Loop Resistance Calculator

Size addressable fire alarm Signaling Line Circuits (SLC) under NFPA 72: calculate total loop conductor loop resistance (ensuring loop wire resistance remains strictly <50 ohms for 250 detector/module addresses on Class A Style 6/7 fault-tolerant isolator loops), select 18 AWG / 16 AWG twisted shielded pair (FPLR), and fire systems contracting profits.

1. Project & Operating Inputs

Addressable SLC Loops Installed (Loop Count e.g. 6 SLC Loops)

Average Loop Conductor Length (Feet e.g. 3,500 ft Class A Loop)

Customer Bid Price for Supplied, Wired & Mapped SLC Loops ($ / Loop)

Photo Detectors, Pull Stations, Monitor Modules, 16 AWG FPLR & Labor ($ / Loop)

2. Financial Breakdown & Yield

NFPA 72 ADDRESSABLE SLC LOOPS

Turnkey Addressable SLC Package Profit

Fire Protection Contractor Margin

0.0%

Gross Revenue / Bill

Total Project CapEx

Operating / Material Cost