Fire Alarm Reference Charts

ABOUT THESE CHARTS

These charts cover the numbers fire alarm contractors and low-voltage installers look up while laying out a system: minimum strobe candela by room size for wall and ceiling mounting, the corridor allowance, smooth-ceiling smoke detector spacing and the 0.7 rule, the heat detector ceiling-height reduction factors, the heat detector temperature classes and their color codes, public and sleeping-area audibility levels, device mounting heights, and manual pull station placement.

Fire alarm is the most edition-sensitive trade we cover: NFPA 72 re-issues every three years and jurisdictions enforce editions from 2013 to 2025 side by side, with values and even table numbers changing between them. Every chart states the edition it reflects (the 2022 edition unless noted) and flags known deltas. These are working references for licensed installers and designers, not a substitute for the code book, the equipment listing, or the authority having jurisdiction — who has the final say on candela layouts, monitoring, and coverage.

Candela, spacing, and mounting are layout look-ups; the circuit side of the trade — standby battery calculations, NAC voltage drop, and wire sizing — is on the Phase 2 roadmap and will link to the NORDIX electrical calculators.