What is a NAC and why does my fire alarm panel need a booster for it?

Q: Do I need a smoke detector or a heat detector in an unconditioned garage?

NFPA 72 disallows smoke detectors in spaces that routinely see temperatures below 32°F or above 100°F — that rules out a typical attached garage. A fixed-temperature or rate-of-rise heat detector is the right call there; it will not nuisance-alarm on car exhaust or dust but still trips on a real fire.

Q: When does code require VESDA instead of regular smoke detectors?

Aspirating smoke detection is required (or strongly preferred) for high-value, high-airflow, or hard-to-access spaces: data centers, telecom MDFs, cold-storage warehouses, historic museums, and clean rooms. The system pulls air through sampling pipes back to a central laser chamber, so it detects smoke 10–100× earlier than spot detectors at the ceiling.

Question

What is a NAC and why does my fire alarm panel need a booster for it?

Accepted Answer

A Notification Appliance Circuit is the wiring loop that powers horns and strobes. Each FACP NAC has a finite current budget (often 3 A); once your strobe-current totals exceed that, you add a booster panel — a NAC expander — to source the extra current while staying synchronized with the main panel.

What is a NAC and why does my fire alarm panel need a booster for it?

Answers