Fire alarm + PA voice evacuation
the cause-and-effect spine.

/ Engineering body

What this integration is and where it lives

In any building above the NBC 2016 threshold (typically B+G+4 for residential, B+G+1 for hospitality and healthcare), fire alarm and PA voice evacuation are not two systems but one cause-and-effect spine. A detector activation on floor 12 zone B does not just sound a bell — it triggers the PA system to play a zoned voice message on floor 12, alert messages on floors 11 and 13, and a steady tone elsewhere. The matrix is documented in the engineering pack, programmed into the fire panel and the PA matrix, and verified by walk-through during commissioning. The interface is typically a hardwired contact pair or a serial protocol (RS-485, more recently IP) between the fire panel and the PA matrix. Each zone in the fire system maps to one or more zones in the PA system, and the mapping must be commissioned with the AHJ (Authority Having Jurisdiction). The PA system separately must meet EN 54-16 or IS 14735 — including STI ≥ 0.5 in the evacuation zone — and the speakers, amplifiers, batteries and cabling must be certified or equivalent. Mis-coordinated, the integration looks fine on a single-point test but fails on a multi-zone cascade.