Studio Matrx Monthly · Volume 1 · Issue 2 · July 2026
Amogh N P
 In loving memory of Amogh N P — Architect · Designer · Visionary 
Detection zoning

Fire Alarm Zone Calculator

A fire-alarm system is split into detection zones so the panel shows where the fire is and searchers reach it fast. Enter the floors, protected area and stairwells to get an indicative zone count and the panel size to plan for. This is an indicative planning estimate; it runs in your browser.

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Detection zones
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Plan panel size
Rule of thumb
Plan for at least a 8-zone panel or an addressable loop. For a building this size an addressable loop (device-level location) is usually better than many conventional zones.
How the count is built
  • One-per-floor zones (4 floors)4
  • Area-driven zones (area ÷ per-zone limit)2
  • Base zones (floors govern)4
  • Stairwell zones (one each)+2
  • Total detection zones6

A searcher must reach any point in a zone quickly, so keep zones identifiable per floor or compartment. Stairs, lift lobbies and plant rooms are always separate zones.

This is an indicative planning estimate, not a compliant fire design or a statutory calculation — the actual requirement depends on your occupancy classification, building height and the AHJ. A licensed fire consultant must design the detection system and the local fire officer / AHJ signs it off. A wrong number here can cost lives — verify everything against NBC (SP 7:2026) Part 4 and IS 2189 for your occupancy.