When to Replace a Fire Alarm System: The 10–15 Year Decision

The replacement signals, ranked

• Parts drought: discontinued panels (and closed protocols whose maker lost interest) turn every fault into a sourcing hunt — the definitive end-of-life signal
• Detector age: optical chambers degrade with dust/age; past ~10 years false alarms rise as real sensitivity falls — manufacturers and BS 5839-1 maintenance logic both point at planned head replacement
• Chronic false alarms despite servicing: design-era detectors in changed environments (offices now kitchens, open plan now partitioned) — sometimes re-design, often replace
• Category mismatch: building use changed (sleeping risk added, extensions, mezzanines) and the existing system can't stretch to the assessment's requirement
• Battery/cabling era issues: pre-FP cabling installs, capacity exhausted panels, zone plans that no longer map reality
• The economics tell: when two years of repair invoices approach a replacement quote's delta — stop feeding the old platform

Replace what, exactly? The phased options

Fire systems replace in parts better than security systems: Panel-swap (keep compliant wiring and recent heads, new MxPro/C-Tec brain): the classic obsolete-panel cure — £1,500–£5,000 typical against full-system money, one weekend's disruption. Head replacement programme (panel sound, heads aged): rolling per-floor swaps at service visits spread cost and keep certification continuous. Full replacement (both ends tired, or category change): the clean-sheet — at which point wireless/hybrid options re-enter for occupied-building economics (see the wireless comparison). Conversions wired-conventional → addressable can reuse compliant cabling, which is the quiet cost-saver surveys exist to find. Every path keeps the building continuously covered — temporary detection bridges any panel-down windows; 'rip out Friday, compliant someday' is not a method.

Decision discipline and documentation

Run the decision like the liability it is: current fire risk assessment in hand (its category requirement is the target — the categories guide explains the bands), a system condition survey with device-age census (we produce these as standard takeover/major-service outputs), repair-vs-replace economics over five years (servicing £200–£900/yr either way; chronic-fault systems add call-out drag), and the false-alarm ledger (each unwanted evacuation has a cost — the false-alarm guide tallies them). Then document the plan: phased replacement schedules satisfy inspectors who'd condemn drift — a dated programme is compliance management; 'we know it's old' is evidence against you. Budget owners get the same memo every time: fire systems age into liability quietly, and the cheap year to act is this one.