A multi-tenant office building shares fire safety: one BMI for a building in which every floor (or wing, or tower) has its own tenant — each with their own in-house emergency response (BHV), their own IT, their own reception. That complicates the evacuation strategy.
Below is how an OAI is set up in such an environment per NEN 2575, how it fits within VVE arrangements or split-incentive ownership, and the three most common pitfalls.
1. The core problem: one building, multiple risk profiles
On one floor sits a law firm with 40 people during office hours. On another, a 24/7 fintech start-up. On a third, a medical practice with clients who do not know the building. What if one of these triggers a smoke alarm?
Evacuating the whole tower simultaneously is in 80% of cases disproportionate — it costs productivity, undermines confidence in the system (cry-wolf effect), and is operationally destructive. But not evacuating at all is obviously not an option.
2. What NEN 2575 allows
NEN 2575 recognises the concept of phased evacuation alarm:
- Direct alarm zone — the zone with detection, plus the floors directly above and below it (the typical smoke-rise zone). These zones evacuate immediately
- Other zones on "stand-by" — receive a pre-alarm or attention message; the BHV on the floor decides on alarm extension
This requires one technical whole (one BMI with multiple alarm zones), not separate installations per tenant. Separate installations lead to inconsistent detection, conflicting alarms and legal ambiguity over responsibility.
3. Who is responsible?
In a multi-tenant complex the roles are typically:
- Owner / VVE — owner of the shared installation, ultimately responsible for inspection and maintenance
- Building manager (property manager) — operationally responsible; day-to-day operation, logbook
- Tenants — responsible for their own BHV and internal evacuation procedure; receive the alarm signal from the shared OAI
- PAC / regional alarm centre — depending on the agreement in the PoR
A good PoR locks down this role split explicitly. In practice we recommend producing this document before the first tenant moves in, because tenants are contractually bound to it through the lease.
4. Three common pitfalls
The owner leaves detection to tenants. Each tenant installs their own detectors in their own space without integration. Smoke on a common corridor goes undetected by all installations, or the alarm goes off selectively in one tenant zone while the rest continue working.
Pre-alarm strategy without BHV procedure. A phased alarm only works if BHV is on site to evaluate the alarm and extend it. In a complex with flex-office tenants who have no fixed staffing this is not realistic — in that case simultaneous alarm is actually safer.
Renovation by one tenant = design question for the whole. When tenant X replaces an open-plan office with 20 closed offices, the detection strategy of that zone changes. But that has consequences for the PoR of the whole building, because the coverage class of the zone changes.
5. Practical setup
In a typical project we apply these steps:
- Per-wing zoning — each wing or floor gets its own detection zone with its own alarm zone
- Central unit in technical room — preferably in a neutral location (not in a tenant's space), with access for maintenance without dependency on a tenant
- Voice-guided alarm — "Floor 3, wing A: evacuate immediately. Other floors: stand by for instruction." For multi-tenant this is essential — tones alone give too little contextual information
- Signal transmission to a 24/7 PAC — not to individual tenants; the PAC validates and informs the owner / property manager
6. At inspection
Multi-tenant complexes need extra attention at inspection:
- Evidence of alignment with all tenants during renovations
- Logbook in which tenant-specific incidents are separately traceable
- Functional tests that demonstrate the evacuation strategy per zone, not just "the central panel works"
Closing
Fire safety in a multi-tenant complex is at least as organisationally complex as it is technical. The OAI must reflect the physical building layout, the tenant composition, and the BHV organisation. A good installation is one that does not only detect, but also delivers the right message to the right people at the right moment.
Do you have a complex where the OAI is dated, or was never set up for multi-tenant use? Schedule a dossier check — we look at PoR, tenant arrangements and the current installation and give an honest redesign track.