Must fire detection remain active during renovation works?
Yes, the obligation to maintain operational fire detection never stops during construction, as long as the building remains occupied. The Royal Decree of 7 July 1994 requires continuous protection adapted to the building category (low, medium or high), and nothing in this text provides for an exception during works. Construction actually increases risk: grinding, welding, sanding, temporarily stored flammable products, provisional wiring. Vigilance must therefore be reinforced, not relaxed. The question is never whether protection can be suspended, but how to maintain it despite construction constraints: dust, vibrations, partition cuts crossing existing detection zones.
How to isolate a construction zone without cutting detection in the rest of the building?
Isolation is always done at the fire detection and alarm panel (TDS) level, zone by zone, never by cutting the complete installation. The zoning plan defined during design according to NBN S 21-100-1 allows precise identification of which loops or detectors serve the construction zone. Only these elements are deactivated, the rest of the building continues to be monitored normally. This approach assumes the zoning plan is up to date and readable before works begin: it is often the first document to verify with the installer before opening a construction site in an occupied building. Without an updated plan, the risk is deactivating more zones than necessary, or worse, forgetting an active one in the construction perimeter.
How to record a temporary detector deactivation?
Every deactivation must be recorded in the building's safety register, with date, time, affected zone, responsible person's name and expected duration. This register, provided for in the maintenance and control framework according to NBN S 21-100-2, constitutes the record that allows knowing at any time which zones are covered and which are not. In practice, a monitoring table displayed near the TDS, coupled with the register entry, avoids oversights during shift changes on a construction site lasting several weeks. Each reactivation must be tested and signed with the same rigor as the initial deactivation, otherwise the register loses all evidential value in case of inspection by the emergency zone (hulpverleningszone).
How to avoid false alarms related to dust and cutting?
False alarms during construction almost always come from plaster or concrete dust clogging optical smoke detectors, or cutting fumes (grinding, welding) triggering real but non-fire-related detection. The solution is not to deactivate the entire zone, but to install approved dust protection covers on only the exposed detectors, for the duration of construction. For hot work, a formalized work permit must provide for continuous human surveillance of the zone during and after the operation, with a fire extinguisher nearby. This dual approach, targeted cover plus human surveillance, allows keeping automatic detection active in the rest of the zone while neutralizing the risk of inadvertent triggering.
Must the emergency zone be informed before starting works?
Yes, the territorially competent emergency zone (hulpverleningszone) must be informed as soon as a partial or total detection deactivation is planned, especially if it exceeds a few hours or extends over several days. This information prevents a real alarm signal in an uncovered zone from being misinterpreted, and allows fire services to integrate the building's temporary configuration into their intervention preparation. In buildings accessible to the public or healthcare establishments, this prior contact is often part of the conditions set by the emergency zone during previous opinions. A simple letter or construction site form transmitted beforehand, with dates and affected zones, is sufficient in most cases.
What compensatory measures should be implemented during a deactivation?
Compensatory measures serve to fill the temporary absence of automatic detection in a zone during construction. The choice depends on the deactivation duration, building occupancy and nature of works.
| Compensatory measure | When to use it | Point of attention |
|---|---|---|
| Reinforced surveillance rounds | Short-duration deactivation, infrequently occupied zone | Frequency to be adapted to presence of people in the building |
| Posted security agent | Hot work, continuously occupied zone | Must have direct alert means to TDS or control panel |
| Additional fire extinguishers nearby | Any cutting or welding zone | Check equipment inspection date before construction |
| Provisional detector wiring | Long-duration construction, risk zone | Requires validation by certified installer before commissioning |
How to return the system to normal configuration after works?
Complete recommissioning requires a functional check of each detector previously deactivated or protected by a cover, before reactivating the zone on the TDS. This check must be performed by an installer or company with qualified personnel, in accordance with NBN S 21-100-2 maintenance requirements. Dust protection covers are removed one by one, with trigger testing using test key or appropriate aerosol, never by simple visual observation. The safety register is updated with the recommissioning date and technician's name. If construction lasted several months, it is useful to verify whether an intermediate periodic inspection has not become necessary before the normal deadline set by the emergency zone (hulpverleningszone).