Fire systems
Fire Detection
Clear warning, appropriate coverage. Fire alarms and air sampling designed around the way your building is used.
Fire alarms & air sampling
Detection designed around your building.
The right system brings detectors, manual call points, alarm devices and building interfaces together. We start with the fire strategy, the risks and the people who need to respond.
System technology
Choose the right approach.
Understanding the difference
A zone circuit identifies an area of the building.
Individual device addresses provide a more precise location.
Illustrative circuit layouts from Protex. Actual zoning, device positions and wiring are determined by the project design.
BS 5839-1 categories
Define the coverage objective.
M describes manual warning, L categories protect life and P categories protect property. The category is agreed through the fire strategy and risk assessment, with insurer and client requirements considered.
M · Manual warning
Manual call points provide the alarm. Category M does not require automatic fire detection.
L1 · Maximum life protection
Automatic detection throughout the building, subject to the applicable standard’s exclusions.
L2 · Additional life protection
L3 coverage with additional detection in specified high-risk or high-hazard areas.
L3 · Standard life protection
Automatic detection along escape routes and in rooms opening onto those routes.
L4 · Escape-route protection
Automatic detection within escape routes, such as corridors and stairways.
L5 · Specific life-safety objective
Bespoke detection arranged to meet a defined life-safety objective. It is not simply a lower level of L4.
P1 · Whole-building property protection
Automatic detection throughout the building to support an early response and limit property loss.
P2 · Selected-area property protection
Automatic detection in specified parts of the building where the property risk requires it.
Life-protection systems generally include manual call points. Combined life and property objectives can apply. Category selection does not, on its own, confirm that a complete design meets the standard.
Coverage and system technology are separate decisions. Both need to support the agreed fire strategy.
Detector selection considers ceiling height, airflow, dust, steam and the activities in each space. Optical smoke, heat, multisensor, beam and aspirating detection each have different applications.
An agreed cause-and-effect schedule defines what happens when a device operates: which alarm zones activate and how interfaces such as smoke control or access-controlled doors respond. Life-safety functions remain independent of the security management platform.
For non-domestic premises, BS 5839-1 provides the relevant design framework. We coordinate coverage, zoning, audibility and any visual alarm requirements with the client, consultant and fire strategy.