How to Choose an Intrusion Detection System for Your Office or Warehouse
An intrusion detection system is your building's early warning network — detecting unauthorised entry through doors, windows or open areas and triggering an immediate alarm. Designing it correctly requires understanding the different detection technologies and where each is most effective.
Core Components of an Intrusion Detection System
Control Panel: The brain of the system. Receives signals from all sensors, manages zones, triggers alarms and communicates with a monitoring centre or sends SMS/app alerts.
Motion Detectors (PIR): Passive Infrared sensors detect the heat signature of a moving person. Most effective for open spaces — corridors, large rooms, open-plan offices.
Door and Window Contacts: Magnetic reed switches fitted to door/window frames. When the door or window opens, the circuit breaks and the alarm triggers. Simple, reliable and low-cost.
Glass Break Detectors: Acoustic sensors that detect the specific sound frequency of breaking glass. Essential for ground-floor glass facades or shop fronts.
Beam Detectors: Infrared beams between a transmitter and receiver. Ideal for perimeter protection, large warehouses or boundary walls.
Wired vs Wireless Systems
Wired systems are more reliable (no battery changes, no RF interference) and better suited for permanent installations in new buildings or during fit-out. They require cabling to every detector but have lower long-term maintenance cost.
Wireless systems use RF communication between sensors and the panel — no cabling required. Ideal for retrofit installations, historic buildings or temporary protection. Battery life on modern sensors is typically 3–5 years.
Zoning Your System
A well-designed intrusion system divides your premises into zones — groups of sensors that can be armed, disarmed and alarmed independently. Common zone types:
- Entry/Exit zones: Main doors — with a delay to allow you to enter and disarm before triggering the alarm.
- Perimeter zones: All external doors and windows — immediate alarm when breached.
- Interior zones: Motion detectors inside — only active when building is unoccupied.
- 24-hour zones: Always armed regardless of system state — panic buttons, safe areas, fire exits.
Monitoring Options
Modern intrusion systems communicate alerts via multiple channels: loud local siren (deters intruders, alerts neighbours), SMS and mobile app alerts to nominated contacts, and central station monitoring (a 24/7 monitoring centre that dispatches police or security on confirmed alarm). For high-value premises, central station monitoring with police response is strongly recommended.
Key Takeaways
- Combine door contacts, PIR motion detectors and glass break sensors for complete coverage
- Divide your premises into zones for flexible arming and disarming
- Wired systems are more reliable; wireless is better for retrofits
- Entry/exit delays prevent false alarms when you arrive and leave
- Central station monitoring with police dispatch is recommended for high-value sites