Alarm grading (EN 50131 and US equivalents)
In the UK and Europe, commercial intruder alarms are graded against EN 50131 — typically Grade 2 for low-value commercial and Grade 3 for most commercial premises carrying meaningful stock or risk.
In the US, UL 681 and UL 2050 cover installation and equipment standards, with insurer-driven schedule specifications often setting the practical bar.
Sensor technologies
Modern commercial alarms typically combine multiple sensor types so that an intrusion has to defeat several independent detection paths.
- PIR — passive infrared, the workhorse motion sensor
- Microwave — Doppler-based motion detection
- Dual-tech — PIR + microwave, only triggers on both
- Vibration / shock — door, window, safe protection
- Magnetic contacts — door and window position
- Glass-break — acoustic detection of breakage
Sequential and audio verification
Sequential verification requires two separate sensor activations within a defined window before escalating. Audio verification adds an operator listen-in to the protected area. Both significantly reduce false-alarm-driven response loss.
Control panels and signalling
The control panel is the brain of the alarm — graded, tamper-protected and connected via dual-path signalling to the ARC. Modern panels integrate cleanly with access control and remote management.
Alarms alongside CCTV and perimeter detection
Intruder alarms cover internal space and the building shell. They complement — rather than replace — perimeter CCTV and external detection. The strongest commercial designs use all three in a layered model.
Frequently asked questions
What grade of alarm does my commercial site need?
Most commercial sites sit at Grade 2 or Grade 3 under EN 50131, with the exact requirement set by the insurance schedule and a risk assessment. High-value or high-target premises may sit at Grade 3 or higher.
Do I still need an alarm if I have monitored CCTV?
Usually, yes. Alarms cover internal areas and the building shell efficiently and meet insurance specifications; monitored CCTV adds detection at the boundary and during approach. The two complement each other.
How often should an alarm be serviced?
Commercial alarms typically require at least one preventative maintenance visit per year, and additional inspections where insurance schedules or grading requires. Remote inspection is increasingly used between physical visits.
How is Grade 2 different from Grade 3 in practice?
Grade 3 systems assume an intruder with basic knowledge of alarm systems and appropriate tools. Grade 2 assumes an opportunist with limited technical knowledge. In practice, this means Grade 3 requires higher-specification tamper detection, dual-path signalling, more resilient control panels and stricter installer certification. Insurers set the required grade based on premises risk.
Do I need separate systems for perimeter and interior?
Not usually — a well-designed commercial control panel handles perimeter contacts, interior motion detection and shock or vibration sensors as different zones on a single system. Truly separate systems are only appropriate on very large sites or where distinct monitoring contracts are required, such as bonded areas or premises with mixed tenant occupancy arrangements.
What happens during a scheduled maintenance visit?
A preventative maintenance visit covers full sensor walk-test, battery testing, signalling path verification, event log review and firmware update where applicable. The engineer produces a documented report suitable for insurer audit. Skipping preventative visits usually invalidates system certification and can void insurance cover in the event of a claim, so the discipline matters.
Can I arm and disarm the alarm remotely?
Yes — modern commercial panels support authenticated remote arming through an app, subject to appropriate authorisation controls. Remote disarm is generally discouraged operationally because it removes the physical presence check that on-site keypad arming provides. Most sites use remote monitoring rather than remote disarm to handle out-of-hours situations securely and defensibly.
Continue in the intruder detection hub
The intruder detection hub sets out how this technology fits alongside the other layers of a complete commercial design.
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