Commercial Intruder Alarm Installation — Graded Systems to EN50131 and PD6662
Risk-assessed, graded intruder alarm design and installation for commercial and industrial premises across Yorkshire, Lincolnshire and the Humber.
SPS Technical designs and installs graded intruder alarm systems for commercial and industrial premises across Yorkshire, Lincolnshire and the Humber. Every installation begins with a risk assessment that determines the correct grade under EN50131 and PD6662 — from Grade 2 for low-to-medium risk premises up to Grade 3 for higher-value commercial sites requiring confirmed alarm response and ARC monitoring. As an SSAIB-certified installer, every system we commission is eligible for a police Unique Reference Number for Type A confirmed response.
Grading explained
Under EN50131 and PD6662, every intruder alarm must be graded to reflect the level of risk at the premises. The grade determines detector specification, panel capability, signalling requirements and ARC monitoring standards. Getting the grade wrong means either under-protecting your premises or paying for unnecessary capability — and insurers and police check compliance. SPS Technical carries out a full risk assessment before specifying any system.
Alarm grading
EN50131 alarm grades — choosing the right level
Under EN50131 and PD6662, every intruder alarm must be graded to reflect the level of risk at the premises. The grade determines detector specification, panel capability, signalling requirements and ARC monitoring standards.
Grade 1
Low risk
Premises unlikely to attract targeted intruders. Opportunistic threat only. Rarely specified for standalone commercial premises.
Grade 2
Low to medium risk
Minimum standard accepted by most insurers for commercial premises. Assumes opportunistic intruder with basic tools.
Grade 3
Medium to high risk
Standard for most commercial premises with valuable stock or assets. Required for police URN and Type A ARC response.
Grade 4
High risk
Very high value premises. Assumes planned attack and specialist knowledge. Intruder may attempt to tamper with the system itself.
Detection technology
Intruder Detection Technology
Modern commercial intruder alarm systems use a combination of detection technologies to minimise false alarms while maintaining reliable detection. PIR detectors are the standard for most internal spaces. Dual-technology detectors combine PIR and microwave to reduce nuisance alarms in challenging environments. Door contacts, shock detectors and vibration detectors provide perimeter coverage. Grade 3 systems require detectors with anti-masking capability to prevent deliberate interference.
PIR detectors
Passive infrared movement detection, the standard for most commercial spaces
Dual-technology detectors
PIR plus microwave, reducing false alarms in challenging environments
Door and window contacts
Perimeter detection on all access points
Shock detectors
Glass break and impact detection for perimeter security
Vibration detectors
Structural attack detection for high-risk premises
CCTV-verified detection
Visual confirmation reducing false alarm callouts
Alarm Signalling and ARC Monitoring
Grade 3 systems require dual-path signalling to an Alarm Receiving Centre — two independent transmission routes so that a single path failure cannot prevent an alarm reaching the monitoring centre. SPS Technical installs IP and 4G dual-path signalling to EN50136 on all new Grade 3 systems. With the PSTN analogue telephone network being switched off across the UK, all new installations use IP or 4G signalling as standard.
Dual-path signalling
Grade 3 requires IP/4G dual-path
Grade 3 systems require dual-path signalling to an ARC — two independent transmission routes so that a single path failure doesn't prevent an alarm reaching the monitoring centre. SPS Technical installs IP and 4G dual-path signalling to EN50136, maintaining ARC connection and police response eligibility even if one path is disrupted. With the PSTN switch-off underway, all new installations use IP/4G signalling as standard.
Our process
How a Graded Intruder Alarm Installation Works
Every SPS Technical intruder alarm installation follows a structured process from risk assessment through to SSAIB certification. No system is commissioned without full zone testing, entry/exit timing verification and ARC connection confirmation.
Risk assessment
Premises, contents, occupancy and threat level assessed
System design
Grade determined, detector placement and panel specified to EN50131/PD6662
Installation
Detectors, panel, sounders and signalling equipment installed
Commissioning
All zones tested, entry/exit timing configured, ARC connection established
Certification
SSAIB certificate of compliance issued, police URN applied for
Risk assessment
Premises, contents, occupancy and threat level assessed
System design
Grade determined, detector placement and panel specified to EN50131/PD6662
Installation
Detectors, panel, sounders and signalling equipment installed
Commissioning
All zones tested, entry/exit timing configured, ARC connection established
Certification
SSAIB certificate of compliance issued, police URN applied for
Knowledge Centre
Related Technical Guides
Emergency Intruder Alarm Repair and Maintenance: A Business Guide
A practical guide to commercial intruder alarm faults, emergency repair, planned maintenance, signalling issues, system takeovers and reducing security downtime.
Commercial Intruder Alarm Systems: A Business & Facilities Manager's Guide
A practical guide for business owners and facilities managers on choosing a commercial intruder alarm, including risk, Grades 2 and 3, monitoring, police response, SSAIB certification, integration and lifecycle maintenance.
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