What BS 5839-1:2025 Actually Requires
The new standard gets specific about alarm transmission equipment for Category L systems: the ones responsible for summoning the Fire and Rescue Service when things go wrong.
Two performance criteria matter most:
Single-path failures must reach the ARC within 90 seconds. That’s your window. If one signalling path drops, the ARC needs to know fast.
Catastrophic failures (when both signalling paths go down) must trigger indication at both the ARC and the control equipment within three minutes.
These are deliberate numbers. They’re designed to ensure that when a fire alarm system loses connectivity, someone knows about it before it becomes a critical safety gap.
Why Dual-Path Matters More Than Ever
Single-path signalling was always a risk. One network failure, one cut cable, one router reset, and your alarm signal goes nowhere.
Dual-path solves this by running two independent communication routes simultaneously. If the primary path fails, the secondary takes over immediately. It’s redundancy where it counts.
According to AddSecure’s announcement, the NGP Advanced Extra DP4 uses LAN and 4G with dual SIM capability to provide DP4-grade signalling. That combination covers both wired and wireless paths, which means you’re protected even if broadband goes down.
The device delivers:
- 90-second single-path failure reporting
- Step-up reporting on the secondary path when primary fails
- Three-minute catastrophic failure indication
All aligned with BS 5839-1:2025 requirements.
What Sets DP4 Apart from Other Options
AddSecure offers three DP4 products in its range:
Ultimate with Access Line: Includes a managed broadband service and router that stays operational during power outages. Critical for premises where power reliability is questionable.
Ultimate without Access Line: Uses customer-managed broadband, giving you flexibility if existing infrastructure is solid.
Advanced Extra DP4: The latest addition, designed specifically to meet the new BS 5839-1:2025 requirements with LAN and 4G dual-path resilience.
All three carry third-party certification through the Loss Prevention Certification Board (LPCB) and a BSI Kitemark for IoT cyber security. Plus, they’re certified for both fire and security applications: one device across multiple systems.
Nicholas Whiting, VP Alarm Signalling at AddSecure UK, notes: “The launch of NGP Advanced Extra DP4 reflects AddSecure’s commitment to supporting the industry through critical changes such as the PSTN switch-off and the move to IP networks.”
Compliance Includes Cyber Security
Cyber security matters more than most installers realize. Fire alarm signalling devices sit on networks, which makes them potential entry points.
AddSecure’s dual-path products exceed the requirements of the Product Security and Telecommunications Infrastructure (PSTI) Act. The company also holds ISO 27001 certification: a recognized standard for information security management.
That’s practical protection. It means the devices are built with security protocols that protect against unauthorized access, data breaches, and network vulnerabilities.
What This Means for Your Installations
If you’re specifying fire alarm signalling for Category L systems, BS 5839-1:2025 compliance is required. The standard is here, and projects moving forward need to meet it.
Dual-path signalling is the baseline for meeting those 90-second and three-minute reporting requirements reliably.
And with the PSTN switch-off forcing the industry toward IP-based solutions anyway, this is the time to get ahead of both transitions at once.
AddSecure entered the UK alarm signalling market in June 2024 after BT Redcare closed. Their approach focuses on zero upfront costs, with billing on activation or after 60 days. This removes a procurement barrier for many installers.
Whether you’re upgrading existing systems or designing new installations, understanding the new standard and the technology that meets it puts you in a stronger position with clients who expect compliant, resilient fire safety.
Ready to future-proof your fire alarm installations? Learn more about AddSecure’s fire alarm signalling services and how the NGP Advanced Extra DP4 meets BS 5839-1:2025 requirements.