Grades 1-4, and the core standards that define them - BS 4737, PD 6662, BS 9263, BS 8243, BS EN 50131, BS EN 50136 and SS 2004 - are covered in full on our intruder alarm system grades guide. If you haven't read that page yet, start there for the fundamentals - what each grade means, the signalling grade tables, and the DualCom, Redcare and LiveTalk signalling options.
This page goes a level deeper, for engineers, facilities managers and anyone else who wants the full technical detail behind those standards: battery backup durations, what an Alarm Receiving Centre is actually required to do, what a BS 9263 maintenance visit involves, the security specification behind signalling paths, and the practical difference between a Grade 2 and a Grade 3 installation.
1) Battery backup requirements by grade
Every graded intruder alarm needs a standby battery so it keeps working through a mains power cut. How long that battery has to last depends on the system's grade:
| Grade | Required backup |
|---|---|
| Grade 1-2 | 12 hours |
| Grade 3 | 12-24 hours (24 hours required if there's no mains-fail messaging) |
| Grade 4 | 24 hours |
In other words, a Grade 3 system without mains-fail messaging back to the monitoring centre needs to assume the worst case and provide the full 24 hours, the same as Grade 4 - it's only the presence of a mains-fail signal that allows the shorter 12-hour minimum.
2) BS 5979 - Alarm Receiving Centres
BS 5979 covers the standards an Alarm Receiving Centre (ARC) itself must operate to - not the alarm system in the building, but the monitoring station that receives its signals. That includes AMCO's own monitoring centre, which handles LiveTalk audio verification and signal processing around the clock.
An ARC certified to BS 5979 has to meet requirements around staffing levels, premises resilience, power redundancy and operator procedures, so that a genuine activation is always received and actioned - whatever else is happening at the centre at the time.
3) BS 9263 - maintenance in detail
BS 9263 is referenced on our grades page as the maintenance standard, but it actually sets out two distinct types of maintenance work, plus the checks required when a system is first commissioned:
- Preventative maintenance - scheduled visits to test and service the system before anything goes wrong, catching wear or drift in sensors and signalling before it causes a fault.
- Corrective maintenance - reactive callouts to fix a fault once one has been reported, whether that's a false alarm, a signalling dropout or a failed component.
- Commissioning checklists - a formal set of checks completed when a system is first installed or substantially altered, confirming every device is correctly fitted, tested and recorded before the system is signed off.
In practice, this translates into a simple visit schedule: bells-only systems (with no monitoring path) need one maintenance visit a year, while monitored systems need two. A typical compliance check on-site takes around 45-60 minutes. See our alarm maintenance service for how AMCO schedules and carries these out.
4) BS EN 50136-1 - signalling device design specifics
Our grades page covers the DP1-4 fault-reporting grades that BS EN 50136-1 defines for signalling equipment. Beyond those reporting-time requirements, the standard also specifies a set of technical safeguards for the signalling path itself:
- Denial-of-service protection - the signalling device must resist attempts to jam or flood its communication path to prevent an alarm getting through.
- 128-bit encryption - signals between the premises and the monitoring centre are encrypted to that standard, so they can't be intercepted or spoofed in transit.
- 3-year event recording - a record of signalling events must be retained for at least three years, giving a full audit trail if it's ever needed.
- 99.8% availability - the signalling path itself has a mandated minimum uptime, so the route between panel and monitoring centre is very rarely unavailable.
This is the security specification working alongside the DP fault-reporting grade - the DP grade defines how quickly a fault has to be reported, while these requirements define how secure and resilient the signalling path is day-to-day.
5) Clause 6.4.4 (BS 8243) - confirmed alarms and entry doors
BS 8243 covers confirmed-activation systems used for police response, and clause 6.4.4 deals specifically with what happens during entry and exit. Opening the entry door within the entry-procedure window disables "confirmed alarm" status for that particular activation - the idea being that a legitimate entry, using the timed procedure and keypad code, shouldn't itself be able to trigger a confirmed (and therefore police-eligible) alarm.
One point worth flagging: many insurers consider a code-only entry procedure "unacceptable" as the sole method of entry, and require a digital key or app-based alternative alongside the keypad code. Check your policy wording, or see our insurance specifications page for AMCO's own compliance detail on this.
6) Grade 2 vs Grade 3 - the practical engineering difference
It's tempting to think of Grade 3 as simply "a better version" of Grade 2 equipment, but the standard actually requires specific technology aimed at a more capable, determined intruder - not just higher-spec versions of the same parts:
- Anti-masking sensor technology - detectors that can tell if their field of view has been blocked or covered, rather than simply failing silently.
- Smash-resistant metal enclosures - panels and housings built to resist physical attack, not the plastic casings typical of Grade 2 equipment.
- A mandatory external bell - Grade 3 requires an external sounder as standard, rather than it being optional.
Because a system's overall grade defaults to the lowest-graded component fitted, all three of these need to be present and correctly installed together - see our Texecom installation expertise for how AMCO specifies a true Grade 3 system component-by-component.
For the fundamentals - grades 1-4 explained simply, the full standards list, and the signalling grade tables - head back to our intruder alarm system grades guide. For anything specific to your property or policy, our team is happy to talk it through - call 0800 13 03 999 or get in touch online.