Quick reference · Intruder and hold-up alarm systems
BS EN 50131-1 and PD 6662: quick reference
The requirements for intruder and hold-up alarm systems: security grades, environmental classes, power supplies and standby time. PD 6662 sets how the European standards are applied in the UK.
The rules for burglar and hold-up alarms: the four security grades, where equipment can be fitted, and how long the battery must last in a power cut.
BS EN 50131-1:2006+A3:2020, PD 6662:2017. PD 6662:2017 is the UK scheme for applying the European intruder alarm standards. NSI calls it the current edition.
Confirmed two or more sources agree, or a source quotes the standard. Check one source, or a detail that could not be confirmed. Check it against the standard.
The grade says what kind of intruder the system is designed to resist. Grade 1 is low risk: an intruder expected to have little knowledge and a limited range of easily available tools. Grade 2 is low to medium risk, with limited knowledge and a general range of tools and portable instruments. Grade 3 is medium to high risk, with a comprehensive range of tools and portable electronic equipment. Grade 4 is high risk and is used when security takes precedence over all other factors.
A higher grade is for a more capable burglar. Grade 1 is an opportunist, grade 2 someone with some know-how, grade 3 someone well equipped, and grade 4 is for the highest risk, where security comes before everything else.
Each step up is for a more capable intruder. Grade 4 is used when security takes precedence over all other factors.
Class I is indoors with a well maintained temperature, +5 to +40 °C. Class II is general indoor areas, -10 to +40 °C. Class III is outdoors and sheltered, -25 to +50 °C. Class IV is outdoors and general, -25 to +60 °C.
The class says where equipment can go: I is a warm indoor room, II is a general indoor area, III is outside but sheltered, IV is outside and exposed.
The class says where the equipment can be fitted, by the temperature range it works over.
Grades 1 and 2: 12 hours. Grade 3 under PD 6662: 24 hours, or 12 hours if mains failure is reported to the monitoring centre. Grade 3 under BS EN 50131-1: 60 hours, or 30 hours if reported. Grade 4 figures differ between sources, so use the value in the standard.
Grades 1 and 2 need 12 hours on battery. Grade 3 needs 24 hours (12 if the power failure is reported to the monitoring centre) under PD 6662, and 60 hours (30 if reported) under the European standard.
Standby hours as printed in panel makers' manuals. Grade 4 has no preset because sources disagree.
These are the figures printed in panel makers' manuals. Check them against the standards. Grade 4 has no preset because sources disagree.
Estimate the standby current and the alarm current, and take the standby period from the grade. Add the standby charge (standby current times hours) to the alarm charge (alarm current times the alarm period, 30 minutes by default, times a de-rating factor of 1.75), then multiply by an ageing factor of 1.25. Makers use different ageing figures, and less in some.
Add up the current the alarm uses on battery, multiply by the hours it must last, add the alarm sounding, and allow extra for the battery ageing.
The same formula as the fire alarm battery calculator (BS 5839-1, Annex E), applied here to intruder alarms. An estimate, not a rule in PD 6662 or BS EN 50131.
The UK scheme for applying the European standards for intruder and hold-up alarm systems. Insurers and the inspectorates (NSI and SSAIB) work to it. The 2017 edition is the current one.
The UK's way of applying the European burglar alarm standards. It is what insurers and the inspection bodies expect.
A system with a police unique reference number (URN) gets response until three false calls in a rolling 12 months. A written warning follows after two. Response is withdrawn no sooner than 14 days after the letter, and the URN is deleted if response stays withdrawn for over 6 months. Two police documents (2018 and 2021) give these figures.
Three false calls in a year and the police can stop attending. You get a warning after two, and at least 14 days' notice.
Three false calls in a rolling 12 months and the police can withdraw response.
Police policy is updated from time to time. Check the current version.
Under the 2018 policy, an unconfirmed system must be upgraded to a confirmed one. A confirmed system needs the cause found, a fix, and 90 days without a false call unless another confirmation method is added.
To get police response back, find and fix the cause, and upgrade an unconfirmed system to confirmed. Confirmed systems must then run 90 days without a false call.
From the April 2018 police policy. Check the current version.
Under the 2018 police policy, a hold-up alarm has police response until two false calls in 12 months, then it is withdrawn. Phone call-back alone is not acceptable for commercial premises from 1 April 2018.
Hold-up alarms lose police response after two false calls in a year. Ringing back to check is no longer enough for businesses.
From the April 2018 police policy. Check the current version.
An alarm caused by detector activation with no damage or entry, or by a line fault, unless proved otherwise. The installer, maintainer, customer and receiving centre must all filter false calls, following BS 8473.
A call with no break-in behind it, such as a detector going off with no damage. Everyone involved must work to cut false calls.
In the older PD 6662:2010 scheme: X is siren only, B is siren plus one receiving centre link, C is two links, and D is one link. PD 6662:2017 moved the notification options into BS EN 50131-1.
The options describe how the alarm is reported: siren only, or one or two links to a monitoring centre.
A bells-only system needs one visit a year. A monitored system needs two a year, or one site visit plus one remote check, and two site visits for Grade 4 (BS 9263).
A bells-only alarm is serviced once a year. A monitored one twice a year, or once plus a remote check.
From trade guides that cite BS 9263. Check the standard.