I completed several talks on DD243 at the exhibition on behalf of SSAIB which attracted extremely good audiences, and it was good to see and hear that installers and surveyors are, in many cases, coming to terms with the intricacies of the document's requirements.
Having said this I still find that a few installers are still looking to circumnavigate the requirements and find ways to get a police response which will not actually meet the requirements of DD243.
In my opinion the best policy is to apply DD243 in the spirit in which it has been written. Changes to DD243 are looking likely so, hopefully, it should become more user friendly. Hope springs eternal! Here are some of the questions asked as a result of the talks at Securex.
Bells-only systems
Q: Do I need to install to DD243 if the system being installed is a bells-only?
A: You only need to install to DD243 when you are installing a police calling system. If you are using, for instance, private security or other means to police your system you do not have to install to DD243. Installers in Scotland need to install to DD243 only when systems lose police response and require reconnection as a police calling system.
The next two questions have been answered in my previous articles but I think it's worth running it past you all again as they continue to raise queries and particularly for those readers who have not had the opportunity to read the articles before.
Overlapping answers
Q: What is the definition of a sequentially confirmed alarm and can movement detectors overlap?
A: For an intruder alarm system to be regarded as sequentially confirmed the intruder alarm system should be: configured so that at least two separate alarm conditions are reported, each originating from an independent detector within the confirmation time and,the two detectors should be (i) different technologies or, (ii) same technology and not have overlapping areas of coverage. Two detectors of different technologies having overlapping areas of coverage are permitted to cause a sequentially confirmed alarm. However in the case of two movement detectors, at least one should be a dual technology detector.
Where movement detectors are configured for the purpose of providing sequential confirmation, regular walk-testing is important.
It is permissible for two independent dual technology movement detectors incorporating the same two technologies to have overlapping areas of coverage. Individual movement detectors should be located to minimise the possibility of false alarms so careful consideration should be given to locating detectors where there are any overlapping areas of coverage. Move-ment detectors should therefore be located some distance apart.
Even where there is no overlapping area of coverage care should be taken to locate movement detectors far enough apart to minimise the possibility of sequentially confirmed alarms being false alarms (environmental conditions).
Where movement detectors are configured for the purpose of providing sequential confirmation, regular walk-testing is important. To be regarded as independent, each detector should report alarm conditions separately to the control indicating equipment. The confirmation time, that is the time within which the two detectors are required to operate, should be not less than 30 minutes and not more than 60 minutes.
Examples of configurations not regarded as offering sequentially confirmed alarm conditions are; two single technology movement detectors with overlapping areas, a double knock configuration, a dual technology detector, two or more vibration detectors with overlapping areas, two or more break-glass detectors with overlapping areas, two or more protective switches fitted to the same door.
Structured risk analysis
Q: How can effective confirmation facility be achieved?
A: This really depends on the needs and expectation of the customer. The first issue to tackle before deciding on the design of a security system is to conduct a structured risk analysis and evaluate the risk. Dependant on the risk assessed you will then be in a position to complete a system design. DD243 states that one of the following is to be implemented:
a: An effective confirmation facility throughout the whole of the protected premises. The whole of the intruder alarm system should be designed and configured such that when an intruder enters any part of the protected premises: i) it is capable of providing confirmation of activity throughout the whole of the protected premises; and ii) there is a reasonable expectation that the intruder alarm system will normally provide such confirmation, provided that the intruder has gained access by a means/ route intended to be protected by the alarm system.
b: An effective confirmation facility throughout specified parts of the protected premises. In this case the intruder alarm system should be designed and configured such that when an intruder enters specified parts of the protected premises: i) the system is capable of providing confirmation of activity throughout the specified parts of the protected premises; and ii) there is a reasonable expectation that the intruder alarm system will normally provide such confirmation, provided that the intruder has gained access by a means/ route intended to be protected by the alarm system.
The first issue to tackle before deciding on the design of a security system is to conduct a structured risk analysis and evaluate the risk
The system design specification and the system record should identify the specified parts of the protected premises that do, and do not have, effective confirmation facility.
Designation as confirmed should be made on a case by case basis for each alarm condition, as it may not be possible to say that all alarm conditions originating from a given system will result in a confirmed alarm. Generally it is advisable to speak of intruder alarm systems incorporating alarm confirmation technology and/or intruder alarm systems capable of generating confirmed alarms and not confirmed systems.
This is based on the facts that your system design and proposal will be structured on a room by room basis dependant on the risk analysis outcome.
Isolated question
Q: If the control unit I'm using is unable to provide an isolation signal to the ARC when a detector which has caused an unconfirmed alarm is unable to reinstate after the confirmation time has elapsed, will this contravene DD243.
A: If a detector is unable to reinstate after the confirmation time has elapsed the system must signal an isolation signal to the ARC and the keyholder must be informed.
Finally, thank-you to everyone who came to the talks on DD243 at Securex and contributed to the seminars. It was good to hear your views.
Source
Security Installer
No comments yet