Working with DD243
Over the next few months in Security Installer I will be taking a look at some of the most frequently asked question about DD243 to come from installers and surveyors. But to start off this series here is an overview of the draft for development.
Reducing false calls is the aim
DD243 is required to be applied on a provisional basis to enable information and experience of its practical application to be obtained. Effectively, the document is an effort to reduce the number of false calls to intruder alarm systems.
A review of DD243 will be carried out no later than two years after its publication and, at that stage, and in view of comments from the industry on it use, it will be decided what action should be taken. The standard was published in January 2002 and became effective on July 1 2002.
Risk Analysis
Conducting a structured risk analysis of the premises to be protected will now become fundamental in the process of system design. The specification will also be structured differently incorporating secondary means of entry and identifying which parts of the system do and do not constitute confirmed alarms. You will also need to have written acceptance for certain methods used for unsetting of systems where all means of confirmation will be disabled. You will also need to include in the specification what action will be taken for certain events between the customer and the ARC.
The following is a short overview of some parts of DD243 and its requirements. There are three forms of confirmation technology:
DD243 also allows confirmation to extend to signalling. As a result, a confirmed alarm may be generated in the following ways, providing you have dual path signalling:
- Transmission fault followed by alarm signal.
- Alarm signal followed by a transmission fault.
- Two transmission faults.
Audio Confirmation
Intruder alarm systems may be confirmed audibly utilising an Audio Listening Device (ALD) which is triggered by an intruder detector or an Audio Monitoring Device (AMD), which is a single device which provides a dual role as an Audio Monitoring & Audio Listening Device.
When using audio confirmation you need to ensure that the:
- Audio coverage matches the detection coverage
- Audio confirmation does not commence until an alarm has been signalled to the ARC.
When an audio alarm is received at the ARC the listening periods are a minimum of:
- 60 (s) for intruder detection
- 30 (s) for audio detection
For audio confirmation of intruder detection: There is a 10 seconds pre-recorded stored audio before any activation and at least 15 seconds stored after the activation, this can be accessed by the ARC on receipt of an alarm activation.
For audio confirmation of audio detection: 1 second of stored audio before an activation and 15 seconds stored audio after an activation which can be accessed by the ARC on receipt of an alarm activation.
Video Confirmation
Video equipment may be triggered by an:
- Intruder Detector
- Video Monitoring Device (VMD)
When using video confirmation you need to ensure that the:
Video coverage matches detection coverage, and Video confirmation does not commence until an alarm has been signalled to the ARC. Site identification must be provided by the remote equipment before the ARC begins viewing. When the site identification is achieved, there will be a minimum of 3 images following the activation: 1 image at the time of activation followed by 2 images after the activation and within 5 seconds.
Sequential Confirmation
Intruder alarm systems will be design based on the assessed risk of the premises and an alarm signal will generate confirmation when two independent detectors within the confirmation time activate.
The confirmation time, within which the two independent detectors are required to activate is 30 to 60 minutes.
Sequential confirmation requires movement detectors to meet the following criteria:
Different technologies (may overlap). In the case of two movement detectors at least one should be a dual technology detector.Same technologies (may not overlap). However for the purpose of DD243, two dual technology movement detectors incorporating the same technologies may be regarded as detectors of differing technologies. Therefore two dual technology detectors may overlap.
One important factor to note is that detectors must not be triggered by same “event” – e.g. 2 door contacts on same door wired as independent circuits.
Examples of Sequential Confirmation may be:
- passive and dual technology detector
- 2 dual technology detectors
- passive infra-red and microwave
Other sequential configuration may be:
- 1 movement detector and – – acoustic detector – break glass detector – inertia detector – door contacts
For sequential confirmation, an alarm condition from the first detector should generate an unconfirmed activation.If there is a subsequent alarm within the confirmation time a sequentially confirmed activation should be signalled. Following an activation from the first detector, if a second (confirmed) detector does not activate within the confirmation period the following applies:
a) Reinstatement of the first detector if possible;
b) If not isolate and signal isolation to the ARC;
c) If it is a perimeter detector the ARC must initiate key holder action. (This needs to be agreed with the ARC);
d) If the entry door is isolated an alternative means to initiate the entry timer is required.
With reference to (d): The secondary means of entry would normally be programmed Access and take over as the Entry circuit if the original entry circuit becomes isolated.
This is an attempt to stop the keyholder entering the premises and causing a confirmed activation in the case where the key holder maybe attending an unconfirmed alarm.
Means of Completion Setting the System
There are a 5 ways in which DD243 allow the system to be set:- Key operated shunt lock on the final exit door
- Push button switch outside the premises
- Door contact on final exit door
- Set in conjunction with the ARC
- Portable ACE (Ancillary control equipment) new method of setting police signalling jobs.
The unsetting requirements for IAS are significant and care is required in their selection. As you will discover in some cases the Confirmation Facility will be disabled.
Means of Unsetting.
Unlocking the initial entry door unsets the whole or unsets part of the system facilitating the following:a) In part set, entry to areas to be prevented by locks;
b) Unlocking the doors to set areas unsets that part of the system;
c) Status of locks to be monitored at the control panel and;
d) System will be prohibited to set until all relevant doors are locked.
Unlocking the initial entry door disables all means of confirmation
If the entry timer expires it will be signalled to the ARC as an unconfirmed alarm. Any deviation from entry route will be signalled as an unconfirmed alarm.
When using this option there must be written confirmation to the customer informing them that all confirmation throughout the protected premises will be disabled during entry. The alarm company should also obtain written acceptance from the customer of the disabling of the means of confirmation.Opening the initial entry door disables all means of confirmation.
If the entry timer expires it will be signalled to the ARC as an unconfirmed alarm. Any deviation from entry route will be signalled as an unconfirmed alarm.
When using this option there must be written confirmation to the Customer informing them that all confirmation throughout the protected premises will be disabled during entry. The alarm company should also obtain written acceptance from the customer of the disabling of the means of confirmationCompletion of Unsetting Using Portable ACE
Unsetting from outside the protected area is now permitted using a portable ACE (i.e. key fob). If this method is used the entry door must still be fitted with an entry timer. Or opening the entry door starts the entry timer and then the system is unset using a key fob or other token.
If an alarm occurs during entry or as a result of the expiry of entry time, the alarm should be notified to the ARC as unconfirmed.
Using this method of unsetting a confirmed alarm can occur if two or more independent detectors located off the entry route are activated after expiry of the entry time.Although we have only covered some of the areas within DD243 in this article, we will take a closer look next month and cover some of the most frequently asked questions by installer and surveyors.
Working with DD243
Over the next few months in Security Installer I will be taking a look at some of the most frequently […]
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