BS 7992:2002 pdf download – Code of practice for Exterior deterrent systems
5.2 Components
An EDS should include the following components: a) CIE, which may be incorporated in any other system component; b) one or more detectors and/or one or more sensors with associated processor(s); c) one or more PAWDs; d) one or more power supplies, which may be combined with other system components or may be housed separately. Additionally, an ATS may be incorporated. Systems incorporating an ATS may be configured so that the PAWD sounds only as described in 6.5.5. Systems incorporating an external loudspeaker may be configured so that the PAWD sounds only in the event of a tamper condition.
5.3 Environmental suitability To ensure the correct performance of the system, components should be suitable for use in the environment in which they are required to operate. The influence of environmental conditions should not change the state of the EDS, nor damage system components nor substantially change system performance.
5.4 Functions
5.4.1 Detection of intruders and recognition of faults General The EDS should include means for the detection of intruders and of tampering, and for the recognition of faults. Other events may be detected, provided that this does not adversely affect the detection of intruders and tampering, and the recognition of faults. Detectors should be configured so that any failure to communicate with the CIE within the required time period should be treated as a tamper signal. When a detector relies upon the interruption of an interconnection to create an intruder or tamper signal, the intruder signal should be different from a tamper signal.
NOTE 1 This includes instances where the interconnection passes directly through a mechanical or magnetic switch (contact) or through the relay of a detector or a tamper switch (contact). When an interconnection is extended to form an intruder detector or tamper detector, the resulting signal should be treated as an intruder or tamper signal.
NOTE 2 In this case, the CIE effectively forms part of the detector, as the CIE is directly monitoring that part of the interconnection which is acting as a detector. (An example is continuous wiring.) Means provided to adjust the field of view of a detector should be made inaccessible to unauthorized personnel. Alternatively there should be means to detect unauthorized adjustment. In this case, unauthorized adjustment should be treated as tampering. Care should be taken to minimize the risk of accidental adjustment. Intruder detection An EDS should only include detectors which are suitable for the environment and application. A detector can incorporate more than one form of technology; for example, passive infra-red and microwave or ultrasonic. Individual detectors may be logically grouped so that the generation of one or more intruder signals or messages from one or more detectors is necessary to generate a security alert. An individual detector may be configured so that more than one activation is necessary to generate an alarm signal or message. Detectors can be classified as follows:
a) simple change of state devices; for example, mechanically or magnetically operated devices;
b) active detection devices, i.e. devices which include active components; for example, movement or vibration detectors. Active detection devices should provide individual means to confirm that they are operational. Recognition of faults
The system should be able to recognize the following faults:
a) primary power fault;
b) primary cell fault (where fitted);
c) fault in the CIE;
d) fault in the ATS (where provided).
Other faults may be recognized, provided that this does not adversely affect the recognition of faults a) to d).
5.4.2 Operation Design
The EDS should be designed so that the possibility of operator error during setting or unsetting is minimized. Partial setting or unsetting may be possible.