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5.6
Appendix 6 –Network Design Principles
This section gives recommendations on the design of the installation to cover specific EN54-2
requirements and typical national codes of practice.
[EN54-2: 1997, Clause 13.7] Not more than 512 fire detectors and / or manual call points and their
associated mandatory functions shall be affected as a result of a system fault in the C.I.E.
5.6.1 Mandatory
Functions
For full compliance with the requirements in EN54-2, the configuration and operation of all
mandatory outputs shall comply with the guidelines below.
Sounder Devices [EN54-2: 1997 Clause 7.8]:
Care should be taken with the cause and effect programming to ensure that any sounder / sounder
output is configured such that its fire response operation will only be affected if there is a system
fault on the chassis / panel to which it is directly connected.
Consideration should also be given to the applicable code of practice or national standard
regulations for fire systems installation (for example BS5839-1: 2002) for installation and operation
of sounder devices.
Fire & Fault Routing [EN54-2: 1997 Clauses 7.9 & 8.9]:
Network: If provided, then at least two fire and fault routing interfaces or a fail-safe redundant
connection shall be provided. These should be programmed to report all fire and all fault conditions.
See 2.5.13 and 2.5.12 for further information.
5.6.2 Network
Wiring
Where the installation design and codes of practice deem the network connections to be a 'Critical
Signal Path' then consideration should be given to the use of the
Ad-NeT-PluS
®
Fault Tolerant
Network.
In addition, the routing and type of cables employed is important to limit the risk of multiple failures
causing overall or partial loss of the network functions. BS5839-1: 2002 Sections 24-2 and 26.2
provide a useful guide.
— Use fire resisting
cables.
— Configure
the
network as a loop.
— Employ
diverse
routing of incoming
and outgoing
circuits, except in the
immediate vicinity of
the sub-panel.
— There is no loss of
communication to
any sub-panel in the
event of a single
open or short circuit
on the loop.
Detector Loop Wiring
5.6.3 Parent
Functions
Parent functions shall be provided with a redundant capability. Typical parent functions are Fire
Routing, Fault Routing and Fire Brigade Panels.
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