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Modular fire alarm

Fire alarm systems are like good suits; they have to be made to measure. Only if the system has been tailored to meet the unique requirements of the client or of the location, is it possible to guarantee safety on the one hand and cost-efficient operation on the other. But what happens when the made-to-measure suit has to grow with the customer?

Even the best fire alarm system can only fulfil its role to optimum effect if it is designed entirely in line with the circumstances at each installation location. And it is also important to bear in mind the service life of the installed systems. Fire alarm systems often have a lifecycle that is counted in decades rather than in years. In this period not only the conditions of use at the location change, but also the specific requirements in terms of fire safety and evacuation technology. Together with the changes of use within the life of the system, there are several other good reasons why it is important to look for flexibility and modularity when selecting a fire alarm system.

In order to offer installers and customers an alternative to monolithic systems, Bosch first presented a modular fire alarm system in 2005. This has since been consistently further developed. In the case of the FPA-5000, each control panel can accommodate up to 46 functional modules, which can be used to connect LSN elements, signalling devices and display elements or to provide relays or various interfaces.

The modular architecture not only enables installers to configure the system to the client’s specific needs, but also ensures that it can grow with future requirements without forfeiting the capital investment that has already been made. With one fully equipped control panel it is possible to create systems of medium complexity with up to 4000 call points and detectors.

The networking of several control panels is suitable for large-scale application in extensive industrial areas, shopping centres, airports, etc. A network of this type can include a maximum of 32 control panels with up to 32 000 call points and detectors.

Simple expansion by means of networking

In the Serdika Centre, one of Bulgaria’s biggest shopping centres, two control panels were installed and networked together in spite of the fact that there are only 2400 call points and fire detectors. A third control panel of the FPA-5000 series within the same network takes care of fire safety in the adjacent office building, where there are a further 1500 detectors and call points.

This is a good example of decentralised and extensive environments where it may make sense to network several control panels. In this way it is possible to keep short the cable paths from the control panel to peripheral elements, or to separate individual parts of a building logically.

The technical basis of such a network of control centres is formed by the CAN bus (controller area network), which was originally developed by Bosch for the networking of control units in automobiles and was later standardised by ISO. As the CAN bus was developed for critical environmental conditions, it provides a series of data backup mech­anisms which also make it ideal for use as a transmission system in safety technology.

A high degree of system stability is guaranteed when the control panels are networked in a ring. In the event of a cable failure, the system remains functional and the redundancy conditions according to EN54-2 and EN54-13 are satisfied.

Each control centre has two CAN interfaces, so no additional components are required to set up a network. The distance between two control panels in the loop can be up to 1000 metres. It is also possible to network the control centres via fibre-optic cables in conjunction with special CAN/fibre-optic adaptors. In this case, ranges of up to 15 km can be achieved.

Fire protection at Loftus

The modular structure of the control panels and the networking of several control panels enable flexible and extendable system configurations. In the Loftus Versfeld Stadium in Pretoria, one of the Soccer World Cup stadiums in South Africa, the local installers managed to satisfy the requirement for the inclusion of other areas in a second section of the building. Three more control panels are now networked with the first FPA-5000, which had already been installed while the stadium was being built.

It would also be possible, for example, to integrate a new building on a factory site, a university campus or in a clinic into the existing fire alarm system.

Flexibility

Detectors, call points and peripheral elements are connected via an LSN bus, which is supplied with 300 mA or 1500 mA by the respective LSN module in the control panel and hence supports cable lengths of 1600 or 3000 metres. Each of these modules can connect up to 254 elements in loop, branch or T-tap topologies. For example, with these basic conditions up to 100 base-sounders of the Bosch FNS-420 series can be operated.

In addition to the central control unit, the FPA-5000 has a large number of sockets into which the functional modules can be plugged in using hot plugging. This means that cost-intensive wiring errors can be avoided from the outset. It is equally easy to replace a module, which significantly reduces maintenance costs. Furthermore, all the modules are encapsulated and the sensitive electronics are protected even when fitted in rather harsh environment of the building site.

In order to guarantee the greatest flexibility, Bosch offers a large number of different modules for the fire alarm control panels, including display modules, open collector outputs, a notification module, relay modules and an interface module for alerting the fire department. A serial interface for the connection of voice evacuation systems is also available.

Voice alarm

When there is a fire, it is not only necessary to call the fire department, but also to alert everyone in the building and to guide them as systematically as possible to the clear escape routes. So there are ever more frequent demands for a comprehensible voice announcement appropriate to the situation, instead of the acoustic alarm signals which normal citizens can hardly be expected to interpret correctly.

The voice output system is triggered in many cases via contact interfaces, with each contact interface representing a voice announcement for one alarm area. Particularly in the case of larger installations or if different announcements are required for the same alarm area and depending on the situation, this rapidly leads to many parallel inputs and outputs and the corresponding mass of complicated wiring.

For that reason, an RS-232 data interface has been developed specifically for the FPA-5000 and the Bosch Plena VAS voice alarm system. It permits up to 120 inputs of the Plena voice alarm system to be triggered by means of a monitored data protocol. There is no longer any need for complicated wiring or special interface hardware. Together with the Plena VAS, the FPA-5000 forms an integrated fire alarm and evacuation system.

Controls and displays

The system is operated via the control and display unit that is integrated into the control panel, or via remote control units that are integrated into the CAN network just like a panel. The visually attractive remote control units permit the flexible operation of the entire control panel network, and can be either surface- or flush-mounted. They have the same graphic, multilingual and intuitive user interface as the integrated control and display units. It is helpful and useful to have location information and the control measures initiated in the event of an incident graphically displayed in building plans on computers that are specifically set up for the purpose.

Integration into central management system

The BIS (building integration system) centralises the monitoring and control of all the functions in a building that use network connections, including fire and intruder detection systems, video systems (CCTV) and access control. Emergency exits and elevators or escalators can also be controlled by the central system. The FPA-5000 has a standardised Ethernet interface (OPC server) for the purpose of integration into the higher-level BIS risk management system. Overall, the initiation and coordination of measures is carried out extraordinarily efficiently in this way.

In an environment with a central management system, it is also possible for digital sound systems such as the Bosch Praesideo system to assume warning and evacuation functions. For example, at the new airport in Bratislava three networked FPA-5000 fire alarm control panels have been installed, which can communicate with a Praesideo system via the BIS. The latter is primarily used for the announcement of travel information, but also for the systematic evacuation of individual sections of the terminal or of the entire terminal, in the event of an alarm.

As a result of its flexible architecture, the FPA-5000 is suitable for all standard fire alarm applications, from small systems through to very large and complex environments. The system complies with the current standards, EN54-2 and EN54-4 parts 1 and 2. The FPA-5000 also has country-specific certifications and approvals in those cases where they are necessary. The monitoring of transmission paths is carried out according to the current EN54-13 test conditions for short circuits and circuit breaks.

The FPA-5000 modular fire alarm control system has proven effective with its modular structure, and stable in many different applications and environments.

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