Worldwide there are many country-specific standards and regulations for security technology, all of which must be taken into consideration when planning and designing a fire alarm system. Even the European Standard EN 54 did not bring the desired improvements. The situation is made even more complex by the numerous local regulations and cultural differences in many countries with respect to fire alarm systems. This is the main reason why there are so many different types of fire panels. A further important reason is the high variation per project of the quantities of detectors, sounders and interfaces connected to fire panel.

In most cases each type of fire panel has specific, different installation and operation requirements. This results in high-cost, time-consuming training for installation, maintenance and operating personnel, as well as the cost of spare part storage. Further costs would occur if statutory regulations change or if the existing fire panel has to be removed due to expansion of the system or building.

Input from installers and users was essential in defining the design criteria, chiefly based on customer benefits. They include the following, aimed at finding a common denominator for all the different requirements a new fire panel should meet.

• The panel must be easily expandable
• It must meet country-specific standards and guidelines
• The user only needs to buy the components actually required
• The system must be able to be operated easily and intuitively
• Low training outlay, or none at all
• No need to store spare parts
• Inexpensive installation and initial set-up
• Rigid and reliable in installation and operation

Using the given criteria Bosch decided to design a fire panel based on the building block principle. This consists of individual modules, such as housings, network equipment and power supplies, which can be easily combined as necessary. Carrier units, using a common bus system, enable connections that facilitate communication and route power between the modules. Every module is a logical functional unit. Bosch designed versions of the modules according to different country's standards and regulations and customized for specific country's markets.

In the past, manufacturers of fire alarm systems provided a basic, specific level of equipment, which the customer could expand by purchasing optional functional components. Expansion in this way was not an easy task. For example, vulnerable PC boards could be easily damaged through static discharge or incorrect handling. This is resolved in the new design where the functional units consist of completely encapsulated modules which connect to panel rails on the 'click and go' principle.

Modules are encased in plastic housings that make them suitable for use on building sites. PC boards are protected from touch and static discharge. The pre-wired panel rails prevent errors in the internal power supply and communication data bus.

An installer can choose modules according to a wide range of requirements. Based on the 'click and go' principle, connection is straightforward and fast since every module slot is identical and any combination of modules is possible.

The terminal blocks also make it easy to replace or add modules at a later date. They can be simply removed or replaced since there are no leads to be disconnected. Building up fire panels in this way means that each one is unique but can be adapted flexibly to changing needs.

As in a personal computer, the 'plug-and-play' principle allows fire panel modules and the components attached to them to be automatically recognized by the central control unit. This means there is no need to perform a costly and time-consuming test of the entire system. The system can be programmed using a Windows-based software program with a Windows interface. The program offers on-line assistance to users if they have questions, and print out of required data. The system offers the advantage of a built-in diagnostic tool that displays any faults in detail. Because modules are 'hot swappable' it is possible to expand the fire alarm system at a later date without powering down operation.

The most important component is the Local Security Network (LSN) module. With LSN a single two-wire line routes both power and communication between the connected devices. If an element fails due to cable breakage or a short circuit the faulty loop section is isolated and the loop structure is converted to a two-stub configuration. Loop modules with 300mA and 1500mA are offered with the 5000 Series Modular Fire Panel. This means that a large number of alarm sounders can be connected via the two-wire line, with no need for expensive E30 (fire-resistant) wiring.

Bosch developed a user-friendly interface for the new modules in collaboration with software ergonomics experts from the Eidgenössische Technische Hochschule (ETH) Zürich (Federal Technical High School of Zurich.) The interface allows safety personnel to navigate through the software quickly and effectively if a fault or alarm occurs. The user can manually select the required menu on a functionally designed control panel with a built-in touch screen. A clear program interface display and intuitive, easy-to-follow menu navigation make for easy operation.

All major functions such as diagnosis options and complete call-up of all incoming messages and events are built into the system. The software also allows the user to sort the connected elements into different groups in a number of different ways. This means that functions can quickly and easily be assigned to entire element groups without having to call up each element individually.

There is virtually no limit to how far the modular system can be expanded. Stand-alone fire alarm control panels can be generated from a single loop with up to 254 elements up to a maximum of 32 loops with a total of 4096 elements. Larger fire alarm systems are designed by networking stand-alone fire alarm control panels.

Since the modular fire panels can be customized to suit customers' needs, they only pay for what is actually required.

The modules and the operating unit with touch screen are now extensively used in fire alarm systems of many types and sizes. Experience in installing modules according to the 'click and go' principle and use of an easy-to-understand operating unit menu help installers to handle larger fire panels without problems. This reduces training costs to a minimum.

Since building blocks are interchangeable they serve as spare parts for all fire panels, meaning that it is no longer necessary to keep a separate stock of spare parts.

Bosch's modular fire panel concept allows fire alarm systems to be used in a wide range of applications, regardless of size or structure. The new design means that the number of different panels and components can be kept to a minimum while also allowing modules to be easy to combine with each other and expand. The building block principle allows lower procurement, installation, storage, training and expansion time and costs.