Types of Fire Alarm Systems


There are two main types of fire alarm systems: conventional and addressable.

Conventional fire alarm systems – cable line out of the control panel and ending with a final (end of line) component, usually a resistor. Detectors and manual call points are connected along the cable line. Organized in this way lines are called conventional areas (conventional zones).

Addressable fire alarm systems – cable line, which connects various devices, start from the control panel and return to him. Lines of addressable systems are called circles or loops (optics loops). These lines allow full identification of each circuit device mounted on an individual address that it owns, which is the principal advantage of these systems.

Advantages of addressable compared to conventional fire alarm systems:

– Allows accurate tracking and positioning of fire due to individual address of the activated device;

– The movement of information is two-way – from the control panel to the alarm / signaling devices and vice versa. Among other benefits, such as continuously monitoring of the device status, this structure keeps working capability in the event of cable failure, unlike conventional systems;

– Allows reducing the length of cables needed to build a system using smaller and optimal length of the cord, unlike conventional systems;

– Store information about the state of addressable devices and events occurring in the system;

– Allow building pads to the group, which may be used in conventional devices – that is addressable by the application of additional modules and both cables are saved.

The fire alarm systems, allowing you to get much larger amounts of information from fire alarm devices, are called intelligent. They are a special type of addressable systems in which the values of the devices are processed by a microprocessor control panel in accordance with the algorithms set out therein, which helps to significantly reduce false bedding. The values of analog detectors can be: normal, necessary maintenance, damage, pre-alarm, alarm, etc.. Intelligent systems have the possibility of simultaneous and continuous processing of multiple signals, taking into account the maximum number of signal characteristics (energy, amplitude, speed change, etc.).

An important method for facilitating location of fire and evacuation of people in the building is zoning. It consists in grouping of devices in the lines (conventional or addressable) within certain areas and allows the separation of the site to an appropriate number of sub-zones. Zones must be divided into separate fire compartments (parts of the building with limited fire resistant structures) for the purpose of evacuation. In dividing the site over a number of areas, the fire is detected more quickly and easily. Activation of a zone in the system can be indicated at the control panel and by light signals via LED indicators. Factors such as floors, escape routes, stairway etc. must be taken into consideration in the process of zone configuration.

In conventional systems, activation of one unit of the zone gives an indication on the control panel to activate the whole zone, without indicating the exact place / device. Therefore, in this type of system is recommended handheld detectors and automatic detectors to be arranged in separate areas. Usually in these systems the scope of the area match the number of installed devices in one line. It is not recommended to install more than 32 devices on one zone – restrictions on the maximum protected area and thus the failure of one or more detectors does not affect significantly the performance of the entire system.

Source by Kiril Petrov