Automatic fire alarm: Alarm area - Concept and Application in design and construction!

In the usual industrial and civil buildings, the alarm area is a virtual area defined according to the linkage function, which is mainly used in linkage programming and does not assume the function of indicating the alarm part.

The alarm area set up for the convenience of programming and debugging must be subdivided, and there is a cross-overlap phenomenon, and the same detector may belong to a number of different alarm areas.

The alarm area is the basic element of the alarm linkage control, and the design document should clarify and refine the division requirements of the alarm area, so that the subsequent construction debugging can be correctly implemented. However, in many practical design documents, there is a misunderstanding of the alarm area, which brings confusion to the construction debugging. In the end, the construction personnel have to undertake the work of the designer, temporarily define the alarm area on the site, and reluctantly deal with the linkage relationship. The construction personnel's understanding of the design specifications and building functions is limited.

According to the requirements of the code, the alarm area is the alarm scope of the automatic Fire Alarm system according to the fire zone or floor division of the unit, according to the intent of the code, the purpose of dividing the alarm area is to quickly determine the alarm and fire location, while solving the fire linkage design problem. However, in practical applications, the fire alarm host may not show the alarm area where the fire alarm is located, the alarm area is only a virtual partition set for convenient programming and debugging, and to adapt to the functional needs of the building, the alarm area may need to be subdivided on the basis of the fire zone or floor, there may be cross-overlap, and will not be limited to the fire zone or floor as a unit. Specific instructions are as follows:

First, in practical application, the alarm area is a virtual area defined for the convenience of programming and debugging, when the fire occurs, the alarm area name of the fire usually does not appear on the alarm host, and many manufacturers' fire alarm hosts do not support the function of displaying the alarm area:

1, the modern building function is complex, a fire zone thousands of square, or even tens of thousands of square meters, fire zone or floor as a unit to indicate the alarm area, has no substantive significance.

2. The current fire alarm host has rich functions and can provide detailed description of the alarm points. The personnel on duty can quickly grasp the location of the fire alarm according to the alarm prompt, and there is no need to divide the alarm area.

3, many manufacturers of fire alarm host, also do not support a separate alarm area display function.

Second, the alarm area is of great significance in programming and debugging, but it is no longer limited to the fire zone or floor as a unit, it needs to be divided according to functional requirements, and there is a phenomenon of overlapping of different alarm areas:

1, for a single function, and each floor (or each fire zone) building area is not large building, the alarm linkage relationship is simple, you can divide the fire zone or floor alarm area.

2, for the building function is relatively complex, and the floor or fire protection zone is large, it may be necessary to subdivide on the basis of fire protection zone or floor.

Example 1: A fire protection zone includes office, archive room and computer room, respectively equipped with automatic sprinkler system, water mist fire extinguishing system and gas fire extinguishing system, these systems are basically independent, alarm linkage should be divided into their respective areas as units, must be divided into different alarm areas. Moreover, each protection area of the gas fire extinguishing and water mist system should also be classified as an independent alarm area to facilitate the handling of the related linkage.

Example 2: The functions of some commercial areas are complex, the same fire zone may have catering, entertainment, supermarkets, commercial shops and affiliated offices and other functions, there may be automatic water spraying, automatic cannon, water curtain, fire roller curtain, smoke control and other types of fire facilities, but also need to divide alarm areas according to the functions of each region. For example, the smoke exhaust system needs to prevent the smoke zone from dividing the alarm area, and the fire roller shutter may be divided into the alarm area by the fire zone, which overlaps with each other, and so on.

Third, the alarm area set up for the convenience of programming and debugging is inevitably subdivided, and there is a cross-overlap phenomenon, the same detector may belong to a number of different alarm areas:

The alarm area serving the programming and debugging must be subdivided, such as each protection area of gas fire suppression and water mist, each smoke protection area of the mechanical smoke exhaust system, etc., should be defined as their own independent alarm area.

In the gas fire extinguishing and water mist system of Example 1, each protected area can be used as an alarm area, and the linkage signal corresponding to the protected area (zone control valve, zone starting device, etc.) can be connected. In fact, the computer room, archive room, office and other public areas of this example, its fire zone is also an alarm area, related to the linkage signal of this fire zone (fire roller curtain, mechanical pressure air supply system, etc.), therefore, for the convenience of programming and debugging set up alarm area, must be subdivided, there must be cross-overlap.

The linkage in example 2 May be more complex, the detector in a certain area may belong to a smoke protection zone alarm area, but also belong to an automatic gun alarm area, and so on.

4. Reasonable definition and division of the alarm area will greatly facilitate programming and debugging work:

The alarm area as a unit to define the logical relationship, will be greatly convenient programming and debugging, for example, a computer room or a shopping mall due to local adjustment need to increase the detector, system debugging, as long as the increase of the detector into the alarm area can be automatically established, eliminating the complicated programming work, greatly reduce the occurrence of errors and omissions.

Note: At present, there are still some manufacturers do not support the function of defining the logical relationship through the alarm area, and changing a detector requires rewriting the related linkage formula.

Note: For fire fighting equipment requiring linkage control of automatic fire alarm system, the linkage trigger signal should adopt the "and" logical combination of two independent alarm trigger device alarm signals. These two independent alarm signals should belong to the same alarm area signal, the two signals of different alarm areas, should not be used as a condition for confirming the fire alarm signal, which is also the important significance of the division of the alarm area, can solve many contradictions in practical applications, greatly reduce system misoperation! For example, the rain valve linkage of the rain shower system should use the "and" logical combination of two independent alarm trigger device alarm signals, which should belong to the rain valve group protection area, but also belong to the same alarm area.

It should be noted that the above is mainly for conventional civil buildings and industrial buildings, for the special buildings described in the code, such as tunnels, storage tanks, train cars, etc., the division of the alarm area should still be handled according to the relevant code requirements and in combination with this article!