Types of fire alarm and communication. Type and type of fire alarm in the school

Not everyone is paying attention to the small devices that are hiding on the ceilings of the premises. This is natural, because seeing something everywhere and everywhere, the brain simply ceases to perceive this something as an unusual phenomenon. Moreover, one must also take into account the fact that any such devices are made with the expectation of maximum mimicry with a surface on which they are fixed. Such a complicated explanation was demanded by the ordinary fire alarm, the importance of which should not be underestimated.

Design of the fire detector

Even if you paid attention to different sensors, it does not mean anything. The fact is that such catchers are just a system of control, so to say, external senses that serve the entire system. They can react to a variety of irritants, and therefore, if we discuss the types of fire alarms, do not touch on this topic can not.

The detector, which is the same warning system that is proudly called an alarm system, consists of many parts where the sensors are only the outer part of the structure. So, for example, in addition to catchers reacting to different fire factors (smoke, temperature, open fire, etc.), it can be still a whole system of signal recognition, communication nodes with other components, as well as an automatic fire-fighting mechanism, E.

Types of fire alarm and communication

The classification of such devices is quite wide. This is mainly due to the fact that they are used everywhere. It is reasonable that different types are used for each class of premises.

However, it is rather difficult to list the main types of fire communication and signaling, simply because they classify these mechanisms very differently. The device is quite complex, and there are also a lot of technical solutions, so we will go through the main types.

Type of transmitted signal

Actually, the system of signal transmission from signaling to other elements is an obligatory part of the design, regardless of the type. Indeed, if the sensor captures a fire, but the signal does not arrive, there is no point in such a device at all. But the mechanism of action can be of four main types:

• Single mode, which only signals a fire as such. That is, the sensors are turned on only if the necessary conditions arise. But such types of fire alarm are no longer applied.
• The most common are dual-mode. The point here is that when the detectors do not fix a dangerous situation, they transmit a signal that everything is in order. This indicates that the system is functioning normally. If the signal does not pass, the sensor is broken, and it must be replaced.
• Multi-mode models are "sharpened" specially for large buildings. After all, the examiner will not walk along the kilometer corridors just to check why the trap does not transmit. Such a system is the main type of fire alarm in the school. Security requirements are high there, and they can only be provided in this way.
• Analog - the most advanced. They react not to the critical, but to any change in the monitored indicators.

Signal transmission

This characteristic can also differentiate the types of fire alarm from each other. The transfer can be:

• Wire, using cables;
• Wireless, where you use a radio signal, or even just a Wi-Fi network.

Further, too, there is a classification of signal transmission, but here it is more about the parameters of the information itself:

• Models with threshold detection start transmitting only at a time when temperature, smoke, or some other characteristic passes the permissible threshold;
• Differential detectors emphasize every change in parameters. So you will receive a notification at any increase or decrease in the value;
• Combined systems work by identifying critical changes, but tracking all others at the same time.

Number of sensors - localization rules

Salt is that for rooms of different sizes, the types of fire alarm will be different. For this parameter, all fire detectors will be classified in this way:

• Point models are one sensor that is most often attached directly to the detector to save space and ease of use. Just such a functional you can see in almost every apartment.
• Multipoint models are a set of sensors that hide in one particular place. That is, if point devices respond to any one particular parameter, then these devices can track a whole pleiad immediately.
• Linear, in turn, are interesting in that they track a number of devices. That is, an arbitrary line is drawn from the detector, during which, for example, radiators and photocells are put. The latter allows you to monitor the smoke level of the room. Such systems, as in the example above, are called paired, but they can also be single.

Type of sensors

The classification of catchers is precisely the factor by which the signaling working area is determined. Despite the importance of the previous items, the choice is most often made on the basis of the quality of the sensors. From this can not escape.

For example, the type and type of fire alarm in the school can be very different. But what kind of catchers will be installed determines the law on fire safety of institutions.

Heat traps

This is the oldest type, because they used them a hundred and fifty-two hundred years ago. Today, their design is a conventional thermocouple, which, in turn, begins to work, that is, conduct current, only at a certain air temperature. These types of fire alarm, photos of which are available in the article submitted to the readers, can be seen in any building of the last century.

The problem here is pretty obvious - the air temperature rises only when the fire flared up. That is, with the speed of reaction there are disagreements. The last century became the bloom of such sensors, they were put everywhere. At the same time, they are gradually replaced by other species.

Smoke Detectors

If we talk about such specific things as the types of automatic fire alarm systems, then it would be sacrilege not to recall the smoke detectors. After all, they are today occupy a leading position in this special in all senses market.

Smoke is one of the main signs of the appearance of fire. Interestingly, he appears first in most cases. Often, it is even possible to observe the smoke for quite some time, until a flame appears - for example, when the wiring is smoldering. So, the advantages over the previous type are obvious. The fire is being tracked at the embryonic stage, and therefore it allows taking preventive measures.

Everything works on the transparency of the air, but it is possible to determine the smokeiness according to different principles. Linear models use a directed beam of different ranges in operation - a reflective or photoelectric cell is also required for operation, which will react to the beam hit. When there is no reaction, then the transparency is broken, the sensor will work.

If the first type uses the optical and ultraviolet range of waves, then in the second, point, the work is based on infrared radiation. Such waves simply should not return to the trap under normal conditions. If the signal is reflected back, it means the presence of foreign matter in the air.

Point sensors are less linear, but the latter, respectively, are more reliable. So you still have to choose.

Flame sensors

This kind is common for industrial premises, workshops, etc. That is, you can work only with a flame, as the air is dusty, and the temperature is a priori increased.

The flame sensors can be infrared or ultraviolet - these are the two main types. Thus, the device reacts to the heat generated, but immediately, and not when it heats the air, as it does with the heat traps. You can also use electromagnetic sensors - they will react to this component of the flame, thus avoiding false positives.

Signaling

The fire can be tracked also due to the usual ultrasonic security system of the apartment. The bottom line here is on what principle the device works. In this case, this is the movement of air masses.

The alarm will respond not only to the intruder, who moves the air while moving, but also to an open flame. The latter necessarily lifts a whole layer of heated air up, which will trigger the device.

However, you should not rely on such a system, because it is not designed to track fires.