Types of fire alarm systems (security and fire alarms). Types of fire alarms: scope of application Types of fire alarm systems
Fire alarms are systems that must be present at every operating facility, be it industrial real estate, a private building or a residential building.
The main task of such systems is the timely identification of fire sources and effective management of fire extinguishing equipment, notification of people and their evacuation. Depending on the type of building and its purpose, they can be used different kinds fire alarm.
Application area
Fire alarm systems have received widespread practical use at various sites. They are installed:
- at industrial enterprises;
- in office centers;
- in educational and medical institutions of various types;
- in shops and warehouses;
- in private houses, cottages and apartments;
- in parking lots and garages.
Fire alarm structure
The basis of fire protection systems is the following key devices:
- an electronic unit or electronic panel that controls the operation of the alarm system, receives and processes the signal from fire detectors, generates and transmits an alarm signal to the fire service control panel and the telephone numbers of the owners of the protected property;
- sensors and detectors that are located in certain areas of the premises in order to detect an increase in temperature, the appearance of smoke, and the occurrence of an open flame;
- actuators and systems that connect to the alarm system and provide the functions of autonomous fire extinguishing, smoke removal, personnel notification and management of the evacuation process;
- power supply system – provides continuous work all equipment.
Main types of fire alarms
Currently in use following types fire alarm:
- threshold devices;
- addressable analogue systems;
- address survey systems.
Difference between types of fire alarms using the example of "Bolid"
- Threshold
This type of system contains special detectors - fire sensors that respond to an increase in temperature, the presence of smoke or fire. They have a certain response level, upon reaching which the sensor transmits a warning signal to the central alarm unit.
The threshold fire alarm system is distinguished by the radial topology of its structure.
Note!
Several “loop-rays” extend from the central electronic unit, which include up to 30 sensors.
When one of them is triggered, the central unit receives information only about the number of the triggered loop, without detailing the exact location where the sensor that transmitted the warning signal is located.
- Targeted survey
This type of system differs from the previous one in the way it receives information from the fire detector. If the threshold alarm is waiting to receive a signal from the triggered sensor, then the address-interrogation alarm is constantly in active state. It periodically sends signals to connected sensors, polling their status.
Thanks to this, it becomes possible to monitor the serviceability of the detectors used. In response to a request central block the sensor gives a signal about its functionality, the presence of a malfunction, the absence of a threat or the presence of a fire. Using addressable alarms, you can receive information about a triggered sensor, thus determining the exact location of the fire. The topology of this signaling has a ring structure.
- Analog addressable
This equipment is more functional than the types of fire alarm systems listed above. Its important difference is that the “decision” about the occurrence of a fire is made not by the detector, but by the control panel.
It uses special algorithms that analyze in detail all the information coming from sensors and, based on the data received, makes a decision about the occurrence of danger in a particular area. Thanks to the use of this type of security device, it is possible to detect a fire at an early stage, which will allow taking measures to extinguish the fire in advance and prevent major damage to the facility.
Conclusion
Thanks to the fact that they exist Various types fire alarm systems, you can select the optimal configuration of equipment that will provide the required level fire safety on the object.
The alarm can be selected according to functionality, and by price category. The cheapest in this regard are threshold systems. True, you shouldn’t save too much on purchasing security devices - it should correspond to the values that exist at the site ( important information, technology, jewelry, securities and financial resources).
The installation of fire alarms in schools is mandatory in accordance with the requirements of 123-FZ. Absence, improper condition or non-compliance with standards is not only an administrative, but also a criminal offense. Taking into account the specifics of operation, special requirements are imposed on fire alarms used in schools:
- high sensitivity of the equipment and comprehensive testing of all factors for identifying the source of fire;
- the control panel must be located in a room with limited access;
- cables connecting the control panel and detectors must be in heat-resistant insulation that does not emit carcinogenic or toxic substances during operation or thermal exposure.
Specifics of the fire alarm system at school
Premises should be equipped with hybrid sensors that monitor several parameters at once, or with several sensors that monitor air composition (the appearance of smoke or carbon dioxide), temperature (threshold value and dynamics of change), presence infrared radiation(radiant energy from an open flame). Detectors must be installed both in the main premises and in technical, utility and basement areas.
Cable networks must be laid in a closed way using grooves or boxes located out of direct reach. This will not only prevent students from damaging cables, but will also allow the system to monitor the situation during a fire, transmitting relevant information.
It is allowed to use only addressable or addressable-analog systems, which can not only detect the very fact of a fire, but also determine its location. At the same time, the use of addressable analogue systems is preferable, since they are more reliable and fully comply with the fire safety requirements for the protection class for schools and preschool educational institutions.
UNITEST development and production systems
- "MINITRONIK A32" for schools from 50 to 5 thousand square meters. m.
- "MINITRONIK A32M" for schools from 50 to 10 thousand square meters. m.
School fire alarm maintenance
The regulations for maintaining fire alarm systems in schools include the following work:
- external inspection to identify possible damage to the housing;
- checking the functioning of detectors, control panel and software in complex;
- if necessary, adjust settings and sensitivity of detectors;
- cleaning of equipment, especially smoke detectors (every 3 months);
- checking the power supply, measuring battery parameters, replacing them if necessary.
The main purpose of the system is a quick and timely response to the initial sources of smoke and gas contamination for the timely transmission of the corresponding signal to the control control devices with automatic activation of local fire extinguishing sensors. Modern requirements are aimed at the need to use fire warning systems. This is due to the purpose of preserving the life and health of workers and preventing damage to property.
For round-the-clock monitoring it is necessary constant provision power supply For central control panels, the source is a permanent network; for point devices, it is necessary to connect secondary low-voltage power devices. For execution regulatory requirements for uninterrupted operation in daily monitoring and in case of emergencies, connection is required within three hours additional food with help backup sources.
Fire detectors
Local devices for detecting focal lesions are detectors. Their characteristics may differ in the nature of the action of the capturing sensor and in the method of transmitting data for central control. They can be of active and passive principles of action. The first ones accumulate the signal at the object. The second ones give an alert about a border violation or a source of smoke.
Classification of fire systems
Fire alarm systems can be classified according to the method of data transmission into the following types.
- threshold - the response of each individual, local device to the central console occurs in parallel at a certain specified sensitivity threshold. Another feature of this system is a specific system of signal paths. The loop controls the operation of 30 notification devices. When a signal is sent from each, only the number of the loop in the control area of which the device was triggered is sent to the remote control.
This system has a low cost and simple operation, which makes it especially attractive. Disadvantages include the lack of information in sending signals from metering devices, the inability to monitor the performance of detectors, late notification of danger, which can lead to the risk of emergency situations;
- addressable – each local device has its own label and manufacturer settings for one or more alert thresholds. This enables location-specific detection of an emergency. Installation required for precise monitoring of danger thresholds large quantity sensors Required amount devices and maintenance are the same as in threshold system;
- addressable-polling - in this system, the control device waits for an alert and periodically sends requests to local sensors about changes in state. The control beams close in a circle. The positive aspects are the good low price and High Quality, maximum control over the operation of sensors. Among the disadvantages, the long detection of an emergency situation stands out;
- addressable analogue is the most popular fire safety system for its functionality. It contains everything positive characteristics previous systems. In addition, the control function is performed not by the local warning device, but by the central console. This is the most complex of all warning systems. The control device maintains continuous communication with detectors, analyzes their condition and independently makes a final decision on how to respond to an emergency situation.
This method of work allows you to identify sources of fire at the inception stage and take measures to eliminate the situation and prevent possible damage.
The advantages of such a system include early detection of emergency situations, low material costs for installation, full control over the operation of local devices. Unfortunately, this system quite expensive, however, you cannot save on the life and health of employees.
Interaction of systems
To perform a full cycle of building security, during installation the system is switched on full cycle work with other systems used for these purposes. For example, when one of the detectors is triggered, the air conditioning and air supply systems must be de-energized, the power supply must be de-energized, smoke detectors must be turned on, exits for a safe, emergency exit from the building must be opened, and a general alarm must be turned on.
Peripherals
Part common system includes peripheral devices, with the exception of local sensors, designed as independent, structural devices and connected to control device or the console via communication lines.
- control device – carries out the general control process using local devices;
- circuit monitoring relay - to ensure the operation of the beams when the wiring is short-circuited;
- connection relay – used in threshold systems;
- relay device – increases the functional set of alerts;
- relay input/output – monitors and controls external connecting systems;
- device for printing messages;
- sound warning relay – gives a sound warning in a specific place of the building;
- light warning relay – gives a light warning at the required point.
Control modules
To provide control functions in the system, devices are divided into the following functions: devices for control, recording of primary information, central devices, stations and metering consoles. All of them carry out the collective function of recording and analyzing primary information. The only difference is the amount of information received.
Types of primary information metering devices
Based on the type of monitoring of physical parameters, sensors are divided into thermal, smoke, light, ionization, combined, and hand-held devices. All of them are designed to control certain characteristics. Each manufacturer provides detectors with individual properties. This must be taken into account when purchasing products.
- thermal - the sensor is triggered as a result of a thermoelectric effect, the beginning of which is the achievement of a certain temperature specified by physical parameters. From negative aspects late response can be noted;
- smoke detector - notifies about smoke in the room. The first sign of fire is smoke. Smoke detector sound notification detects the slightest smoke even without open flames. In residential premises, its use is more effective than a heat detector;
- fire sensors - these detectors are installed mainly in industrial workshops, where the use of smoke detectors and heat detectors is impossible due to the nature of the work performed production work. For different processes use ultraviolet and ultrasonic sensors.
For efficient work devices require qualified installation of equipment by specialists. In this case, the following basic rules must be observed. Detectors should be installed on the ceiling or, in extreme cases, at the highest point of the wall, on columns no further than thirty centimeters from the ceiling.
It is recommended to combine no more than five detectors per loop for industrial workshops, and no more than ten for office and residential premises. When using an addressable system, the number of detectors can be doubled.
IN office premises the distance from the top point of the racks to the local metering device must be at least 60 cm. The physical parameters of the detector must correspond to the area of the protected premises; exceeding is unacceptable. In this case, additional devices should be installed.
Price should not play a major role when choosing a fire alarm system. According to the specified parameters of the protected area, installation, operation, maintenance Qualified specialists will help you choose a system and assist you in choosing a system.
Not everyone pays attention to the small devices that are hidden on the ceilings of rooms. This is natural, because, seeing something everywhere, the brain simply stops perceiving this something as unusual phenomenon. Moreover, we must also take into account the fact that any such devices are made with the expectation of maximum mimicry with the surface on which they are attached. Such a complex explanation was required by an ordinary fire alarm, the importance of which should not be underestimated.
Fire detector design
Even if you paid attention to the various sensors, this still does not mean anything. The fact is that such catchers are just a control system, so to speak, external sense organs that serve the entire system.
They can react to a wide variety of stimuli, and therefore, if we discuss the types of fire alarms, it is impossible not to touch upon this topic.
The detector, which is the one that is proudly called an alarm system, consists of many parts, where sensors are only outer part designs. So, for example, in addition to catchers that respond to various factors fire (smoke, temperature, open fire etc.), it may also be the whole system signal recognition, with other components, as well as an automatic extinguishing mechanism, etc.
Types and connections
The classification of such devices is quite wide. This is mainly due to the fact that they are used everywhere. It makes sense that different types are used for each class of premises.
However, list the main types fire communications and signaling is quite difficult, simply because these mechanisms are classified very differently. The device is quite complex, and technical solutions There’s also a lot, so let’s go through the main types.
Type of transmitted signal
Actually, the signal transmission system from the alarm to other elements is a mandatory part of the design, regardless of the type. Indeed, if the sensor detects a fire, but no signal is received, 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 there are the necessary conditions. But these types of fire alarms are no longer used.
- The most common are dual-mode. The point here is that when the detectors do not detect 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 through, then the sensor is broken and must be replaced.
- Multi-mode models are “tailored” specifically for large buildings. After all, the inspector will not walk along kilometer-long corridors just to check why the catcher is not transmitting. This type of system is the main one at school. Security requirements there are high, and they can only be ensured in this way.
- Analog are the most advanced. They react not to critical changes, but to any change in the monitored indicators.
Signal transmission
This characteristic can also distinguish types of fire alarms from each other. The transfer can be:
- wired, using cables;
- wireless, where they use a radio signal, or even just a Wi-Fi network.
- Models with threshold detection begin transmission only at the moment when temperature, smoke, or some other characteristic crosses an acceptable threshold;
- Differential detectors focus on every parameter change. So you will be notified whenever the value increases or decreases;
- Combined systems work by detecting critical changes but monitoring all others at the same time.
Number of sensors - localization rules
The salt is that for the premises different sizes Fire alarm types will vary.
According to this parameter, all fire detectors will be classified as follows:
- Point models are a single sensor that is most often attached directly to the detector to save space and ease of use. You can see just such functionality in almost every apartment.
- Multipoint models are many sensors that are hidden in one specific location. That is, if point devices respond to one specific parameter, then these devices can monitor a whole galaxy of them at once.
- Linear ones, in turn, are interesting because they monitor a whole range of devices. That is, an arbitrary line is drawn from the detector, along which, for example, emitters and photocells are installed. The latter allows you to monitor the level of smoke in the room. Such systems, as in the example given, are called paired, but they can also be single.
Sensor type
The classification of traps is precisely the factor by which the working area of the alarm is determined. Despite the importance of the previous points, the choice is most often made based on the quality of the sensors. There is no escape from this.
For example, the type and type of fire alarm in a school can vary greatly. But what kind of catchers will be installed is determined by the law on fire safety of institutions.
Heat traps
This is the most old type, since they were used one hundred and fifty to 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 alarms, photos of which are available in the article presented to readers, can be seen in any building of the last century.
The problem here is quite obvious - the air temperature rises only when the fire has flared up.
That is, there is something wrong with the speed of response. Last century became the heyday of such sensors, they were installed everywhere. At the moment, they are gradually being replaced by other species.
Smoke eliminators
If we talk about such specific things as species, it would be blasphemy not to remember smoke detectors. After all, it is they who today occupy a leading position in this market, which is special in every sense.
Smoke is one of the main signs of fire. Interestingly, it appears first in most cases. Often you can even observe smoke for quite a long time until a flame appears - for example, when wiring is smoldering. So, the advantages over the previous type are obvious. The fire is monitored even at the embryonic stage, and therefore this allows preventive measures to be taken.
Everything works based on air transparency, but smoke levels can be determined by different principles. Linear models They use a directed beam of different ranges in their work - a reflective or photocell is also required for operation, which will react to the beam.
When there is no reaction, it means that transparency is broken and the sensor will work.
If the first type uses optical and ultraviolet wavelengths, then the second, point type, works based on infrared radiation.
Such waves simply should not return to the catcher in normal conditions. If the signal is reflected back, this indicates the presence of foreign substances in the air.
Point sensors cost less than linear ones, but the latter are, accordingly, more reliable. So you still have to choose.
Flame sensors
This type is common for production premises, workshops, etc. That is, you can only work with a flame, since the air is dusty and the temperature is a priori increased.
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 works with heat traps. You can also use electromagnetic sensors - they will react precisely to this component of the flame, thus avoiding false alarms.
Signaling
The fire can also be tracked using conventional ultrasonic security system apartments.
The point here is the principle on which the device operates. In this case, this is the movement of air masses.
The alarm will respond not only to an intruder who moves air while moving, but also to open flame. The latter will certainly lift a whole layer of heated air upward, which will trigger the device.
However, you should not rely on such a system, since it is not designed to track fires.
The task of fire alarms is to timely detect the location of a fire and generate special control signals for fire warning systems with subsequent automatic fire extinguishing.
Purpose of fire alarm
Fire alarms are provided by various technical means. Detectors are used to detect fire, and control equipment and peripheral devices are used to process, record information and create control signals.
In addition to the above main functions, the fire alarm must create commands to turn on/off automatic installations for fire extinguishing and smoke removal, fire warning systems, as well as engineering equipment of objects. Modern fire alarm equipment has its own developed warning function.
Structure of security and fire alarm systems
There are several main categories of fire alarm equipment:
Centralized control of fire alarms (in small systems, centralized control tasks are performed by the control panel);
Equipment for collecting and processing information from fire alarm sensors:
Devices - fire alarm sensors and detectors.
Power supply for fire alarm devices
All fire alarm devices require uninterrupted 24-hour power supply. As a rule, the main power supply is used for fire alarm control panels; the remaining devices are powered from low-voltage secondary sources direct current. Taking into account modern domestic fire safety standards, fire alarms are required to function uninterruptedly in the event of a loss of mains power supply at the facility for 24 hours in standby mode and at least 3 hours in alarm mode. To meet these requirements, the fire alarm system must use a backup power supply system - additional sources or built-in batteries.
Fire detectors
To receive a signal about an alarming situation at a facility, the security and fire alarm system includes detectors that differ from each other in the type of controlled physical parameter, the operating principle of the sensitive element, and the method of transmitting information to the central alarm control panel.
Based on the principle of generating an information signal about intrusion into an object or a fire, fire alarm detectors are divided into active and passive.
Active fire and security alarm detectors generate a signal in the protected area and respond to changes in its parameters.
Passive detectors respond to changes in parameters environment caused by intruder intrusion or fire.
Each security and fire alarm uses security and fire detectors that monitor various physical parameters. The following types of security detectors are widely used: passive infrared, magnetic contact, glass break detectors, perimeter active detectors, combined active detectors. Fire alarm systems use heat, smoke, light, ionization, combined and manual call points.
Types of Fire Alarms
Currently, there are several main types of fire alarm systems:
1. Threshold
In such a system, each fire detector (sensor) has a built-in response threshold. For example, if we are talking about heat detector, then when a certain ambient temperature is reached, such a sensor will send a corresponding signal to the fire alarm control panel, but until the temperature reaches this threshold, the detector will be silent.
Second distinctive feature of such systems is a radial topology for constructing signaling loops. Those. from the control panel to different sides There are cables of fire trails, they are often called beams. Each such beam usually includes about 20-30 sensors, and when one of them is triggered, the control panel displays only the number of the loop (beam) in which the fire detector was triggered.
Advantages:
Low equipment cost
Flaws:
There is no way to monitor the performance of detectors
Relatively low information content of received signals from sensors
2. Addressed survey
An addressable interrogation fire alarm system differs from a threshold fire alarm system in the principle of communication between the control panel and the fire detector. The control panel in the threshold system “awaits” a signal from the fire detector about a change in its state, and in the address-poll system the control panel periodically “interrogates” the connected fire detectors in order to find out their status.
Also, this algorithm of fire alarm operation allows you to determine the state of the sensors. Types of signals received from the sensor: “Normal”, “Fault”, “Absence”, “Fire”. The fire plume has a ring architecture.
Advantages:
Favorable price/quality ratio
High information content of received messages
Flaws:
Late detection of fire
3. Analog addressable
These fire alarm systems are currently the most functional. They have all the advantages of the above systems and a number of their own advantages. The main difference between addressable analogue systems is that the decision about the state of the facility is made by the control panel, not the sensor. The control panel in this fire alarm system is a complex device that makes continuous dynamic communication with connected sensors, receives and analyzes the values obtained from them and makes a final decision based on the results of processing this data.
For example, heat sensors constantly transmit the value of the ambient temperature to the control panel, and the panel itself monitors the value of this value and the dynamics of its change.
This type of fire alarm system makes it possible to detect fires at the most early stages its development and prevent possible damage in a timely manner.
Advantages:
Truly early fire detection
Savings on installation work and consumables
Monitoring the performance of fire detectors
Sensor sensitivity compensation
Flaws:
High cost of equipment
Fire alarm integration with complex systems building safety.
When installed, the fire alarm system is integrated with other security systems of the facility. This is important for a quick response to a fire message or signal received from fire alarm sensors, as well as to ensure favorable conditions to eliminate the emergency situation that has arisen.
For example, in response to a fire message, the following actions may be performed in the alarm zone:
The ventilation is turned off,
The smoke removal system is turned on,
The power supply is turned off (except for special equipment),
Turns on emergency lighting and light indication of paths and exits for evacuation of people,
Emergency exits for evacuation are opened,
The warning system is turned on with information for the alarm zone.
Thus, a fire alarm is integral part overall security system, while issues of interaction of all subsystems are resolved.
Fire Alarm Peripherals
Peripheral devices are the fire alarm system devices (except for detectors), which have an independent design and are connected to the fire alarm control panel via external communication lines.
The following are the most commonly used types of fire alarm peripherals:
Control panel - used to control fire alarm devices;
Short circuit isolation module - used in fire alarm ring loops to ensure their functionality in the event of a short circuit;
Non-address line connection module - for monitoring non-address fire alarm detectors;
Relay module - to expand the warning and control functions of the control panel;
Input/output module - for monitoring and control external devices(For example, automatic installations fire extinguishing and smoke removal, technological, electrical and other engineering equipment);
Sound alarm - to notify about a fire or alarm at the required point of the object using an audio alarm;
Light signaling device - to notify about a fire or alarm at the required point of the object using a light alarm;
Message printer - for printing alarm and service system messages.
Reception and control equipment
Reception and control equipment is used to receive and process alarm signals.
Types of control and control equipment:
Central stations,
Control panels,
Reception and control devices.
The main difference between them is information capacity. There are also fire alarm control panels for small, medium and large objects.
Sensors (Detectors)
Sensors are used to signal an alarm situation at a facility. The sensors differ in their principle of operation, the type of parameters being monitored, and the method of transmitting information to the fire alarm control panel.
Fire alarm systems use:
Thermal,
Smoke,
Light,
Ionization,
Combined,
Manual call points.
Each type of detector has its own list of basic technical characteristics, defined by the relevant standards. At the same time, even sensors of the same type differ in design features components, ease of use, reliability, which also needs to be taken into account when choosing a particular device or manufacturer.