Wiring diagram installation of a fire alarm. Fire alarm: connection diagram, installation, principle of operation

At the moment, security and fire alarms have become quite common, which increase the level of protection of various objects. Thanks to its "many-sided" functionality and component composition, not only a fire is detected in a timely manner, but also a thorough control over the protected area is carried out. Such a device is quite complicated and expensive to install and maintain, but you will not find an electronic device that is so reliable.

How does a fire alarm system work?

A fire protection system is a whole "set" of various technical devices that ensure the fire safety of various types of buildings, equipment, people, and material assets. It includes two systems: alerts for people in the building and a fire alarm.

Due to the fact that the software and hardware dispatcher was installed, you will always see the source of ignition on the site plan. If the semi-automatic mode was set on the alarm, then after an alarm signal is received from it, the security service must turn on the fire warning system for personnel and at the same time activate visual, voice, and voice messages.

When the fire alarm in the building is confirmed, the main signal will be transmitted to the ACS - the "message" system and thereby bring all the alarm elements into the emergency evacuation mode. Also, the signal will be sent to the control system of various engineering networks of the building, after which they will switch to the fire hazard operation mode.

The automatic fire device performs the following functions:

• Identification of the fire zone;
• Detection of the focus after 2-time confirmation from the moment of registration;
• Control of network failures for short circuits, as well as breakage with reference to the building plan;
• Detection of the focus at the initial stage;
• Management of different blocks with displaying the results obtained on the dispatcher workstation;
• Viewing the fire-prevention status of building areas on a detailed as well as a general plan, which are displayed on the dispatcher's console in text and graphic format.

Features of design and calculation

The design of the fire alarm system is the main stage on which the effective operation of the entire system depends. Such work should be done by professionals, since this is a complex scheme with a number of calculations, a significant number of devices and their location. However, since they are all interconnected by a loop, it is therefore necessary to design the trajectory of further laying. In addition, it is necessary to take into account the possible nuances that are being developed in the project to eliminate emerging threats.

However, the development of an FEA project is a subjective process, since each object must be carefully studied taking into account the characteristics of use, as well as plans. And you need to evaluate:

• The complexity of the design;
• The size of the rooms;
• Planning specifics.

Attention should also be paid to places with the most likely outbreak. The design of the fire protection system is carried out taking into account the PUE, as well as DSTU. The project includes a huge number of different works:

• Terms of reference, which takes into account all the wishes of the client;
• Study of premises;
• Creation of a standard project with all estimated estimates for the work performed;
• After agreeing on all the nuances with the client, all documents and estimates are signed;
• Installing and testing the operation of the OPS.

In the process of preparing for the installation of an alarm system, it is necessary to carry out a lot of calculations, thanks to which you can choose the most ideal type of device and at the same time avoid additional costs, for example, with the maintenance of detectors or the installation of the system itself.

The most important stage of calculations is to determine the ideal capacity for the energy source itself. In other words, it is necessary to decide which type of power supply is most suitable for connecting the detectors. Not only batteries, but also ordinary batteries can act as a source.

The required source capacity is usually indicated in the fire alarm operating instructions themselves. Therefore, it is necessary to check the value on the battery case with the available information in the instructions. If the power capacity is not enough, then buy a more powerful device. If you are connecting several batteries, then you need to make sure that they have the same voltage.

Also, specify the required wire cross-section for the OPS and pay attention to the characteristics of the battery capacity for different operating modes (alarms, standby). Next, you need to summarize these values, after which you will get the total battery capacity of your particular OPS.

Types of systems

To date, there are a huge number of different fire alarms of various levels of complexity. However, they all perform the same function - they control the protected object with the help of detectors. Most modern fire systems can transmit a signal to the main security console at a distance and even perform many other service functions. But their main task is the timely detection of fire on the territory of the facility or illegal entry. Depending on the method of determining the fire threat, systems can be divided into the following types:

• Non-address. Conventional sensors (manual, thermal, as well as smoke) are connected to the receiving and control devices, which display only the number of their loop. At the same time, they do not transmit the address of the room, as well as the number, to the main panel.
• The address system works according to the following principle - the control panel receives data from the detectors, due to which the exact area of ​​the fire is determined.
• Addressable analog signaling is a very efficient and reliable device, since the received information is sent to the main panel, and then it is analyzed by the main processor. To give an alarm or not, the software package decides, and not a specific detector.
• The threshold system with radial loops is the most budgetary, however, its installation will be expensive. At the same time, this type of alarm can often give false alarms, so it will be necessary to duplicate the detectors, which will lead to an increase in costs.
• The modular threshold system is more advanced, since you can track any malfunction on the PC, which means that you can immediately take the necessary measures and troubleshoot. The disadvantage is the high price.

The main types of sensors

Fire detectors or sensors are special devices that allow you to record certain properties of fire ignition with its initial detection and further prevention. Also, sensors are the main element of the entire alarm system, providing fire safety. The reliability of the detector determines, in general, the effective operation of the system, and they are divided into such types as:

Heat detectors

They react to changes in air temperature and can be divided into:

Use a heat detector only if heat is the main symptom of a fire.

Smoke detectors

They help detect the presence of smoke in the air, and they work on the principle of scattering infrared radiation on smoke particles. The disadvantage of smoke sensors is that they are able to operate even with a significant amount of dust and steam in the room. But meanwhile they are very popular, although smoke detectors are not used in smoking rooms or heavily dusty rooms.

Flame detectors

They work only from an open flame or a smoldering hearth. They are installed mainly in rooms where fire is possible without the initial release of smoke. They are also able to detect a fire in the initial stages, that is, in the absence of most factors, such as temperature changes and smoke. Flame detectors are used in industrial premises characterized by significant heat exchange and dust content.

Gas leak detector

These sensors are suitable for a variety of applications as they respond to smoke, heat and even gas in the air. They operate on the principle of identifying a series of chemical reactions. These detectors contain particles of carbon monoxide, and the settings, working in automatic mode, can determine the ideal temperature of the monoxide, when the temperature changes, this is signaled.

Combined sensors

Able to detect signs of fire immediately in several ways. Basically, these are devices that have the functions of not only a smoke, but also a heat sensor, thanks to which it is possible to specifically identify signs of fire, and then notify people.

Installation and connection of fire and security alarms

1. You must determine the required number of detectors. And for this you need to know the height of the ceiling of the room, as well as its area. According to the documentation, with a ceiling height of more than 3.5 meters and 80 sq. m. area you will need one detector, however, safety regulations state that even in a small room a minimum of 2 sensors should be installed. Therefore, it is best to follow these rules.
2. Where the sensors will be installed, it is necessary to designate the place. The distance from the detector to the wall should be about 450 cm, while the distance between the sensors should be approximately 900 cm. This rule applies to single-level ceilings with a maximum height of 350 cm. Wall detectors are installed at a distance of 200 mm from the ceiling.
3. At the initially marked places, it is necessary to fix the detectors, after which they are connected to a power source with 2-wire wires. Devices must be connected in series with each other. The resistor is installed in the block of the latest sensor.
4. After you connect the last detector, they must be checked for operability. To do this, it is necessary to hold a flame from a lit match or candle near the detector.

Where and how to install fire detectors

The standards for the installation of OPS detectors are quite liberal: between the sensors it is 9 meters, from the wall - 4.5 meters. However, this placement is done solely for the sake of comfortable configuration of a particular fire system. In this regard, we can conclude that the installation and location of the detectors is a more complicated matter.

When installing sensors on walls, the distance must be at least 200 cm, otherwise they will give a false alarm, as they will be in the “smoke pocket”.

The sensitivity of the detector depends directly on the distance of the source of danger and it does not survey the entire hemisphere. In an empty room, the area monitored by the sensor depends only on the ceiling height.

By flame:

• Up to 15 sq.m. - from 6 to 9 meters;
• Up to 20 sq.m. - from 3.5 to 6 meters;
• Up to 25 sq.m. - 3.5 meters;
• More than 9 meters - it will be impossible to control, because the ignition will become a fire, and the sensor itself will not work.

• Up to 85 sq.m. - it is up to 3.5 meters;
• Up to 70 sq.m. - this is from 3.5 to 6 meters;
• Up to 65 sq.m. - it is from 6 to 10 meters;
• Up to 55 sq.m. - from 10 meters.

However, an accurate calculation of the location of the detectors needs to be simulated on a PC or by a professional.

How the notification system works

When the detectors detect a fire, the fire warning system automatically turns on. Warning systems according to their principle of operation, as well as composition are divided into:

The notification function is realized thanks to the output as well as the input interfaces. In order for the information to be displayed, alphanumeric and light indicators, as well as sound signaling devices, are used.

Possible malfunctions after installation

Improper prevention is the main cause of fire alarm failures. In other words, it is necessary to constantly carry out all preventive work. Smoke detectors often fail, as various particles and other debris enter their chamber. However, there are loop breaks or system errors that also cause malfunctions.

Considering the fire alarm system, the main problems are highlighted:

Dirty and heavily dusty work areas, high humidity or high temperatures often cause significant damage to fire alarms. Also, banal reasons, for example, cable breakage, due to which the alarm can even squeak, flash, and so on, even without fire, become the cause of failure of the OPS. But the most serious cause of malfunctions is still the intervention of unskilled specialists, amateur performance, or the term of operation approaching completion.

How to remove the fire alarm yourself

If the alarm went off for no reason, then it can be completely turned off. The most elementary option is to remove power (battery) from the sensor or disconnect the control panel from the network.

Attention! In this case, the fire alarm will become useless and will not be able to warn you about a real fire.

In addition, many fire alarms are equipped with auxiliary power sources and a button located on the sensor on the front side, which will also need to be turned off. When you press the button, the device goes into alarm mode, and the sound signal is reset automatically.

Also, the fire alarm is turned off using a centralized control panel, but for this you need to know the password. If you cannot find out the cause of the device failure, then solve the issue radically - cut the wires that go to the sensor, but in this case the device will stop working altogether and will simply resemble a decorative element.

Video: how to connect an OPS with your own hands

Human safety is a top priority, regardless of whether it is at the workplace or at home. This can be ensured by installing the OPS in combination with other devices. But in order for the alarm system to work as efficiently as possible, it is necessary to adhere to certain rules for design, installation and operation.

During installation, we use a specific connection scheme for fire detectors. This article will just talk about it. Various connection schemes have fire sensors. It is worth remembering when planning the circuit that the alarm loop is limited in the number of fire detectors connected to it. The number of connected sensors per one loop can be found in the description of the control device. Manual and smoke fire detectors contain four outputs. 3 and 4 are closed in the diagram. This design makes it possible to control the fire alarm loop. More specifically, by connecting a smoke detector using pins 3 and 4, a “Fault” signal will be generated on the control device if the detector is removed.

When connecting, it is worth remembering that the outputs of fire sensors have different polarities. Pin two is often a plus, and pin three and four is a minus, the first pin is used when connecting a final or control LED. But often it is not used.

If you look into the connection diagram, you can see three resistances, Rok, Rbal. and Radd. The resistor values ​​can be read in the manual from the control device and are usually supplied already complete with it. Rbal. according to its functions, it is needed for the same for which Radd. is used in smoke detectors and manual ones. The set of the control device is usually not included. Are bought separately.

During normal operation, thermal sensors are usually short-circuited, so our resistance Rbal does not participate in the circuit until a trigger occurs. Only after that our resistance will be added to the circuit. This is necessary in order to create an "Alarm" signal after one or two sensors are triggered. When we use the connection in which the "Alarm" signal is generated from two sensors, then when one is triggered, the "Attention" signal is sent to the control device. These connections apply to both smoke and heat sensors.

By connecting smoke sensors and using Radd in the circuit, "Alarm" will be sent to the control device only after two sensors are triggered. When the first sensor is triggered, the control device will signal "Attention".

If the resistor Rdop is not used in the circuit, the "Alarm" signal will be sent to the control device as soon as the sensor is triggered.

Manual call points are connected only in one mode, that is, so that when one device is triggered, the "Alarm" signal immediately appears in the system. This is necessary for immediate notification of a fire.

A fire alarm system is a prerequisite for the construction of some facilities. First of all, this applies to buildings where explosive substances are stored. This number includes buildings of health care, general education, and manufacturing industries.

The safety of any premises depends on the correct installation of fire alarms. Incorrectly performed installation work will not only not protect the structure during a fire, but also contribute to the issuance of fines.

Alarm device

The main function of a fire alarm system is to detect a fire in a room using installed sensor systems. Modern manufacturers suggest using the following sensors in fire alarm systems:

• optical;
• smoke;
• thermal.

Optical sensors are capable of capturing infrared or ultraviolet radiation, which are released during the combustion process. Smoke sensors react to the occurrence of increased smoke, and thermal sensors react to a sharp increase in temperature. Often, for the reliability of the system, devices of different types are combined.

All sensors can be divided into wired and wireless. All of them are connected to the central console, which receives the corresponding signals from the sensors. After processing the information, the place of fire is determined, the control signal is turned on, which starts the warning and fire extinguishing system.

This system is quite complex, so the installation of a fire alarm can be carried out if there is project documentation that takes into account the purpose of the object.

The design, connection and maintenance of the alarm system is allowed to be carried out only by those companies that have certificates and licenses to carry out these works.

In the preparation of project documentation, a technical task is developed. It is further used to make the layout of cables and devices.

Norms and rules of installation

The list of all norms and rules that describe the installation features is quite large. But the main ones should be mentioned.

You can get acquainted with the full list of rules in GOST and SNIP. In addition, attention should be paid to the Federal laws on which the project documentation is based. It is also necessary to comply with the requirements of the Fire Safety Regulations.

If the installation requirements are not met, it is necessary to dismantle the installed equipment and carry out all work in accordance with the regulations. Dismantling in this case is carried out at the expense of the contractor.

The installation of a fire alarm must be carried out taking into account all the requirements:

• fully comply with the project documentation and the specifics of the premises;
• quality work performance.

In a protected building, it is advisable to divide all premises into several control zones, each of which is equipped with a certain number of sensors.

Power supply norms

Power supply and communication networks are also given special attention. After all, they must be resistant to fire. When the room temperature rises, their insulation must be maintained.

Communication and power wiring must be laid in different channels. In places where they intersect with the mains, they must be equipped with additional reliable insulation.

The central control panel must be placed in a certain room. Access to it should be limited to service personnel. There are several types of control panels. Each of them can be used in certain conditions. Accordingly, the assembly of each device is individual.

When choosing, choose a conductor with a larger cross section than for lighting fixtures.

Installation

Current legislation does not prohibit the installation of fire alarm systems on their own. All work must be carried out in accordance with certain rules that are prescribed in the project documentation.

But experts recommend that the system be installed by professionals. Independently, with skills in working with such systems, you can assemble a system for the home. Complex structures should be carried out only by specialists who guarantee the integrity of the structure as a whole.

Specialists connect the sensors in accordance with previously prepared diagrams and instructions for the devices.

An example of installing a foam or water fire extinguishing device. They are used in libraries, shops, hospitals, hotels, etc. The water flow in such a system must be at least 10 l / s. Water supply in case of fire should be at least 30 minutes, and the distance between sprinklers should be no more than 4m.

The installation of a fire alarm must be carried out at a temperature of about +200, a humidity of about 60%, in the presence of a forced exhaust ventilation.

After installation of the structure, it is necessary to carry out verification work.

The cost of performing work on installing an alarm system directly depends on the area of ​​​​the protected premises, and, accordingly, the amount of equipment used.

End of work

After the installation of the fire alarm system is completed, the executing company and the customer need to draw up a set of as-built documentation. It is necessary to prepare the following documents:

• magazine and executive schemes;
• acts of statements and tests, surveys of hidden works;
• quality passports of the materials used, their certificates;
• working drawings.

A complete list of all required documents can be found on the website of the Ministry of Emergency Situations.

How to turn off the fire alarm system

Well, the connection is made in accordance with all the rules. The work order was followed. But during operation, the fire system can work for no reason. At this time, you need to make sure that there is no fire, after which the device must be turned off. We figured out how to connect the systems, but how to turn it off? After all, an unpleasant specific sound is often made. To disable the alarm, you must:

1. determine the cause of the alarm. Maybe for some reason there was an accumulation of smoke in the house or a small fire broke out. In this case, the room must be well ventilated;
2. if the cause is not observed, then it is necessary to turn off the device. A simple alarm can be simply turned off by turning off the power source from the sensors. Complex involves turning off the system from rooms with a central control panel. In this case, you will need to enter a specific code;
3. a radical method of eliminating unpleasant sound is to cut the wires. But remember, in order to restore the operability of this alarm, in this case it will be necessary to carry out a number of consecutive works.

How to protect your apartment, house or cottage from fire? Only timely revealing even the slightest sign of fire. This is where a fire alarm can help you. But its effectiveness can be counted on only under one condition - if the installation of sensors is carried out in accordance with all norms and rules. Therefore, further we will figure out how to install the alarm system with your own hands: to your attention are the basic principles of installing sensors, step-by-step instructions, a detailed connection diagram, as well as an explanatory video.

Preparation and design

First, let's clarify what a fire alarm is, in order to get a general idea of ​​\u200b\u200bwhat you have to work with in the future. A fire alarm is a whole complex of devices that consistently detect signs of fire and inform about their localization. The system includes the following elements:

• sensors;
• communication lines;
• source of power;
• receiving device.

Actually, the preparatory stage of the installation of a fire alarm system involves the choice of working devices. The first step is to decide on the sensors - they directly respond to certain dangerous factors and transmit a signal to the receiving point. Depending on the principle of operation, sensors are divided into three groups:

Flame sensor

1. Thermal - react to an unnatural rise in temperature in the room.
2. Smoke - react to smoke.
3. Flame sensors - react to open sources of fire.

There are also combined sensors that detect both an increase in temperature and the appearance of smoke and fire.

Advice. When choosing a sensor, pay attention not only to the way it works, but also to durability, a guarantee against false positives, and the speed of signal transmission.

The second component of the system that requires special attention is the communication lines. Choose wires with low resistance, low flammability, and minimal signal loss.

The installation of a fire alarm system must be preceded by a system design. At this stage, it is necessary to create an approximate layout of all working signaling devices and cable lines, taking into account the area and configuration of each serviced premises.

Calculation of the number of sensors

To get the exact number of sensors to ensure the most effective fire alarm, professionals use special simulation programs, but if you do not have this opportunity, you can do the calculations yourself. To do this, you need to know three indicators: the area of ​​\u200b\u200bthe serviced room, the height of its ceilings and the type of sensors used. So, one smoke device in a room with a height of 3.5 m is able to control an area of ​​up to 85 sq.m., and one heat device - up to 25 sq.m. In rooms with a height of 3.5 to 6 m, the smoke sensor "sees" up to 70 squares of area, and the thermal one - up to 20 squares. Accordingly, the greater the height, the smaller the coverage area of ​​the device.

When calculating the required number of sensors for the entire apartment, house or cottage, keep in mind that devices must be in every room, residential and non-residential, and on each floor. Even the attic and basement are not an exception, because any area of ​​​​the object can be prone to fire.

Mounting the fire safety sensor

Sensor placement

Fire safety sensors can be installed both on the ceiling and on the walls. But adhering to certain rules:

• distance from walls and corners - 450 cm;
• the distance between the sensors (provided that the ceiling is single-level) - no more than 900 cm.

At first glance, the norms are absolutely democratic, but the catch is that they are designed only for convenient configuration of the fire alarm system in general. We immediately warn you that in reality such an arrangement of sensors is far from always possible. Why? There are two reasons. Firstly, mounting the sensors on the wall is allowed only if the distance to the ceiling surface is at least 20 cm. Otherwise, there is a risk that the device will fall into the smoke pocket, which can provoke a false alarm. Secondly, the sensitivity of the sensor is directly dependent on the distance to a potential ignition source.

Important! If beams are installed on the ceiling, the sensors must be placed only on their lower surfaces, and not on the side surfaces. It is also not recommended to install devices between the beams, as the probability of getting into the smoke pocket increases, and this is fraught with a malfunction of the system.

Mounting sensors

When all fire alarm devices are selected and purchased, you can proceed with their installation:

1. Attach the sensors to the marked positions.
2. Connect the sensors to the receiving device loops. This procedure is performed according to the instructions that come with the equipment. A terminating resistor must be installed in the last loop.
3. Connect all sensors in series.
4. Using a two-wire cable, connect the sensors to a power source.

After that, each sensor needs to be tested - for this it is enough to hold a burning candle near it.

The key to the proper functioning of a fire alarm system is regular maintenance of its components. If the system is powered by a lithium battery, the sensors should be checked for function monthly. The power source needs to be changed every year - as practice shows, it is during this period that it wastes the entire resource. It is advisable to change the reacting devices themselves every 7-8 years. Also remember to check wired communication lines regularly.

Thus, self-installation of a fire alarm is a difficult, but quite feasible task. The main thing is to understand the basic nuances of mounting sensors and connect them according to the instructions. So do not neglect the proposed recommendations - remember that your safety and the safety of property will directly depend on the quality of work.

How to install a fire alarm sensor: video

Fire alarm: photo

It has always been difficult to honestly ensure one’s well-being, but it’s a shame to lose what was righteously acquired in a fire or theft, and you need to earn money again ... Fire and security alarm (OPS) allows you to minimize the risk of property loss from misfortune to a minimum, and insurance premium rates for housing equipped with it are significantly below. In our time, another favorable circumstance has appeared - do-it-yourself installation of a fire alarm can be done by a person familiar with the basics of electrical engineering and homework, and legitimizing a properly assembled system most often does not require complex formalities.

Really? OPS is a serious matter, the Ministry of Emergency Situations should respond to the alarm. And the installation of fire alarms by law must be carried out by a licensed organization, everyone knows this. Yes, but modern electronics have simplified the construction of automatic security systems (AOS) so much, while at the same time increasing their functionality and reliability, that, figuratively speaking, well-fed wolves vigilantly guard a grazing herd: professionals have a stable income, focusing exclusively on security functions, and citizens , without straining the budget, ensure their safety.

To understand why a do-it-yourself security and fire alarm system has become quite real, and how to do it correctly, let's briefly get acquainted with the evolution of AOS, their structure as a whole and their components, and the principles of organizing residential security services.

How AOS developed

Before chips and reed switches

Initially, AOS were built in the form of a chain of opening thermal sensors: spring contacts were soldered with Wood's or Rose's alloys with a melting point of 70-86 degrees. The chain was forcibly closed by a manual call point with normally closed contacts. All this together formed a loop Sh. From heating, the solder melted, the contacts diverged, the circuit broke, the relay included in it also released with normally closed contacts, its contacts closed and turned on an alarm. By pressing the detector button, it was possible to give an alarm manually.

At the very least, such systems worked as local ones, but communication with the central console required a long line (LS) that was prone to malfunctions and had its own leakage resistance, wire resistance, capacitance and inductance, which could cause both false alarms and failures due to real danger. .

Therefore, on the consoles, they began to include beams - loops with LS - into the diagonal of the electric bridge, and into its opposite diagonal - the balanced circuit of the BC (see Fig.). The beam was no longer characterized by the resistance of the loop R W, but by the total resistance (impedance) of the subscriber Z A. By adjusting the BC, we achieved the equality of its impedance Z K to the impedance of the subscriber Z A. Under this condition, the potentials in the diagonal of the bridge 1-2 turned out to be equal, and the voltage U 1 -2=0. When the sensor was triggered, U 1-2 >0 occurred, which triggered the alarm.

The AOC bridge scheme allowed for an important improvement: parallel to the detector, they began to turn on a resistor of a strictly defined value R Ш. This made it possible to judge the nature of the operation by the value of U 1-2: if R Ш remained in the circuit, then someone pressed the detector button, then U 1-2 will be approximately half the maximum ; This is the "Warning" signal. If the sensor opens, we will see a clear open circuit and a maximum of U 1-2; this is "Alarm".

Such a system was not very reliable: the slightest malfunction gave a false alarm, a squad left, and then the fitter, expressing his thoughts on this matter in an arbitrary form, went to look for and eliminate. False alarms reduced the degree of trust in the AOS and from the order to the fitter the object remained open. Moreover, splashes of solder sometimes fell between the open contacts, and the sensor, “squeaking”, calmed down again. There were cases when the criminals fired at the sensors with an air gun through the window, and when they saw that the outfit had left, they knew that they had at least an hour to "case".

The BC also caused a lot of trouble: the parameters of the drugs "floated" a lot. A worker with an electrical engineering education at the control panel was greeted with open arms by the police and firefighters, but often soon they had to sign a statement “on their own”: the salary was small (it doesn’t fit under the knife and under the bullets), and the hassle is no less than that of operas.

In large facilities consisting of many subscribers (department store, post office), the beams from the premises were reduced to a local control panel - a control panel (PKP), which automatically gave an alarm over the telephone line when one of the beams was triggered. This made it possible to reduce the dependence of the BC on the state of the LS, which were already under the control of signalmen, but reduced reliability: by competently digging into the control panel, it was possible to disconnect the entire object from the console and operate there at your pleasure.

At the same time, attempts were made to use the parallel connection of sensors with thermobimetallic normally open contacts, shunted R Sh. ​​In theory, this would allow judging from the remote control the value of U 1-2 and the place of triggering, which the serial system does not allow. However, the open bimetal turned out to be extremely unreliable: the sensor with oxidized contacts did not announce itself in advance, and then was silent, like a fish on ice, when the fire was already blazing with might and main.

reed switches

Sealed magnetically controlled contacts - reed switches - made the first revolution in AOS and OPS. Reed switches withstand billions of operations without oxidation of the contact surfaces, and the problem of temperature operation was easily solved by using holding magnets made of materials with a Curie point of 70 degrees: when heated, the magnet stopped magnetizing, and the contacts opened.

The principle of the reed switch design allows it to be switched, which gives a reliable sensor suitable for both serial and parallel OPS. True, the accuracy of determining the place of triggering by analog methods remained low, therefore, parallel analog OPSs were not widely used. Nevertheless, it was thanks to the reed switches that a fire alarm system appeared in the apartment: the reliability and low cost of the sensors ensured the cost of the system, accessible even to an ordinary Soviet consumer.

The first smoke sensors also belong to the “reed-contact era”, but by no means household ones: the smoke detection was provided by the ionization of the gap between the fixed contacts, for which it was illuminated by an ampoule with a radioactive isotope. Alarm fitters were afraid of such sensors, in a thick steel case and marked with a radiation hazard sign, like fire, and they were rarely used, at especially important facilities.

At the same time, control panels began to transform: the use of microcircuits of a medium degree of integration and analog-to-digital converters (ADCs) made it possible to simplify the BC or completely abandon them and measure the beam parameters directly. The first wireless self-powered control panels also appeared, which, regardless of telephone lines, gave an alarm to the remote control using the Altai system - the prototype of modern mobile communications, invented in the USSR back in the 50s.

Chips and lasers

A real revolution in the OPS was made and made available to the public by large integrated circuits (LSI, chips) and miniature semiconductor lasers. This affected all links of the OPS, and the best of the previous achievements organically fit into the new system (see the figure below in the text below).

Sensors with the help of laser detectors control the temperature and smoke in several parameters at once, which eliminates false alarms (see the figure on the left). Some sensors combine the functions of motion detectors, they will be discussed later. "Smart" sensors can be autonomous, equipped with a built-in battery.

The control panel of our days is a computerized device that can work both with "smart" junior colleagues and with old, but absolutely trouble-free and very cheap reed switches. This made it possible to include SPU in the household alarm systems - a signal-starting device that, at the signal of the control panel or directly from the sensor, includes indicator boards, flashing lights, sirens and opens the valves of the automatic fire extinguishing system.

Modern alarm systems are digital-analog parallel-address: each sensor has its electronic address programmed, and the control panel knows exactly where and what happened. Analog sensors with the help of advanced software are also quite accurately controlled by the parameters of the loop. The alarm signal is sent via GSM to the owner's mobile phone and to the computer of the security organization. The alarm can be duplicated directly from the chipped sensor, and the activation of the STC can be, in addition to it, from the checkpoint.

Motion sensors based on the same chips and infrared lasers have made fire alarm systems truly security: they control the entire volume of the room or the area of ​​the yard. The laser scanner signal is converted into a code, and the control panel processor continuously compares the codes one by one, filtering out interference from weather, precipitation, and small safe objects.

The capabilities of a modern full-featured OPS are shown in the figure. This is very expensive, but the system is simpler, quite reliable for an apartment, you can assemble it yourself. How - will be described later, but for now let's see what is needed and what can be achieved in general:

1. An uninterruptible power supply (UPS) is necessary for the OPS to continue to operate in a de-energized apartment;
2. Universal sensors-annunciators: on the left is a group of autonomous ones, for example. in the garage;
3. Motion sensors;
4. Electronic lock;
5. Reed anti-burglary contactor;
6. Scoreboard-pointer;
7. Local alarm;
8. Display with control panel;
9. OPS machine.

Let's give some explanations. Firstly, reed sensors of opening are still holding their place, not competing with motion sensors, and it's not just about cheapness and reliability. The small reed contactor is easy to hide, its operation is not detected by the anti-scanner. The search for such a "bug" (and it is not known whether it exists at all) with skillful installation requires so much time that hacking loses its meaning.

Secondly, instead of any of the devices in pos. 7, 8 can be connected to SPU. Thirdly, according to item 10: the fire alarm system must be powered from a separate machine, switched on BEFORE the apartment one, otherwise the reliable operation of the system is not guaranteed. And, finally, a remote control with a display by access code allows you to independently reset, test and reconfigure the alarm system.

organizational structure

A radical improvement in the technical base also led to an improvement in the organizational structure of the fire protection service: subscribers rarely get on the MES console, it is expensive and overloads both equipment and personnel. The role of signal concentrator was taken over by private security firms. It doesn’t burn or sneaks everywhere and not always, and with an acceptable load they can gain a lot of subscribers, which, with a small monthly fee, provides a decent income.

Such a system is also beneficial for the owners: a private licensed security guard will be happy to advise, help with advice, he does not need experience in interacting with the Ministry of Emergency Situations and the police. And since the owner still pays him his hard-earned money, then it’s easier to demand in which case it’s easier than from a government agency.

We take care of the alarm

Do you need a project?

A fire alarm project is needed, and not so much for formal reasons. Only a security guard with extensive experience will be able to accurately indicate the location of the devices, their types and connection scheme. Otherwise, the flames can rage to the point of irreparable, and the attacker, immediately spotting the “self-propelled gun” (they are well versed in signaling), will only grunt and, having “bombed the hut”, sit comfortably in the master’s favorite chair, drinking the master’s cognac, smoking the master’s cigar, gently stroking the sack on her knees, tightly stuffed with the master's goods and looking ironically at the sensors in full combat readiness.

However, security firms, in general, rightly believing that the main thing is real security, not paperwork, often go easy on potential subscribers: they agree to make the project cheaper, a draft, or they limit themselves to even cheaper advice: where to install which sensors, where to place the control panel, which cable and how to connect everything.

Then, having checked the work, they take it to the guard, and according to the documents, they carry it out retroactively. This is no worse for the owner: since the contract is signed and the apartment is already on the remote control, the entire measure of responsibility falls on the guards. The components of a modern fire alarm system are completely reliable, the maintenance of a fire alarm comes down to a periodic check of its operability and readiness, which, together with the duty officer of the security organization, can be carried out by the owner himself, so, as a rule, there are no problems with the service either.

How to do what?

The law does not prohibit doing the OPS yourself, only they won’t take one on the remote control. We will have to limit ourselves to sending an alarm to a mobile phone, but this is already a serious help in misfortune: the Ministry of Emergency Situations and the police are obliged to respond to any signals from citizens. Therefore, we will describe which equipment to choose for which case, and how to correctly assemble it into a workable whole.

PKP

Types of modern control panels are shown in the figure. The first from the left is a professional multipath analog-to-digital. These can work with any alarm system schemes, connect in cascade, ensuring the protection of objects of any degree of complexity and conduct a dialogue with the computer of the security organization, capturing and transmitting a complete picture of the development of the situation. Do not apply in everyday life.

The next one is semi-pro, digital for parallel addressable OPS. It is shown open, because outside it is a blank box. At the bottom right in it - IP; next to it is a battery, quite powerful, as you can see, for several hours, up to a day, battery life.

At the top left is an electronic unit, and in an empty place near it in round-the-clock guarded premises there is a control panel, but usually it is taken away. The fact is that such a heart of the OPS, although equipped with a self-defense system, is still the most vulnerable spot of the security system. The work of the processor can be detected by a special scanner, like car thieves do, and interfere with it in an undesirable way for the owner.

Therefore, it is highly recommended to place the control panel in a hidden, hard-to-reach and fairly well electrically shielded place, say, in a reinforced concrete basement. As for the RS482 serial interface, which connects the control panel and the control panel, its signals are very well encoded, and it is impossible to get through to the processor through it.

Semi-professional control panels are used in everyday life in elite estates individually or collectively in residential complexes: one such control panel allows you to connect up to 255 sensors to it.

The next one is a multi-beam household control panel. This device is already affordable for an ordinary citizen. Such a device is intended for private households with outbuildings: in addition to servicing reed and chipped wire beams, it can process signals from 2-8, depending on the model, wireless sensors.

Far right - the simplest apartment control panel. The cheapest models are served by only one beam (there is no need for more in the apartment), but, like all of the above, they can transmit a signal to a mobile number. The number in inexpensive household control panels without code access from your remote control is flashed upon purchase or at a security company, so you need to keep the phone with it charged and with a non-empty account: mobile operators charge a fee for receiving messages via GSM.

Household control panels must be supplied with detailed instructions with typical alarm system diagrams, a list of types and models of sensors compatible with the control panel, and recommendations for system installation. Often, the kit includes a beacon for the front door and a sticker "The object is under protection." These are very useful additions: their presence most often forces villains and vandals to get out.

The control panel must comply with the European standard EN54, which is provided by SPB, LPCB or VdS certificates.

Sensors

Sensors and their connecting wires are the key node of the OPS, which determines its reliability as a whole. First of all - about the wires. Sensors no longer connect with telephone “noodles”, fragile and unreliable: there are many types of signal two- and multi-core cables on sale in a round outer sheath, which can be laid along the walls so that they are not conspicuous, and hidden under decorative sheathing. But we should talk about the actual sensors in more detail.

Choice

For an apartment, the best option is the good old reed "caps", see fig. A chipped one is desirable for the kitchen, reacting, in addition to heat, to smoke. If significant valuables are stored in the apartment, then it is better to put full-function ones with motion detectors near their locations.

In a private house, a motion sensor in the yard with a built-in SPU loaded on a lighting lamp will be useful. And it will scare away uninvited guests, and you yourself will not have to stumble in the dark: the SPU will illuminate.

Multifunctional sensors are necessarily equipped with an indicator LED, and the simplest ones can be with or without it. The former are preferable: glowing or vice versa, the indicator going out indicates a sensor malfunction. In case of a false alarm, you do not need to climb the ceiling with a tester - a bad sensor is immediately visible.

Accommodation

At first glance, the standards for the placement of OPS sensors are very liberal, see the figure: no further than 4.5 m from a wall or corner and no more than 9 m between the sensors. But this was done only for the convenience of configuring a specific OPS, but in fact, the location of the sensors is a delicate matter.

Firstly, when placing them on the walls, there must be at least 0.2 m to the ceiling, otherwise the sensor may end up in a smoke pocket and give a false alarm. Have you seen smoky rooms? There, after all, the upper corners are most smoked. Secondly, with beams on the ceiling, sensors must be placed on their lower surfaces, and not on the side or in the space between the beams, for the same reason.

And, finally, the sensor does not survey the entire hemisphere, and its sensitivity depends on the distance to the source of danger. The controlled area in the form of a circle in an empty room depends on the height of the ceiling as follows:

• Up to 3.5 m - up to 85 sq. m.
• 3.5-6 m - up to 70 sq. m.
• 6-10 m - up to 65 sq. m.
• From 10 m - up to 55 sq. m.

By flame:

• Up to 3.5 m - up to 25 sq. m.
• 3.5-6 m - up to 20 sq. m.
• 6-9 m - up to 15 sq. m.
• Over 9 m - not controlled; the fire will turn into a fire before the sensor is triggered.

"To" in front of the area means that this is the maximum achievable value - in an empty room with proportions in terms of 3/4. Accurate calculation of the location of sensors in habitable rooms requires computer simulation or the eye of an experienced specialist. If the alarm is done independently without outputting to the security console, then we can assume that one sensor in the living room “sees” a square with side L equal to the height of the ceiling up to 4 m below. - at a distance L from each other. In long and narrow rooms, the distance between the sensors is primarily taken into account.

Example: corridor in Khrushchev 1.75x4 m; ceiling height - 2.5 m. Two sensors are needed, located at 1.75 / 2 = 0.875 from the end walls. In the bedroom of the same Khrushchev 2.5x4.5 m, two sensors are also needed 1.25 m from the end walls.

Connection

Connection of fire alarm sensors is carried out strictly according to the instructions for them. The beam loop always ends with a terminating resistor R. Its value is specified in the instructions for the control panel. Default R=470 ohm, but 680 ohm or 910 ohm ratings may be required. Let us explain in more detail only two frequently requested points.

First- inclusion of five-terminal IP-212 sensors, which have proven themselves well, into a two-wire loop. How to do this is shown in the figure on the left.

Second– connection of conventional sensors with one terminal block. The cable wires must enter / exit the terminal block MIRROR, as shown in fig. on right.

The third– sensors with two terminal blocks. The left block is FOR the LINE, which is connected according to the instructions or as described. But the right one should be dealt with already at the time of purchase: it is designed for autonomous activation of the SPU; some of the most common circuits for such sensors are shown in the last figure.

If the loop contacts (terminals 1-4) and SPU (terminals 6-8) are electrically separated, as in the extreme right position, then you need to find out the allowable voltage and current or power of the SPU. If the contact is common, as in the other three positions, then the voltage is 12 V at a current of up to 200 mA, and it will go to the SPU from the loop, i.e. load the sensor with light bulbs, bells, etc. impossible - the control panel will fail.