Smoke detectors types, principle of operation and selection

Application area

Fire protection devices can be used at various facilities:

• industrial and domestic facilities;
• schools;
• medical institutions;
• office centers;
• shops and warehouses.

Fire alarm systems and devices must, at the first sign of fire, immediately transmit information to the fire department control panel. In addition to identifying fire factors and transmitting alarms, the alarm system should also provide:

• remote control of fire extinguishing and smoke removal systems;
• manage the access level control system in order to quickly evacuate people from premises in which a fire has been detected;
• transmit alarm signals to the mobile phones of the owners of the protected facility (if there is a special GSM-Module in the security device).

INSTALLATION OF MANUAL FIRE STATIONS

The rules for placement and installation features of manual fire detectors are described in the relevant regulatory documents and technical data sheets for the device from the manufacturer.

When choosing an installation location, it is necessary to remember to ensure maximum accessibility to the equipment, taking into account the emergency evacuation of personnel.

During installation, it is recommended to adhere to the following rules:

• installation height - 1.5 m above the floor;
• distance between devices: indoors - no more than 50 m, outdoors - no more than 150 m;
• the installation site should be visible from all sides during the daytime, and well lit at dusk;
• near the device it is necessary to attach the icon "Manual fire detector";
• it is unacceptable to install devices behind finishing materials, put cabinets in front of them or cover them with other objects.

FUNCTIONAL CAPABILITIES AND PERFORMANCE CHARACTERISTICS

Depending on the model, manual call points can signal an alarm in different ways. The simplest is to open the loop circuit.

Technically more advanced devices, when an alarm signal is given, change the electrical parameters (resistance) of the loop. Also, there are models with a wireless method of transmitting a signal over a radio channel.

Connection is made both on two-wire, and on a four-wire cable. In the second case, alarm and information signals are transmitted through the first two wires, and power is supplied through the remaining pair. Connection to the control panel is carried out through a dedicated interface.

Simple models are unaddressed. That is, when an alarm message is sent, the operator will only know the number of the loop, and the exact location of the fire will be unknown.

The address device additionally has a unique code programmed into the factory preset. When transmitting an alarm signal or an on-duty message, the device code is added to the standard information, by which the control panel determines its location on the object.

In fire and explosion hazardous industries, manual call points are used in an explosion-proof housing (resistant to chemical and biological corrosion). They are connected to intrinsically safe circuits of low-current power supply.

Manual fire call points are inexpensive but effective fire alarm system devices that significantly increase the fire safety level of a building.

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Overview of popular smoke detector models

The most popular and widespread sensor model IP 212-141

Model IP 212-141 is intended for fixing smoke in enclosed spaces.It connects to the system via a two-wire cable. The "Alarm" signal is also transmitted through the loop. The design of the sensor is reliably protected from temperature extremes, humidity levels, flames and the amount of illumination in the room. Works around the clock in conjunction with the control panel PPKOP 019-8-1 or PPKOP 0104065-20-1. Its sensitivity allows detecting the smallest concentrations of smoke particles (0.05-2 dB/m) in the air. For stable operation, a constant voltage of 9-30 V is required. An LED is installed on the case, by changes in which one can judge the health of the sensor and its transition to the "Alarm" mode.

After the smoke is eliminated, the sensor will maintain the “Fire” position until its status is reset on the control panel with a complete power off for a few seconds. It is used in warehouse and office rooms. The weight of the detector IP 212-141 is about 200 gr. The minimum guaranteed service life is 10 years. The design of the optical-electronic detector IP 212-141 consists of a smoke sensor and a socket. When the state of the photodetector changes, its resistance decreases, after which the LED stops blinking and its glow becomes constant.

Detector model “Aurora-01”

Model "Aurora-01" - fire smoke detector IP 212-81 - an autonomous device designed to detect signs of combustion in a room. The smoke detector responds to changes in the state of the air environment by generating an alarm signal in a separate room.

The advantage of IP 212-81:

• high sensitivity;
• reliable protection of the photodetector from aggressive environment;
• convenient installation of the device;
• minimum duration of work more than 10 years;
• eliminates false positives;
• maintains stable operation at high and low temperatures;
• there is a built-in siren for notification;
• light indication of the sensor is visible from all sides.

The Avrora-01 brand sensor can function both in stand-alone mode and in the complex of an automatic fire detection and extinguishing system. The design includes a pair of dust collectors to protect the structural elements of the device, a reflector with additional protection from third-party lighting, a special mesh to protect against insects, as well as an ultra-sensitive smoke chamber that works in all directions of the room.

Optoelectronic smoke detectors brand IP 212-142 are able to detect a fire even at the stage of formation of minimal smoke. It is installed in premises of any purpose. The device does not change its state when the air temperature changes, in the presence of a flame, as well as the presence or absence of lighting in the room. The IP 212-142 fire detector and the built-in microprocessor form the "Alarm" and "Fire" signals as accurately as possible.

Smoke detector IP 212-142

Advantages of the IP 212-142 model:

• within 10 seconds, a “Fire” signal is generated with a maximum guarantee of the result;
• there is no possibility of false positives;
• case design fits into any interior;
• works in the temperature range -10 ... +55 degrees Celsius;
• The kit comes with a 9V battery.

Due to its low cost, this model of a fire smoke detector can also be installed in socially significant buildings and structures. The price is due to the fact that the plastic from which the detector housing is made is a recyclable material.

Sensor DIP-34AVT

The DIP-34AVT brand manufactured by the Bolid company with a pulsating signal is connected to the system via a loop. Controls the presence of smoke in the premises in case of fire. It is installed most often on the territory of cottages, country houses, kitchens, boiler rooms.When the photodetector of the sensors is triggered, a “Fire” signal is generated, after which the built-in siren is launched. A unique feature of this smoke detector model is that the sensor itself notifies you when the battery needs to be changed.

Advantages of the detector and siren DIP-34AVT:

• fire detection at the ignition stage;
• a “Test” button is installed on the case, which allows you to determine the operability of the equipment;
• There is a built-in protection against insects and dust.

Video: Types of smoke detectors

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Sensor device

Devices of this type are compact devices based on a temperature measurement system. To accomplish this task, special sensitive sensors are used. Their role can be performed by mechanical, thermally sensitive, optical or electromechanical devices that can change their electrical, mechanical or optical operating parameters depending on changes in the temperature of the environment. The main task of these elements is the continuous control of the temperature regime in a certain area of ​​the room.

smoke

A fire alarm sensor device of this type includes an element that generates a light beam - a laser or LED and a photocell that receives a direct beam from the emitter or reflected from a smoke area. Depending on the design features of the device, it will work when the generated beam hits or does not hit the photocell.

The presence of a flame

Sensors of this type are mainly used at production facilities, where the presence of smoke in the environment and elevated air temperature is typical. In this case, heat and smoke detectors are simply not suitable for such conditions.

The basis of flame sensors are detectors that are able to capture one or another region of the spectrum - IR, UV, electromagnetic.

Ultrasonic sensors

Detectors of this type are built on the basis of highly sensitive ultrasonic sensors that act similarly to security motion devices. Devices of this type allow you to capture the movement of air and issue an alarm in this case.

The principle of operation of sensors

Thermal

This type of device should transmit an alarm signal to the central alarm unit when a certain temperature or its rate of increase is reached. Depending on the operation algorithm, thermal devices can work:

1. to increase the temperature of the controlled medium, above the selected setting;
2. on the rate of temperature increase above the set value;
3. in parallel, on the increase in temperature and on the rate of its increase.

Smoke

The functioning of this type of detectors is based on continuous monitoring of the transparency of the air in the controlled area. In the case of a linear smoke detector, a directional UV or IR beam is generated, which, after passing a certain section of the path, must fall on the photocell. If there is smoke in the room, then it enters the active zone of the sensor, which leads to the scattering of the beam and not hitting the photocell. In this case, the device is triggered and an alarm signal is generated to the central unit.

Point smoke detectors do not function in the same way as line-type fire detectors. These devices send a low-intensity infrared beam into the air, which scatters in clean air.

The work of flame sensors is based on capturing their sensitive sensors of radiation in a particular region of the spectrum. This type of device can detect UV or IR radiation generated by an open flame. There are also sensor configurations that are multiband and provide response in both spectral bands.There are also devices that respond to the pulsing or flickering effect of IR radiation, which is typical for an open flame.

ultrasonic sensors

The functioning of such sensors is based on the different propagation of ultrasonic waves in still and moving air. When a fire occurs, heated air moves upward, causing air masses to move. It is this movement that triggers a sensor that detects the start of a fire.

Conclusion

When buying fire detectors, how their functional part works will be an important aspect of making the right choice. After all, an incorrectly selected detector will either give false alarms or will not work when factors indicating the onset of a fire appear. Correctly selected and correctly placed sensors will guarantee the effective operation of the fire alarm and a high level of safety at the facility.

Detector types

Fire detectors are devices that are part of an automatic fire detection and alarm system. According to the principle of operation, they are classified as smoke detectors, heat sensors, flame detectors and gas analyzers. The first ones have a reaction to the smoke in the room, the second ones start the system when the critical air temperature in the protected area is reached, the third ones will work when visible infrared radiation from the flame is detected, gas analyzers recognize combustion by-products, for example, carbon monoxide. The correct choice of the detector determines the time during which the fire will be detected, and the subsequent effectiveness of the fight against fire.

Types and features of models

Despite the simple device of manual models, they still have some differences. So, according to the number of operations, they are divided into:

• Single entry
• Multiple activation

The first has a rod that breaks when a button is pressed. Such models can continue to be used only after the replacement of the failed part.

Equipment of repeated inclusion, depending on the external parameters of the case, are:

1. With or without glass
2. With special sliding lids
3. With plastic breakable elements

Manufacturers, models and their advantages

Many foreign and domestic enterprises have mastered the production of equipment for fire alarms. They produce it in a wide range, ranging from simple hand-held sensors, which are a red box with the inscription “press the button in case of fire”, to modern ones.

One of them is a hand-operated electrocontact fire detector with special opening covers.

It is used in conjunction with an automated alarm system. Among Russian products, the IPR-513-3 model can be cited as an example. This device is manufactured by Rubezh, it has a modern design, a long service life with a guarantee of up to 10 years and a low cost of 209 rubles.

Structurally, the IPR 55 is a device enclosed in a plastic case; to turn on the sensor, it is not necessary to break the glass, it is enough to break the plastic cover.

There are even easier to use models. For example, IPR 513-10, also refers to manual call points and is produced by the Russian company Bolid. To turn it on, you just need to open the lid and press the button. The device is turned off with a special key. For this manual fire detector, the price is only 107 rubles.

Among foreign products there are a large number of samples worthy of attention. It is worth noting the Simplex brand equipment. They are used not only for manual signaling, but also for switching automatic alarms and fire extinguishing systems into alarm mode.

Inside the device there is an addressable module that allows you to connect the siren to addressable loops.The sensor is triggered by a lever, which is also an indicator of the device status.

product video IP 535 explosion-proof:

Each of the modifications considered has its own design features, but nevertheless, a manual type fire detector for outdoors or indoors has one main advantage - the ability to provide 100% reliability in detecting a fire. Therefore, they are used as widely as automatic sensors.

Requirements for installation and installation

Any devices included in the fire alarm system have their own placement standards. Certain rules also apply to this equipment. Usually they are located on each floor of the building, in places accessible for human activation.

Fire safety regulations require their installation in the path of people, and the distance to the nearest manual call point should not exceed 61 m from any point in the room.

Height is also regulated in the regulations. It cannot be more than 1.37 m above the floor level. The use of manual sensors in electrical signaling systems requires its installation at the end of the beam with automatic heat detectors. They can also be used to duplicate the operation of automatic devices.

Consumer opinion

The design of manual annunciators, the technology of their manufacture allows them to be used even in explosive areas. In addition, they are designed for repeated on / off and provide trouble-free operation throughout the entire period of operation. These qualities are most often noted in their reviews by consumers.

Another argument in their favor is the possibility of using not only in heated, but also in cold rooms. The explosion-proof fire detector is designed for operation at temperatures from -30° C to +70° C.

The right choice of sensor is the key to safety

The use of these devices made it possible to avoid many fires, saving property and people's lives. This fact is the main reason for justifying the need to install an alarm in a residential or industrial premises. And the use of manual type annunciators can significantly increase the efficiency of electrical systems, so they are still used everywhere.

API what is it

The design feature of the detector is the combination of three elements in one device.

So in the body of the device are enclosed:

• Optical smoke detector
• Sounder
• Battery

The first element of the detector consists of a measuring optical chamber, which excludes the penetration of the light flux, but at the same time freely passes the air masses.

Inside the device are an emitter and a receiver operating in the infrared range. At the same time, they are located in such a way that light hits the receiver only when it is reflected from a solid particle of smoke that has entered the controlled area.

But the autonomous smoke detector has a big drawback - it also works when dust, insects, and steam are in the chamber.

We watch the video, the device and the principle of operation:

The sound fire annunciator which is the integral element of API or a siren. It works simultaneously with the smoke detector, while emitting a shrill beep. In it, the role of the emitter of sound vibrations is played by a piezoelectric element, as it has low power consumption.

Since the detector is an electronic device, energy is required for its operation. For this purpose, the API is equipped with a nine-volt battery, which lasts for a year of operation of the device.

Scope of detectors

Various types of fire detectors contribute to the fact that these devices have a wide practical application in various configurations of fire protection systems.

Depending on how the fire detector works, it is installed on the site to detect the presence of smoke, a sharp rise in temperature, or the appearance of an open flame. Objects where such devices can be used include:

• residential buildings;
• educational institutions of various types;
• shopping centers, markets, pavilions, etc.;
• office centers;
• warehouses;
• industrial facilities.

Recommended installation locations for fire detectors

Purpose and device

Autonomous fire detectors are models that quickly respond to the smallest particles in the room. Typically, such devices are distinguished by a rounded design and small dimensions.

The main feature of such devices is that they can work completely offline. In other words, the design does not have any hidden wires, so there is no need to connect them to communication networks. The device is powered by a regular battery, which is enough for a year of stable operation of the device. If there is a minimum amount of charge, and it is time to replace the battery, then the siren will start flashing the indicator light.

Among the advantages of such detectors, the following nuances can be distinguished.

• There is no need to use an external power source. It will be enough to insert ordinary batteries.
• The devices are loud. There is no doubt that all employees and customers in the office will hear the siren.
• The location of the detectors may change.
• Installation does not require any special knowledge. The device is extremely easy to mount, so anyone can handle this task.

There are several requirements that an autonomous fire detector must meet.

• Autonomy of work. It is necessary to buy only those devices that can operate on a battery for at least a year.
• The presence of an LED indicator that will indicate that the device is in working condition. Almost all models on the market give a signal once a minute.
• Signal volume. If the device detects a fire, then the sound signal should be at least 85 dB. In addition, there are certain time limits - the notification must last at least 4 minutes. Experts believe that it is precisely such sound signals that can report a fire even to a sleeping person.
• Ability to work both in sub-zero temperatures and in extreme heat.

Types and features of models

The development of modern fire alarm systems requires manufacturers to constantly improve the elements included in them. This has led to the creation of various types of sensors.

Considering them, three groups should be distinguished:

1. Point
2. Linear
3. Aspiration

The principle of operation of a point smoke detector is based on the detection of particles entering the device chamber by an optoelectronic device. Then there is an increase in the current consumption of the loop, which monitors the control panel that generates the signal.

Point smoke detectors are able to control a room up to 80 m². Power is supplied to them through the system loop, and polarity must be observed during installation.

When choosing linear smoke detectors, you need to remember that this type differs from point ones in the absence of a smoke chamber. They also control smoke in the room by reducing the power of the optical beam emanating from the transmitter. Linear models are considered more complex.

Aspiration sensors work on the principle of checking air samples taken from various points in the room. This requires the installation of additional equipment, including pipelines up to 100 m long.Therefore, smoke-type fire detectors are not widely used, since, in addition to the difficulties with installation work, they have a rather high cost. The types of detectors are also described in detail in the article Understanding the variety of types and types of fire detectors.