Fire sensors of the security system

Fire alarm system designed to detect fires, points in the room with high air temperature and smoke. These measures include an alarm system, fire suppression, smoke extraction, shut-off of supply ventilation and air conditioning to stop the spread of fire in the event of an emergency.

What are the components of a fire alarm system

Fire alarm systems include sensors, receiving and control equipment, warning systems, communication channels, backup power supply, special software and other elements.

Fire sensors are divided into four main types:

1) The heat sensor of the fire alarm system reacts to the presence of temperature changes. Heat sensors are divided into:

• a) threshold - with a given limit of a certain temperature level, after which the sensors will be triggered.
• b) integral — respond to a rapid temperature increase. Due to the temperature threshold at which the sensor is activated, which is approximately 70 °C, threshold fire sensors have relatively low efficiency. The low cost of these sensors is the only factor affecting demand. Fires at an early stage can be detected with the help of built-in fire detectors. However, due to the fact that they use two thermocouples, one outside the sensor and the other inside, and the signal processing system is built into the sensor itself, the cost of such fire detectors will be high.

Only when heat is the primary symptom of a fire can heat sensors be used for fire alarms.2) Smoke detectors. Smoke in the air is detected by smoke detectors. The theory of scattering of infrared radiation on smoke particles is the basis of the operation of almost all types of smoke detectors. The disadvantage of such a sensor is that it can work in environments with high levels of steam or dust. Although it is obviously not used in dusty or smoky environments, the smoke detector is used quite often.3) The flame sensor indicates the presence of an open fire or smoldering fireplace. Flame detectors must be installed in places where a fire can start without the prior release of smoke. Because flame detection occurs at an early stage, when conditions such as smoke and a significant increase of temperature are absent, they are more effective than the previous two types of detectors. In addition, in some industrial buildings, which are characterized by high dustiness or significant heat exchange, only fire detectors are used.4) Combined fire alarm sensors combine different fire indication identification methods. Most often, combined sensors combine a heat detector with a smoke detector. This makes it possible to more accurately determine the presence of a fire indication so that an alarm signal can be sent to the remote control. The complexity of the technologies used to create these sensors affects their cost.A correctly constructed fire alarm system, which depends on the information from the fire detector, is directly responsible for the entire effectiveness of the fire extinguishing system. Thanks to this, you can evaluate the effectiveness of the fire protection system of the building as a whole, taking into account the optimal location, the use of the appropriate type of sensor for certain rooms and the quality of fire detectors.In the event of a fire, notification systems for residents, guests, or personnel of buildings and structures contribute to the prompt evacuation of people. Using the Ajax sensor as an example, we will show the principle of operation and features of combined fire sensors.

FireProtect 2 (Heat/Smoke/CO) — a wireless fire detector with smoke, temperature and carbon monoxide sensors

The FireProtect 2 (Heat/Smoke/CO) wireless fire detector is designed for quick fire detection. A dual-spectrum sensor can distinguish between smoke and water vapor. The thermistor quickly reacts to the burning of synthetic materials. The one-of-a-kind smoke chamber does not require frequent cleaning, and simple software reduces false alarms. All this complies with the latest fire safety regulations. The well-thought-out mounting and design of the sensor, as well as the settings via smartphone, ensure easy and quick installation of the fire sensor. A built-in siren for alarm and event notification is included in the fire detector. The FireProtect 2 (Heat/Smoke/CO) wireless fire detector can function both independently and as part of the Ajax security system.

The sensor is available in two versions. Model with replaceable batteries and non-replaceable - RB and SB, respectively.

The principle of operation of the Ajax FireProtect 2 (Heat/Smoke/CO) wireless fire detector

Detecting smoke and not ignoring water vapor with the fire detector Ajax FireProtect 2 is possible thanks to a bispectral optical sensor with blue and infrared LEDs. LEDs emit light with different wavelengths. This allows the device to determine the size of the volatile particles and react to the smoke.The smoke chamber of the sensor is protected from external debris and insects. Dust does not threaten detection and does not damage the device, even if it enters and settles in the smoke chamber. Air particles or insects cannot be in two beams at the same time and cause an alarm due to the structure of the optical system.Two built-in thermistors are responsible for the response to the increase in temperature of the wireless fire detector. Thermistors are located outside the sensor for better threat detection. The sensor detects rapid temperature rise and sounds an alarm if the room temperature exceeds 64 °C or rises by 10 °C or more within one minute, even in the absence of smoke. In FireProtect 2 (Heat/Smoke/CO), a built-in chemical sensor with a service life of at least 10 years is responsible for detecting a dangerous concentration of carbon monoxide.Carbon monoxide (CO) is a colorless, tasteless, and odorless gas produced when the fuel in heating engines and vehicle engines that use coal or other natural fuels does not burn completely. For example, it can be created through heating systems, boilers or fireplaces. In closed, sealed rooms with insufficient ventilation, life-threatening concentrations of carbon monoxide can accumulate.The interconnected fire alarm fire alarm function activates the built-in sirens of all Ajax fire detectors in the system if at least one of them has responded to the trigger. This makes it possible to notify as many people as possible inside the building in the event of a fire.

The sirens of all FireProtect 2 (Heat/Smoke/CO) sensors can be activated in 20 seconds thanks to the advanced algorithm of the synchronized alarm.

FireProtect 2 (Heat/Smoke/CO) sensors can be used without connecting to an Ajax control panel. In this case, the sensor notifies of fire alarms with a built-in siren and LED indication, but does not send a notification to the user's smartphone, Ajax Translator or the PRO Desktop application.

Jeweller wireless communication technology

A radio protocol called Jeweller provides fast and reliable two-way communication between connected devices and the hub of the security system. The protocol allows wireless connection of the control panel with FireProtect 2 (Heat/Smoke/CO) at a distance of up to 1700 meters. Even on very large objects, sensors can be installed thanks to such a communication range. In a system with any number of FireProtect 2 (Heat/Smoke/CO), the radio protocol also allows for a synchronized alarm of fire detectors to be triggered in 20 seconds. Thanks to Jeweller, users and the monitoring panel can always view the current status of detectors in Ajax applications.The wireless fire detector Ajax FireProtect 2 (Heat/Smoke/CO) constantly checks the state of the battery and built-in sensors. If a fault is detected, the hub will immediately notify users and the monitoring console. And the sensor will turn on the built-in siren and LEDs for light and sound alarm notification, respectively. In Ajax applications, all sensor states can be checked at any time.The sensor can be tested manually. When you press the front panel of the sensor, it turns on. The mechanical button on the front panel can be pressed both by hand and, for example, with a mop. During the test, the built-in siren is activated, and the sensors are checked. This allows the installation engineer to test the device when necessary and show the customer how the sensor will react to different types of alarms with sound and light.

Autonomous operation of the FireProtect 2 (Heat/Smoke/CO) wireless fire detector

The FireProtect 2 (Heat, Smoke, CO) fire alarm sensor is available in two models with replaceable and fixed power cells. Sensors with replaceable batteries can last up to 7 years with CR123A batteries already installed. Discharged batteries can be replaced with new ones.The permanent battery model uses built-in lithium power cells for at least 10 years of operation. Such a sensor must be replaced with a new one after the batteries are discharged.

Installation and connection of the Ajax FireProtect 2 (Heat/Smoke/CO) wireless fire detector

It is not necessary to open the sensor enclosure to install FireProtect 2. Pre-installed replaceable or fixed power supplies are available, and no tools are required to remove the SmartBracket from the sensor. The SmartBracket mounting panel allows you to later align the position of the sensor after installation.In less than a minute, the sensor is connected to the Ajax security system. You need to run the Ajax app, scan the QR code and add the device to the security group and room.