Saturday, March 27, 2021

HOW DO FIRE ALARM SYSTEM WORKS?

 FIRE ALARM SYSTEM



A fire alarm system is made up of equipment and technology that work together to detect, inform, and warn people about flammable gases, fires, and other situations. Some fire detectors or manual call points or pull stations can activate these alarm systems automatically.

The fundamental goal of a fire alarm system is to notify us as soon as a potential fire situation arises. It's a fully automated system that detects, monitors, identifies, and locates flammable vapor that could cause a fire. A fire alarm system's primary function is to detect, alert, monitor, and control fires. In offices, factories, and public buildings, fire alarms are installed.

When the alarm is activated, sounders will go out to notify everyone in the building to leave for safety reasons, regardless of the mode of detection. A remote signal system that alerts the fire department via a fire station may be included in a fire alarm system. We'll look at the structure, operation, and different types of fire alarm systems in this post.

HOW FIRE ALARM WORKS 

The fire alarm control panel is the heart of the fire alarm system. It serves as the central point for all detector signals to be wired to. It offers users with stationary indications. The machine can also be configured to simulate a fire alarm for use in routine fire exercises. Every member of the organization is trained in how to respond in the event of a genuine fire.




CATEGORIES OF FIRE ALARM DEVICES

Fire alarm systems is grouped into two categories: Manual and Automatic.

MANUAL FIRE ALARM SYSTEM - To activate a manual fire alarm system, an operating personnel must be present. In the case of an emergency, the manual fire system allows for swift action.

AUTOMATIC FIRE ALARM SYSTEM - The automated system might be activated without human involvement by recognizing the presence of smoke, heat, and combustible/poisonous gases. An automatic fire system is programmed to provide early warning indicators of a fire hazard.

TYPES OF FIRE DETECTORS

Heat detectors, smoke detectors, carbon monoxide detectors, multi-sensor detectors, and manual call-points are among the several types of fire detectors.

HEAT DETECTOR

Heat detectors can either work on a fixed temperature basis, triggering an alarm when the temperature exceeds a preset value, or on a rate of change in temperature basis. In most cases, a heat detector functions similarly to an electrical fuse. The detector has a heat-sensitive eutectic alloy. When the system detects that the temperature has risen to a specific level, the alloy transforms from a solid to a liquid, triggering the alert.


SMOKE DETECTOR

Ionization smoke detectors, light scattering smoke detectors, and light obscuring smoke detectors are the three types of smoke detectors.

IONIZATION SMOKE DETECTOR

Ionization smoke detectors work by placing a radioactive material, generally an alpha particle, between two electrically charged plates, which ionizes the air and causes current to flow between them. When smoke enters the chamber, it disrupts the flow of ions, resulting in a reduction in current flow and the activation of an alarm.



LIGHT SCATTERING SMOKE DETECTOR

The tyndall effect is used in the light scattering smoke detector. A darkened chamber separates a photocell and a light source, ensuring that the light source is not incident on the photocell. Smoke entering the chamber would disperse the light from the source, causing it to fall on the photocell. The alarm is activated using the photocell output.


LIGHT SCATTERING SMOKE DETECTOR


LIGHT OBSCURING SMOKE DETECTOR

Smoke collides with the light beam between the light source and the photocell in a light-obscuring smoke detector. After that, the photocell measures the amount of light that falls on it. Changes in the photocell output are utilized to set off an alarm. With the light source and photocell separated by some distance, this sort of detection is utilized to safeguard broad areas.



CARBON MONOXIDE(CO) DETECTOR

CO-fire detectors are another name for carbon monoxide detectors. These are electronic detectors that detect the presence of carbon monoxide in the air to signal the start of a fire. Complete combustion produces carbon monoxide, which is a deadly gas. As a result, the detectors are not the same as carbon monoxide detectors, which are used in homes to protect residents against carbon monoxide poisoning caused by incomplete combustion in appliances like gas stoves or boilers. Sensors used in carbon monoxide fire detectors are comparable to those used in homes, although they are more sensitive and respond faster. Carbon monoxide detectors have an electrochemical cell which senses the presence of carbon monoxide in the air.




MULTI-SENSOR DETECTOR

The optical and heat sensors are combined in the multi-sensor detector. It uses a sophisticated algorithm integrated into the detector circuitry to process the inputs. When the detector is triggered by the control panel, it returns a value based on the combined responses of the optical and thermal sensors. They're made to be sensitive to a variety of flames.


MANUAL CALL POINT

 A manual call point, also known as a break glass call point, is a device that allows personnel to trigger the alarm system in the event of a fire by pressing a frangible part.



TYPES OF FIRE ALARM SYSTEM

Fire alarm systems can be broken down into four main types:

(i) Conventional fire alarm system

(ii) Addressable fire alarm system

(iii) Intelligent fire alarm system

(iv) Wireless fire alarm system

CONVENTIONAL FIRE ALARM SYSTEM

A traditional fire alarm system is one that is intended for small buildings. It is necessary to connect each gadget to the main fire panel with its own wire. A standard system necessitates more cabling than an addressed system. They can be divided into zones, each with its own control panel. Installing it is less expensive. A core cable is used to connect many call points and detectors in a traditional fire alarm system. The signals from each zone's call points and detectors are linked back into the central control unit. On the fire alarm control panel, each zone is denoted by an indicator bulb, a text display, or both in some circumstances. It's a good idea to split the building into zones so that the alarm may be set more precisely. A minimum of two sounders kits, which can include a bell, electronic sounders, or other related devices, are wired to the control panel. When these devices are triggered, they sound the alarm.




ADDRESSABLE FIRE ALARM SYSTEM

he detecting mechanism of an addressable fire alarm system is similar to that of a traditional system, with the exception that detectors are assigned addresses using a DIP switch. Which call point activates the alarm can be determined via the control panel. The fire panel is connected in a loop to all of the installed fire equipment. It makes it simple to locate a fire or, in the case of a false alarm, it identifies a malfunctioning equipment. The detection circuit is linked in a loop, and each loop can have up to 99 devices connected to it. The loop is sectioned to ensure that a single short circuit or defect only affects a limited piece of the system, rather than the entire system.

Detectors are not considered intelligent in the previous two systems, namely the conventional fire alarm system and the addressable fire alarm system, because they can only provide output signals reflecting the values of detected.


INTELLIGENT FIRE ALARM SYSTEM

Each detector in an intelligent fire alarm system has its own computer that analyzes the environment around it and communicates to the control panel whether there is a fire, a problem, or whether the detector head needs to be cleaned.

Intelligent systems are, in essence, significantly more complicated and need far more resources than conventional or addressable systems. The main goal is to reduce the number of false alarms that arise.


WIRELESS FIRE ALARM SYSTEM

Traditional wired fire alarm systems are being replaced with wireless fire alarm systems. To connect the sensors and equipment to the controllers, they use a secure license-free radio connection frequency. It offers a number of distinct advantages, including service flexibility and mobility. It enables the installation of a complete fire detection system without the need for wiring.




SUMMARY

In the event of a fire emergency, fire alarm systems are installed in every building. Heat detectors, smoke detectors, carbon monoxide detectors, multi-sensor detectors, and manual call points were among the principal types of fire detectors studied.

Finally, we examined the many types of fire alarm systems, including traditional, addressable, intelligent, and wireless fire alarm systems.


 Thanks for viewing! 






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