What is a Fire Alarm System? (Fire Detection System)

Understanding “what is a fire alarm system” is crucial for safety in any residential or commercial building. In the UK, these systems are essential for detecting smoke, heat, or harmful gases and alerting everyone inside.

They use alarms and lights to facilitate quick evacuations and can also alert emergency services. This article will explain how fire alarm systems work, their key components, and their importance in protecting people and property.

A fire alarm system works by detecting potential fire-related events, such as smoke, heat, or carbon monoxide, using sensors. These sensors send signals to a Fire alarm panel, which then activates alarms, sprinklers, and alerts building occupants or emergency services.

Wireless systems transmit signals via radio frequency, while addressable systems identify the specific location of the fire. The system plays a crucial role in detecting, alerting, monitoring, and controlling fire risks to ensure life safety.

Fire detectors are devices that sense fire or related hazards like smoke, heat, or harmful gases such as carbon monoxide. They trigger alarms to warn people and help them take action. Different types of fire detectors are designed to detect specific hazards and provide early warnings to keep everyone safe.

Heat Detectors

Heat detectors detect fires by sensing temperature changes, either at a set point or rapid increases. Heat detectors come in two main types:

Fixed Temperature Detectors: These set off an alarm when the temperature reaches a specific level, using a meltable alloy that needs replacing after use.

Rate-of-Rise Detectors: These detect rapid increases in temperature and may also have a fixed temperature component. They work like an electrical fuse, where a heat-sensitive material melts to trigger the alarm.

Smoke Detectors

A smoke detection system senses smoke to alert people of a fire and it comes in three main types:

Ionization Smoke Detectors: These use two chambers—one with a radioactive source—that detect smoke by measuring changes in electrical current.

Light Scattering Smoke Detectors: These detect smoke by scattering light in a chamber, which then triggers an alarm.
Light Obscuring Smoke Detectors: These detect smoke by measuring how smoke blocks a light beam between a source and a photocell.

Carbon Monoxide Detectors

Carbon monoxide (CO) fire detectors sense CO, a toxic gas from burning materials, to detect fires. They are more sensitive than standard CO detectors and can detect smoldering fires but may not be as effective for flaming fires. They should be replaced every seven years and can also react to temporary CO from things like gas heaters.

Multi-Sensor Detectors

Multi-sensor detectors use both optical and heat sensors to detect fires. They process signals from these sensors with advanced algorithms to provide a more accurate fire detection. The detector responds to both smoke and rapid temperature changes, making it versatile for various fire situations. It can replace ionization detectors in many cases and features drift compensation to maintain accuracy. Key factors to consider include circuit type, voltage, mounting options, and current demand.

Manual Call Points

A manual call point is a device used to quickly activate a fire alarm. It should be easily visible, placed near stairways, exits, and on each floor landing at about 1.4 meters high. No call point should be more than 30 meters apart to ensure accessibility in an emergency.

In high-risk areas or where people move slowly, more call points may be needed. There are also special versions for hazardous areas and those without glass. When installing, consider the mounting location and the type of circuit required.

When considering “what is a fire alarm system,” it’s important to know there are three main types: manual, life protection, and property protection. The right choice depends on your building’s type, contents, and risks. A fire risk assessment will help determine the best system for your needs.

Manual fire alarm systems are the simplest type and depend on building occupants to detect a fire and alert others. To activate the alarm, someone must press a button or pull a lever, often found in break glass units around the building. These systems may include basic devices like hand bells or gongs, and can be purely manual or use electric components for added features.

Category L fire protection systems are designed to safeguard lives within a building. They are divided into five sub-categories, here’s a brief guide to the key levels:

L1 Fire Alarm System: Provides the highest level of protection with detectors in every room, corridor, and compartment, ideal for high-rise commercial buildings and large spaces.

L2 Fire Alarm System: Offers extra protection with smoke detectors in key areas like escape routes, corridors, and high-risk spots, suitable for factories and residential premises.

L3 Fire Alarm System: Focuses on escape routes and connecting rooms, used in smaller or lower-risk buildings to ensure safe evacuation.

L4 Fire Alarm System: Detects smoke in escape routes like corridors and stairwells, suited for smaller, low-risk buildings where room-by-room coverage isn’t needed.

L5 Fire Alarm System: Targets high-risk areas within a building, such as kitchens or rooms with valuable equipment, often working alongside other systems for enhanced life safety.

Category P fire alarm systems focus on building security system. They come in two types:

P1 (Maximum Property Protection): This system has detectors installed throughout the entire building. It aims to detect fires as early as possible to minimise damage and ensure quick action by fire-fighters.
P2 (Minimum Property Protection): This system places detectors only in high-risk areas. It provides early detection where fires are most likely to start but does not cover the entire building.

Fire alarm systems detect smoke or heat and sound an alarm to alert people to evacuate. Some systems also send signals to call the fire brigade. What is a fire alarm system? It comes in four main types:

Conventional Fire Alarm Systems 

A Conventional Fire Alarm System connects detectors and call points to a central control panel using wires. What is a fire alarm system? It’s a setup that divides the building into zones to identify which area has triggered the alarm. Although these systems are simple and affordable for smaller buildings, they only provide a general location of the fire.

Addressable Fire Alarm Systems

In an Addressable Fire Alarm System, each device has a unique address, allowing the fire alarm panel to pinpoint the exact location of an alarm. What is a fire alarm system in this case? It’s a system that uses a loop to connect up to 99 devices, offering precise information on fire location and helping emergency services respond quickly.

Intelligent Fire Alarm Systems

These advanced systems, or Analogue Addressable Fire Alarm Systems, feature detectors with built-in computers. What is a fire alarm system here? It’s a system where detectors analyze their environment and provide detailed information to the control panel. This setup, capable of managing up to 127 input devices and 32 output devices per loop, is ideal for large buildings, reducing false alarms and pinpointing exact fire locations.

Wireless Fire Alarm Systems

Wireless Fire Alarm Systems use secure, license-free radio signals to connect components like smoke detectors and call points to the control panel. What is a fire alarm system in this context? It’s a modern solution that eliminates extensive cabling, making it ideal for challenging installations and incorporating smart technology for integration with various software applications.

A fire alarm system detects fires using its initiating devices. These devices are connected to the control panel via 2- or 4-wire circuits, which allow the fire alarm panel to monitor their status. It displays whether the devices are in normal or alarm mode. When a fire occurs, smoke or heat will trigger an initiating device, or a manual pull station will be activated, setting the system to alarm mode.

Installing a fire alarm system is essential for ensuring property and life safety and protecting property from the dangers of fire. Here are the key benefits:

Alerts:Fire alarms provide loud and visible warnings to help people evacuate quickly.

Fire Monitoring: They automatically notify the fire department, speeding up response times.

Early Detection: Rapid detection limits damage and reduces the risk of loss of life.

Insurance Savings: A fire alarm system can help lower your insurance premiums.

Safety: They are vital for safeguarding both people and property from fire hazards.

Legal Requirement: Fire alarms are required by law for businesses to ensure safety and compliance.

What is a fire alarm system? It’s a setup of detectors, alarms, and control panels designed to alert occupants in emergencies. Proper installation involves positioning devices according to regulations, thorough testing, and ensuring integration with existing safety measures. Regular maintenance is key to keeping the system reliable.

Initiating Device

These detect smoke, heat, or flames and include smoke detectors, heat detectors, sprinkler water flow sensors, and manual pull stations. They send signals to the control panel about a potential fire. They come in two types: automatic fire detection (on its own) and manual (requires human activation) system.

Indication Appliances

These alert occupants to a fire through audible and visual signals. Examples include horns, chimes, bells, and strobe lights. They ensure people are warned and can evacuate quickly.

Notification Appliances 

Designed to inform occupants about a fire using both visual and audible signals. They include pulsing lights, flashing strobe lights, sirens, and alarm sounders, and operate using power from the fire alarm system or a backup power source.

Power Supplies

Fire alarm systems are powered by main electricity, 12V batteries (for up to 24 hours of backup), and sometimes generators for extended outages. Batteries and generators ensure the system remains operational if main power fails.

Auxiliary Devices

Enhance the system’s functionality. A key example is the remote annunciator, which allows emergency personnel to view and control the system from outside the electrical room.

Fire Alarm Control Panel (FACP)

The central unit that manages the system, displays its status, and controls initiating devices and notification appliances. It also communicates with monitoring agencies during alarms.

Siren

Loud devices like wall horn strobes and alarm bells used to alert people quickly in emergencies. They can also deter intruders and can be integrated with systems like Kisi.

Additional Devices

Include LED indicators for fire zones, remote displays, alarm silence switches, and electromagnetic door holders. They can also manage safety features like fire doors and elevator controls, often integrating with modern security and smart technologies for comprehensive building security.

To maintain fire alarm systems, test a different manual call point weekly and ensure audibility, with extra off-hours tests for shift workers monthly. Check standby power and run the generator monthly, inspect and top up batteries quarterly, and have a technician perform a thorough system check every six months.

Choosing the right fire alarm system depends on the specific risks and needs of your building. Start with a professional fire risk assessment to determine the best system for your premises. Ensure the system complies with legal requirements, fits your budget, and integrates well with your current security setup. Look for additional features like a hush button or backup battery to enhance functionality. Consult with experts and read reviews to find a reliable system that meets your needs.

BS 5839 is a British Standard that guides fire or smoke detection and alarm systems. It covers the types of systems, their design, installation, and maintenance. The standard ensures that fire alarms are properly set up and maintained for safety.

In summary, understanding **what is a fire alarm system** helps us see how various components work together to keep us safe. Heat detectors sense temperature changes, smoke detectors identify smoke through different methods, and other devices alert us with loud alarm sounders and security lights. Each part plays a crucial role in detecting fires and ensuring a quick response.

Don’t forget to read about: what is CCTV cameras.