A fire alarm system is a collection of interconnected devices that can detect and alert occupants to the presence of fire. An essential component of buildings when it comes to protecting public safety, which fire alarm system that is adopted depends on the structure of the property.
What is a Fire Alarm System?
A fire alarm system usually comprises the following components;
Fire Alarm Control Panel (FACP)
The fire alarm control panel is the brain of the fire alarm system, receiving signals from the initiating devices and activating notification devices.
Initiating Devices
Initiating devices are sensors that are a part of the fire alarm system that detect the presence of fire. Initiating devices include items such as smoke detectors, heat detectors and manual pull stations.
Notification Devices
Notification devices alert occupants and those in the vicinity of a building to the presence of fire. Common notification devices includes horns, strobes and voice evacuation systems.
Power Supply
Fire alarm systems require a power supply to fully function. Usually, fire alarm systems have a primary power supply (e.g. AC power) and a back-up power supply, such as batteries, in case the primary power supply fails.
Fire Alarm Categories
As per British Standard BS 5839-1:2017, the design, installation, commission and maintenance of fire detection and alarm systems in non-domestic properties specifies that there are eight categories of fire alarm systems. The categories are defined by the level of life and property protection required.
Manual Fire Alarm Systems (Cat M)
Category M fire alarm systems are activated manually by the public or fire safety expert. Manual systems are typically employed in low-risk areas such as smaller office spaces or retail environments.
Automatic Fire Alarm Systems (Cat L1-L5)
Category L fire alarm systems are automatic designs that are essential for protecting life. Typically utilised in higher risk areas, such as hospitals, schools or hotels, Category L fire alarm systems include five sub categories, ranging from L1 to L5.
Category L1
The most comprehensive fire alarm system, Category L1 fire alarms provide maximum protection. Category L1 fire alarms are required to be installed throughout all areas of the building, including roof spaces and voids.
Category L2
Providing additional life protection, Category L2 fire alarm systems require automatic detectors to be installed in all high-risk and hazardous areas such as escape routes and rooms leading to escape routes.
Category L3
A standard life protection automated system, Category L3 fire alarms require automatic initiating devices to be installed on escape routes and rooms leading to escape routes.
Category L4
A modest life protections system Category L4 requires automatic detectors to be installed in high-risk and hazardous areas, in addition to escape routes, corridors and stairways.
Category L5
Localised fire protection systems are utilised to identify fire in particular areas of a building. This is typically due to specific rooms posing a particular risk because of the materials stored or business activities carried out, often identified via commercial fire risk assessments.
Automatic Fire Alarm Systems for Protection of Property (Cat P1-P2)
Category P fire alarm systems are automatic mechanisms specifically designed to protect properties and are used in high value areas like warehouses, factories and commercial spaces.
Category P1
Providing maximum protection, Category P1 fire alarm systems require detectors to be installed throughout the building and is crucial to a business’ day-to-day operations.
Category P2
Minimum property protection systems are utilised in high-risk areas of a building, and should be used to provide early detection for most likely causes of a fire scenario.
Types of Fire Alarm Systems
There are two main types of fire alarm systems, these are conventional and addressable.
Conventional fire alarm systems are the simpler of the two. Dividing the building into zones, each zone is monitored by a single initiating device, such as a smoke detectors or heat detector. Once a fire is detected, all notification devices will activate to quickly notify occupants.
An addressable fire alarm system is most complex than conventional mechanisms, offering superior versatility and control. Each initiating devices in addressable systems have a unique address which allows the FACP to conveniently identify the precise location of the fire or smoke. This can be key when it comes to implementing all out policies, stay-put policies and directing fire fighting services correctly.
Other fire alarm system types include;
Wireless Fire Alarm Systems – Wireless fire alarm systems utilise radio waves in order to transmit signal from initiating devices to the FACP, removing the need to run fires through the structure. This makes wireless fire alarm systems a viable solution for retrofit applications or complex buildings with hard-to-wire areas.
Voice Evacuation Systems – A voice evacuation system uses speakers to deliver either pre-recorded or live voice messages to direct occupants in the event of a fire. This can be crucial when it comes to delivering the accurate details the public need in fire scenarios.
Gas Detection System – Gas detection systems effectively identify the present of flammable or toxic gases. This can be crucial when it comes to properties with a risk of Class C fire scenarios.
Aspirating Smoke Detection Systems – Aspirating detection systems utilise purpose-built fans to attract air from specified areas and direct it through a series of filters, which then check for the presence of smoke particles. Aspirating smoke detection systems are perfect for locations with high ceilings like warehouses or data centres.
Linear Heat Detection Systems – With a cable that’s installed along ceilings or walls of an area, a linear heat detection system contains a temperature-sensitive component that checks for any sudden increase in temperature. Linear heat detection systems are ideal for areas where it’s difficult to install normal smoke detectors like cable trays and conveyor belts.
Wireless Mesh Fire Alarm Systems – With a network of wireless devices which communicate in unison and with the FACP, wireless mesh fire alarm systems are well-suited for large and complex buildings and are easily scalable for suitability in dynamic, fast-moving environments.
Maintenance & Testing
Whilst fire alarm systems are essential for life and property safely, they’re only effective if properly maintained and tested. Fire alarm systems should be maintained on a regular basis by a qualified fire alarm approved contractor.
A fire alarm system maintenance check using includes cleaning smoke detectors and initiating devices to ensure functionality, testing batteries, inspecting wiring for damage and ensuring all components are working.
Choosing the Right Fire Alarm System
When choosing the right fire alarm system for a property, whether a residential building or commercial space, numerous factors have to be considered.
The size and type of property will likely have an impact, as more complex layouts will require more sophisticated fire alarm systems. Properties with high occupancy levels, like hospitals, schools or busy areas, will require fire alarm systems that provide early warnings for quick and effective evacuations.
A fire risk assessment from Melwood Facilities will assess the alarm requirements of a premises, and will take into consideration aspects such as a business’ or organisation’s budget and the level of protection required.
