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Fire Alarm Installation Categories

BS 5839 splits fire alarm systems into three system design categories (L, M and P). These design categories are broken down into eight fire alarm categories that your system can fall.

Fire Safety
Fire Alarm Installation Categories

The Regulatory Reform (Fire Safety) Order 2005 makes it a legal requirement that the fire alarm system installation at your business premises or site is fit for purpose and in working order. Before designing a fire alarm system, a Fire Risk Assessment must be carried out to define the system’s main objectives as part of the fire system specification.

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Fire alarm systems installations in buildings fulfil two objectives—protecting life and protecting properties. There is also protection against business interruption and the environment, though the BS 5839: Fire Detection & Alarm Systems for Buildings accepts this as property protection.

BS 5839 splits fire alarm systems into three system design categories (L, M and P). These design categories are broken down into eight fire alarm categories that your system can fall. They vary depending on the nature of your business and the other factors stated above. The fire alarm categories include:

  • Category M – Manual fire alarm system
  • Category L1 – Maximum life protection automated fire alarm system
  • Category L2 – Additional life protection automated fire alarm system
  • Category L3 – Standard life protection automated fire alarm system
  • Category L4 – Modest life protection automated fire alarm system
  • Category L5 – Localised life protection automated fire alarm system
  • Category P1 – Maximum property protection automated fire alarm system
  • Category P2 – Minimum property protection automated fire alarm system

Take a look at the different fire alarm categories below and how it is broken down to find the correct and most suited fire alarm system for your premises:

Category M Systems:

Category M Systems are manual systems and incorporate no automatic fire detection. This category is used commonly in properties where the occupiers are likely to detect a fire quickly but cannot be used for sleeping accommodation. Common places of work such as warehouses, factories, public houses, and restaurants.

Category L Systems:

  • Category L1 – Systems installed throughout all areas of the building. The goal of a category L1 system is to receive the earliest possible warning of fire to achieve the longest available time for escape. They are used commonly in hotels, student accommodation, hospitals, and large office blocks.
  • Category L2 – Systems installed in defined parts of the building. A category L2 system includes the coverage necessary to fulfil the recommendations of this standard for a category L3 system. The main objective of a category L2 system is the same as an L3 system, with the additional aim of offering early warning of fire in particular areas of high fire hazard or risk. They are used commonly in hotels, public houses, student accommodation, hospitals, and large office blocks.
  • Category L3 – This category specifies fire alarm systems designed to warn of fire at an early enough stage to enable the occupants, other than potentially the room of fire origin, to escape safely before the escape routes are impassable. Typical uses of this category are shopping centres, phased evacuation buildings and residential care.
  • Category L4 – installed in escape routes compromising circulation areas and circulations spaces, such as corridors and stairways. The objective is to notify the occupants by warning smoke within the escape routes. They are used commonly in places of assembly (cinemas, theatres, nightclubs and leisure centres).
  • Category L5 specifies fire alarm systems in which detectors, protected areas and locations are designed to meet a specific fire objective (other than that of an L1, L2, L3 or L4 system). The design is based on a localised need for detection in part of a building. The system could be as simple as a detector in one room in which the outbreak of fire would create undue risk to the occupants. Or the system could be comprehensive detection through large areas of a building where structural fire resistance is less than regularly specified (prisons and transportation terminals).


Category P systems
 

This category specifies fire alarm systems intended to protect property, commonly used for insurance purposes.

  • Category P1 – Systems installed throughout all areas of the building. The objective of a category P1 system is to provide the earliest warning of fire to ensure a quicker arrival of the fire brigade.
  • Category P2 – Systems installed in defined parts of the building. The main objective of a category P2 system is to warn of fire in areas of high fire hazard or risk.

Choosing the correct category:

Firstly, are you protecting life or property? It is crucial to determine this because even though category L1 and P1 systems are similar, they can be designed completely different. For example, if you are protecting property with a P1 system, you would have detection in all areas though you would not need audible or visual indication. An L1 system protects life; therefore, you require audible and visual devices.

BS5839-1 does not recommend which system category needs installing in any premises. The categories are considered a ‘menu’, in which purchasers, specifiers, enforcing authorities, insurers or designers can choose a suited system for a building. Though, as above, we have shown which are used typically in types of properties. Our fire alarm installation specialists can carry out a fire risk assessment to determine which category is the correct one for your premise.

ClearView Fire Alarm Installation:

Accredited by BAFE and as FIA members, our fully certified engineers can supply, install, maintain, commission and remotely monitor all types of fire alarm systems to the highest standards as well as design all fire alarm systems to the relevant BS5839-1.

ClearView is highly certified in the fire industry, see our certifications and accreditations here, alternatively contact one of our specialists for more information on our fire safety services.

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