Understanding Fire Alarms

Abbion Fire and Security Systems appreciates that purchasing a new fire alarm can be a confusing and time consuming business.  Here on this page, we will try and help you understand a little more about Fire Alarm Systems in a commercial property and what you may need to know or do in the best interests of your business.  Please keep checking back as we will always try to keep you updated of new developments wherever possible.  Any further questions or queries will be answered as soon as possible by contacting us.


Nearly all commercial or industrial premises will be required to have some form of fire alarm system installed. Sometimes, the system is better described as a fire detection & alarm system, as it's primary function is firstly to detect a fire or fire condition, and secondly to sound audible alarms in all of part of the building. At it's most basic, the system may be simply consist of a Fire Alarm Control Panel and a series of Break Glass Units, otherwise known as Manual Call Points or MCP'S. These basic systems are known and classified as a Manual Fire Alarm System. At the other end of the scale, a more complex system can have multiple and varying types of smoke, heat and other forms of detection spread throughout the building, potentially linked to adjoining buildings or area and connected to Alarm Receiving Centres (ARC'S), sometimes known as monitoring stations. It is essential that any fire alarm is correctly designed, specified and installed to meet the requirements of the building and the buildings purpose (e.g. a place of work).   The system may primarily be designed to protect the property and/or life  hence reliable, long term operation is essential. All design and installation details of the fire alarm should always be agreed with all relevant parties including the Local Fire Office (Fire Brigade), the local District Surveyor (Council), Insurers, Site Fire Officers, as well as architects and structural engineers. All may impose specific requirements relevant to their field. The over-riding standard for the design of a Fire Alarm System is BS5839.  This is a comprehensive document and is nearly always cited as the required standard. It includes requirements such as for the detection cabling to be fire proof, adequate battery backup to be provided and a wealth of other design features. It is common for the fire alarm system in a building to be classified in accordance with classifications noted in BS5839. These have recently been updated and reference should also be made to BS5839:2002 in respect of the requirements

System Classifications

Systems for protecting life

Type M - Manual System - A fire alarm system that relies upon Manual Call Points (MCP'S) being operated by building occupants. If a MCP is smashed then the alarm sounds. This system depends upon the presence of people.

Type L1 - Life 1 - A fire alarm system with automatic detectors installed throughout the building, including escape routes, stairs, every room, store and void. In addition, MCP's are installed on all exits and between zones. This system will operate even when people are not present.

Type L2 - Life 2 - A fire alarm system with automatic detectors installed along all escape routes as well as in high risk areas, such as plant rooms, storage facilities or any other area where a fire would cause a high risk to life. In addition, MCP's are installed on all exits and between zones. This system will operate even when people are not present.

Type L3 - Life 3 - A fire alarm system with automatic detection installed only along escape routes and in areas where free passage is essential to protect life. MCP's are also installed at exits and between zones.

Systems for protecting property

Type P1 - Property 1 - A fire alarm system with automatic detectors installed throughout the building, including escape routes, stairs, every room, store and void. In addition, MCP's are installed on all exits and between zones. This system will operate even when people are not present. In the majority of cases a P1 system can be taken as having the same cover as an L1 system.

Type P2 - Property 2 - A system with automatic detectors installed only in high risk areas, such as plant rooms, storage facilities or any other area where there is a high risk of fire. In addition, MCP's s are installed on all exits and between zones. Note that a P2 system does not necessarily cover escape routes and may not provide adequate life protection. The type of system used will depend upon the building. Note that the actual requirements MUST BE VERIFIED as this information is a guide only.


 Manual Call Point or MCP: A small device usually mounted adjacent to fire exits and where an escape route leaves a zone. Smashing the glass will cause a circuit to be either made or broken.
 Automatic Detection: Designed to monitor environments and surroundings with various types of detection, including but not all, smoke detection, heat detection, flame detection. For more complex systems, aspirating systems and other forms of detection are available.
 Sounders: These devices produce a high volume sound and are located throughout the building. In the event of fire, all the sounders will be activated (unless the fire alarm system requirements state otherwise) and they will continue until silenced at the panel.  On older systems, bells may been installed but these have now been superceded by the electronic sounder.  Dependant on your requirements, strobe lights may also be required.  Sounder heads that fit onto your automatic detection are also available.

 Control Panel:The fire alarm panel is the central hub of your fire alarm system. It monitors the detection wiring and devices for faults and operation. If an alarm condition is identified then the panel activates the sounders as well as any other controlled equipment such as remote communicators.The panel is fitted with various indicators and internal buzzers. The zone in which the alarm originates is shown, also with addressable systems, the actual device number and location may be given. The fire alarm panel may contain standby batteries (else they are located remotely). The panel may operate on an addressable or conventional basis.

The fire alarm panel must always be situated in a position where the Fire Brigade can easily see and find it (normally by a front entrance). It is hence best to obtain their agreement prior to installation, however this isn't always possible.  A complete, highly visible Zone List along with the Fire Alarm Maintenance company's details is also recommended.

Special arrangements may existing in large complex sites with secondary or "repeater" panels being common in areas such as security desks, second entrances and fire control points.

Additional equipment dependent on the type of system and environment is available.

Addressable or Conventional

Conventional Fire Alarm Systems are an older type of technology.  The system is cabled via a series of cables running from the main Fire Alarm control panel to the devices on each zone. If a device operates then the panel will only indicate the appropriate zone. The actual device which has operated is not indicated. Such systems are still commonly used for small buildings, or where a more affordable yet still suitable type of operation is required

Addressable Fire Alarm Systems rely on more modern technology to individually address each device in the fire alarm system. When a device operates, the panel indicates both the appropriate zone and the actual device number or even the room location if appropriate. This considerably helps fire location and helps fire crews to get to the point of fire origin very quickly.
Such systems are cabled by means of one or more loops with only the loop ends being connected at the panel. Obvious cable savings can be made using an addressable system.

Abbion Fire and Security can provide either conventional or addressable fire alarm systems to suit any budget.


All but the smallest building will require segregation as far as the fire alarm system is concerned. The primary purpose of zoning is to aid the identification and to speedily locate a fire. In essence, the building should be split up into small areas (zones)  in which operation of any devices in the zone will cause a zone indication at the panel. Zone divisions are dependent upon many factors, all detailed in BS5839. However, it is common for zone divisions to be closely related to the building fire compartmentation. A zone should not exceed 2000m²


All cabling should be done in fire resistant cabling compliant with the relevant British Standards

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