27Jan 2011
by Nick Potter

Fire Alarm Systems Terms and Abbreviations Explained

Fire Alarm Systems

This is a short guide to some of the terms and abbreviations used with fire alarm systems.


Addressable – Addressable Fire Alarm Systems can have a text location assigned to a component on the system which pinpoints exactly where that device is located.  This is often achieved by numbering the device and assigning a text location to that device using a laptop with the control panel.

AFD – Stands for Automatic Fire Detection (examples of this could be a smoke detector which automatically detectors smoke in the environment).

Analogue – An analogue fire alarm device is capable of monitoring the analogue levels within the unit.  For example an analogue smoke detector will be able to indicate how much smoke is in the chamber of the smoke detector head.  This is particularly useful in false alarm management as a pre-alarm can be set up to indicate before the smoke detector has enough smoke in the head to activate the control panel into full alarm.

Analogue Addressable Fire Alarm Systems – Analogue Addressable Fire Alarm Systems are wired using loop circuits which can accomodate both detection equipment and alarm equipment.  These systems are more advanced that Conventional / Non-addressable fire alarm systems as they provide can provide mush more information than the more traditional conventional systems.

ARC – Stands for Alarm Receiving Centre.  These are central monitoring stations which are constantly monitoring for signals from fire alarm system for fire alarm activations.  They will often automatically call out the fire brigade once a fire alarm activation has been received.

ASD – Stands for Aspirating Smoke Detection.  These systems are sometimes referred to as air sampling systems.  The basically work by drawing air from an area usually through tubing of some sort and sample that air for any signs of smoke.  These systems are particularly useful for areas which aren’t easily accessed for maintenance.

ATEX – ATmospheres EXplosive

BAFE – This is the acronym for the British Approvals for Fire Equipment

Beacons – Beacons on fire alarm systems give a visual indication via a flashing lense that the fire alarm system has been activated.  These units a most commonly used where ambient noise levels in an area are high and a traditional fire alarm sounder may not be heard.  They are also used to comply with DDA requirements in a building.

Beam Detectors – Beam Detectors generally use an optical beam which is monitored for obscuration of smoke particals.  Beam Detectors can be either reflective of point-to-point.  These units are generally used in large open areas and atriums.

Break Glass – A break glass unit is a manually operated point commonly sited next to final exits of buildings and entrances to stairwells which enables the fire alarm system to be activated manually by pressing the glass element within the unit.  Fire Alarm Break glass units are almost always red in colour.  Break Glass units may also be referred to as Call Points, Manual Call Points and MCPs.

BS5839 – BS5839 is the relevant British Standard associated with Fire Alarm Systems.

Category L Fire Alarm Systems – BS5839 Category L Fire Alarm Systems are designed primarily to save life.

Category P Fire Alarm Systems – BS5839 Category P Fire Alarm Systems are designed primarily to save damage to property.

Category M Fire Alarm Systems – BS5839 Category M Fire Alarm Systems have only a Manual means of operating the fire alarm system i.e. Manual Call Points.

CIE – Stands for Control & Indicating Equipment.  This is an abbreviation which is normally used as a short form for the fire alarm control panels and other such control equipment.

CO – Stands for Carbon Monoxide.

CoP – Stands for Code of Practice.

Competent Person (CP) – Fire Alarm Engineers are usually (but not exclusively) known as the competent people for working on fire alarm systems.  The definition of a competent person is as follows – “a person with the necessary training and experience, and with access to the requisite tools, equipment and information, accepted by the relevant authorities as capable of carrying out a defined task”.

Conventional Fire Alarm Systems – Conventional Fire Alarm Systems are Non Addressable Fire Systems commonly used for smaller systems which wired using radial zone circuits for detection circuits and radial alarm circuits for the sounders and beacons.

CPC – Circuit Protective Conductor

CSP – Critical Signal Path

dBA – Deci – Bel Audio.  Fire Alarm Sounders are rated using decibels.

EN54 – EN54 is the European Standard which specifies requirements for all component parts of a fire alarm system.

FD&A – Fire Detection and Alarms

Fire Proof Cables (FP) – Fireproof Cable cable used for fire alarm systems which is specially designed to be much more resistent to fire than standard cables.

Fixed Temperature Heat Detector – Fixed Temperature is a specific type of heat detector which will activate once the thermal element has detected that the atmosperic temperature has reach a set point.

Intrinsically Safe – Intrinsically Safe fire alarm equipment is specifically designed to be used in environments with a high risk of explosion.

Ionisation Smoke Detector – Ionisation smoke detectors work by using a small radioactive source and receiver within its chamber to detect the levels of smoke particles in its chamber.  These units are now generally being replaced with the more environmentally friendly optical smoke detectors.

LED Beacons – These are beacons that use LED technology for the flashing element of the device.  LED beacons generally don’t need as much current as Xenon type beacons.

LPCB – Loss Prevention Certification Board.  The LPCB offers a 3rd party approval for fire alarm products and services.  The LPCB has been working with industry and government for over 100 years to ensure that fire and security products and services perform effectively.

MCP – An MCP is a manually operated point commonly sited next to final exits of buildings and entrances to stairwells which enables the fire alarm system to be activated manually by pressing the glass element within the unit.  MCP units are almost always red in colour.  MCPs may also be referred to as Call Points, Manual Call Points and Break Glass units.

Optical Smoke Detector – Optical Smoke Detectors are a specific type of smoke detector which senses smoke particles in its chamber by detecting the obscuration of a beam of light within the detector chamber.

Pyro Cable – Pyro Cable otherwise know as MI or MICC (Mineral Insulated Copper-Clad Cable) is a type of electrical cable made from a copper conductor inside a copper exterior.  Between the conductor and sheath is a layer of magnesium oxide powder insulation.

RoR – RoR stands for Rate of Rise which is a particular type of heat detector which is monitoring for the rate of change of temperature rather than a particular set temperature point.

RP – RP stands for Responsible Person.  In relation to Fire Alarm Systems the responsible person is the person on-site who is responsible for the day to day operation of the fire alarm system.  Not to be confused with the CP (Competent Person).

SLA BatteriesSealed Lead Acid Batteries used in fire alarm systems as a back-up in the event of a mains failure.

Sounder – Sounders on fire alarm systems are the audible warning devices which emit a tone when the fire alarm system has been activated.

Sounder Beacons – Sounder beacons on fire alarm systems are units which combine a sounder and a beacon together in one point.  These units can save on installation costs and can also help to comply with DDA regulations.

Two Wire Fire Alarm Systems – These are similar to conventional fire alarm systems however they are specially designed to allow detection devices (smoke & heats detectors) and warning devices (sounders & beacons) to be connected to the same circuit instead of on separate circuits.

Wireless Fire Alarm SystemsWireless Fire Alarm Systems are fire systems which don’t require cables to the detectors, call points and warning devices on the system.  The devices on the system are battery powered and communicate with the control panels using radio signals.  These systems are particularly useful for ornate buildings where traditional wired fire alarm systems would not be difficult to install and would not be aesthetically pleasing.