Fire Alarms & Life Safety Sytems

Fire Alarms and Life Safety Systems

Fire alarm systems are a means of securing company premises and the lives of those employees who operate within.

The choice of fire alarm system depends on the building structure, the purpose and use of the building and current legislation. The main standard for fire alarm systems is BS5839 pt1:2013

All Fire Alarm Systems essentially operate on the same principle. If a detector detects smoke or heat or someone operates a break glass unit (manual break point), then alarm sounders operate to warn others in the building that there may be a fire and to evacuate. It may also incorporate remote signalling equipment which would alert the fire brigade via a central station.

Fire Alarm Systems can be broken down into four main categories:
Conventional
Analogue Addressable
Wireless systems
Aspirating systems

Conventional Non Addressable Fire Alarm System
In a Conventional Fire Alarm System, a number of call points and detectors are wired to the Fire Alarm Control Panel in Zones. A Zone is a circuit and typically one would wire a circuit per floor or fire compartment. The Fire Alarm Control Panel has a number of Zone Lamps. The reason for having Zones is to give a rough idea as to where a fire has occurred. This is important for the fire brigade and of course for the building management. The accuracy of knowing where a fire has started is controlled by the number of Zones a Control Panel has and the number of circuits that have been wired within the building. The Control Panel is wired to a minimum of two sounder circuits which could contain bells, electronic sounders or other audible devices. Each circuit has an end of line device which is used for monitoring purposes.

Analogue Addressable Fire Alarm Systems
Analogue Addressable Fire Alarm Systems are often known as Intelligent Fire Alarm Systems. There are several different types of Analogue Systems available which are determined by the type of protocol which they use. The bulk of standard Analogue Detectors available are fairly standard as the Detectors can only give output signals representing the value of detected phenomena. It is left up to the Control Unit to decide whether there is a fire, fault, pre-alarm or other. With a true Intelligent Analogue System each detector effectively incorporates its own computer which evaluates the environment around it, and communicates to the Control Panel whether there is a fire, fault or the detector head needs cleaning. Essentially Analogue Systems are far more complex and incorporate far more facilities than Conventional Systems. Their primary purpose is to help prevent the occurrence of false alarms. With the Analogue Addressable System, up to 200 devices i.e.: Smoke Detectors, Call Points, Heat Detectors, Sounders, VADS and interface devices may be wired to each detection loop. Analogue Systems are available in 1, 2, 4 and 6 loop versions which means large premises can be monitored from one single panel. Isolator units should be connected between sections of detectors as described for Addressable Systems.

Wireless Fire Alarm System
Wireless fire alarm systems are an effective alternative to traditional wired fire alarm systems for all applications. They utilise secure, licence-free radio communications to interconnect the sensors and devices (smoke detectors, call-points, etc.) with the controllers. It is a simple concept, which provides many unique benefits and is a full analogue addressable fire detection system without the need for cable.

Aspirating Systems
In an aspirated detection system, air is sampled from the protected area through a network of pipes or tubes, actively drawing the air towards the detection system using a high pressure aspirator fan.
There are 2 main considerations for choosing an aspirating system

The sampling pipework used in aspirating systems is more resilient to harsh environments than a standard point smoke detector.
Aspirating systems can often give a much higher sensitivity than a standard smoke detector, - it can detect smoke before it is visible to the human eye.

Despite modern Fire Alarm Systems being very simple to use, full on-site training will be provided and if there are ever any issues - we are on hand 24/7 to provide help if it is ever required.

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