Radio linked fire alarm systems

Some of the recommendations, applicable to wired fire alarm systems, are unsuitable for, or cannot be applied to, radio fire alarm systems. These include, in particular, those relating to power supplies and fault monitoring.
Additional recommendations apply to radio-linked fire systems in order to address the integrity and performance of the radio communications link between components and the fire alarm control and indicating equipment.
In practice, no fire systems can have total reliability, but one of the objectives of good fire system design is to reduce the probability of the fire alarm system being inoperative in the area of a fire when the fire starts. It is useful that the advantages and disadvantages between the two technologies, hardwired and wireless fire alarms and radio linked systems, are different because this allows for a system to be installed that suits the site. Great care needs to be taken when assessing a site and choosing the technology to use, as neither the wireless fire alarm nor hardwired system is singularly suitable
for every site.
Components of a fire system interconnected by radio-links may include fire alarm devices, such as fire alarm
sounders, as well as detectors and manual call points. However, exercising the fire system with testing and evacuation drills in excess of those recommended by the manufacturer can reduce the life of the radio-linked fire alarm sounder batteries. Automatic silencing of radio-linked sounders on wireless fire alarm systems, is sometimes employed to overcome the potential for undue discharge of sounder batteries. However, sounders with this facility need to reactivate with any new fire or phased evacuation command. Such a facility ought not to impair the system’s ability to provide an adequate audible warning to the occupants of the building in the event of fire.
Other components of a radio fire alarm system may include radio relay units, which are installed remote from
the control and indicating equipment so as to extend the range of the system. Where such relay units are separate control and indicating panels, this is a form of networked system .
Radio communications may also be used to link a small number of detectors and other components to what is essentially a wired system. The recommendations of this standard apply equally to integral radio-linked systems of this nature.