Radio based fire detection systems have been employed for more than 30 years. Recently, the integrity of these systems has been considerably improved by using licence-free channels and long life self powered components such as MCP--detectors with purpose designed control panels. Radio based systems can now meet the most stringent performance requirements, the revised BS5839-1 2002 recognises their role in appropriate environments where wire based technology would be difficult or inappropriate for the application.

RADIO SURVEY

It is imperative that a radio site survey is accepted by the person responsible before an application is supplied. The survey will determine the appropriate radio receivers, transmitter type, location of aerials and the positioning of devices. This survey is vital for confidence in the system's long term trouble free performance and to ensure compatibility with the other electronic equipment present in addition to the building's construction materials and layout.

Subject to the survey, systems can provide protection in areas where it is difficult or inappropriate to drill or surface-fix cables. Typical applications may include heritage, clean rooms, and asbestos-clad areas. Even the latest high tech environments may benefit from a radio system that can be implemented around complex systems. One such recent installation was the Imperial College Flowers Building which had a clutter-free exposed services design but with NMR, electron microscopes and super computers for working on ground breaking medical research that needed protection.

Modern radio devices have built-in battery power packs, which typically give each device a five-year life under normal operating conditions before they need replacement. Normal operating conditions include regular system tests, including sounders, as specified in the standards. The latest devices now incorporate alkaline off-the-shelf batteries bought from the high street and do not require the purchase of specialised modules from the supplier--further reducing replacement costs and addressing the environmental issues of using lithium batteries.

The health of each battery pack is monitored by the system and a `low battery' warning is raised well in advance, often allowing battery replacement to be undertaken during normal maintenance.

COMPATIBILITY WITH OTHER SYSTEMS