I believe it would be possible to interface intruder alarm detection and intruder alarm warning devices into what is primarily an addressable fire alarm system and still keep the fire alarm system otherwise compliant with the BS. However the cost of doing so would probably be more expensive than two seperate systems.
Adding smoke detection to a system that is primarily an intruder alarm system can be a very cost-effective method of providing automatic fire detection. However, I believe it is impossible to include a BS5839 Part 1 fire alarm system within an intruder alarm system. At the very least the intruder alarm would not comply with the fire alarm BS in respect of cable fire resistance, fire detector removal monitoring/circuit continuation and battery standby duty.
Can anyone confirm Buzz's point that Part 6 smoke detection as part of an intruder alarm might be recognised under some circumstances. I don't know for sure and can't be bothered to wade through part 6.
In all events, if TWs' fire system should be Part 1 then I believe that the most cost-effective solution is always two seperate systems anyway.
Knew I'd find it!!
From Part 6:2004
B.5 Grade C (Fire detectors supplied with power from a common power supply unit, with
central control equipment)
B.5.1 More effective control and monitoring of a fire detection and fire alarm system can be provided by
connecting all fire detectors to a common power supply, comprising the normal mains, rectified and
regulated as appropriate, with a standby supply, such as a secondary battery. Examples of such systems
include:
a) one or more smoke alarms and heat alarms operating at extra-low voltage and connected to a control
unit at an appropriate location in the dwelling;
b) intruder alarm systems or social alarm systems that incorporate control and indicating equipment to
which one or more fire detectors are connected; the detectors can be smoke alarms or fire detectors with
independent sounders.