I can't argue with Kurnal's logic. Whilst communal communication systems should not be relied upon, it doesn't mean to say we should discount them completely. They do represent an extra tier of protection in my opinion.
As the only means of rasing an alarm I would of course agree that communal communication is totally inappropriate. But where it is installed, comms can compliment the protection offered by the Part 1 (communal) / Part 6 (individual flat) fire alarm systems.
If a resident has kealed over in their flat, left cooking on, and a blaze occurs, it would only be if and when the communal system activated that other residents in the scheme would be alerted to the fire, and call the emergency services. By that time the resident may have persished.
With a part 6 alarm linked to the communal comms system someone at a control centre will be alerted to the fact an alarm has been activated. The call centre staff may attempt voice communication with the resident. If there is no response they would call the fire service. Furthermore it might be argued that this process could occur faster than the time it takes for the communal alarm system to activate, and other residents to call 999. So when used in that way I don't see why there is a problem with comm/comm systems.
I appreciate that it all depends on the quality of the call monitoring centre staff, and you can't solely rely on comm systems only to raise the alarm for obvious reasons.