This is a full building evacuation facility for installation in blocks of flats that are designed to support a stay put fire alarm response. I beleive that discussions areung this concept are further ahead in Scotland that they are in England/Wales, but various Housing providers are looking at this as an option.
First and foremost, if the building is designed, constructed and maintained in accordance with building regulations, then there is not need for such a system. They should only be considered as an interim risk reduction measure, in place until the building can be brought back into compliance with the regulations/standards.
If they are installed, they should of course be available to F&RS personnel only. And in my opinion, it should be possible to evacuate the floor of fire origin and the floor above, and then escalate the evacuation floor by floor, prioritising those at greatest risk.
In addition to installing such a system, it would need to be tested and serviced fairly regularly, which won't upset the occupants at all. And then the F&RSs would need to be trained in the use of the system, and arrangements would need to be implemented to ensure the safe evacuation of occupants with disabilities, small children or elderly relatives. This just would not be practical. Far better and safer to bring the building back into compliance with the building regs/standards.
