Not an expert (ex FRS) but.. In very high buildings, or high occupancy evacuations can be 'staged'. One or more floors at a time. Beginning with floors above and immediately below the fire / emergency. Modern buildings have excellent fire separation and can withstand extreme fires for long periods, however only where doors are kept closed etc etc. In my experience the building managers have a duty to liaise with tenants to make suitable arrangements for mass evacuation. Either staged, or simultaneous. Evacuating a large or tall building is difficult and relies on good comms during an emergency and excellent pre- planning. If it were me? I'd be looking for a meeting with building management and tenant representatives to discuss the problems. Present possible solutions and explain the obvious dangers inherent in a tall building. I would also be looking from advice from the LOCAL fire service. They have standard operating procedures (High Rise SOP) they will follow when making a response. Your evacuation plan will impact upon their standard response. (and it will be a standard response for ALL tall buildings, you won't change that!) They must be part of your evacuation plans and will help the building managers and tenants formulate a workable plan. I'm afraid this is not as simple as stating "it's your problem, sort it." It's everyone's problem in that building. Including the building management staff. They must have an escape plan too?

Hammer/ nail interface there I think roshqse!

Had experience in just this sort of situation. Each organisation is responsible for the control and evacuation of thier people in the event of an alarm sounding. Each employer must have plans and arrangements in place to ensure all his people evacuate as quickly and quietly as possible within certain predetermined timescales (such as say five minutes) and informing the building controller when all employees are clear of the building so he can report to the senior fire officer on the status of evacuation. This has the effect that only one person from each company feeds information to the building controller who in turn is the only person who advises the fire service. This works because each person understands the exact position at any one time thus reducing the risk of miscommunication. This system works well and has been tested on numerous occasions. It is simple and effective.

Ahhh...

In addition to these all the building Manager shall aware of the elderly and physically handicapped occupants who needs help during the evacuation process in case of a fire incident. If possible a random mock drill also can be conducted with the help of other occupants ( Quarterly/Half Yearly).