Duplex fire separation

[Guest Steve]

Hola, in a 9th floor flat that is set over two floors with the sleeping accommodation on the lower floor, is there a requirement for Fire separation between floors or can it be open plan like a lot of normal houses, except upside down, so to speak. The higher risk is upstairs in the kitchen/lounge area, which also has a fire exit directly to the protected stairwell.There is a smoke alarm in the flat connected the communal alarm and also smoke extraction on the lower floor of the flat. Many thanks

[AnthonyB]

The fact it's got it's own smoke control system suggests it is a non standard (not to Approved Document B) layout mitigated by a fire engineering approach.

Layouts that are more open plan than the default approach of enclosed stairs and lobbies are not uncommon, usually using sprinklers and/or smoke control.