The ground floor storey of a modern purpose built block of flats is separate from the upper storeys.  There is an external communal entrance door that leads to a corridor, at the end of which there is a door which leads to a flat lobby with entrance doors to three flats.  There is a riser cupboard (with landlord's consumer unit and water pipes) within the entrance corridor and access panels to service duct/risers within the flat lobby.  The flats do not have alternative external exits.

Is there any guidance that applies to this scenario in relation to means of escape, travel distances, ventilation requirements etc? (for example, is it a case of adapting the guidance for "Flats served by a single escape stairway" in the Purpose-Built Blocks of Flats guide to apply where 'outside' is effectively the stairway?)

Do the flats not have means of escape windows?

If modern then Approved Document B or BS9991 will have been used at the time of build.

Thank you Anthony.  I am unsure if appropriate windows are installed, I will check.