In these days of non-prescriptive solutions to major building difficulties and the thought process of risk reduction and prevention, the provision of sufficient staff training to respond to an L1 system is sufficient. Whilst the shop process will allow people to resort to these premises, sufficient staff training will allow escape on early detection. Surely we are not suggesting that a fire will grow to sufficient proportions to stop escape. All doors are fire doors, rated to such or not and even those that are rated may not be satisfactory once put in position without the frame and screen they were tested with.
I recenetly visited Rome, a european country subject to that nice piece of legislation which gave us the Workplace Fire Precautions Legislation, and stayed in a lovely hotel. The fact that it had a 4 metre ceiling height, was 8 storeys with a basement, had a basement kitchen open to the single staircase with no doors to the staircase, the bedroom doors had vents in them, smoking was allowed within all areas with nice sand trays by the lift, not in a lobby, for the disposal of cigarette ends, had flaked canvas hose in a box for use if needed and as a by the by the staircase did not discharge to open air. No problems for our Italian colleagues, so perhaps the earlier discussions may be considered a burden to business and ever so slightly over the top.