According to the guidance, notional fire doors in purpose-built blocks do not need to usually be upgraded or replaced if they match the standard of the time that the block was built.

Does the same apply to converted buildings. E.g. if a house or office block was converted into flats at a time when notional fire doors were accepted?

Generally yes, but like with purpose built flats it depends on the size and layout - it's not an across the board approach and certain scenarios, even in purpose built, still require upgrade or replacement of doors.

Thanks very much!