In the early stages of converting ground floor garage to airbnb in our 3 storey property. Confused about fire door requirements! Airbnb guests would only have access to the ground floor, separated by stairwell and lockable door. Would we get away with fire doors on their entry/exit and the door between us and them - and normal doors on the residential part of our property, or do we have to put fire doors everywhere on all 3 storeys??