What is a "residential floor"?

That is acrobatics and not fleeing

So please, I am not called the contortionist for nothing

Ok so that means: as long as there is no escape route, it is not a residential floor?

as long as there is no escape route, it is not a residential floor?

According to my understanding, as long as there is no second escape route, it cannot be classified as a residential floor.

But someone else with more expertise will surely comment on that. Otherwise, a look into the state building code also helps.

What do the construction drawings say as room designations? That could be a clue.

In my opinion, a residential floor presupposes habitability and thus living space, which would need to be verified.

Layman's opinion: does your basement have a second escape route? Then it is a living floor.

So, there are basements that have a second escape route (basement stairs to the outside or proper windows with spacious light wells) and are still not living floors.

Of course there are windows on the upper floor – in the basement too. If you climb up the light well, you are free.

A normal light well is not a second escape route. Windows on the upper floor must be on a vertical wall to be recognized as an escape route. Attic floors, for example, may not have living or habitable rooms if there is no second escape route.

Living floors in the common sense are floors that are used for living and mainly consist of habitable rooms (kitchen, living room, and bedrooms). Storage rooms and freezer rooms then belong to the living area, so they are also allowed on this floor.
Living floor with kitchen/living room or also the sleeping floor(s).

A basement does not become a living floor just because there is a second escape route, a heating system inside, or the ceiling height is correct.
Since a sauna, storage, heating, or laundry room, for example, are not habitable rooms, I would say that a floor must have 50% habitable rooms to be recognized as a living floor.

That would be my! interpretation of living floors.

The habitable room is generally considered a room within apartments or buildings that is suitable for a longer stay of people. Whether a room possesses this suitability essentially depends on requirements regarding room size, room height, lighting, and ventilation. To ensure the safety and health of people who work and/or live in habitable rooms, certain minimum requirements are defined by state building codes. Source: Wikipedia

Edit: the term basement actually implies that it is not a living floor, but a basement floor.

that a floor must have 50% living rooms to be recognized as a residential floor.

then, however, it will probably also be a full floor in terms of calculation, which is included in the floor area ratio.

Interesting question... even though residential floors somehow do not legally exist at all

Phew, the work plan only says "Keller 1-3" - the basement rooms will later be used as offices or lounges with TV connection, etc. They do not differ in equipment from the other living spaces in the house.