Symbol on the pipelines in our design plans

Hello everyone,

I have a question regarding a symbol in the draft plans of our house. Unfortunately, there is no explanation for it in the legend of the plan and I can’t find anything about it online either.

What exactly is the meaning of the symbol (half black, half white with a 45° arrow, rising from left to right) next to the drain "S5"?

The toilet and sink apparently share the same drain, which is located in the wall by the toilet.

I hope someone here can shed some light on this for me.

To me, it looks like two symbols are placed on top of each other.

The arrow for ventilation and the "S/W box" for ceiling breakthrough (with a pipe running through it?)

But I could be mistaken.

It would of course be good if you can see the entire bathroom with the piping. Then the process of elimination would also be possible. I think the vent pipe is planned there.

Yes, that is the [Strangentlüftung].

Thank you already for your answers! I have now asked GU for a joint appointment regarding this in order to get an answer from him, let's see when he moves.

Explanation of the illustration:

Arrow pointing up - pipe goes up through the floor slab.
DD = ceiling breakthrough 18/18 = dimensions of the breakthrough.
So a pipe starts from this floor and goes up through the floor slab via the recess in the ceiling.
This will actually be the ventilation, as this is explained in the note about the DD.

If an arrow pointing down were drawn, it would mean that a pipe starts here and leads downward.
If the arrow does not break through the circle, it is a pure starting point of a branch or a pipe. Then there is usually no DD there.
For S5, I would now assume that S stands for branch and all branch pipes were numbered.

Best regards, Jann