DIN standard for sound insulation in open stairwell to apartment corridor?

Hello,

we currently own a condominium. In my opinion, the sound insulation between the open stairwell (completely outdoor area) and the apartment hallway is not very good.
So far, I have only found specifications on the internet in the DIN for closed stairwells -> apartment living space and closed stairwells -> unoccupied space, but no specifications for the case where an open stairwell exists (open stairwell = completely outdoor area).

In our case, it is enough if someone in the open stairwell or courtyard speaks normally that you can hear them through the door.

Upon inquiry with the builder, with whom we are currently generally in a legal dispute, they say everything is fine and according to DIN.
Documents were sent, which I have attached here. I do not know if anything can be deduced from them.

On our windows, the manufacturer and the manufacturing number are indicated on the frame and "inside" the window.
I cannot find any names or numbers on the door. I am also attaching pictures of the door.

Since I have so far only seen the door on many garages at houses, I am unsure whether the door really fits. Especially in the morning hours, when the sun shines directly against the door and it is dark inside, you can slightly see the sun shining through as a "horizontal line".

Hello, you will not find the fulfilling answer here. It is a very specific problem that calls for an expert. Either privately paid and questionable or by the court, which then also means a lawsuit. Sorry, I would have liked to give a better answer.

Your door has 34 dB, it says so in the document ... if a noise of 60 dB is generated, your door reduces it by 34 dB. Of course, you can still hear people talking in the hallway ... sound insulation class 2, so ... if you didn’t explicitly order something else somewhere, then you got the normal standard .... unfortunately. Whether it is installed correctly is of course another question, because if not, the sound will of course get through ... but only a blower door test can clarify that, unless you already notice a draft ...

Since I only found the specification that 34dB doors apply from a closed stairwell into the apartment, I thought that for doors from the outdoor area -> apartment there might be higher values that need to be met. Generally, I have the impression that the door installed there is not the one specified, or isn't it the case with normal doors that the manufacturer's company name and possibly also some kind of serial number are printed on them? Otherwise, I probably was just unlucky... but at least I was able to gather a lot of knowledge from the condominium about how not to do things - and that you especially need everything in writing with exact details^^ Learning the hard way. Unfortunately, too much with this apartment.

Does the door have a sound insulation seal? If not, check if it can be retrofitted with plastic. This lip at the bottom helps enormously, additionally increase the contact pressure on the surrounding frame.