Which drainage channel for floor-to-ceiling windows?

Hello,
both our site manager and our construction supervisor have pointed out to us that drainage channels must be installed in front of floor-to-ceiling windows that are used as exits, according to a DIN standard (I suspect 18195).
In our case, two double doors (each about 2m wide) are affected. Part of the terrace will adjoin from the outside. The surface will be wood or WPC and flush with the windows.
Our garden landscaper cannot help here because he has never installed anything like this and, in his opinion, it would not be necessary.

I have looked around but do not know which channels I should use here.
From ACO, I found the wooden terrace channels, but I do not understand how the drainage takes place there.
On Amazon, I also found the "Rinnenset V2A superflach" which looks quite good visually. Here, drainage is via an outlet at the bottom, but I do not know if there will still be enough space for a DN50 bend afterwards.

I would be interested to know who has channels installed in front of their floor-to-ceiling elements and which models were used here.

Funny, with us this chipping was not done at the windows, but when paving was done up to the facade/exterior plaster or some terrace covering/ground was worked on.

As they used to say back then, something like "If a window can't withstand splash water, it shouldn't have been a window."

Are you sure it's the windows meant in your case and not the facade and exterior plaster?

Or do you have threshold-free balcony doors?

Don't know that either. They also have the WPC terrace right up to the floor-to-ceiling window, without a gutter.

Yes, very sure. Asked there several times and was confirmed by both. I also already had the feeling that this is more theory than practice. It is probably more about extreme cases like heavy rain and such... Maybe someone will still find who has heard about it or maybe even implemented it themselves

Gutter is theory, no gutter is lived practice. Save the money and treat yourself to something nice. In addition, enjoy the more beautiful terrace without the gutter.