Bathtub in front of window, railing too low, contractor is obstructing

You will hit a brick wall, that's my assessment. Because, as has been written several times, the regulation on parapet heights is based on adults. And since the bathtub only extends a little in front of the window and a bathtub is not a standing surface, it will have been planned correctly.

Let's see, as the emperor would say ;)

When I look at the letter from the Ministry of Economic Affairs ("If there are components in front of the window parapet, such as cable ducts or ventilation ducts, which are suitable for climbing on, ..."), it does not matter whether the component is intended to stand on, but whether it is suitable for it (regardless of whether adults or children). And I would definitely see that as the case with the bathtub, especially the shelf.

Shafts or channels that one can climb are something different than a 20 cm corner on a bathtub at a height of 80 cm.

I am always amazed at what people trust their children to do. I also know a family where ALL the windows no longer have handles because the children open them and throw everything out or don't see any danger, but these are precarious conditions and cognitively impaired children. I was already able to tell my daughter very clearly at 2 1/2 years old what she had to stop doing. So I don't know your children, but you mentioned possible playdates... By then they should be old enough not to experiment with that. And before that, they are too young.

Shafts or channels that you can climb on are something different from a 20 cm corner on a bathtub at a height of 80 cm.

I am not an expert in this field and don’t know if you are one, so I can only rely on what the expert, whom I pay exactly for something like this, says. And that is as follows:

"Narrow projections may have a maximum depth of 4 cm. Projections larger than 4 cm can be used as a stepping surface, i.e. the highest standing surface shifts." (Excerpt from Bauprüfdienst (BPD) 3/2013)

I don’t know off the top of my head how deep the shelf is, but definitely more than 4 cm. And the entry height of the bathtub is probably around 60 cm rather than 80 cm, which is no problem for a 3-year-old child.

I’m always surprised what people trust their children with.

That has nothing to do anymore with the question of whether a safety measure is legally required, but yes, from experience, I trust our daughter, who just turned 3. She climbs on our current bathtub and balances on it if you let her.

I was already able to firmly tell my daughter at 2 1/2 years what she had to leave alone.

And does she always and without exception stick to that in every situation? Our daughter is not a wrecking ball either, but children at that age want to try new things, and if you don’t want to watch them 24/7, you have to assume that they will do something you have previously told them not to do. And in some cases, that one time is already too much...

As written - window hinge in the other direction and with the window open you can neither climb onto the tub nor fall out. How does your expert calculate?

Window hinge on the other side

And that would be so much more practical as well ;)