How can one identify drainage pipes under plaster?

You will laugh your head off about me again:

In our hallway, the drain pipe from the upstairs apartment runs through the wall. It is not exactly centered. I have a picture of the shell construction here. The whole wall is 3.90 m long. How long do you think such a white stone is?

Problem: I bought a coat rack and the middle part needs to be dowelled. It would, of course, be extremely unfortunate to hit the drain pipe. I believe the calcium silicate brick is 24 cm wide. Then I probably have to roughly count it out. Or is there another method?

if it's a metal pipe, a metal detector will find it. If HT or KG pipe is inside, you can hear by tapping where the hollow pipe is in the wall. However, some experience is required for this.

I would count. If you take 3.9m / 16 stones (I tried to count correctly) you get 24,... cm. So this should be OK, since there are 24 x 24 cm KS stones. You probably have to place the wardrobe a bit to one side so that you don't block the sockets and network outlets.

What are so many network outlets next to the wardrobe actually for?

Would "knock it out." A 100 or 150 KG pipe is clearly audible in the wall.

if it's a metal pipe, a metal detector will find it. If it's HT or KG pipe inside, you can hear by tapping where the hollow pipe is in the wall. But some experience is necessary for that

What do you tap with? And can the furniture assemblers probably do something like that?

I would count. If you take 3.9m / 16 stones (I tried to count correctly) you get 24,... cm. So this should be OK, as there are 24 x 24 cm KS stones. You probably have to place the wardrobe a bit to one side so that you don’t block the sockets and network outlets.

Why actually so many network outlets next to the wardrobe?

On the far left there should be a nice old chair, since the wood stove will be opposite. Then the dresser (66 cm wide) follows (with the phone on it) with an old mirror (90 cm wide) above it, then the wardrobe (100 cm wide) and then on the far right the cabinet (100 cm wide). You also place it somewhat with gaps.

My hope is that the wardrobe parts don’t necessarily have to be fixed exactly on the outside, but maybe flexibly towards the middle?