You might inform the ceiling elevation..............

@JAN MOYER what do you mean ?

my ceiling height is about 8’

I had a similar situation with a 2nd story addition and bathroom plumbing slope. We chose to do a tray ceiling in the kitchen (but my ceiling is 10' +), originally I had designed it with white beams but in the end I left the beams out to keep the middle of the tray at max height. I know that your location isn't like mine, but faux beams etc can disguise plumbing that cannot be moved. Additions bring their own challenges...it's not a new that would have had a different design. Good luck!

Ps. We added lots of expensive insulation between the floors and even inside the tray to keep sound to a minimum...guests cannot believe how quiet our home is 😊.

Editing keeps eating some of my words...cannot fix, sorry...

How far will you have to drop down?

In the upstairs bathrooms which had ducts and things in them and we only had to drop down about 4-5" we dropped the entire ceiling rather than using soffits and you can't tell the difference because the bathrooms are relatively small.

You may want to design a complete shape over the kitchen rather than having a weird bump in one part of the ceiling. Could you do a closer up shot of that part of the plan with the exact location of the plumbing?

The thing is my kitchen, dining, family room is entirely open and i cant drop the whole ceiling by 4” it seems such a waste as i only have 8 foot ceilong

i can hide 4” drain on steel beam area and i only really have about 6 inches of buldhead about 4” thinkiness

I am not recommending dropping the entire ceiling in this case or in a room this big necessarily. But you may want to design something that looks intentional rather than having a random soffit or bump down in one spot in the middle of the kitchen ceiling. It will probably have to be a lot bigger than functionally necessary to look seamless, or intentional, instead of a dinky little bump that might as well have a sign on it that says "This is a pipe that couldn't go anywhere else"

Do you have a plan without that green rectangle drawn on it?

@palimpsest yes i agree with putting something big to make it intentional.

something like this?

first one i think it would look ok if all walls are nearby but mine is completely open and not sureif i can do it second one mighe be a better ?

Has this beam already been placed and all the framing finished, so you are prepping for rough plumbing? If so, do you have a picture of the space? Or is this still in the visualization stage?

A couple things without seeing pics that pertain to the soffit size. The steel beam is called out as a W200x46 (imperial W8x31) which is 8" tall and 8" wide. The drawings do not say it is a flush beam (which is built inset up into the floor framing above) rather than below, but I assume it is flush because it has the perpendicular 7.5" LVL (7 1/4"?) meeting in the same plane. So there may be existing floor joists hung off the side of this beam where you want to run the pipe negating running the pipe through the steel beam web. Also, if you could run the 4" waste within the steel beam web, you might have to turn out prior to the wall since the beam has whatever it is bearing on that can't be cut into for the pipe to make the turn down.

Yes its flush beam and there is space to run drain pipe around steel beam and only buldhead is really 6inch from beam…where arrow is pointing and its where toilet will be

So the 4" pipe will be below the beam. And will need a wider soffit to make the elbow down then turn towards the wall under that beam. And at the wall will turn parallel to the outside wall (not within) so there will need furred out on that wall as well?

Note that the floor joists under the bath are deeper than the existing ones over the Kitchen, so there would be a change in ceiling plane anyway, unless you fur down the Kitchen ceiling.

@3onthetree

And will need a wider soffit to make the elbow down then turn towards the wall under that beam. And at the wall will turn parallel to the outside wall (not within) so there will need furred out on that wall as well?

-)) not sure if I understood what you mean..

I would suggest walking through it in person with your plumber, who is holding some various 4" plumbing fittings in hand. I can only see info from 1 pic perspective.

Starting at the toilet, it will elbow down and run within the joists nearer the bottom of the joist. Then it needs to elbow down to get below the joist, prior to the beam. Then it needs to elbow turn towards the wall under the beam. Then it will run under the beam. Then it will elbow turn towards the sink. Then it may elbow back into the outside wall to connect to the main. There will be a host of routing issues the plumber will work out, like where you can elbow and need a cleanout depending on what else is on this run, or have to wye which takes up more room, or effective length from vent. Canada code I don't know, I see ABS to boot, and assume 4" because you have more toilets and fixtures on this same run.

Oh i thought they can bring drain to all the where wall kitchen cabinet will go not going across kitchen island..

Yes drain will be 4”

Would it be strange to put like post in the room to hide the drain?

A post just depends. I would also confer with HVAC, as in Canada and I suppose forced air you probably have ductwork to contend with. Sometimes, flushing beams for a continuous, open ceiling doesn't play well with HVAC and plumbing.

@3onthetree

yes you are totally right in that flush beam doesnt work well in open concept i am doing in floor heating stapling up and it will create small bulkhead but since its only 1 inch it doesnt matter it will be fine

problem is the drain.. oh well…

Radiant heat everywhere, or just the bathroom above? Because there are other rooms on the floor above. You may have other soffits in adjacent rooms (that are visually seen in open concept) to contend with, so maybe all of them can work in a unified ceiling design language.

@3onthetree

plumber put pipes yestetday and its how it looks where pipe is as bulkhead towards wall is basically where I have gas range..

and my kitchen island start from about 7” away from bulkhead area

Sorry, Yun. You have a lot more than a soffit for the toilet pipe to contend with. You have the radiant tubing homeruns and the high-velocity HVAC which also look like they will eventually be run across the ceiling. And some odd framing along the wall where the studs stick out beyond a hinge point of a top plate. You spent a lot of money on those beams (W200, LVLs w/flitch plate, flushing) without thinking about MEP (mech/elect/plumb). You will have a bunch of soffits - the only way to minimize their haphazardness is for someone to coordinate it in person. I don't know who that person can be for you.