Washing Machine Plumbing Questions

You guys know I've been working on plans for remodeling and I'm having trouble finding some info.
In terms of water supply for the washing machine, it was mentioned that check valves are needed.
*What type of check valves?
*Where would the check valves be located?
*How should they be oriented (vertical, horizonal, doesn't matter)?
(Pictures would help)

For the DWV, I'm trying to find out if I need a P-trap that is completely solvent weld or if I need something threaded that I can take apart (or do they even have those in 2"?) I've seen all solvent weld and some that are mixed (like the arm is threaded). Any recommendations? (It will be PVC)

Additionally, I plan to have the vent directly above the drain and I want to have a cleanout.
*What is the best height for the cleanout (I know it has to be accessible)?
*What sort of fitting should I use? Sanitary tee with a cleanout glued on? OR a tee with a female threaded inlet that has no sweeps?
*If it is a sanitary tee, in what direction would the sweep go (I'm leaning toward vent if it is up high)?
*Does it have to be above the flood level of the fixture or can it be lower?

For the part where it connects to the main soil pipe, does it matter how close it will be to the tub tying in? Can it be upstream of the tub?

Hello my lady
inless your local code calls for it, you do not need a check valve

the tie in to the sewer needs to be 5' from anything else to stob suds from bubbling up

the sweep of the co tee would be fasing down

Frodo! It's great to "see" you! How are you doing?

Thank you!

Ok, so sanitary tee with a 1.5" cleanout solvent welded into the side outlet/inlet, sweep facing down?

I haven't been able to find anything in the codes about check valves. I'm under IPC 2012 now (since Louisiana ditched it's own plumbing code).

I've been working on the sketches and I think I have it narrowed down but I want to make sure it will work before I finalize anything. (Already started demo on the bathroom).
This is the room layout I'm going for:

From the little stub left of the wall (which has light switches) to the shared interior wall it's about 76.25". (the interior wall spans 94.5". The main vent is between 13" to 15" from the exterior wall (I haven't been able to reach to measure). Main soil pipe is directly under where the old toilet used to be (so about 12" or so from the interior wall). In my diagrams the soil pipe is to the left of the wall.

Since the vent is so close to where the tub drain will be, I'll have to turn the trap to face the opposite way and then run its vent back to the main vent inside the wall. I don't have the vents and drains drawn in because I'm having trouble with sketchup in that regard, but instead of putting the laundry stuff inside the wall, it will be inside the room in front of the wall hidden behind the machines and will then come up just next to the dryer and up through the shelf. I'll have some cabinets above to conceal the horizontal run of the vent. It will go through the wall and then turn to meet up with the main vent. I will have an access panel on that interior wall just behind the tub so I can access the valves and overflow.

This was a line drawing of the planned layout


And this shows the fittings


But if the washing machine can't tie in that close, I could run it's drain somewhat parallel to the soil pipe until it reaches the 5' past the toilet tie-in. Btw, vent for toilet routes outside bc the load-bearing wall nearby and the exterior wall have extra thick wood underneath so it would be hard to drill through. AAVs are temporary and will be under the cabinets. I wanted to save pipe and fittings by having the lav tie in to the toilet's line and knew I couldn't do that if I vented the toilet inside that interior wall.

I forgot to mention that the cleanout tee wouldn't have the opening facing the side-- it would be to the front but I couldn't find a picture that had the angle I needed.

Old thread, but somehow I just discovered that a lot of the modern washing machines already have a built-in check valve inside. The water inlet hoses/pipes connect to check valves near the top of the machines.