On my bathroom remodel project, I'm trying to figure out the best
course for my building drain, for ease of tying in my branch drains
and connecting to the building sewer. A couple questions came up:
1) If I want to transition a drain from vertical to horizontal, and I
have enough space/altitude, which is better, a long turn 90, or two
45s with a short section of pipe in between?
2) If I have a vertical drain line that is offset from a horizontal
drain I want to tie into, I could use a long turn 90 to go
horizontal, and then use a WYE (flat) to join the horizontal
drains. Is it better to roll the WYE inlet up and use a shallower
bend on the vertical drain (e.g. a 60 or a 45 + a 22.5)? That
seems trickier to line up.
3) If a horizontal drain line goes vertical, and then goes horizontal
again, is there any restriction on the net angle in the plane the
drain has turned? For example, if I stack two long turn 90s, can I
have an arbitrary angle between the horizontal inlet and the
horizontal outlet (as seen from above)?
Someone else suggested that two 45s, with a short pipe in between,
would be easier to snake and less prone to clog. Does it make a big
difference? I imagine that the sweep of a 45 + a street 45 is equal
to the sweep of the LT90, when the 45s are in the same plane.
Well, if I roll the WYE exactly 45 degrees above horizontal, then I
need a 60 degree bend to get the branch inlet to vertical. That was a
tricky calculation I did with a nice simple answer.
Right, good point. Are 45s true 45s?
My question about the LT90's is this: suppose I have two horizontal
drain lines, one is two feet above the other, and they are not
parallel: viewed from above, there could be any angle from 0 to 90
degrees between them, or taking into account the direction of flow,
any angle from 0 to 180 degrees between them. Now I could connect the
upper one to the lower one with two LT90's: the first one takes the
upper line from horizontal to vertical, and the second one takes the
vertical back to horizontal (but two feet lower).
Could I legitimately reverse the direction of flow this way (180
degrees) as seen from above, or is there a restriction on how much
that angle can be, when I only fall two feet? I imagine that if I had
a lot of fall, say one story, there would be no restriction. What
would be the minimum fall needed to have no restriction?
You can get into trouble here due to the fact that the EL's are
more than 90 degrees. (Picturing this stuff gives me a headache!)
You can fudge it using plastic pipe and fittings because they are
forgiving, but in some situations it will affect how they go together.
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