[BIG-D]

A waste pipe is graded at 2.5 persent. It begins a 29 foot run at an elevation of 81.5 feet and ends at a waste holding tank. What will the elevation of the pipe be at the holding tank? Dose anyone have a formula for this qustion? Please help!
BIG-D

[ballengerb1]

Depending on the size of the waste pipe it should drop 1/4" per foot so about 7.25" unless 4" pipe or larger. I am not sure what you mean by "graded at 2.5 persent" can you explain that a bit more

[mygirlsdad77]

As Bob explained, you need 1/4 inch drop per foot for three inch or smaller piping. IF you have four inch or larger pipe, it can be graded at 1/8 inch per foot.

Formula for three inch or smaller pipe.

length of run=29 feet.
required sloap=1/4 inch per foot, or .25 percent.

29x.25=7.25.

7.25 is the drop from point A to point B(holding tank)

So, Point A is 81.5 feet.

Point B=A(81.5 feet) -7.25 feet.

B-A = 74.25 feet.

74.25 feet would be the logical elevation of your inlet to septic or holding tank. Hope this helps. I know it hurt my brain.

Now, tell us what your up to and maybe we can give you some better answers.

[BIG-D]

Thank you for the help, It was a question I had from trade school, I was not putting in the pipe or tank.

[mygirlsdad77]

Okay.