CL is the centerline of pavement elevation
The invert is calculated by finding the difference between the upstream and downstream invert elevations divided by the distance between the inverts to determine the slope. Then multiply the slope by the distance from MH to the point you want to determine and you will have a delta elevation to add or subtract from the starting manhole depending on if you are going upstream or downstream.
I hate be the bearer of bad news but the aforementioned mechanical engineer is practicing outside of his area expertise (and can be fined & reprimanded) and you have just aided & abetted him in his crime, which is a common issue if you look at most states boards of registration Disciplinary & Enforcement Actions
The ME did exactly what he should do when he sees acronyms he is not familiar with, he asked questions. He is not practicing outside of his expertise. I disagree.
Au contraire, please direct your attention to his attached pdf file, he's asking how to calculate the INV ELEVATION AT ANY POINT IN THE SEWER LINE ... the lack of knowledge to perform a simple rise over run equation is prima facie evidence that he's practicing outside of his area of competence. He needs to contact a Civil Engineer or Land Surveyor, depending what state he resides in. If you have any doubts about about my concerns, call up your state board and run the above scenario by them and see what they say about the blatant violation of the rules & regulations let alone the morality of the situation.
I answered on the assumption that he was working on his own property. That would not be illegal.
Believe this is a case of being unfamiliar with the specific terms. ?ÿEngineers are fully trained in understanding slope calculations. ?ÿALL ENGINEERS. ?ÿElectrical, chemical, etc. ?ÿINV is not commonly used elsewhere to mean what it does relative to sewer lines. ?ÿOne does not need a land surveyor's license to work around a sewer line.
IMVHO, it would be illegal were he to be installing the sewer lines.
That takes someone with a State License and current with their CEUs in installing that type of sewer systems.
It could be illegal for him to design the complete system or any part of it if the state requirements exclude a ME.
?ÿ
Far too many regulations in some parts of this country. ?ÿHave never heard of such a thing as a State-licensed backhoe operator.
The OP is probably only concerned with some mechanical equipment to be located in or adjacent to a building being designed by a structural engineer or architect. ?ÿThat mechanical equipment may produce water that needs to go by some means, eventually, into a drain line. ?ÿIs it better to run a line to the main sewer line or or pump it via piping back inside the building to a drain there? ?ÿSimple process of deciding which route to take. ?ÿThis has nothing to do with land surveying.
In Texas, were that backhoe operator be installing sewer pipe, field lines, grease trap, sock line, sewer separation tank and/or other components they best be working under a licensed person or have one themselves or else the State will require the whole system to be dug up and removed at the client or the operator's expense because it was not installed by a licensed operator.
Then they get a hefty fine on top of everything.
Must have a permit in hand and licensed person in charge before the first shovel enters the ground.
The licensed plumbers and others involved in the business police this and keep track of every foot of sewer pipe and accessories heading down the road.
Mr. ME,
You did everything right.?ÿ You asked what you did not know which is one of the reasons you have or will have a PE license.?ÿ Surround yourself with other good professionals and you will do well.?ÿ
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No problem, plus I just right clicked on his avatar and he is in Queens, New York which is highly unionized ... so he's liable to get a visit from some guy named Guido who'll convince him that his knee caps are more important than trying to engineer something out of his realm of comprehension.
FWIW - Don't Feed the trolls !
Saw the grade issue right away. Poor centerline labeling doesn't help but over a foot difference.....