TOP and BOP Tags don't match with Pipe Elevations

[Anonymous]

Hello team,

I really don't understand why MEP Cad 2016 is giving me the wrong bottom and top of pipe elevations. If you see the picture you will see that the End Elevation of my pipe (the center of pipe elevation) is at 7/16" and when you see the Bottom Of Pipe is at 11" and the Top of Pipe is at 1' 2".

I went to the style manager tool  and then I went to Pipe object and opened the Definition window to check the formulas and the formulas are correct.

I also attached a picture of the formulas so you can see they are accurate. There is something here that does not make any sense. 

I'd really appreciate your help on this one.

[Keith.Brown]

Those tags are not for sloped pipe if I remember correctly. (It's been a couple of years since I used the software). I believe there are some start elevation and end elevation tags for sloped pipe.

[CADmonkey_UK_Building_Services]

If the pipe is sloping, you need a custom Label Curve that reports the End point plus or minus the pipe radius. You're probably reporting the mid-point.

I worked it out and set it up years ago but now I just use it. I can't recall exactly what I did. You're in the right place.

[info]

Hi all,

scheduling slooped pipe is a little bit tricky:

The value of the position of the pipe reports the starting point. That can be the highest or the lowest point of the pipe, depending wether you 're drawing with negative or positive sloop.

You can mange this for a pipe, I also did it years before, but i did it with al lot of work:

calaculating the mid point with:

absolue value of difference beetwenn start and endpoint and adding it to the smaller of the both values.

If you have a long slooped pipe, the difference between start and Endpoint is large, so the midpoint is not that interesting.

To avoid this trouble, I'm doing the sheduling at the connectors, that's quite easy and exact.

[VitalyF]

Hi,

Try this TOP, BOP Tag for slopped Pipe

Vitaly

[CADmonkey_UK_Building_Services]

Given that this is an MEP forum, I think you may have misunderstood the requirement.

What you've supplied are the Maximum & Minumum heights of the pipes 'bounding box' which is the rectangle produced using the pipe as the diagonal. I'm not sure where the missing millimetres are, though!

I think what the OP needs is the ability to take a BOP measurement at any given point along the length of the pipe. ("465" in the screenshot) This is usually noted at the high end of the pipe, so the installer knows where to start from. The solution requires a custom property set that takes the End OR the Start elevation and subtracts the diameter. I don't think it is possible to take the measurement from any other point (ie 2/3rds along the pipe). It's not just the complexity of such an equation (revit does it) but the pipe wont 'see' the point you're specifying, it will only see the whole pipe with start and end points.

BOP (or more properly Invert Level) is preferred to Centre Of Pipe because when the drainpipe eventually turns into an open drain/culvert on it's way to zero/sea level then the only measurement that can be taken is from sea level to the lowest level of liquid. Basically they stand a ruler up in the water and measure the wet end. From this they can work out gradients, flow rates, etc. For Building Installations, it is accepted that the BOP refers to the outer and not the inner diameter, so it is negligibly wrong by the thickness of the pipe wall.

[VitalyF]

Hi,

@Anonymous wrote BOP (or more properly Invert Level) is preferred to Centre Of Pipe...

Is a variant where the BOP refers to the midpoint of the slopped pipe.

Vitaly

[CADmonkey_UK_Building_Services]

I've never heard BOP used to describe the midpoint of a pipe. Maybe  'BP' for Balance Point? BOP in process piping can mean "Blow Out Preventer." but that's a fitting. In 20 years I've never heard of a need to know where the midpoint of a pipe was. What if the pipe changes length? It doesn't sound very useful.

This is an MEP environment, the OP is using Sanitary pipe. The BOP is the Bottom of the Pipe, and is ideally measured at the high end of the pipe.

BOP is used in place of IL (Invert level) for 2 reasons as far as I am concerned:

1. "IL" is harder to read / easier to misread than BOP

2. Too many people use the term 'Invert Level' incorrectly to describe any point in the Z-elevation. ("Put more inverts on the ductwork!") - Bottom of Duct (BOD) or the Centre of Duct (COD) or  the underside of Cable Tray (BOT)

For the ultimate definition of BOP, one should of course refer to the project drawing legend!

[Deependra.YadavQBF2C]

Is there any solution for it now? Can we do BOP tags as we do in the Revit?