Invert Elevation???

[Anonymous]

The Invert Elevation of pipes is really confusing me. What is it referencing exactly? I've heard it is referencing from the Project or Survey point. But, that can't be true. Because if I move either of them. The Invert Elevation does not change. Also, people in our office have gotten results that look like they are reference both of them. The issue we have is that we want to reference the survey point for our Invert Elevation. But, for a specific project we can't. Any clarification on what is actually going on with this parameter would be greatly appreciated.

[kadmonkee]

try this video in the link

SPOT ELEVATION VIDEO

this link defines the options

TIPS FOR SPOT ELEVATION

[Anonymous]

That is some great information on spot elevation. I will use it in the future for sure.  The issue we are having, is with the Invert Elevation parameter that we have in a tag (Pipe Parameter). We would like it to read the elevation from the Survey Point and/or Project Point. Currently it just reads from the reference level, I believe. Curious if there is a way to control this? Our PM wants a tag that has the pipe size, type and IE.

 

[kadmonkee]

try this explanation

What-is-pipe-invert-elevation

[Anonymous]

After doing a little more research. There is apparently a glitch in Revit with the Invert Elevation parameter. Its directly related to the internal Project Base Point. So, no matter where the Project Base Point is moved. It is always referring to the original internal Project Base Point. In my opinion, making it completely useless. Who cares what the Invert Elevation is in comparison to some random point in the model. Curious why it would not change if the location of the Project Base Point moves.

[kadmonkee]

so if it relates to the asociated level can that work for you?

High point 12'-0" AFF

Low point 10'-0" AFF

LEVEL = 0'-0"

I know too many workarounds but sometimes we are at the mercy of Revit's Limitations

[Anonymous]

That works fine for me. Apparently not the PM. HA! I have a meeting with the PM this afternoon. I think they are confused on what they actually want and how they were getting results in past jobs. I'll get it sorted out and respond back on here.  

[kadmonkee]

good luck

i get that alot too

what they want 

what they expect

What Revit can give them are never the same

[Secttor]

Hi guys.

I have 2 questions here..related. 

1. Invert Elevation value in my example is  -1011 or 1011 (positive)? 

2. Where should be measured the spot elevation for a sloped pipe ? From the center of the pipe ?

[kadmonkee]

in post #2 the second link explains the options for SPOT / SLOPE Elevation of a pipe

either TOP or BOP top Of Pipe or Bottom of Pipe

[Secttor]

@kadmonkee.. well, my question was.. if someone ask you which is spot elevation for that pipe, which will be your answer? 

[kadmonkee]

my answer is what it says in the link in post #2

are you measuring from the top of Pipe or Bottom of pipe?

what result are you looking for?

and placement of the tag will determine the value based on the level the pipe is associated with.

[Andy6640]

Would people PLEASE be careful about terminology? Invert elevation (or invert level, traditionally) and bottom of pipe elevation are NOT necessarily the same thing. Use without qualification, the term "invert" commonly refers to the lower inside surface of the pipe. This will differ from the bottom of pipe by the thickness of the pipe wall, which can be significant in some cases. It can mess up your hydraulic calculations and site installation if you get this wrong! Used with qualification, the term "invert" can be modified to mean the same as bottom of pipe, or other things (such as those associated with hydraulic gradients etc).

Drainage and sewerage engineers commonly work with "invert levels" and "soffit levels" and these refer to the inside pipe surface, unless stated to the contrary. Furthermore, the levels (alternatively termed elevations), are usually referred to the survey datum.

Sorry to be a boring pedant, but getting things right is important.

So: Revit does not tag that which is traditionally used by drainage and sewerage engineers. I have not yet found a way to work around this. There is also doubt in my mind about using calculated parameters and sheared parameters to work around it, especially as these seem to favour the project datum, rather than survey datum.

All a bit of a poor show really.

[BiMBoXiT]

Hi, I too don't underrated about pipe invert elevation where its exactly taking from. if someone clarify the doubt will be useful. the inverts values is not even taking bottom of pipe as you can see attached snapshot. 

[Radish_G]

Hi @BiMBoXiT,

The following image may help you.

[gbeck]

In the world of storm and sanitary drainage that my experience has seen, a pipe's INVERT  can mean EITHER the lowest inside pipe of a pipe (the same as the pipe Flow Line elevation) OR INVERT can alternative mean the bottom of the pipe of where it sits.   So you may need to ask and confirm this each time between parties.

For thin wall PVC pipe, the Invert can be very close to the Flow Line where the wall thickness may be 3/16" to 1/2", but for Reinforced Concrete Pipe (RCP) the wall thickness can be 3 or more inches.  For large diameter RCP pipe, the total slope can be very small (0.25% and less) so in this case a 3 inch elevation variation may be the slope occurring over 100 feet of pipe.   

[pkolarik]

---

@gbeck wrote:

In the world of storm and sanitary drainage that my experience has seen, a pipe's INVERT  can mean EITHER the lowest inside pipe of a pipe (the same as the pipe Flow Line elevation) OR INVERT can alternative mean the bottom of the pipe of where it sits.   So you may need to ask and confirm this each time between parties.

For thin wall PVC pipe, the Invert can be very close to the Flow Line where the wall thickness may be 3/16" to 1/2", but for Reinforced Concrete Pipe (RCP) the wall thickness can be 3 or more inches.  For large diameter RCP pipe, the total slope can be very small (0.25% and less) so in this case a 3 inch elevation variation may be the slope occurring over 100 feet of pipe.   

---

Huh, that's interesting because in our storm and san world here "invert" always means the inside-bottom of the pipe. No one here really cares about the outside-bottom of the pipe, just where the fluid flows (flow line) as it enters and exits that stick of piping.

If they have to core drill a new pipe into an existing manhole/tank/etc., then they use the centerline of said pipe, which is much easier to figure out from the inside-bottom rather than the outside-bottom of the pipe.

[gbeck]

Does anyone have a smarter Revit pipe or elevation tag that can accurately choose display a pipe invert along a pipe run at any clicked point?

[coltonE4L9R]

I am having this same problem it seems from researching that you need to do the math to get the the invert correct?

[Anonymous]

The best way is to enter the level by hand.