Pipe pressure loss report and critical path

[karli_aau]

I have such an issue that i´m creating a small piping network and trying to get the total pressure loss of the critical path. But when i create the report it doesn´t seem to find the critical path. If i look the parameter in the model it is not filled up. And when i look into the pressure report it doesn´t seem to be found.

[iainsavage]

It would help if you posted some screenshots

[karli_aau]

I thought i did, but for some reason they are not shown in here. Trying again.

[karli_aau]

I managed to resolve the critical path problem by just connecting another mechanical equipment elemenat and thus creating a circular system.

But now there is another issue which i can´t understand. From here https://knowledge.autodesk.com/support/revit-products...  i see that the relative roughness should be inside diameter/pipe roughness. In my case that would be 32,8/0,0000015=21866666 But when i look into the pipe properties dialog it is zero. Why?

[fabiosato]

Hello,

You insert this information is the mechanical settings, in pipe segments.

[karli_aau]

Yes, I insert the pipe roughness in the segment dialog, but the relative roughness parameter is automatically calculated. It seems to me that the equation on the previous link i mentioned is wrong and the actual equation is e/D in which case the relative roughness would become so small that for Revit it would be zero.

[iainsavage]

It should be as you say e/D. Check your units. All units should be the same so in your equation diameter should be in metres or absolute roughness should be in mm (0.0015)