Adding elevation loss to Pipe Pressure Drop calculation using source code

[Anonymous]

PipePressureDrop is currently using the length of pipe and friction to calculate pressure loss. However, it does not take into account pressure loss due to elevation. Below is the default method for pressure drop calculation from source code:

Total pressure loss must include pressure loss due to elevation. To do this, we must include the normal offset difference of the pipe segment and multiply that by the pressure drop per elevation offset difference. Below is how the pressure drop would ideally be calculated in source code.






Currently all variables being used for calculations are referencing class Autodesk.Revit.DB.Plumbing.PipePressureDropData.

StartOffset and EndfOffset are referenced in class Autodesk.Revit.DB.Extrusion.




How do we use dDeltaOffset within public void Calculate(PipePressureDropData data)?

[gopinath.taget]

Hello,

To summarize, would your question be how to obtain the pipe's start and end point elevations in the Calculate method of the IPipePressureDropServer? Or am I missing something?

Thanks
Gopinath

[Anonymous]

Yes, the Start Offset and End Offset would need to be in the calculation method of the IPipePressureDropServer. Currently those attributes of the pipe are not available to make calculations from. Is there a way to pull that information from Extrusion and PipePressureDropData?

[jeremytammik]

If the question is reduced to obtaining the start and end points of a pipe, the answer is simple:

Ask the pipe for its location curve and use those endpoints.

Am I missing something?

Best regards,

Jeremy

[gopinath.taget]

Hi Jeremy,

Do we have any sample that shows how to obtain a reference to the pipe element in the IPipePressureDropServer implementation? 

Thanks

Gopinath

[jeremytammik]

Hi Gopi and deubanks7525,

I checked with the development team, and here is their response:

"I don't think there is a way to get a ref to the pipe, and the calc framework doesn't support elevation changes... But, then, friction loss isn't dependent on elevation changes... So that stands to reason. Probably better to add logic to the pressure loss report to account for such open systems... I don't think we have an example, however."

I hope that helps.

Best regards,

Jeremy

[Teun_Ham]

---

@Anonymous wrote:

"...But, then, friction loss isn't dependent on elevation changes..."

---

Are you sure they said friction loss? Because we are talking about pressure loss here, and pressure loss is dependant on elevation changes.

[gopinath.taget]

Hello,

Thanks for the patience. I do have some feedback from the engineering team. Apparantly the IPipePressureDropServer was intended to only compute friction loss.

According to engineering:

*-------

the method is based on drop due to friction… and probably would have been better named ‘friction loss’… the methods by which friction is computed varies, and as such, made sense to expose a customizable way.  

*-------

And 

*------

the customized calculation method is not expected (as there is no need for it) to account for elevation loss; it is only supposed to calculate pressure drop caused by friction.

*------

So you do not have to account for elevation loss separately.

Hope this helps.

Best Regards,

Gopinath

[Anonymous]

Thank you for the response. This seems unfortunate.

Wouldn't the "critical path" produced from the "pressure loss report" be void because of this? Pressure loss due to elevation plays a large roll in multi-story applications. If Revit assumes all pipe is horizontal (accounting for only friction loss), then the calculations cannot be trusted. I believe the critical path to the most hydraulically remote fixture includes pressure loss due to friction and elevation.

If IPipePressureDropServer was only intended to compute friction loss, is there a way to include pressure loss due to elevation in the pressure loss report?

Thank you.

[arnostlobel]

deubanks7525:

I think the previous post (by Gopinath) might have been misunderstood. It is not that Revit treats all pipes as horizontal and would not account for elevation is overall pressure-loss calculations. It does; However, it does not expect (and does not want to, in fact) an external pressure-loss-by-friction calculator to account for elevation differences. It would in fact be duplication of what Revit already does. The friction calculator is separated from all others pressure-loss calculation that Revit internally preforms and the reason for it is that the friction default calculation may not be liked by some who would rather prefer to use a different (or modified) formulas. But hat is just for the friction part.

Thank you

Arno?t L?bel
Autodesk, Revit R&D

[D.Svigir]

Hello,

to everybody. I'm MEP engineer from Croatia and I work in firm which is Autodesk Gold Partner. We work in Autodesk Revit our projects, BIM implementation, trainings and we also are developing tools for simpler use of Revit. Currently we have developed addin for Domestic Water Systems. This addin adds new calculation method for Plumbing Fixtures using FU. Calculation method is based on DIN 1988-W308 norm, also we have added the elevation loss calculation through addin. Applications can calculate critical path based on line pressure loss in pipes and elevation loss.

You can find our application on Autodesk Exchange.

https://apps.autodesk.com/RVT/en/Detail/Index?id=appstore.exchange.autodesk.com%3awatersystemcalcula...

Best Regards,

[jeremytammik]

Dear D.Svigir,

Please note that this discussion forum is dedicated to programming Revit using the Revit API.

Therefore, your information about the availability of your commercial end user product is not completely appropriate, unless you want to help the Revit add-in developer community by pointing out and explaining certain interesting technical aspects of its internal implementation.

I hope this clarifies.

Thank you for your understanding.

Best regards,

Jeremy

[andrei.bejenaru]

Hi,

Have you made any progress on this issue?

The critical path should take into account the pressure loss due to the elevation difference.

In my opinion the pipes should have a new parameter indicating this pressure loss.

[guilherme]

I have the same problem with pressure loss with elevation. The part of the report I managed to develop.
But I have another problem, is it possible to set the critical path in the system? I researched the api and internet and got nothing about it.

Sorry my English, my default language is Portuguese Brazil.

[reylorente1]

Hola a todos,parce ser este un tema algo ya viejo,pero asi todo aqui va la pregunta(Mi ingles es terrible),estoy haciendo un addin, solo para mostrar los calculos de la de   la ruta critica,pero como sabemos,no muestra la altura,del mueble sanitario,entonces,deberiamos colocarlo,manualmente ,o existe una forma de extraerlo desde el programa,otra cosa,tambien estoy tratando de colocar en el metodo de perdida de las piezas(tee,codos,etc)el valor de la longitud equivalente,ya que el metodo que trae revit,es algo confuso,.por alguna idea de como poder hacerlo?Tengo una idea,crear un parametro compartido y despues almacenar los datos con ExtensibleStorage.

Cualquier idea ,por favor seria bienvenida,

Muchas gracias

[jeremytammik]

Dear Reynaldo,

Here are some links to articles by The Building Coder that may be of interest to you in this context:

Modeless pressure drop tool (eleven years old!):

http://thebuildingcoder.typepad.com/blog/2009/10/modeless-pressure-drop-tool.html

More examples of using extensible storage:

http://thebuildingcoder.typepad.com/blog/about-the-author.html#5.23

[reylorente1]

Ok,gracias los mirares.

[engrodriggo2]

É totalmente possível Guilherme

[reylorente1]

A partir del Revit 2021.1.2,ya existe en unidades de proyecto el mca o metro de columna de agua, si se lo adicionamos al Flow Pressure(presión del equipo) la altura de la toma de agua del equipo, y se vuelve a calcular,los valores serian diferentes y la ruta critica cambiaria a la toma de agua mas alta(Puntos mas desfavorable).Puedes crear desde la familia ,este parámetro o   adicionarlo manualmente, creando un pequeño addin,

Espero que te sirva de ayuda

[reylorente1]

Escribí en Revit Idea ( Adding elevation loss to Pipe Pressure Drop calculation), para que en el futuro, se tenga en cuenta en los cálculos 

!Apoyémoslo!

Gracias

I wrote in Revit Idea (Adding elevation loss to Pipe Pressure Drop calculation), so that in the future, it will be taken into account in the calculations

Votes!

Thanks