Flow through a Wye fitting

[jkleinowski]

Is there a way to get correct fixture unit calculations for a pipeline after a wye or tee in the system? It looks like you can only share parameters with two connectors which means you cant have a correct FU count in your main after a three or four way connection. is this correct or am I missing an important step here?
If this is the case then will I have to write individual pieces of text when I create a riser diagram and have to place periodic tags on the lines to clarify fixture unit counts and pipe sizes?

[mjdanowski]

This is a good question. If it was anything other then a fitting I would say do the calculation of flow in a family parameter, but with fittings you do not have that option.

[kyle.bernhardt]

Is there a way to get correct fixture unit calculations for a pipeline after a wye or tee in the system? It looks like you can only share parameters with two connectors which means you cant have a correct FU count in your main after a three or four way connection. is this correct or am I missing an important step here?
If this is the case then will I have to write individual pieces of text when I create a riser diagram and have to place periodic tags on the lines to clarify fixture unit counts and pipe sizes?

This will work if configured properly. You can look at some of our OOTB fittings as a guide. I'll get one of our developers to give me the proper explanation and I'll get you some info next week.

Cheers,
Kyle B

[jkleinowski]

Kyle, looking at the out of the box families I only see a few of them actually carrying the FU count through from all directions. But when I compare those families to the ones I am trying to use I dont see any differences. They only have two of the connections linked as well and are adding in the third (or fourth for tee's) connection's FU count seemingly by magic? I would be grateful to you (yet again) if you could pass on any secrets you get from the developers.
Thanx!!!!

[BigBadBIM]

I wanted to kick this back to the top and see if anyone has ideas on this... Kyle?
:?:

[kyle.bernhardt]

Can't you just go ask the developers of this program?? :p I am delinquent on this one, so my guilt has lead me to corner our developer who architected our flow code.

There isn't much to this in the end, although there really are two topics at hand here:

Flow within the Pipe Network

This is caulcated based upon 2 factors:
The Fixture Unit count defined on the Connector that is connected to the Pipe Network. The Connector is generally located on a Plumbing Fixture Family.


The Flow Direction defined on that Connector.


With these defined, we have flow defined in the Pipes that are directly connected to the Plumbing Fixtures. From there, the Flow needs to propagate through the Fittings and Pipes within the network.


At Fittings, Revit MEP will try and determine the logical flow path through the fitting, regardless of Connector linking, as long as each Connector is set to be "Fitting" System Type.

As long as there is a logical solution for flows at the Fitting, flow will propagate. By logical solution, as long as there aren't multiple valid solutions. For example, if you've got a defined flow in a Pipe, and that Pipe runs into a Tee with unconnected Pipes on the other two ports, there there are multiple solutions and flow will not propagate.Flow Calculated on the System

We also calculate the Fixture Unit count on the system itself, and this is much simpler. We simply sum the Fixture Units defined at each connector on the System, regardless of how the actual network is connected for that System. This allows you to know your Fixture Unit count in the initial stages of the project before piping is in place.Hopefully that all makes sense to you all.

Cheers,
Kyle

[kyle.bernhardt]

After reading my last post, it makes perfect sense to me, but not necessarily to somebody who doesn't live and breath this stuff. My guilt still strong, I went ahead and cut a quick video further explaining this situation. It's basically a video record of what I wrote previously. I also uploaded the Revit file that I used for the video.

Let me know if you've got any questions.

Cheers,
Kyle B

[ran.154477]

Thanks for another great video. The flow only propagates when the end is capped. What about vent piping? When you add vent piping, it doesn't work. In your example file, if you turn the end elbow into a Tee, it doesn't calculate. This is the same as adding vent piping. The tee just goes up, rather than horizontal.

The only way I can get it to calc, is to cap each vent line and fake the vent system. I want the vent lines to be displayed in my 3D riser view, but they are just dumb lines. Could I create a new system for the vent and get that to propagate through the roof? Plumbing vent lines have to be sized (by code), as well as the water supply or drains. It would be great to include the vent system in the BIM.

[kyle.bernhardt]

The flow only propagates when the end is capped. What about vent piping?

No, the flow only propagates when there is a logical flow pathway, which doesn't require a cap at the end of a pipe. You'll see in my video that there is an open end at the end of the drain line, and flow still propagates. If there is a three port fitting, then two of the ports need to be defined for there to be a logical pathway.


When you add vent piping, it doesn't work. In your example file, if you turn the end elbow into a Tee, it doesn't calculate. This is the same as adding vent piping. The tee just goes up, rather than horizontal.

In this specific example, adding the Tee presents two openings with undefined flows to the System, which allows for multiple possible flow states. This will result in undefined flows, as I explained in my previous post and video.

Our flow calculation system isn't set up to handle Vent piping OOTB, but can be made to work with some tweaking. The flow system is designed to handle the flow of a single medium (e.g. water, sanitary waste, gas, etc). In that case we only need to account for one medium within the Pipe System. Sanitary Systems are really two mediums; the Sanitary Waste and the Vent Gas.

You'll need to tweak things to effectively create two separate Systems, in order to account for the different mediums. This basically requires that you create special "Vent" fittings that don't have all Connectors configured as Fittings. The Vent connection needs to be configured as a "start" point of the System, like the connection on your Fixtures. You'll define the flow for the Vent System there.

I haven't done this myself, but would expect it to work out okay.

Cheers,
Kyle B

[BigBadBIM]

Can't you just go ask the developers of this program?? :p
You know, I would, But I seem to have misplaced their numbers. Could you just go ahead and post those here? Thanx. ;)


Hopefully that all makes sense to you all.
After reading this, it all does make sense. (Now, that's weird.) I think it would have made sense if I had thought about it a little more, rather than just expecting a spoon feeding from my AUGI friends. Oh well, what are friends for?

[DMagillIII]

It's been quite a while since this thread, but I'm having exactly the same issue in Revit MEP 2012.

When creating our Storm drainage system, I found that the Sanitary configuration doesn't seem able to carry GPM flow. Our workaround was to set the system as a Hydronic Supply. We can now carry the GPM through the pipes, but we run into a snag when using a three connector fitting. If I don't have a fixture actually feeding a preset GPM value to 2 of the three connectors, I lose the Flow. Capping or plugging makes no difference to this effect.

Essentially, I'm asking 2 questions:
1. Is there a way to carry GPM data through a Sanitary configuration?
2. Do I need to do something specific to the caps or plugs in order to make them work, without additional Flow being required? (I found that changing the cap to a fixture and adding 1 GPM makes it possible, but that's inaccurate, to say the least)

Thanks in advance for any assistance.

[DMagillIII]

EUREKA!

I took the OOTB Cap - PVC - Sch 40 changed it from a pipe fitting to a pipe accessory. I then cleared out the OmniClass Number and set Part Type to Breaks Into.

For the connector, I set the Flow Configuration to Preset and the Flow Direction to Out. Loss Method is Not Defined, Allow Slope Adjustments is checked, and System Classification is Hydronic Supply per the previously mentioned workaround. Flow is set to 0 GPM, in order to not affect the total. et voila

I hope this helps someone else in the future.

[sven.129574]

You'll need to tweak things to effectively create two separate Systems, in order to account for the different mediums. This basically requires that you create special "Vent" fittings that don't have all Connectors configured as Fittings. The Vent connection needs to be configured as a "start" point of the System, like the connection on your Fixtures. You'll define the flow for the Vent System there.

I haven't done this myself, but would expect it to work out okay.


Kyle,

I'm not sure whether this worked or not in Revit 2009, but it doesn't seem to work in 2012. My limited tests in 2013 weren't successful, either.

It looks to me like a fitting only wants to be part of one system. Even if you give it a connector that is specifically given different system classification (See "family.jpg", below).

In the family below, for instance, I was trying to trying to make a fitting to represent a carrier with a vent connection. (Our engineers have discussed Joel Londenberg's otherwise very elegant solution for carriers, but feel that we use so many possible variations of carriers that it isn't feasible to include the carrier as part of the wc.) The "carrier" has 4 "fitting" connections and a "vent" connection. But when you put it in a sanitary system, the fixture seems to try to include the vent connection in the sanitary Fixture Unit calculations. The family works fine without the vent connector, but when the family includes the vent connector, it can't figure out the downstream FUs in the sanitary system. Even if you cap off the vent pipe, it can't figure out the FU's.

What's more, the fixture wants to make the pipe connected to the vent connector be sanitary, too. Even though the connection has a classification of vent. Even if you cap off the vent pipe. Even if you redefine the cap to be a pipe accessory or a plumbing fixture with a vent connection, so that the pipe has vent connectors at both ends, the fixture still makes the pipe connected to it sanitary. See the second image, "FUs.jpg."

If anyone has gotten this sort of thing to work, I'd love to hear how. I tried variations of Don_M's workaround, but couldn't seem to get them to work.