Fabrication 2025 – Coupling Limit

You may have noticed a new setting in Fabrication 2025. You can see it when you edit the properties of a Service Template. It’s shows as Maximum # couplings. Valid settings are 1 to 10. So what is this setting you may ask? Well, don’t go with your instincts. The name is as unintuitive as possible.

To start, couplings are any ITM made from Pattern (CID) 2522. So not necessarily an actual “pipe” coupling. So this setting only applies to any fitting made from Pattern 2522 regardless of what it does in the real world. No other patterns are affected.

Your initial instinct might be that this limits the number of coupling patterns on a service template. You’d be wrong. When you think about it, a lot of things are made from Pattern 2522. Couplings obviously, but also Welds, Flanges. some Reducers, Adaptors, Unions, Bolt Sets, Gaskets, etc. That can easily push the number over 10. So what exactly does this do?

First, a little background. To start this setting only applies to Revit. No other Fabrication products are affected aside from using them to edit the setting. Next, you should know that there was always a coupling limit as it pertained to Revit. It was hard coded to 6 I’m told. This change in the 2025 Fabrication products made it editable to a smaller (minimum 1) or larger number (maximum 10).

What this settings does is control the connect and coupling logic in Revit. Revit’s autofill features like Route and Fill, Multi-Point Routing, Quick Connect and Design to Fabrication are affected. This is because the coupling pattern is special. In most scenarios, pipe is connected to fittings. In come cases, fittings to fittings. Coupling patterns on the other hand, can connect to other coupling patterns repeatedly.

These autofill functions need to process the various options for fittings. This can have performance implications that increase exponentially the more parts you have using those patterns. Let’s look at an example….

The below image shows a pipe flange connection. It’s using 6 coupling patterns in a row in the model. But in your service, there may be even more. Different types of flanges, welds, gasket and bolt set options, etc. It needs to look at all of those to determine the options available. In this case, a coupling limit of 6 would work. That’s how many 2522 patterns you would ever string together to make this connection. So after 6, Revit no longer needs to keep looking for couplings and can limit it’s analysis to other pipe or fittings in your service.

As you can see, the old hard coded value of 7 would be enough to cover most flanged or dielectric connection options. In some very limited edge cases, you might need more. So now you can bump it up to 10. However, you may want to actually reduce it lower. If you’re using ancillaries for gaskets and bolt sets and not drawing ITM’s to quantify them, a setting of 4 would be sufficient. For some systems, you might even be able to go lower.

What happens if the coupling limit is lower than what’s needed? Well, you might have to make those connections manually. Autofill functions wouldn’t provide all of the possible options. In some cases, you might event get broken connections.

Personally I’ve not been able to create a sample dataset and configuration that really demonstrates functionality working or not based on the setting. For the most part, it’s likely not going to affect most users however lowering it might provide some performance improvements in Revit. They tell me ideally the setting would be 3 or 4. But as you can see, if you’re using ITM parts for Bolt Sets and Gaskets, 6 is likely your “Go To” number. But on a plastic system? 3 or 4, maybe even 2 would be sufficient.