Ductwork Drafting - wye vs conical tap

[matthew.shultzSZQLZ]

When drafting ductwork, I have found it tedious to produce 45 degree wyes in round duct. The screenshot attached shows two connections for round ductwork, shown on the right. The top is a wye fitting, the bottom is a radius saddle tap. For clarity on our drawings I only want to draw and show wye fittings, however this involves manually placing wyes whenever this connection is needed. 

What I usually do with pipe work is trim or trim/extend single/multiple to join at 45 degrees, which would produce a wye fitting no problem. On ductwork, it will only produce a radius saddle tap when used with trim/extend. When a straight length is trimmed to a 45, a normal round elbow is produce, however when that is clicked, then '+' clicked to add an outlet, it returns "The converted fitting was not defined in the routing preference. Please assign one on the connected curve types." Maybe this is the source of the issue, although I can't figure out how to fix it. 

Is there a solution to this? I've tried changing duct system routing settings to no avail. Any suggestions welcome.

Thanks,

Matthew

[iainsavage]

There's an angle branch which could be used.

I think you should also be able to change the part type of your wye fitting to a Tee and then just use it as a 45deg tee?

[matthew.shultzSZQLZ]

The angle branch could be used but we definitely want the wye fitting if possible. As stock my fitting is a 'lateral tee' type, I tried changing it to just 'tee' to no avail. I did try changing it to an 'adjustable tap' but it gave me an error about the family.

[fabiosato]

Hello,

You can create a tee with a flexible angle, I know it works for pipes, but I am not sure if it works with ducts.

[iainsavage]

---

@matthew.shultzSZQLZ  schrieb:

 we definitely want the wye fitting if possible. 

---

If you want the fitting to be classed as a wye then you need to keep doing what you're doing and place them manually.

The fitting can only be used in the automatic routing preferences if it is set as a part type of Tee or Tap.

[matthew.shultzSZQLZ]

So I had another go at this based on your response. I was able to get the behavior I wanted from 45s by changing the duct routing preferences from 'tap' to 'tee' then changing my wye family to be 'tee' instead of 'lateral tee'. (Really this should be 'wye' to provide good pressure loss figures.) This allowed me to join branches to main at 45s with the use of the appropriate fitting (shown as 3 instead of 2 below), however in exchange my perpendicular taps were forced to become tees (shown as 4 instead of 5 below). 

Since there's many more perpendicular taps than wyes, I am probably going to leave my settings to be 'taps' and just deal with placing wyes as needed, using align command to help line things up. A tedious workaround would be to create a second type of round duct with one set to 'taps' and the other set to 'tees' for easier switching. 

The only other thing I'm giving up by staying with 'taps' is that when selecting an elbow, pressing the plus icon to add another outlet doesn't work, but it does work with the "adjustable tee" aka wye fitting allowed by 'tee' duct routing setting. 

Maybe some super complex family would be able to do it but as it stands now, same with plumbing, Revit doesn't differentiate between a 45, 90, 37.89, whatever angle connection. As I understand it, a branch joined to a main will only produce taps or tees based on the routing preferences, there's not really an override to say 'use taps UNLESS the join is at 45 degrees, then use tee'. That's what would work perfectly for me.

[iainsavage]

Sometimes you just have to keep going into routing preferences and changing preference for some joints, then change back again. Set one fitting for your perpindicular branches, then change preferences before doing the 45s, then change back again. PITA but only takes seconds to do.

[iainsavage]

Another option is to have two similar but different duct types and use them both as appropriate. I did this when I had a mix of radius bends and mitre bends in different parts of a system.

One reason for doing this method is that if you upgrade your model then the systems will be rebuilt and the duct type preferences will be reapplied so during the upgrade process connections will break all over the place if you haven't got the appropriate preferences set at the time of the upgrade.

Could slightly mess up your schedules though but with a bit of filtering you could include both duct types in the same schedule.

[tcookYCXTL]

Even if your just doing design layout, I have found the fabrication parts much easier to use.

[iainsavage]

---

@tcookYCXTL  schrieb:

Even if your just doing design layout, I have found the fabrication parts much easier to use.

---

You can't use fabrication parts to do duct sizing and pressure loss calculations etc.