Explore the parameters and settings specific to the mechanical scope of work with regards to duct, air terminals, and other elements in BIM 321 Mechanical course. This article delves into the intricate details of duct specifications, their types, sizes, and how to adjust mechanical flow, as well as introducing the concept of hosting elements for automatic elevation adjustments.
Key Insights
- Parameters of ducts include constraints, horizontal and vertical justification, reference level, top, middle, and bottom elevation, slope, size, and length, among others. Some ducts also have slope, typically grease ducts in kitchens, which can have slopes assigned to them.
- Hosting elements, such as air terminals, to the linked Revit model allows automatic adjustment of elevation when the architect changes the ceiling height. However, if the ceiling gets deleted, the hosted element becomes orphaned. Therefore, the decision to host elements can vary from firm to firm.
- The VAV (Variable Air Volume) devices in a duct system are treated just like mechanical equipment and can have electrical loads and mechanical, along with other analytical data. The size of VAVs varies depending on how much air one needs to push.
Note: These materials offer prospective students a preview of how our classes are structured. Students enrolled in this course will receive access to the full set of materials, including video lectures, project-based assignments, and instructor feedback.
Welcome back to the VDCI course content for the BIM 321 Mechanical course. In the previous video, we kind of relinked the architectural background. We also discussed the MEP system that we're going to be looking at here.
And before we get into modeling, I want to go ahead and talk about some of the parameters and settings specific to the mechanical scope of work with regards to duct, air terminals, those kind of things. So I'm going to go ahead and take a peek into my 3D view here, returning back to my 3D view. And let's take a look at ducts first.
So what ducts have, if I select the duct, you can see I have a whole bunch of parameters that show up in my properties palette here. So you have different constraints, what the horizontal justification is, so where is it up and down, or left and right, the vertical justification, where is it up and down, what the reference level is, so this one is reference level to level two, what is the top elevation, middle elevation, bottom elevation. Previously, Revit only really had the middle elevation as one you can edit, but they've opened it up to where you can have, you can edit top elevation or the bottom elevation, which is great.
You also have a slope. Currently, this duct is not sloping. So it's zero over 12.
And in some instances, you may have slope duct, things like grease ducts in kitchens, whatnot, those can have slopes assigned to them. You have a size. So you can see here, we have a width and a height, pretty big duct at 48 inches by 24 inches.
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What the length is, obviously, this is not really a editable field, you're able to drag in places, but and if you wanted to, you could click here and change the length. But it's not editable here. What the system type is, you can size lock it.
And it has some mechanical flow. And you'll see this throughout the different MEP trades with regards to the analytical properties of the elements. So this is a mechanical flow, I can say, what is the CFM, so on and so forth.
And this is all controlled by other parameters, some identity data phasing, so on and so forth. If it had insulation, it would give the insulation if it had lining, I could have whatever the lining sizes. Looking into the properties of this, though, is that this duct has a radius elbows and taps.
So really, though, this should actually be mitered elbows and taps. If I look at my duct here, you can see that these are mitered elbows, not radius elbows, I'm just going to change this back to mitered elbows and taps. And really what this is talking about, is if I hit Edit type, and I look at the type properties of a duct, you'll see that I have these routing preferences.
If I go into these routing preferences, what this defines is all of the different fittings that want to happen at the different types of junctions. So here I have a rectangle rectangular elbow mitered. Now these are all their own families that are loaded into the project.
What is the preferred junction type is a tap. So that's why we have our, we have mitered elbows and taps. We have a rectangular elbow mitered is our elbow, and then our preferred junction type is a tap.
What other kind of junction we have here is rectangular takeoff. We have a cross transition, a multi-shape. If I was going from a rectangular to a round duct, you also have a multi-shape from rectangular to oval, and you have a multi-shape oval to round.
Now, obviously, this is a rectangular duct. We would never really need to use the oval to round. But in some instances, we may be changing, we transitioning to a round duct, or transitioning to an oval duct, we may want to have those types of transitions loaded.
You also have a union where two ducts will come together and then an end cap, which is like here you can see on the screen, this would be where you'd obviously want to go ahead and end cap this. When you set up in the template and everything, you want to go ahead and make sure you have your duct set up to see your company standards, or maybe the standards of the project. In some instances, maybe they don't want taps, they want T's for their junctions, you would just use a the a duct that has a different type of connection.
You can see I have some other parameters here, nothing super crazy here, I'm going to go ahead and hit OK. So that's really the duct that goes for both this this particular large rectangular duct and even the smaller round ducts. These are taps in short radius.
If I look at edit type routing preferences, you can see I have a round elbow 1d. So that means the radius is equal to whatever the diameter is, you'll see I have a couple of sizes with 1.5 D or 2D. This means that the radius is one and a half times the size of the duct.
And the 2D is the is twice the size of the duct, the radius of the elbow. Okay, I'm going to go ahead hit OK. We have the round, again, same kind of thing.
This is obviously since the round it's giving me a diameter size, it doesn't give me a width or a height. Again, this is still a system type of supplier, additional flow, all those kind of things are listed here. If I look at the next step in this line, I'm gonna kind of zoom in, you'll see I have a VAV here.
When I select the VAV, this is actually a piece of mechanical equipment. So this is a piece of mechanical equipment in line with the elements. This has connectors on it.
So you can see I have a connector for my 10 inch pin. And I have a connector for my out, which is a 14 × 12. Now since this is a rectangular connector, you can see I also have a fitting there that is going to go ahead and change it from a rectangular to a round.
I could have this also be a round connector by adding the family of both. We'll keep going forward. So the VAV themselves, these are just treated like mechanical equipment.
So you can have electrical loads, you can have a mechanical, this is really all the analytical data. You have a level that it's supposed to do, what the elevation of the level is, and the offset. Then I can go ahead, look at the identity data, those kind of things.
There's a bunch of different sizes based on how much air you're trying to push. I can go ahead and look at the type properties. And again, the overall length, it has some supply outlet widths, heights, you can change the sizes of those items if I so need to.
You can also list manufacturer information. So this is kind of where you get into your scheduling aspects, your model, who the manufacturer is, if you had any kind of type comments or type marks, so on and so forth. I'm going to go ahead and cancel.
You can see if I go farther down this line, I have my flex duct. So the flex duct here, this is just a round flex duct, you can adjust it by grabbing these little, these little shape handles, this kind of operates like a spline. And as long as the connections made, even though it doesn't look like the connections made there, in Revit, it is making that connection and you could even it out to where it's maybe a little bit more normal.
There you go. Again, you have flex pattern of single line, what the diameter is the system type and the flow properties. And then lastly, you here have the diffuser.
So this diffuser is a supply diffuser with a rectangular face 24 inch by 24 inch and an eight inch neck. Notice this is hosted at the end of the name. So what's happening is that this air terminal is hosted to the linked Revit model.
You can see here I say host is hosted to the linked Revit model MEP architectural. It's also hosted at an elevation of nine feet. What the hosted means is that will allow me that say let's say the architect change the ceiling height to say like eight foot or eight foot six, my air terminal here would automatically automatically as long as it's hosted to the right face would automatically show up or move and change in its elevation.
I have another air terminal here which doesn't have a color associated with it because it's not connected anything but it is a return diffuser. Notice this one, it does not say hosted at the end of the name. And again, the host at the end of the name is input by either whoever created the piece of content.
So this element is not hosted. It's placed on level one, but it's set at nine feet. So there's kind of an idea between between these two items.
And we've put included both of these here to kind of highlight this. But in some instances, it may be good to go ahead and host your elements. But other offices may decide not to host your elements when you host something to another model, or the face of an element in another model, you're kind of relying on that model to be there.
If that ceiling were to get deleted, what would happen is is that this element will become orphaned. But it does adjust when the ceiling changes this element, it doesn't rely on the hosted model at all. But you also have to individually manage the elevation based on the ceiling.
If the ceiling height changes, it's not going to automatically update. And that's sometimes the hosted can create problems. And it kind of comes to a firm by firm basis, you may want to ask, hey, do you guys host your terminals? Or do you not host them? How do you work through that? It's kind of on a firm by firm basis.
You also see I have some sidewall diffusers. These are kind of my transfer errors to allow air to pass from the rooms. If I go back to my floor plan, you'll see here I have my transfer errors.
Well, these are really you want to go ahead and make sure these are not hosted. You could host these to the wall, I'm going to actually move these back so that they're in the right place. And I could go through and do that right now.
But we're going to get moving. So I can see everything here on my floor plan. But I really want to work on my ceiling plan.
So what I'm going to go ahead and do is I'm going to go over to my ceiling plan, I'm going to go to my ceiling mechanical, I have the same system that you can see here. And a lot of times what I tend to start out with when I begin modeling a project is my diffuser layout. So I can kind of look at the diffusers here.
And there are ways of copying and we're going to go over that. But to kind of get started, we're just going to go ahead and actually place them.