A New BOMA Calc Question

[Anonymous]

I know that Revit is supposed to run area calculations based on BOMA standards, but I've heard that at least with Revit 2009 that the software may have calculation errors when dealing with curtain walls and/or windows in regards to the glazing location.

I'm not familiar enough with BOMA to explain in detail, but I believe that in certain conditions the area is calculated to the glass surface and in other conditions the inside face of wall is used. I've been told that Revit 2009 didn't compute this accurately, and I was wondering if 2010 or 2011 have resolved this. I'm assuming that the user was using Rooms to calulate areas and not Areas and Area Schemes.

Hopefully this question makes sense.

Thanks.

- Alex

[Anonymous]

If you don't allow Revit to apply area rules automatically, then draw the
area boundaries yourself where they need to be given the conditions at that
location in the model, then that becomes a non-issue.

"Jazzster11" wrote in message news:6401992@discussion.autodesk.com...
> I know that Revit is supposed to run area calculations based on BOMA
> standards, but I've heard that at least with Revit 2009 that the software
> may have calculation errors when dealing with curtain walls and/or windows
> in regards to the glazing location.
>
> I'm not familiar enough with BOMA to explain in detail, but I believe that
> in certain conditions the area is calculated to the glass surface and in
> other conditions the inside face of wall is used. I've been told that
> Revit 2009 didn't compute this accurately, and I was wondering if 2010 or
> 2011 have resolved this. I'm assuming that the user was using Rooms to
> calulate areas and not Areas and Area Schemes.
>
> Hopefully this question makes sense.
>
> Thanks.
>
> - Alex

[Anonymous]

Are you suggesting changing the exterior walls/curtain wall/windows to not be room bounding and just use room boundary lines?

I understand that when using areas that I need to manually draw the area boundary lines or let Revit take a shot at it (although it's usually pretty far off with our files...)

I was hoping to hear from others whether or not this problem has been experienced by others and whether or not it had been fixed with newer releases.

Thanks for the suggestion.

- Alex

[Anonymous]

Not at all. Areas and rooms are completely different animals.

"Jazzster11" wrote in message news:6402083@discussion.autodesk.com...
> Are you suggesting changing the exterior walls/curtain wall/windows to not
> be room bounding and just use room boundary lines?
>
> I understand that when using areas that I need to manually draw the area
> boundary lines or let Revit take a shot at it (although it's usually
> pretty far off with our files...)
>
> I was hoping to hear from others whether or not this problem has been
> experienced by others and whether or not it had been fixed with newer
> releases.
>
> Thanks for the suggestion.
>
> - Alex

[Anonymous]

I'm obviously doing a poor job of explaining.

How do YOU go about performing area calculations within Revit?

I usually am just asked to provide GSF numbers, so I have been setting up area plans and using area boundaries to ensure that Revit is including only what I want it to include.

Others have been asked to provide BOMA based departmental areas, and I think we would have to use rooms to calculate this properly. The problem is that at least one person in my office has noticed that Revit calculates the room boundary at a curtain wall differently than at a window, and BOMA has specific guidelines based on wall area for where the boundary should be for the net square footage calculation.

In my original post I was attempting to find out whether a solution had been developed for this issue since the release of Revit 2009.

Thanks Matt.

- Alex

[Anonymous]

I don't use Rooms to calculate anything but the net area within a room, or
to use in energy analysis (gbXML export). They certainly would not be
appropriate for BOMA calculations because no matter how you set them up,
they will always calculate to the same location in every wall, regardless of
the condition at the wall. Additionally, frequently a good number of rooms
can be grouped together under the same BOMA classification (Commons Space,
Office or Retail, etc.).

For that reason, Area Plans are the tool of choice for BOMA Calculations.
You can prevent Revit from creating the area boundaries and applying area
rules automatically, therefore you don't have to worry about whether or not
it's putting the boundary lines in the correct place. You can draw all of
them manually, based on your judgement as to where they need to go, whether
to the face of glass or the face of the wall, which face of the wall, etc.

Note the two attached images. One is an area plan, the other shows the
individual rooms - it should be obvious which is which. (Yes, I know this is
an extremely inefficient building - it's a training file).



"Jazzster11" wrote in message news:6402226@discussion.autodesk.com...
> I'm obviously doing a poor job of explaining.
>
> How do YOU go about performing area calculations within Revit?
>
> I usually am just asked to provide GSF numbers, so I have been setting up
> area plans and using area boundaries to ensure that Revit is including
> only what I want it to include.
>
> Others have been asked to provide BOMA based departmental areas, and I
> think we would have to use rooms to calculate this properly. The problem
> is that at least one person in my office has noticed that Revit calculates
> the room boundary at a curtain wall differently than at a window, and BOMA
> has specific guidelines based on wall area for where the boundary should
> be for the net square footage calculation.
>
> In my original post I was attempting to find out whether a solution had
> been developed for this issue since the release of Revit 2009.
>
> Thanks Matt.
>
> - Alex

[Anonymous]

Good to know.

Obviously I was mistaken when I thought Revit could use the rooms to calculate area takeoffs based on BOMA.

Thanks for all the help Matt.

- Alex

[Anonymous]

Jazz:

But wasn't a key part of your questions whether or not revit has the smarts to make the right decision about whether to measure out to the glass at exteriors?

The standard has some rules about that, base on sill height and so on, does it not?

You question got me wondering if Revit has the logic to make the right decision about what to do at the glass line. Assuming you've done everything else appropriately with setting up the area division lines.

BT