Duct Weight Calculations

[aruckerY7D6L]

Fabrication 2019
I was looking into making a simple report to provide the weight of duct parts but noticed the result was different from what I had come up with by hand.

Basic example:
12x12 24Ga Galv duct (no connections for example's sake) in the generic Imperial database.
Fabrication says it would weight 4.7925lb per foot.

The math I did says it should be 4.624lb per foot.
While this is a minimal difference, when it comes to making a much larger duct, adding insulation, connections, and reinforcement; I feel this issue will compound and the weights could be off.

A second issue is that in our own database, the weight will populate in ft and inches; the same duct example above shows as 4 5/8" for weight? 

Is there somewhere I can see where the system is getting its math and adjust if needed? Thank you in advance.

Generic Imperial database

Our database

[aruckerY7D6L]

Another self-answered question..kind of

1. The weight shows in feet and inches if the Units are set to Architectural.

2. When Units are set to decimal, the math comes out correct but only for the ROUND duct itself; it does not include the weight of connections.

2.5 The math still doesn't seem to be working for rectangular duct, however.

Any further ideas would be appreciated, thank you.

[Mike_Arcari · Accepted solution]

Hi

you may find the differences are a result of seams and the extra material that's required.

did you allow for seam material in your manual calculations?

are you getting the weight of the duct from the properties on screen or are you using the fabrication reports within cad mep?

Thanks

Mike

[aruckerY7D6L]

I was not taking into account the seam in my math, does ACAD do that? I was looking at the property pallet but got the same out of reports. How do I find the input for seam weights?

[Mike_Arcari · Accepted solution]

If you right click a part on Cad-mep and select cadmep properties and then select the costing tab it will show the total weight of the item but that includes the flanges and seams.

I do not use CAD-mep much but it has the same built in reporting that Camduct and ESTduct has and you should be able to utilize or create a report that will do what you want. just right click on the screen and select reports. video link below on how to set these up

just be careful as there are several ways to report weight and some will give you full weight including insulation, flanges etc or you can just report on the main body material weight including or excluding seams.

try these out and should explain it a bit better than me - 

Reporting with Fabrication CADmep - YouTube

Help | Autodesk

Hope that helps you