Thread: Source of long radius 90 deg bends.

Bob posted this a while back because it has a lot of good information. Page 54 gives the equivalent lengths of straight duct for various duct elbows. http://www.lorencook.com/PDFs/Catalo...ok_Catalog.pdf

This is a calculator I like playing with because you can see what a small change or two will make to the static pressure. The higher the loss the poorer the system will perform. You can see what the addition of an elbow will change. Also a good way to play with routes to a machine to see what works better. On-Line Duct Friction Loss

I don't know of any chart or calculator that shows a percentage loss. There could be one, I just haven't seen it.

Pete

Originally Posted by QC Inspector

I don't know of any chart or calculator that shows a percentage loss. There could be one, I just haven't seen it.

This is probably because strictly speaking the %flow loss depends on the actual flow itself.
Slow flows will have minimal % losses while high flows will have greater % losses.

All my testing is for a 3HP, 13" impeller initially drawing ~1000 CFM so if you are using a 2HP 12" DC the % losses on junctions will be smaller while a larger DC will have even greater losses.