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Calculation of converging bullhead tee

Calculation of converging bullhead tee

Calculation of converging bullhead tee

(OP)
Hi,

How do I calculate the pressure loss of a converging bullhead tee in a return duct system. The tee has dimensions 23"x23" for the main duct and the branch. Thank you!

RE: Calculation of converging bullhead tee

..by finding fitting loss in ASHRAE Duct Fitting Database

RE: Calculation of converging bullhead tee

(OP)
The pressure loss for a converging bullhead tee is not listed in the SMACNA "HVAC Systems Duct Design" or the ASHRAE Fundamentals.

RE: Calculation of converging bullhead tee

Could be because it's a bad practice?

RE: Calculation of converging bullhead tee

If it has already been installed,measure it.If not do not do it!

RE: Calculation of converging bullhead tee

I had someone ask the same question around the office here the other day. This is the best I could find:
https://www.google.ca/url?sa=t&rct=j&q=&am...

But I have no idea where they are citing those tables from.

For our system (it was designed by an inexperienced engineer) we will be changing the layout. But I thought I'd provide the reference anyway.

RE: Calculation of converging bullhead tee

calculation is based on those tables, and if you cannot find anything that resembles your case, you are outside usual calculation procedures.

you can either order cfd analysis from some faculty that would possibly cost as much as your total investment cost. the other way is, as sak said, to measure it if it's already installed.

there are ways to make guesstimate, but it remains guesstimate. you can sum loss of "normal" tee and reduction, and double it to take into account additional swirling caused by many direction change.

RE: Calculation of converging bullhead tee

(OP)
Thank you everyone! kacarrol, I have the same document but the source is unknown and I am not sure if I reliable. Thanks again!

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