Obstructions through ducting?

[pmover]

unfortunately, there is ductwork (say 8' square) in which a structural steel beam will diagonally penetrate. try to imagine this scenario, an 8' square duct with a structural steel beam penetrating the duct at approx. 22-degree angle. in other words, when facing square duct, the beam will enter duct at lower left corner of duct and exit duct at mid-height on the right side of duct. lasty, the beam size is roughly 6-inch square.

that being described and i am currently investigating smacna duct construction stds and ashrae, can anyone provide any arguement (pro or con) justifying this design? what design criteria (i.e. fig 2-8 in smacna duct construction stds manual) does the responsible individual need to address in the event that no alternatives are avaliable?

other considerations are OSA temps (-60 degF, is beam made of steel that can withstand -60 degF?), beam sealing, and performance issues. but in this case, a relatively small reduction of air flow (or increased dP) is most likely insignificant.

it is my strong opinion that the engr(s)/designer(s) failed to conduct interference checks, and correct problem before progressing to construction phase. but this belief is now a moot point.

smacna addresses obstructions, but vaguely and this obstruction is rather unique.

thanks!
-pmover

 

[quark]

Obstructions do come during ducting and I can't make any comments with obligation point of view. However, you can Y the duct and again join it after the beam. You can keep each branch with a cross section of 8'x4'.

I will never recommend exposing a steel beam to -60F.

Regards,


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