HVAC Duct Crossing Building Expansion Joints
HVAC Duct Crossing Building Expansion Joints
(OP)
We have a 6'x6' square duct with negative pressure crossing from one building to another with 14 inches (+/-) of differntial movement. The duct is not flexible enough to absorb these movemnts without the use of flexible/expansion joints. Any recommendations would be appreciated. Thank you.





RE: HVAC Duct Crossing Building Expansion Joints
That is better than 1/3 of your duct size. So you will need a long flex joint to prevent a rather sudden change in the duct cross-section and associated variation in system pressure drop.
RE: HVAC Duct Crossing Building Expansion Joints
RE: HVAC Duct Crossing Building Expansion Joints
RE: HVAC Duct Crossing Building Expansion Joints
RE: HVAC Duct Crossing Building Expansion Joints
I was thinking along the same lines at Chris. Unless it is a horribly negative pressure your best bet is probably regular ol' flex duct, oversized just a bit to take into account it's huge pressure drop in comparison to standard metal ductwork.
RE: HVAC Duct Crossing Building Expansion Joints
Thank you all.