Originally Posted by
Matt Hawley
The code says strapping shall be at points within the upper and lower one-third of the AHU vertical dimensions.
I am not sure if I understand the code properly where it says the upper and lower one-third.
???????
Where does it say that? New one on me.
But ... if it is there, to me, that would mean you have an air handler hanging horizontally (or vertically), you draw to imaginary lines through it, one line 1/3 up from the bottom and one line 1/3 down from the top, then attach the support straps in the lower third and the upper third.
That would make sense in that if you attach the supports at the bottom only, the thing could flip over, and, if you attach the supports at the top only, the cabinet could come apart.
Attaching at the bottom carries the weight of the unit, attaching at the top keeps if from flipping over.
Does it say that in the manufacturer's installation instructions? I would think it would be there more than in the code itself.
Unless ... it is referring to *where* you attach them at the trusses, you would *not* want them attached in the center third, that would lead to deflection of the trusses more likely than if attached to the truss near the top of near the bottom.
Just guessing here and shooting from the hip.