I have been inspecting numerous new homes that have the air handlers located in the attic space. The AHU are suspended from the roof trusses with metal straps at each corner. The straps are installed behind the AHU casing. I cant see how far down the straps are connected because they go into the casing/shell.

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.

Any explanations would be appreciated, thanks in advance