I am applying this credit to ten rooftop units that lack a straight duct section long enough to traverse with a pitot tube. The TAB contractor is concerned that measurements taken at the intake louvers will be inaccurate because of the influence of wind. I envision temporarily fastening some kind of manifold/duct section over the RTU's fresh air intake louver to facilitate measurements. Before I propose this to the TAB contractor has anyone tried anything similar (or simpler) with RTU's? Thanks in advance.