Have the situation of an existing metal building with no documentation and unknown manufacturer. The owner's property insurer wants to verify that the existing 8" Zee roof purlins are adequately braced. The purlins are 24' span @ 5' o.c. with (1) 4" channel attaching the purlin midpoints in alternating purlin bays. They are supporting a standing seam roof and 20 psf snow. For some reason the insurer only thinks this is a concern at the bays along the outer wall and not in the interior area, although they the same roof framing exists throughout.
With limited experience in cold-form steel, I am having trouble determining what direction to take. Even after going through the AISI spec and commentary.