Channel sections, with or without flange stiffeners, are usually referenced as C Purlins; Channel sections without flange stiffeners are also referenced as u shapes; Point symmetric sections that are shaped similar to the letter Z are referenced as Z Purlins. Section designations can be regional and even specific to a manufacturer. In steel building construction, secondary members such as Purlins and Girts are frequently cold formed steel C Purlins or Z Purlins or u sections or mill rolled C sections.
