Girts and Purlins should be cold-formed or hot-rolled steel sections, designed to AISI SG-673 PART I or AISC S335 specifications. Cold-formed steel should conform to ASTM A 572 / A 572M with minimum yield stress between 42 and 55 ksi (290 and 380 MPa). Hot rolled steel should be to ASTM A 36 / A 36M or ASTM A 572 / A 572M.
Girts and Purlins should be doubly symmetric shapes either back-to-back channels, "I" shaped or wide flange members. The minimum allowable thickness should be 0.06 in. (1.5 mm) (16 gage).
Connections and splices should be designed to transfer the full capacity (shear and/or moment, as appropriate) of the Girts and Purlins under consideration.