This webinar, which is part of DOE's Building Energy Codes Program Energy Codes Commentator webinar-based training series, provided an introduction into metal building types and systems and how they are defined in the national energy codes and standards. The presentation focused on metal building envelope assemblies and applications (e.g., roofs, exterior walls, fenestration, air barriers, and air leakage), and how the energy code affects various aspects of metal building envelopes and various code compliance options. A demo of DOE's energy code compliance software was shown which focused on how the different metal building assemblies are defined and calculated for code compliance.