The International Building Code (IBC) developed the framework for code compliance. It references nationally recognized standards for determining design loads (wind, snow, seismic, etc.) and for the design of most materials such as wood, concrete, and steel. A design begins by determining the environmental loads the building will be subjected to. These are found in ASCE 7, published by the American Society of Civil Engineers.
The steel references in the IBC point designers to the American Institute of Steel Construction (AISC) for hot-rolled and built-up plate beams and columns and the American Iron and Steel Institute (AISI) for cold-formed steel members, such as Z and C roof purlins and wall girts. Metal building system designs are required to comply with both the AISC and the AISI specifications.