As listed below, committee and working draft versions of the actual STEP standards are typically available online in SOLIS. However, once a document reaches the Draft International Standard (DIS) and International Standard (IS) stages, it is copyrighted by ISO. DIS and IS copies must be purchased from an authorized source such as ISO or your national standards organisation:
International Standards Organization (ISO): <http://www.iso.ch/>
USA: NCGA, 2722 Merrilee Drive, Suite 200, Fairfax, VA 22031-4499. voice: (703) 698-9600
Note: The below online Parts may not be the latest versions. Also, some Parts may not be available online yet(e.g., the 300 Series, as of this writing).