This Supplement F to AWS standard QC7-93 describes testing administrated by Accredited Test Facilities to the requirements of AWS QC4. The welder performance testing for this Supplement was developed using ANSI/ASME B31.3, Chemical Plant and Petroleum Refinery Piping, and ASME Boiler and Pressure Vessel Code, Section IX, Welding and Brazing Qualifications as reference.