The American Welding Society's D1.1 Code is intended to cover the welding for structural steel of 1/8" thickness and over. It covers WPS, PQR and WPQ testing. Most WPSes are "pre-qualified", except GTA and short circuit transfer GMA, and thus do not require procedure qualification. The WPQ is what is commonly called "certification" of the welder. Passing a vertical and overhead plate qualifies a welder for all postions.