Wide gap welding for butt joints shall be qualified by a separate WPQT when the gap is more than 16 mm and up to maximum 1.5×t (max. 25 mm), where t is the plate thickness. The largest gap in production (forremedial welding) shall be used. Gap more than 25 mm shall, unless specially agreed, be repaired by insert.Buttering of the weld groove shall be qualified by a separate WPQT for the following cases: