Prior to production welding commencing you notice that the drawing has been revised and now includes a pipe with a wall thickness of 30 mm, WPB only covers wall thickness of 28mm,

A. continue with production welding as the difference is less than 10%

B. apply for concession to change the thickness to permit the welding on the 30mm wall thick pipe

C. change the range on WPB to 30mm and allow welding to commence