ABSTRACT
Edge preparation for any pressure and nonpressure joints shall be in accordance with the design given in the concerned drawing prepared according to code and specifications. Variations in the configuration (such as a change in “V” angle, etc.) shall be within normal allowable tolerances. Variation of root gap is one of the major problems seen during fit up of groove welds. Variation of root gap shall be limited within 1 mm to 1.5 mm throughout the entire weld joint (for vertical seams). Though this is not specified anywhere in API 650, provided proper care is taken during edge preparation and subsequent handling and fit up of the shell plates, this tolerance is quite possible. If this is achieved, its impact shall be seen in the final welding, and chances of having a repair shall be much less compared to a joint with more variation in root gap.
