Coded Welder South Africa: Quick Answer A coded welder in South Africa is generally a welder who has passed a practical welder-qualification test under a specified construction code or standard, such as ISO 9606-1, ASME Section IX or AWS D1.1. The qualification is not universal. It normally applies within a defined range involving variables such as: the welding process; base material; filler material; plate or pipe; material thickness or pipe diameter; welding position; joint