What is the minimum plate thickness that a structural welder is allowed to weld on?

The minimum plate thickness that a structural welder is allowed to weld on is 1/8 inch. According to the AWS D1.1 Structural Welding Code, this thickness represents the smallest dimension allowable for welding processes in structural steel applications. This guideline is crucial as it helps ensure that welds can achieve sufficient strength and quality. Plate thickness influences the heat input needed for welding; thinner plates are more susceptible to distortion and burn-through, which necessitates specific procedures to control heat. Therefore, starting at a minimum thickness of 1/8 inch allows for a balance between workable material and the integrity of the weld.