How is the size of an unequal leg fillet weld determined?

The size of an unequal leg fillet weld is determined by the length of its shortest leg. This convention is important because the effectiveness and strength of a fillet weld depend on the shorter side. In welding practice, when assessing the size of a weld, the shortest leg provides a consistent reference that allows welders to ensure that the joint will meet the design requirements and expectations for strength and durability.

While other characteristics of the weld, such as the overall volume or depth, might provide insights into its performance, they do not serve as the standard for determining the size classification of an unequal leg fillet weld. Therefore, measuring the shortest leg ensures that there is a reliable standard for size determination that aligns with the expectations set forth in welding codes and standards. This approach not only aids in quality control but also helps in complying with structural specifications in fabrication.