The external surface of butt welds must be free from undercuts greater than?

The requirement that the external surface of butt welds must be free from undercuts greater than 1/32" is established to ensure the integrity and strength of the weld. Undercuts are localized grooves or depressions that can occur at the weld toe or root, and they can significantly weaken the weld joint by reducing the effective area that carries the load and creating points of stress concentration.

Maintaining undercuts within this limit helps enhance the fatigue resistance and overall durability of the piping system. Exceeding this threshold could lead to problems in service, such as crack initiation and propagation, which can compromise the safety and performance of high-pressure piping systems. Therefore, adhering to this standard is crucial for ensuring reliable operations in environments where pressure and stress levels are significant.