When does a WPS have to be requalified?

When does a WPS have to be requalified?

• A. When there is a change to an essential variable
• B. After every project
• C. When a new welding machine is installed
• D. At the start of each shift

Answer: (A)

A Welding Procedure Specification must be requalified whenever there is a change to an essential variable. Essential variables are the parameters that, if altered, can change how the weld behaves and whether it meets the required quality. If any of these variables change—such as material type, base metal thickness range, welding process, or filler metal—the existing WPS may no longer guarantee a acceptable weld, so requalification tests are needed to confirm the procedure still produces a compliant weld.

This isn’t something you trigger just by starting a new project or a new shift, and it isn’t automatically required by simply installing a new welding machine unless that change affects an essential variable (for example, a different process or metal type).