Proof testing is typically run on parts at a higher RPM than operational speeds but lower than burst speeds to prove the parts are suitable for use. It has three important aspects are suitable for operation: the design, the materials used and the manufacturing processes employed. All critical production parts should be 100% proof tested while less critical parts may only be sample tested. The intention of a proof test is to extract information about the part while maintaining the part in good working order; however, it can burst at any time releasing substantial destructive energy. It is used for the turbine rotor, turbo fans, high-speed fans and turbochargers applications. It will provide evidence that the design, material and process are sufficient. Any flaws that could affect the performance or life will show up more readily when spun at a speed higher than at normal operating speed.