Non-destructive testing (NDT) is the inspection of materials for surface and internal flaws or metallurgical conditions, without interfering in any way with the integrity of the material or its suitability for service.
It is the application of measurement techniques in order to identify damage and irregularities in materials.
When carried out correctly, NDT can provide useful information to assist in the management of amusement device safety. If inappropriate NDT is applied or NDT is not applied correctly, the results may give a false impression of the integrity and safety of the device. NDT is a primary recovery mechanism for errors in design, construction, and operational activities. It may be performed during manufacture as part of quality assurance procedures to ensure that a structure or component is free from significant defects and conforms to the design specification. It can be used as part of the in-service annual inspection to determine whether structures or components have deteriorated to an extent that they are no longer fit for continued service. If such deterioration is detected, then NDT can quantify the damage and provide input to the justification for maintenance or monitoring actions. NDT is only able to lead to a reduction in the probability of failure if appropriate action is taken in response to the results obtained. NDT may also need to be performed on a device where there has been a modification or a repair of a safety critical component.