A flange leak does not establish that the flange contains a crack. The investigation may need to consider the face, gasket, alignment, bolting and operating history together. Agree who owns the joint assessment before separating the inspection into isolated tests.
After the owner has made the joint safe and authorised access, document the sealing face and adjacent areas. Record damage, deposits, corrosion and other relevant features with a location reference. Preserve useful evidence before cleaning or repair changes it.
Surface examination may help investigate a suspected surface-breaking discontinuity when the material and surface condition permit. It does not measure gasket compression or prove that the assembled joint will remain leak-free.
Face geometry, alignment and surface finish may need dimensional evaluation under the applicable specification. A penetrant or magnetic-particle examination answers a different question. Define the reference, measuring arrangement and acceptance responsibility for each activity.
Provide the assessor with the gasket identity, relevant assembly records and operating changes where available. Do not treat a successful NDT result as approval to reuse a gasket or return a damaged joint to service.
Record the initial condition, authorised work and re-examination results against the same joint identifier. Any machining or other repair needs its own approved limits and acceptance basis. Keep the responsible engineering decision separate from the technician’s observations so the final dossier shows why the joint was accepted.
ASNT’s overview of NDT methods provides further background. Use the governing specification and approved procedure for the actual job.
Discuss the examination scope. Include the component, material, service history and decision the inspection needs to support.