Screening indications guide investigation. Qualified examination and engineering review establish the findings and the integrity decision.
Does RMF replace conventional NDT?
No. Residual magnetic field (RMF) screening is complementary inspection information for suitable ferromagnetic components. It can help prioritise locations for investigation. It does not replace ultrasonic testing (UT), radiography, magnetic-particle testing, penetrant testing or other examinations required by the inspection plan, applicable requirements or OEM procedures.
What can RMF tell us?
Under defined measurement conditions, RMF screening can show relative magnetic-response patterns associated with material stress state. Bolt-to-bolt comparisons, local departures and repeat measurements can help engineers choose where to investigate. A magnetic indication is not, by itself, a confirmed defect or a calibrated load measurement.
Why use RMF if hydraulic tensioning is already used?
Hydraulic tensioning is an established assembly method. RMF does not replace or certify that process. A separately qualified RMF examination may add comparative information about the installed joint after assembly and during service. Any numerical preload assessment requires an appropriate calibration and validation for the material, geometry and instrument.
Does RMF replace OEM installation or maintenance procedures?
No. OEM installation, commissioning, tightening, acceptance and maintenance procedures remain applicable. Screening results support the engineering review; they do not authorise a change to an approved procedure.
Why inspect bolts that have already been tensioned?
Installation records document the assembly process. Seating, flange interaction, transportation, operating loads and maintenance can affect the installed joint. Repeat inspections may provide useful comparative information when the measurement locations and conditions are controlled.
Why can responses differ between bolts?
Material and manufacturing variability, residual stresses, geometry, seating, flange interaction, magnetic history and service conditions may influence a response. A different response does not automatically mean incorrect tension, a crack or imminent failure. Interpretation requires reference checks and appropriate follow-up.
How are indications verified?
Agree the inspection objective and reference locations, document acquisition conditions, review geometry and service history, then select suitable verification. This may include UT thickness or weld examination, surface examination, dimensional checks or an engineering-approved assessment of the joint. The verification method follows the suspected mechanism and asset requirements.
Can RMF confirm remaining life or fitness for service?
Not independently. Screening cannot automatically establish defect dimensions, remaining life or fitness for service. Those decisions require verified findings, relevant operating and material data, applicable assessment procedures and competent engineering review. RMF history may be an input to that process.
Is RMF screening the same as a remote magnetometry survey?
No. Direct-contact component screening and ground, aerial or marine magnetic surveys address different objectives. Buried infrastructure surveys map magnetic variations and require site-specific interpretation. Survey anomalies must be correlated and verified before they are attributed to a pipe or damage mechanism.
What should an inspection report include?
Asset and location identification; material and geometry; operating and loading conditions; instrument configuration; reference checks; acquired data and repeatability; indications and interpretation limits; recommended verification; and any confirmed findings. Keep screening indications separate from verified conclusions.
Are partner publications proof of BROT field achievements?
No. SPECTOR research, patent documents and manufacturer materials are attributed to their authors and technology owners. They provide technical context. They do not establish BROT project achievements, operator endorsement or validation for a particular asset.
