Maintenance, Inspection, and Testing
Core concepts
This domain tests planned and predictive maintenance, inspection methods, and testing practice. Understand preventive, predictive, and corrective maintenance and when each applies. Know nondestructive examination methods: visual, liquid penetrant, magnetic particle, ultrasonic, and radiographic testing, and what each detects. Study vibration analysis, oil analysis, thermography, and alignment checks as condition-monitoring tools. Testing topics include hydrostatic and pneumatic tests, pressure and leak testing, calibration, and functional testing of safety devices. Documentation, work orders, and record retention matter too.
Traps to watch
Questions often confuse which NDE method detects surface versus subsurface flaws. Magnetic particle testing works only on ferromagnetic materials; liquid penetrant works on nonporous surfaces but not on rough or porous ones. A common trap is choosing pneumatic testing where hydrostatic testing is safer and preferred. Watch for items on calibration where zero and span errors are mixed up, and for questions that treat a functional test as a substitute for calibration.
Worked example
A vibration reading rises from 2 mm/s to 7 mm/s over a month on a pump bearing. ISO severity guidance places 7 mm/s in the caution zone, so the correct response is increased monitoring and root-cause investigation, not immediate shutdown. Rule of thumb: trend matters more than a single reading; a doubling of vibration over a short interval warrants inspection even if absolute values remain acceptable.