Practical guidance for selecting instruments, understanding measurement methods, and improving inspection workflows.
Intumescent fireproofing on steel structures runs from several hundred micrometres to several millimetres, far beyond ordinary painting, so a wide-range magnetic gauge is the mainstream choice; the English…
Eddy current testing drives a high-frequency coil to induce eddy currents in a conductive substrate and derives non-conductive coating thickness from the change in coil impedance. Defined by…
Wall thickness of pipes, boilers and pressure vessels is measured by ultrasonic pulse-echo: from outside the equipment, the round-trip sound time is converted to wall thickness, to assess…
Choosing a principle comes down to one question: is the substrate ferromagnetic? If yes, use magnetic induction (Fe). If not, and the substrate is conductive, use eddy current…
Hull, yacht and offshore structure thickness surveys share one problem: the surface already has a full anti-corrosion coating, and grinding means repair. Echo-Echo through-coating mode measures the steel…
An ultrasonic thickness gauge fires a sound pulse and times its round trip between the two surfaces of the part, converting that time with velocity × time ÷…
Floor coatings, wood finishes and plastic-part painting share one trait: the substrate is neither magnetic nor conductive, so magnetic and eddy current methods both fail; such scenarios must…
Echo-Echo mode calculates wall thickness from the interval between successive back-wall echoes, automatically ignoring the coating on the surface. Painted, coated pipework and hulls can therefore be measured…
ASTM D7091-22 is a Standard Practice that specifies calibration, verification, adjustment and measurement for magnetic and eddy-current coating thickness gauges. It supplements rather than replaces the manufacturer manual,…
