26.5.5Spark Test

Spark testing is a common non-destructive testing (NDT) technique in industry, primarily used to inspect the continuity and integrity of insulating coatings (e.g., anti-corrosion, lining, insulation layers) on metallic substrates. A spark tester applies adjustable high voltage (0.5–35 kV) to the coating. A sound coating blocks current; defects (pinholes, cracks, bubbles) cause sparking and audible/visual alarms for precise location.
The process includes calibration, grounding, scanning (≤0.3 m/s), marking, and repair, detecting micro-defects as small as 0.02 mm. Widely applied to anti-corrosion linings of tanks, pipes, reactors, cable insulation, and tank coatings in chemical, pharmaceutical, and food industries, complying with standards like HG/T 4090 and ASTM D5162, ensuring equipment safety and coating quality.