Liquid Penentrant in the Energy Industry

            The energy industry includes the gas & oil, nuclear, gas turbine, and wind energy sectors. These sectors rely heavily on liquid penetrant for the inspection of welds, valves, and turbine blades. Red dye liquid penetrant inspections usually involve the use of aerosols because a field technician can perform the inspection with limited or no access to water, power, special lighting, or equipment that is required as with fluorescent penetrant inspection. In some instances, as in the case with the manufacturing of valves in the nuclear industry, the post-emulsifiable method is used with visible red dye penetrants. Other industries that have used the post-emulsifiable method has been the casting industry to reduce the amount of background.

            Liquid penetrant inspection materials must be certified to meet the elemental requirements of the ASME Boiler Pressure and Vessel Code (BP&VC). Met-L-Chek inspection materials are certified to BP&VC, meting the low parts per million content of sulfur, chlorine, and total halogen requirements. In addition to BP&VP, Met-L-Chek red dye inspection materials are AMS 2644 certified.

Common Liquid Penetrant Systems


Approved Met-L-Chek Materials

Type 2 – Red Visible Dye Penetrant

Method A & C: VP-30 Visible Red Dye Penetrant

Method A & C: VBP-300, Visible Red Dye Penetrant biodegradable

Method B & C: VP-31A Visible Red Dye Penetrant


Method B: E-57 Lipophilic Emulsifier


Form d: D-70 Non-aqueous Developer


Solvents: E-59A, R-503, R-504

Alkaline: 300LF