Vacuum Box Testing can be used on lap welds, shell to annular welds, butt welds, pressure vessels, piping systems, among many others. This method is great as it is capable of immediately locating any leaks. It can also detect the smallest leaks inside a given area.
Ned Marine’s professionals are trained and experienced in vacuum box bubble test methods in accordance with the ASME BPVC code, section V, article 10, Appendix II.
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What Is Vacuum Box Testing?
Vacuum Box Testing is a non-destructive method used to detect leaks and discontinuities in welds, tank bottoms, pipelines and pressure-retaining structures. By creating a controlled pressure difference inside a vacuum box and applying a contrast soap solution, even the smallest defects become visible as air bubbles. This technique is especially valuable in environments where safety and integrity are critical, such as maritime vessels, offshore installations and industrial storage tanks. It provides immediate, reliable visual confirmation without damaging the material.
How the Vacuum Box Method Works
The inspector applies a soap solution to the weld and places the vacuum box over it. When the vacuum pump creates negative pressure, any leakage path forces air through the defect, producing clear bubbles. This simple but effective mechanism allows rapid testing of long weld seams with consistent accuracy, even on irregular surfaces.
Where Vacuum Box Testing Is Most Effective
This method is ideal for large surface areas or components that cannot be pressurised internally. Typical applications include storage tank floors, ship hull plating, ballast tanks, pipelines, offshore skids, and pressure vessel attachments. It is particularly useful when other NDT methods—such as UT or radiography—are too costly, slow, or impractical.
Standards and Certification
Vacuum Box Testing at Ned Marine is performed according to recognised industry standards, including ASME BPVC Section V, Article 10, and applicable ASTM guidelines. Our inspectors are certified and trained to ensure precise execution and correct interpretation of all bubble indications. This guarantees compliance for marine, offshore and industrial inspection requirements.
Our Vacuum Box Testing Service
Ned Marine provides mobile vacuum box testing on board vessels, in shipyards, tank terminals and industrial sites. Our team conducts fast turnaround inspections, supports repair teams with direct feedback, and documents all findings in clear inspection reports. With broad experience in maritime and offshore environments, we ensure that safety-critical structures remain compliant, reliable and leak-free.
