Visual Testing in LNG: What It Finds, What It Misses, and What Governs It
What VT is actually used for in lng
Perlite settlement evidence, outer-tank condition and pipework support checks make visual examination a scheduled activity across any LNG facility.
How VT works
Visual testing is the examination every other method is deployed against: direct or remote observation under controlled lighting and access, judged against written acceptance criteria. It finds the majority of reportable conditions in most programmes — weld profile, corrosion, mechanical damage, coating breakdown, leakage evidence — and it decides where volumetric examination is worth performing.
What VT will not do
What VT will not do: see beneath the surface, quantify wall loss, or substitute for a volumetric method where the code requires one. Its weakness is human rather than physical — inconsistent lighting, inadequate access, and acceptance criteria applied from memory rather than from the document.
The lng assets this applies to
Liquefaction trains, cryogenic storage tanks, loading lines and jetties, boil-off handling, and the marine interface.
The damage mechanisms driving the examination
Cryogenic service changes the question: brittle fracture risk drives material and toughness concerns, thermal cycling fatigues connections, and external corrosion under cryogenic insulation is difficult to detect precisely because access is difficult.
What governs acceptance
API 625 and 620 for cryogenic tanks, ASME for pressure equipment, plus jurisdictional and marine-terminal requirements at the interface. On the method side: ASME Section V Article 9; AWS D1.1 for structural acceptance; API 510/570/653 for in-service external and internal examination; ASME B31.3 for process piping. An examination that is technically sound but performed outside the governing regime is not an examination anyone will accept, which is why the code family matters as much as the technique.
How Atlantis delivers VT in this sector
Atlantis mobilises examination teams to your site under Atlantis procedures with ASNT Level III oversight — we do not claim a depot or laboratory in every market, and say so plainly. What you receive is the examination performed to a qualified procedure, findings evaluated against the acceptance criteria your contract names, and records structured to survive a client audit years later.
Visual Testing services · VT training and certification · LNG programme consulting · LNG NDT training · scope a VT examination.
VT in other sectors
Refining · Petrochemical · Offshore · Pipeline · Marine & Shipbuilding · Aviation & Aerospace.