Penetrant Testing in LNG: What It Finds, What It Misses, and What Governs It
What PT is actually used for in lng
Cryogenic plant is austenitic almost throughout, which makes penetrant testing the default surface method — stainless piping welds, aluminium exchanger repairs and nickel-steel transitions all take PT to demanding acceptance classes.
How PT works
Penetrant testing draws a low-viscosity liquid into surface-breaking discontinuities by capillary action, then blots it back out onto a developer where the indication becomes visible — under white light for visible dye, under UV-A for fluorescent systems. It works on any non-porous material, which is precisely why it exists alongside MT.
What PT will not do
What PT will not do: find anything that does not break the surface, work on porous or heavily coated material, or survive a poor clean — the examination is only as good as the pre-cleaning, and most PT failures are cleaning failures. Dwell and developer times are process parameters, not suggestions.
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 6; ASTM E1417 for the process; ISO 3452 internationally; aerospace scopes add OEM and NAS 410 process controls above all of these. 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 PT 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.
Penetrant Testing services · PT training and certification · LNG programme consulting · LNG NDT training · scope a PT examination.
PT in other sectors
Refining · Petrochemical · Offshore · Pipeline · Marine & Shipbuilding · Aviation & Aerospace.