Dexon TechnologyDexon Technology recently completed an API 653 integrity assessment of two large double-wall LPG storage tanks in Thailand—while they were still on stream.
Each tank stood nearly as tall as a 10-story building and spanned 45 meters in diameter, with a single tank storing up to 25,000 tons of LPG.
Our engineers used a combination of NDT methods to build a complete picture of tank integrity without interrupting operations.
Some of the methods included:
• UT thickness measurements
• Eddy current testing
• Thermography
• Settlement surveys
For large storage tank inspections, integrity is not only about spotting corrosion but also about monitoring subtle changes in geometry.
These structural changes include:
• Settlement: the sinking of part of a tank into the ground
• Roundness: how closely the tank maintains its shape
• Plumbness: whether the tank remains vertical
• Peaking & banding: localized bulges near weld seams
Corrosion tells operators how much material remains; geometric defects tell them how well the structure is carrying its load.
Both tanks were confirmed fit for continued service, with no defects requiring immediate repair. The inspection also identified several preventive maintenance opportunities, such as localized coating degradation & aging sealing materials, helping the operator prioritize future work and plan through the next inspection cycle.
Not every inspection needs to find a major defect. Knowing that an asset remains in good condition allows operators to continue their work confident in the asset's safety & reliability.