Short answer: Liquefied petroleum gas (LPG) storage tanks are pressure vessels that store flammable gas under pressure. They are periodically inspected through internal/external inspection, hydrostatic pressure testing, safety equipment checks, and (in buried tanks) cathodic protection checks.

LPG tanks pose a dual risk due to both pressure and flammable/explosive contents. Loss of wall thickness due to corrosion or a faulty safety valve can lead to gas leaks, fires, and BLEVE-type explosions.

Periodic inspections prevent these catastrophic scenarios by verifying tank integrity and safety systems, and documenting compliance with regulations.

What is checked?

• Corrosion, pitting, and cracks in the shell and weld seams.
• Ultrasonic wall thickness (UT) measurement
• Safety valve opening pressure and calibration.
• Pressure gauge, level and temperature indicators.
• Grounding and equipotential connections
• Cathodic protection potential in buried tanks.
• Gas leak detection and filling/emptying fittings

Methods and Non-Destructive Testing

Pressure vessel inspection includes internal and external visual inspection, ultrasonic wall thickness measurement (UT), and hydrostatic pressure testing as needed. Safety valves are verified on a test bench according to their opening pressure. Cathodic protection measurements are also performed in buried tanks due to the high risk of corrosion.

Legal Basis and Period

LPG tanks, as pressurized equipment, are subject to periodic inspections under Law No. 6331 and Annex III; these inspections are carried out by authorized personnel and documented with a report prepared by them.

Common Nonconformities

• Widespread corrosion and paint loss on the exterior surface.
• Safety valve that has outlived calibration or is leaking.
• Insufficient/inadequate grounding.
• Insufficient cathodic protection potential in buried tanks.

Frequently Asked Questions

How often is a hydrostatic test performed on an LPG tank?

This is determined according to the tank type and regulations; the tank condition is evaluated during the annual inspection, and pressure tests are assessed at longer intervals.

Do buried tanks require additional checks?

Yes; cathodic protection measurements should be carried out due to the risk of corrosion.

Why is a safety valve critical?

It is the last safety barrier protecting the tank from excessive pressure; the opening pressure must be verified.

Document Your Security

For pressure vessel and LPG tank inspection Mechanical Equipment Inspections Check out our page; mandatory periodic inspection Check out our guide.