Cleaning and maintaining ISO tank containers is vital—not only to prevent cross-contamination between different cargoes that may affect product quality, but also to ensure safety during transportation and storage. This article walks you through how to test, clean, and repair ISO tanks for safe and reliable use.

1.   How to Safely Use ISO Tank Containers : Key Testing and Inspection Procedures

(1) Conduct One-Bar Pressure & Leak Testing Before Use

Before each use, ISO TANK containers must undergo a one-bar pressure and leak test. This test ensures that all valves are pressure-tight and free from leaks—verifying the container is safe for use.

(2) Schedule Periodic Internal Pressure Tests

From the manufacturing date, ISO TANK containers must be tested every 30 months:

• At 30 months: Pneumatic (air) pressure test
• At 60 months: Hydrostatic (water) pressure test
• This cycle repeats every 30 months.

A certified third-party inspector must verify that the tank maintains pressure with no leakage. Only with a valid Tank Periodic Inspection Certificate can the tank be deemed safe for transport.

2.   How to Clean ISO Tank Interiors to Avoid Cargo Contamination

(1) Create a Tailored Cleaning Plan Based on Cargo Characteristics

To achieve the best cleaning results, tailor the cleaning method based on the cargo’s nature (e.g., water-based, oil-based, odor intensity, or viscosity). The typical cleaning process includes:

1. Fogging Treatment : Use a compressor to spray a low-pressure chemical solvent that dissolves residue inside the tank.
2. High-Pressure Water Jetting : Use a compressor-powered 360° water jet to remove internal residues.
3. Visual Inspection : A trained technician enters the tank to verify cleanliness.
4. Drying : Use blowers to circulate air until the tank is fully dry and free of water marks.
5. Third-Party Cleanliness Certification : An inspector certifies the tank’s cleanliness to prevent contamination.

(2) Preventing Contamination in ISO Tanks

After every cleaning, the tank must pass inspection and be certified clean by a third-party agency. Only then can it be used to load new cargo without risk of contamination.

3.   What Does ISO TANK Maintenance Involve?

After each use, a comprehensive inspection of the ISO tank’s interior and exterior must be conducted. Professional personnel should check for dents, corrosion, or damage and take appropriate repair actions.

(1) Inspecting the Inner Tank

After cleaning, check for:

• Corrosion: Weld, smooth, and acid-treat affected areas.
• Deformation: Smooth out any protrusions caused by external impact.

Choose tank types according to International Maritime Dangerous Goods (IMDG) Code regulations. For corrosive substances, use tanks lined with PTFE or PFA to prevent damage.

Further reading : What Is an ISO Tank and What Is It Used For? A Complete Guide to ISO Tank Types, Sizes, Capacities, and Loading Ratios

(2) Inspecting ISO Tank Valves

Valves such as safety valves, air valves, and bottom valves must be tested after each return to the depot. Faulty valves must be replaced immediately to ensure safe operation.

(3) Inspecting the Tank Frame and Accessories

Inspect the tank body and accessories for damage each time it returns to the depot. Any damage must be repaired immediately to maintain functionality and safety.

Published Date: January 22, 2025