ISO tank containers for bulk liquids: the basics

An intermodal pressure vessel

An ISO tank places a cylindrical stainless-steel vessel inside a standard frame so it can move by road, rail and sea. Designs vary by tank instruction, working pressure, insulation, heating capability, baffles, lining and fittings. Capacity alone is not enough to specify a unit. The product’s transport classification, density, vapor pressure, corrosion behavior and temperature range must be reviewed by qualified parties.

Product compatibility governs selection

Confirm the exact product, concentration, safety data and previous cargo restrictions. Valves, seals, gaskets and tank material must be compatible. Food-grade and chemical service need controlled cleaning histories and allocation practices. Hazardous products bring additional documentation, marking, inspection and handling requirements. Do not substitute a similar product name for a technical review.

Filling level affects safety

Minimum and maximum filling rules can apply to control surge and allow thermal expansion. Product density determines payload at a given volume, while road and container gross limits still apply. Loading temperature, heating needs and discharge method influence the operating plan. Verify weighbridge, hose, pump, earthing and spill-control arrangements at both ends.

Cleaning, inspection and records follow the tank

Tank containers require periodic testing and maintenance. Before loading, review validity, cleanliness, previous cargo where required, valve condition and release documents. After discharge, residual product and cleaning responsibility should be clear. A tank waiting for an approved wash or repair can create substantial delay, so plan the post-discharge facility before the movement begins.