The multi-compartment ISO tank divides the cylindrical interior into 2 or 3 fully sealed compartments of 7,000 to 10,000 L each via full transverse bulkheads (rather than the perforated baffles of a baffled tank). Each compartment has independent loading, discharge, and pressure-relief plumbing, preventing any cross-contamination between cargoes. The build is used for shipping multiple compatible cargoes simultaneously (different chemistries to different receivers in one tank), or for multi-drop partial-load routes.
What multi-compartment is built for
Two distinct use cases. First, simultaneous shipment of multiple compatible cargoes from one shipper to multiple receivers. A two-compartment T11 might carry methanol in compartment A and ethanol in compartment B, with each cargo loaded and discharged independently. Second, multi-drop routes where the same operator delivers to multiple receivers along the route; partial discharge at each stop is straightforward when each cargo sits in its own compartment.
Construction and materials
316L stainless cylinder built to standard T11 spec, with 1 or 2 full transverse bulkheads dividing the cylinder into 2 or 3 separate compartments. Each bulkhead is welded to the cylinder wall and sealed against pressure (rated to the test pressure of the parent T-code). Each compartment has its own DN500 manlid, top discharge / loading flange, sample valve, PRV, and bottom outlet. The plumbing geometry matters: the loading and discharge lines must be physically separated to prevent cargo mix-up at the dock.
Tare runs higher than a single-compartment T11 (4,500 to 5,200 kg vs 4,000 kg) because of the bulkhead mass and the additional fittings. Capacity drops to about 21,000 L total because the bulkheads occupy internal volume.
When multi-compartment is the right choice
Multi-compartment is the right tank for shippers with established multi-cargo routes where loading economics favour shipping multiple chemistries together. Some specialty-chemical houses run captive multi-compartment fleets between specific manufacturing sites and specific customer locations on this exact rationale. Multi-drop routes (a single tank visiting 2 to 3 customers along a route, partial-discharging at each) are the other classic use case.
When multi-compartment is the wrong choice
Multi-compartment is the wrong tank for single-cargo bookings where a standard single-compartment T11 is simpler and cheaper. The build cost premium plus the operational complexity of dual or triple loading and discharge plumbing isn’t justified for one-cargo trips. Multi-compartment is also the wrong tank when cargo compatibility cannot be guaranteed: chemistries that react if cross-contaminated must ship in separate tanks, not in compartments of the same tank.
How a multi-compartment booking is verified
Pre-loading inspection covers the standard plate stack plus a bulkhead-integrity check (visible through the manlid of each compartment), each compartment’s independent fittings (PRV, manlid, valves), and the operator’s history showing successful multi-cargo or multi-drop service. EFTCO ECDs document the cleaning of each compartment separately. Cleaning costs are typically 1.5 to 2 times higher than for a single-compartment tank because each compartment is cleaned independently.