T16 is the IMDG Code Chapter 6.7 portable tank instruction at 10 bar test pressure with bottom outlet permitted only for solids (liquid bottom outlets prohibited) and a frangible-disc plus tell-tale gauge relief regime. The combination of high test pressure, solids-only bottom-outlet rule, and frangible disc places T16 in a niche between T14 (6 bar, no BO, frangible) and T19 (10 bar, no BO, frangible).
What T16 is built for
The IMDG Dangerous Goods List assigns T16 to high-vapour-pressure Class 6.1 toxics and Class 8 corrosives where the assigned cargo profile justifies the 10 bar test pressure and the frangible-disc regime, but where a solids bottom outlet is acceptable. The cargo list is short and specific to UN entries that don’t fit the more common T14 / T18 / T19 profiles.
Construction and materials
316L stainless cylinder, 6 mm reference-steel shell. ASME U-stamp typical for ocean carriage. Top discharge through a dip-pipe; the bottom outlet is plugged or designed for solid product only. Frangible disc plus tell-tale gauge mounted in series with the spring-loaded PRV.
When T16 is the right choice
T16 is the right tank when IMDG DGL Column 13 specifies T16 for the UN entry. The substitution rule allows T16 cargo to ride T17, T18, T19, T20, T21, or T22.
When T16 is the wrong choice
T16 is the wrong tank for cargoes assigned to T11 / T14 / T20 / T22 where the operator fleet is bigger and the lease rate is more competitive. T16 is also the wrong tank where the bottom outlet must be fully prohibited (escalate to T19) or where a frangible disc is not required (T17 instead).