T5 is the IMDG Code Chapter 6.7 portable tank instruction at 2.65 bar test pressure with no bottom outlet and a frangible-disc relief regime. It sits among the lower-pressure no-bottom-outlet codes (alongside T8 which uses normal PRV, and T9 / T10 which step up to 4 bar). T5 is specifically targeted at certain Class 5.1 oxidisers where bottom-outlet failure under fire conditions would compound an already serious oxidiser-fuel scenario.
What T5 is built for
The IMDG Dangerous Goods List assigns T5 to specific oxidiser cargoes including perchloric acid 50 to 72% (UN 1873), hydrogen peroxide solutions in the range where a frangible disc adds a useful safety margin (UN 2014, UN 2015 at higher concentrations), ammonium nitrate solution UN 2426. The H2O2-dedicated build that meets IMDG T14 hazardous-peroxide requirements is closely related but uses a different relief regime; the T5 build covers oxidisers where the IMDG entry specifies T5 directly.
Construction and materials
316L stainless cylinder, 6 mm reference-steel shell, no insulation by default (oxidisers usually ship at ambient temperature), no internal heating. Top fittings: dip-pipe discharge, sample valve, frangible disc plus tell-tale gauge mounted in series with the spring-loaded PRV. The cargoes don’t tolerate iron contamination or rust, so the build maintains a polished interior with no carbon-steel inclusions.
When T5 is the right choice
T5 is the right tank when IMDG DGL Column 13 specifies T5 for the UN entry. The substitution rule allows a T5 cargo to also ride T8 through T22 where a frangible disc and no bottom outlet are present. In practice many T5-eligible cargoes ride T9 or T14 because operator inventory is bigger.
When T5 is the wrong choice
T5 is the wrong tank for the H2O2 fleet where the dedicated T14 H2O2 build (non-insulated, 10 inch rupture disc, breather valve, oxygen-compatible PTFE seals) is the operator-standard equipment. Stolt and Eurotainer publish the T14 H2O2 spec as the canonical hydrogen-peroxide build; T5 sees more limited use.