Selecting the correct portable tank is a compliance obligation, not a preference.
Shippers must match their dangerous goods to a tank code that meets the minimum test pressure, shell thickness, and pressure relief requirements prescribed in the Dangerous Goods List.
Freight forwarders verifying documentation need to confirm that the tank offered by the operator meets or correctly substitutes the specified instruction.
Tank operators can use this table to quickly refer the substitution when allocating equipment across multiple cargo bookings.
Ship operators and their DG superintendents can use this reference to quickly validate tank suitability during pre-loading checks, reducing the risk of non-compliant cargo reaching the vessel.
Portable Tank Instructions T1 – T50
Portable tank instructions define the minimum construction, pressure, and equipment standards that a portable tank must meet to carry a specific dangerous good. The table below consolidates all prescribed tank codes (T1–T22, T23, T50) together with the substitution hierarchy that applies when an equivalent or superior tank code is used.
Tank Code Specifications
§ 4.2.5.2.6
| Tank Code | Min. Test Pressure (bar) | Min. Shell Thickness | Pressure Relief Provisions | Bottom Opening Provisions |
|---|---|---|---|---|
| T1 | 1.5 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 2 shut-off devices |
| T2 | 1.5 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 3 shut-off devices |
| T3 | 2.65 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 2 shut-off devices |
| T4 | 2.65 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 3 shut-off devices |
| T5 | 2.65 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
Safety RV + Bursting Disc | Not Allowed |
| T6 | 4 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 2 shut-off devices |
| T7 | 4 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 3 shut-off devices |
| T8 | 4 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | Not Allowed |
| T9 | 4 | 6 mm | NormalNo bursting disc | Not Allowed |
| T10 | 4 | 6 mm | Safety RV + Bursting Disc | Not Allowed |
| T11 | 6 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 3 shut-off devices |
| T12 | 6 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
Safety RV + Bursting Disc | 3 shut-off devices |
| T13 | 6 | 6 mm | NormalNo bursting disc | Not Allowed |
| T14 | 6 | 6 mm | Safety RV + Bursting Disc | Not Allowed |
| T15 | 10 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
NormalNo bursting disc | 3 shut-off devices |
| T16 | 10 | 5 mm (D < 1.8 m) 6 mm (D ≥ 1.8 m) |
Safety RV + Bursting Disc | 3 shut-off devices |
| T17 | 10 | 6 mm | NormalNo bursting disc | 3 shut-off devices |
| T18 | 10 | 6 mm | Safety RV + Bursting Disc | 3 shut-off devices |
| T19 | 10 | 6 mm | Safety RV + Bursting Disc | Not Allowed |
| T20 | 10 | 8 mm | Safety RV + Bursting Disc | Not Allowed |
| T21 | 10 | 10 mm | NormalNo bursting disc | Not Allowed |
| T22 | 10 | 10 mm | Safety RV + Bursting Disc | Not Allowed |
| T23 | — | See § 6.7.2.4.2 | See § 4.2.1.13.6 / .13.7 / .13.8 | See § 6.7.2.6.3 |
| T50 | — | See § 6.7.3.4 | See § 6.7.3.7 (per gas MAWP) |
Per gas entry |
Permitted Substitutions — When a Higher Tank Code May Be Used
§ 4.2.5.2.5
When a specific portable tank instruction is listed in the Dangerous Goods List, the following tank codes are also authorised as equivalent or superior alternatives. Substitution is always upward in terms of stringency — a tank with a lower code may not substitute for a higher one.
| Specified Code | Tank Codes Also Permitted |
|---|---|
| T1 | T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T2 | T4, T5, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T3 | T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T4 | T5, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T5 | T10, T14, T19, T20, T22 |
| T6 | T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T7 | T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T8 | T9, T10, T13, T14, T19, T20, T21, T22 |
| T9 | T10, T13, T14, T19, T20, T21, T22 |
| T10 | T14, T19, T20, T22 |
| T11 | T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22 |
| T12 | T14, T16, T18, T19, T20, T22 |
| T13 | T14, T19, T20, T21, T22 |
| T14 | T19, T20, T22 |
| T15 | T16, T17, T18, T19, T20, T21, T22 |
| T16 | T18, T19, T20, T22 |
| T17 | T18, T19, T20, T21, T22 |
| T18 | T19, T20, T22 |
| T19 | T20, T22 |
| T20 | T22 |
| T21 | T22 |
| T22 | None — highest code, no substitution permitted |
| T23 | None |
| T50 | None |
Discover more from IMDG Code Compliance Centre
Subscribe to get the latest posts sent to your email.