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Dangerous goods transport for liquids

How a fuel or chemical container moves legally by road, sea and air.

Cartoned cans staged behind a security cage in the Fortitude21 warehouse, ready for dispatch
Packed and staged for export dispatch.

A container that passes its own tests is only half the job. Moving a hazardous liquid legally means classifying the goods and meeting the transport rules for the mode you ship by. This is background to plan around, not a compliance ruling, so confirm the rules for your exact liquid and route before you book.

Classify the goods first

Everything downstream flows from the classification. Each hazardous liquid has a UN number, a four-digit identifier such as UN 1203 for petrol, and a hazard class. Fuels are Class 3, flammable liquids. Acids and alkalis are usually Class 8, corrosive, and some liquids carry a subsidiary hazard as well. Get the UN number and class right and the rest of the requirements fall out of them. Get them wrong and every document after is wrong too.

Getting a dangerous good on the roadClassify the substance, determine the packing group, select UN-approved packaging, then apply the rules for the transport mode: ADR by road, IMDG by sea, IATA by air. Classify
UN number and hazard class
Packing group
Sets the test the packaging must pass
Packaging
UN-approved for that group
Mode
ADR road, IMDG sea, IATA air
The order matters. The packing group decides the drop-test height and pressure the container must survive, so it has to be settled before packaging is chosen.

Packing groups set the performance bar

Within a class, a packing group grades the danger: Packing Group I is high, II is medium, III is low. Most fuels sit in II or III. The packing group is not paperwork for its own sake. It sets the performance the packaging must prove, and it ties directly to the UN packaging code stamped on the container, whose X, Y or Z rating states which groups it covers. Match the two: a Y-rated can covers Groups II and III, a Z-rated can covers III only.

Over-specifying is legal and merely expensive; under-specifying is a compliance failure. That asymmetry is why an X or Y rating is worth buying where the packing group is uncertain or where one stock line has to serve several liquids. A single rating that covers everything you carry is cheaper to administer than three ratings matched exactly, and it removes the picking error that puts the wrong can under the wrong liquid.

What the ADR reliefs switch offLimited quantities cap the inner packaging size and do not reach a 20 litre jerrican. The 1.1.3.6 threshold relieves the vehicle and driver requirements. Neither removes the packaging requirement. Full ADR Under 1.1.3.6 Limited qty Reaches a 20 L can Reaches a 20 L can: suitable for Full ADR Reaches a 20 L can: suitable for Under 1.1.3.6 Reaches a 20 L can: not suitable for Limited qty Driver ADR certificate Driver ADR certificate: suitable for Full ADR Driver ADR certificate: not suitable for Under 1.1.3.6 Driver ADR certificate: not suitable for Limited qty Vehicle placarding Vehicle placarding: suitable for Full ADR Vehicle placarding: not suitable for Under 1.1.3.6 Vehicle placarding: not suitable for Limited qty UN-coded packaging UN-coded packaging: suitable for Full ADR UN-coded packaging: suitable for Under 1.1.3.6 UN-coded packaging: suitable for Limited qty ADR 1.3 training ADR 1.3 training: suitable for Full ADR ADR 1.3 training: suitable for Under 1.1.3.6 ADR 1.3 training: suitable for Limited qty DGSA appointment DGSA appointment: suitable for Full ADR DGSA appointment: suitable for Under 1.1.3.6 DGSA appointment: suitable for Limited qty
The bottom three rows never switch off. Limited quantities are the regime for a case of 1-litre bottles, so a 20 or 25-litre can sits outside the relief by design; the threshold in ADR 1.1.3.6 is the one that reaches a jerrican load. Since 1 January 2023 a consignor-only business must appoint a DGSA whatever the volume.

The rules change with the mode

  • Road: ADR across Europe, with equivalent national frameworks elsewhere, for example 49 CFR in the United States.
  • Sea: the IMDG Code.
  • Air: the IATA Dangerous Goods Regulations, built on the ICAO Technical Instructions, the strictest of the three and with the tightest quantity limits.

Each sets its own packaging, marking, labelling and documentation rules for the class and packing group. A shipment that is legal by road is not automatically legal by air.

Limited and excepted quantities

Small volumes can qualify for relief. Limited Quantity (LQ) and Excepted Quantity (EQ) provisions ease some marking and documentation when the fuel travels in small inner packagings within set limits. Whether your load qualifies depends on the liquid, the pack size and the mode, so it is worth asking, because it can simplify a shipment that looks fully regulated at first glance.

For a jerrican buyer the honest answer is usually no, and it is better to know that early. Limited quantities work by capping the size of the inner packaging, and the caps are small: the typical allowance for a flammable liquid is measured in litres rather than tens of litres, so a 20 or 25-litre can is outside the relief by design. Limited quantities are the regime for a case of 1-litre bottles, not for a pallet of jerricans.

The relief that does reach a jerrican load is different. ADR 1.1.3.6 exempts a transport unit below a points threshold from the driver certificate, the placarding and some equipment requirements, and it is calculated from the quantity carried and a multiplier set by the transport category. That is the arithmetic worth running before assuming a full ADR load, and it is worked through in our 1000-point rule guide.

What no relief switches off is the packaging. The can still has to carry a valid UN packaging code at the right packing group, and it still has to be marked. The reliefs address the vehicle, the driver and some of the paperwork; none of them makes an unapproved container acceptable.

What changes with the modeRoad, sea and air set their own packaging, marking and documentation rules. A shipment legal by road is not automatically legal by air. Road, ADR Sea, IMDG Air, IATA UN-coded packaging UN-coded packaging: suitable for Road, ADR UN-coded packaging: suitable for Sea, IMDG UN-coded packaging: suitable for Air, IATA Own segregation table Own segregation table: suitable for Road, ADR Own segregation table: suitable for Sea, IMDG Own segregation table: suitable for Air, IATA Quantity relief exists Quantity relief exists: suitable for Road, ADR Quantity relief exists: conditional for Sea, IMDG~ Quantity relief exists: conditional for Air, IATA~ Tightest quantity limits Tightest quantity limits: not suitable for Road, ADR Tightest quantity limits: not suitable for Sea, IMDG Tightest quantity limits: suitable for Air, IATA Vehicle plating Vehicle plating: suitable for Road, ADR Vehicle plating: not suitable for Sea, IMDG Vehicle plating: not suitable for Air, IATA
Air is the strictest of the three and has the tightest limits, which is why an empty-but-unpurged can is treated as carrying its previous contents. Segregation is mode-specific too: what is acceptable together by road under ADR is not automatically acceptable by sea under IMDG.

Where the container fits

The container’s job in all of this is to carry a valid UN packaging code, proving it passed the drop, stack, leakproof and pressure tests for its packing group. That stamped code is what a carrier and a customs officer check. It does not classify your goods or write your paperwork; it evidences that the packaging is fit for the danger. Our guide to UN packaging codes shows how to read the marking.

It also has to be the right code for the liquid actually inside, not for the liquid the can was bought for. A Y-rated steel can approved for Packing Group II and III covers petrol and diesel and does not cover a Packing Group I substance, and the marking will not stop anybody filling it. The check that catches this is at the filling point rather than at purchase, which is why the packing group belongs on the filling instruction and not only on the specification.

What the consignor actually signs forMost of the duty in a dangerous goods movement sits with the consignor, and it is discharged before the vehicle moves rather than during the journey. Classify
UN number, class and packing group
Package
Approved design rated for the contents
Mark and label
On the package, correctly and durably
Document
And declare it to the carrier
A carrier can refuse a load at the dock for any of these, and the cost of that refusal lands on the consignor. None of it can be delegated to the driver.

The consignor carries most of the duty

It is a common and expensive assumption that dangerous goods obligations sit with the carrier. Most of them sit with the consignor, the party offering the goods for carriage, and they do not transfer by handing a pallet to a forwarder.

The consignor classifies the substance, selects and fills UN-approved packaging within its stated limits, marks and labels the package, prepares the transport document, and provides the information the carrier needs to load and segregate correctly. Getting any of those wrong is the consignor’s liability even where the carrier is the one stopped at the roadside.

There is a staffing obligation attached that catches small consignors regularly. ADR 1.8.3 requires any undertaking whose activities include consigning dangerous goods by road, or the related packing, loading, filling or unloading, to appoint a Dangerous Goods Safety Adviser. The exemption that once covered consignor-only businesses ended: from 1 January 2023 a company that only offers goods for carriage and never drives them must still appoint one.

There is no volume threshold in the requirement. It attaches to the activity, so a firm consigning a pallet of jerricans a month is caught on the same terms as one consigning a tanker a day. The adviser can be an employee or an external appointment and has to hold the qualification, and the role includes an annual report on the undertaking's dangerous goods activities. A business discovering this at an enforcement visit discovers it late.

Training is the layer below. ADR 1.3 requires everyone involved in the carriage of dangerous goods to be trained to the level their function needs, recorded and refreshed, and that duty survives the reliefs that remove other requirements. Our note on limited quantities and the 1000-point rule covers what those reliefs do and do not switch off.

Which document travels with the goodsThe paperwork required changes with the mode, and a document that satisfies a road movement does not satisfy the same goods going by sea or air. Road Sea Air Transport document Transport document: suitable for Road Transport document: suitable for Sea Transport document: suitable for Air Dangerous goods declaration Dangerous goods declaration: conditional for Road~ Dangerous goods declaration: suitable for Sea Dangerous goods declaration: suitable for Air Container packing certificate Container packing certificate: not suitable for Road Container packing certificate: suitable for Sea Container packing certificate: not suitable for Air Shipper declaration to IATA Shipper declaration to IATA: not suitable for Road Shipper declaration to IATA: not suitable for Sea Shipper declaration to IATA: suitable for Air Driver training certificate Driver training certificate: suitable for Road Driver training certificate: not suitable for Sea Driver training certificate: not suitable for Air
The middle column is the one that surprises exporters. A road consignment that becomes a sea consignment at the port gains a packing certificate it never needed on the way there.

Marking, labelling and the paperwork that travels

  • On the package: the UN number with its prefix, the proper shipping name, hazard diamonds for the class and any subsidiary risk, orientation arrows where required, and the UN packaging code stamped on the container itself.
  • With the consignment: a transport document naming the UN number, proper shipping name, class, packing group and total quantity, in the sequence the mode’s rules require.
  • On the vehicle: plating or placarding where thresholds are met, and the written instructions the driver must carry.

Segregation is the other half. Incompatible classes cannot travel together in one load however well each is packaged, and the segregation tables are mode-specific: what is acceptable by road under ADR is not automatically acceptable by sea under IMDG.

What a shipper actually needs

To move a hazardous liquid you need three things lined up: correctly UN-coded packaging at the right packing group, the marks and labels the mode requires, and a dangerous-goods declaration for the consignment. Trained staff have to prepare it, and a carrier can refuse a load that is short on any one. Confirm your liquid’s classification and your route’s rules before you book the freight, not at the dock.

Booking is also where the choice of carrier stops being neutral. Not every operator accepts dangerous goods, and those that do accept specific classes on specific services, so a rate obtained without declaring the class is a rate for a shipment nobody has agreed to carry. Declare the UN number and the packing group at quotation and the surprises arrive while they are still cheap to fix.

What the packing group actually setsThe packing group is a statement about the severity of the danger, and it flows through to the performance the packaging must have been tested to. PG I PG II PG III Highest test severity Highest test severity: suitable for PG I Highest test severity: not suitable for PG II Highest test severity: not suitable for PG III Greatest drop height Greatest drop height: suitable for PG I Greatest drop height: conditional for PG II~ Greatest drop height: not suitable for PG III Widest choice of packaging Widest choice of packaging: not suitable for PG I Widest choice of packaging: conditional for PG II~ Widest choice of packaging: suitable for PG III Eligible for limited quantities Eligible for limited quantities: not suitable for PG I Eligible for limited quantities: suitable for PG II Eligible for limited quantities: suitable for PG III
The bottom row is where the packing group stops being a technical label and starts being a commercial one: it decides whether the relief that removes most of the paperwork is available at all.

Match the can to the job

The UN code is what a carrier checks. Here is the coded line.

Your use caseRecommended canWhy this one
Fuel, UN 3A1 20L NATO Steel Fuel Can20L NATO Steel Fuel Can Steel jerry can, UN-marked for transport.
Chemicals, UN 3H1 25L Stackable Plastic Jerrycan25L Stackable Plastic Jerrycan HDPE jerrycan, approval per design.
Fuel in plastic Fluorinated HDPE JerrycanFluorinated HDPE Jerrycan Fluorinated HDPE, low permeation.
Fuel, UN 3B1 20L Aluminium NATO Can20L Aluminium NATO Can Aluminium jerry can, weight-critical.

Common questions

What packing group does petrol fall into?

Petrol is UN 1203, Class 3 flammable liquid, packing group II. Diesel is UN 1202, Class 3, packing group III. The packing group sets the drop-test height and hydraulic pressure the packaging must survive, so it decides which UN-marked container you may use.

Can I ship a jerry can by air with fuel inside?

Not as general cargo under normal circumstances. IATA rules for Class 3 liquids are strict on quantity and packaging, and most carriers refuse fuel in portable containers outright. Empty cans ship freely; residual vapour in a used can makes it dangerous goods again.

What is the difference between ADR, IMDG and IATA?

Same UN framework, three transport modes. ADR governs road carriage in Europe, IMDG governs sea, IATA governs air. A container certified to the UN Model Regulations is recognised across all three, but each mode adds its own documentation, segregation and quantity rules on top.

Do empty jerry cans count as dangerous goods?

An uncleaned container that held a dangerous good is still regulated, because vapour and residue remain. It must stay closed and correctly marked until it has been cleaned and purged. Only a cleaned, certified-free container ships as general cargo.

References

The standards and regulations this page relies on, at their issuing body. Where a market rule is named here, check the current revision before you specify against it.

Last reviewed .

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