Dangerous Goods Classes and UN Numbers: An Overview for Shippers

Every dangerous goods document starts with the same basic data: the UN number, the dangerous goods class, the packing group and the proper shipping name of the substance. This guide explains how these entries are structured, how they relate to each other and where the most common errors occur in practice – for road (ADR), sea (IMDG Code) and air (IATA DGR).

Contents

• The UN number
• The nine dangerous goods classes
• Divisions and subsidiary hazards
• Packing groups
• The proper shipping name
• How the entries appear in the document
• Common errors
• Checklist for shippers
• How eDGD helps
• Frequently asked questions

The UN number

The UN number is a four-digit identifier assigned by a United Nations expert committee. It uniquely identifies a substance, a group of substances or an article and applies uniformly worldwide – regardless of whether the shipment travels by road, sea or air. In documents it always carries the prefix “UN”, for example UN 1203.

For air freight there are also ID numbers for goods that have no UN number but are still subject to special rules, such as ID 8000 for “Consumer Commodity”.

A few examples for orientation:

The examples are for orientation only. The dangerous goods list of the currently valid regulation always prevails, because classifications, names and special provisions can change.

The nine dangerous goods classes

The UN system assigns all dangerous goods to nine classes according to their main hazard. This classification applies equally in the ADR, the IMDG Code and the IATA DGR.

Divisions and subsidiary hazards

Many substances have a further property in addition to the main hazard that also poses a risk. This subsidiary hazard is shown in brackets after the class in the document, for example “3 (6.1)” for a flammable liquid that is also toxic. Anyone who forgets the subsidiary hazard creates an incomplete document – and quickly receives a complaint during inspections.

The divisions (e.g. 2.1, 4.3, 6.2) specify the type of hazard. Among other things, they determine which hazard labels belong on the package and which conditions of carriage apply.

Packing groups

Within many classes, the packing group defines how dangerous a substance is compared with others of the same class – and therefore which packaging is required:

• Packing group I – high danger
• Packing group II – medium danger
• Packing group III – low danger

Not all classes have packing groups. None are assigned for explosives (class 1), gases (class 2), infectious substances (6.2) and radioactive material (class 7), nor for some individual entries such as lithium batteries. How a packing group is determined depends on the class, for example on the flash point for flammable liquids or on toxicity for class 6.1.

The proper shipping name

Every UN number has an official name for transport, the proper shipping name. It must appear in the document exactly as the relevant regulation prescribes – trade names or colloquial designations are not sufficient. For collective entries (“n.o.s.” or “n.a.g.”), a technical name of the most dangerous constituents must also be given, depending on the special provision.

How the entries appear in the document

UN number, proper shipping name, class and packing group form the core of every dangerous goods document. Depending on the mode of transport, further information is added:

Read more about the three sets of rules in our article ADR, IMDG Code and IATA DGR at a glance. For the documents themselves, see the German articles Accompanying documents for dangerous goods and Shipper’s Declaration for Dangerous Goods (DGD) (in German).

Common errors

• Deviating name: The proper shipping name does not match the regulation word for word, or the technical name is missing for n.o.s. entries.
• Wrong or missing packing group: Especially for substances that fall into different groups depending on concentration.
• Forgotten subsidiary hazard: The class in brackets is missing or incomplete.
• Outdated regulation version: The ADR and the IMDG Code are updated every two years, the IATA DGR every year – older entries quickly become obsolete.
• Inconsistent quantities: Gross and net quantities or units are mixed up.
• Missing signature or declaration: A frequent reason for rejected shipments, especially for sea and air.

Checklist for shippers

1. Identify the substance and evaluate section 14 of the safety data sheet.
2. Check UN number, proper shipping name, class and packing group against the current dangerous goods list (ADR chapter 3.2 table A, IMDG Code chapter 3.2, IATA DGR section 4.2).
3. Determine the mode of transport and apply the appropriate regulation.
4. Check packaging and quantities, including possible exemptions such as limited quantities.
5. Mark the packages: UN number, hazard labels and other marks where required.
6. Create, check and sign the dangerous goods document.
7. Archive the documents completely.

Anyone who ships dangerous goods regularly should also make sure that all employees involved are trained – our seminars teach the practical knowledge.

How eDGD helps

Compiling the information from this guide manually is time-consuming and error-prone. eDGD from NMMN supports you with exactly these steps:

• Search with autocomplete across UN numbers and packaging codes
• Integrated data validation that significantly reduces rejected shipments
• One tool for road, air and sea
• Archiving and management of documents, statistics and user management
• Use in the browser, including on mobile devices, in German and English

Try eDGD for free now or get in touch.

Frequently asked questions