UN number
Also known as: UN number
A UN number is the four-digit code that identifies a dangerous substance or a group of substances in transport, for example UN 1203 for petrol. Together with class and packing group it determines how the consignment is packed, labelled and documented.
How is a UN number assigned, and what does it cover?
The UN Sub-Committee of Experts on the Transport of Dangerous Goods assigns the numbers. They are the same worldwide, whether the consignment runs under ADR, IMDG, IATA-DGR, RID or ADN. UN 1203 is petrol on the road in Rotterdam and in an aircraft container in Shanghai. The four digits identify the substance or the group, not the trade name and not the goods code. One substance can under circumstances get another number, for example if it is packed in an apparatus, is diluted, or falls as an n.o.s. entry (not otherwise specified) under a group number. Mixtures often land on an n.o.s. number with a technical name in brackets. Anyone who sticks the number of the main constituent onto a mixture classifies wrongly. The number sits in section 14 of the safety data sheet, on the label, on the transport document and on the packages. It does not sit on the import declaration. Anyone who looks for it in DMS looks for a field that is not there. Anyone who does not have it in the file has, at a control, nothing with which to underpin the transport side.
How do UN number, class and packing group hang together?
The UN number is the key. From it follow the class (1 to 9, with subclasses), the packing group (I great danger, II medium, III minor), the labels, the packing instructions and the quantity limits. You do not pick them a la carte. A UN number with class 3 packing group II is a different entry from the same number with another group, if that even exists. The proper shipping name belongs with the number, in the language of the document, with capitals where the regime requires it. A trade name such as 'degreaser' or 'cleaner' is not a shipping name. On the ADR document stands the official name, plus where needed the technical name. On the invoice the trade name may stand. In the file they have to point to the same substance. Tunnel codes, limited-quantity limits and segregation rules also follow from this set. They change if the substance goes into another mode, but they do not change because the declarant has chosen another goods code. The transport classification is leading for the road, the goods code for Customs. Both have to belong to the same article card.
Where does the link with the goods code go wrong?
The goods code classifies for rate and measures. The UN number classifies for transport. They come from different books. A substance can be tariff heading 2903 and UN 1018, or a mixture can fall under a residual heading and still carry a sharp UN number. There is no one-to-one table that you may follow blindly. It goes wrong if someone chooses the code on the trade name and leaves the UN number from an old SDS standing, or the other way round. Then the declaration says something other than the transport document, and at a control that contradiction is the first thing that stands out. After that the classification itself comes into question, even if the rate happened to be right. Test both sides on new articles. SDS section 14 against the UN number in the article card, SDS section 3 against the tariff heading, TARIC measures against the documents in the file. A mismatch is a stop, not a 'look at it later', because otherwise the trailer and the declaration both go out with a different identity.
What if the UN number on the SDS is not the same as that on the consignment note?
Then one of the two, or both, is wrong, or there are two substances in one consignment that may not be documented as one entry. The driver may not drive on a document that does not describe the substance. Customs at that moment still has no problem, until the controller lays the papers side by side. The source is the current SDS of this supplier, this version. A consignment note drawn up on a sheet of three years ago, while section 14 has since changed, is out of date. An SDS that carries an n.o.s. number while the consignment note names a substance-specific number is a classification conflict, not a typing error. Resolve it before the consignment moves. A correction afterwards on the quay is a relabelling, a new document, a driver who waits, and a terminal that keeps the gate shut. A correction in the article card prevents the next twenty times.
How do you treat n.o.s. numbers and mixtures in the file?
N.o.s., not otherwise specified, is a group number for substances that have no UN number of their own. On the transport document then belongs the official n.o.s. name plus the technical name of the dangerous constituents in brackets. Without that technical name the document is incomplete, even if the UN number is 'right'. Mixtures ask for a classification of the mixture, not of the main constituent. The SDS of the mixture, sections 2 and 14, is the source. The SDS of a raw material is not. Anyone who documents a mixture as the UN number of the ethanol in it classifies a product that can have other hazards, or precisely lesser ones. In the article card an n.o.s. entry is an article of its own, with its own SDS, own technical name and own goods code. Merging with a substance-specific article because 'they are both solvent' is how the wrong official name lands on the document.
Which UN data must an article card carry as a minimum?
The number itself, the proper shipping name, the class and subclass, the packing group if it applies, the labels including subsidiary risk, whether LQ or excepted quantity is allowed, and the reference to the SDS from which this set is derived, with version and date. Without that version you do not know at a conflict whether the card or the sheet is behind. Add the mode if the substance may not go everywhere: forbidden in passenger aircraft, restricted in tunnels, forbidden in bulk on inland waterways. Those are not customs fields, but they are fields that stop a consignment after release. The card feeds the ADR document, the label check and the question whether this substance may sit next to that other substance in the same container. The goods code feeds the declaration. Two exits, one substance. If the card cannot feed those two exits, the card is too thin for chemicals.