IATA-DGR:
section 4.2
The UN number
- The UN number is a four-digit number established by an expert committee of the United Nations. There are more than 3000 UN numbers describing dangerous goods.
- It defines a material/object
- either directly (e.g. UN 1090 Acetone)
- or by a collective entry, grouped according to:
- chemical groups (e.g. UN 1987 Alcohols, n.o.s.)
- intended use (e.g. UN 1263 Paint)
- dangers (e.g. UN 2810 Toxic liquid, organic, n.o.s.)
- either directly (e.g. UN 1090 Acetone)
- One or more danger is assigned to each UN number. These dangers correspond to the respective classes of dangerous goods (e.g. UN 2438 Trimethylacetyl chloride: this liquid is toxic, flammable and corrosive!).
