What are UN Numbers?
Tuesday, March 20, 2018
The UN number system is administered by the United Nations under its Model Regulations on the Transport of Dangerous Goods (The "Orange Book" or UNMR) and is accepted generally worldwide via its incorporation in the Dangerous Goods Lists (DGL's) present in all in-force modal regulations (ICAO TI, IMDG Code, US 49 CFR, EU ADR, etc).
UN#'s are assigned to both generic chemical categories, like "Flammable Liquids N.O.S." (UN 1993) and much more specific chemicals, like "Gasoline" (UN1203). Rules of use call for a chemical to be assigned the most specific such number, and corresponding proper shipping name, possible. Thus, although gasoline is indeed a flammable liquid, it is more correct and thus required to identify it by its specific UN number and proper shipping name.