Field help (DCTNUM) 

The transport category, associated with a limit (in hazardous material quantity), is used to define whether a shipment, in other words a Carriage Note (CN), is subjected to or exempted from the ADR prescriptions mentioned in chapter 1.1.3.6.

Note: This setup belongs to the hazardous material functionality.

(ADR : European Agreement concerning the International Carriage of Dangerous Goods by Road)