National Motor Freight Classification (NMFC) is a freight classification system created by the National Motor Freight Traffic Association (NMFTA) and used for interstate, intrastate, and foreign commerce shipping of LTL cargo. NMFC freight codes provide standardized freight classes to determine the ease of transport of many of the huge variety of different commodities being shipped together in LTL shipments every year.
If the couch you are shipping has not been assembled yet and you are shipping various components that you can use freight class 250. If you are shipping a complete product then you should use freight class 175.
NMFC freight classes are determined using four factors: density, handling, stowability, and liability. All of these factors affect the cost to the carrier of shipping goods.