Containers used to group individual products are called master cartons. When master cartons are grouped into larger units for handling this is called containerization or unitization.

The weight, cube and damage potential of the master carton determines transportation and material handling requirements. Firms usually have master cartons of different sizes. The best situation is when the different sizes are equal fractions of the sizes so that multiple smaller master cartons are the same size as a larger carton.

Master cartons that meet retail requirements for shelf space are preferred. The four most common causes of product damage are vibration, impact, puncture and compression.

Packaging for Materials Handling Efficiency

To cube out a truck means that the products fill a truck before the weight limits are reached. To weigh out a truck means that the products achieve the weight capacity of a truck before the space is filled. The optimum is that the truck reaches volume capacity and weight capacity together, which is rarely possible.


All types of unitization have the basic objective of increasing handling and transportation efficiency. Unit loads: minimize unloading time (typically one-fifth), facilitiates material handling, receipts are bar coded, rapid positioning of inventory, and reduces in-transit damage.

Types of Unitization

  • Rigid containers - complete rigid enclosure of master cartons, commonly using returnable containers of standard size for the shipping mode being used. Returnable container reuse must be planned for based on number of uses and cost versus disposable containers.
  • Flexible containers - commonly stacking master cartons on pallets or slipsheets. Slipsheets are less costly but require special lifts. Standard pallet sizes are 40x48, 32x40 and 32x36. Master cartons are stacked using block, brick, row or pinwheel shapes then shrinkwrapped. Flexible containers increase damage potential.


Typical unit/container information includes manufacturer, product, container type, count and Universal Product Code (UPC), Electronic Product Code (EPC). Package information is usually provided via bar code or Radio Frequency Identification (RFID) technologies.


  • Bowersox, Closs and Cooper, 2010. Supply Chain Logistics Management, 3rd Edition
  • Wikipedia, 2010.