You need confidence that strapping is going to hold your load.  The AAR approves manufacturers of Strapping (steel, polyester, and cord) to verify they meet minimum required standards.  If there was a governing body for strapping it would be the rail road.  While you may not need to load rail cars, the AAR number on your banding can give you confidence in the manufacturer.

Currently used numbers: AAR11, AAR82, AAR58, AAR59, AAR53, AAR22, AAR14, AAR57, AAR51, AAR60, AAR63, AAR64, AAR65, AAR66, AAR67, AAR68, AAR27, AAR12, and AAR40 for open top loading.

Great pictures of heavy duty AAR strapping here.