Information on ISO 668:1995: Series 1 freight containers -- Classification, dimensions and ratings can be obtained from the International Organization for Standardization (ISO) (
carol612,
As MLowe states there is some information available. Please see his post...
However, if you are familiar with "typical" structural codes you will be in for an unfamiliar surprise. The way that they go about specifying loads, etc. is a bit different that what we are used to...