[RFI] ft240 Designation

[Chuck Gooden]

Could someone explain where the FT240-31 designation for ferrites came 
from.  I do not see this in the Fair-Rite catalog or any manufactures 
that use this designation as a part number. If you Google "FT240-31" you 
will be directed to a different part number made by Fair-rite

I realize that it means a 2.4 inch diameter torrid of type 31 material.

So is this an industry standard for classifying  the shape and size of 
ferrite components, if so what is the standard?

Chuck K9LC