A/C "Ton"

[STE]

Hi, this is a first for me. I was doing some research online to get to the bottom of A/C compressor's "Ton" term that is use a lot by GC or A/C guys.
But to me and other electricians, it does not mean much. Of course we all know the rule of thumb but what is the actual formula or conversion, if any.

 

[Minuteman]

STE, we just had this discussion @ http://www.mikeholt.com/code_forum/showthread.php?t=53334&page=6&highlight=Tons+amps

But briefly, a "ton" of refrigeration is a measure of heat-flow and is 12000 BTU's per hour. "Ton" comes the fact that 288000 BTU's are absorbed to melt one ton (2000lbs) of ice at 32?F in 24 hours or 12000 BTU's per hour.

(A BTU being the amount of heat need to raise 1 pound of water 1?F at room temp)