Air compressor electric circuit

["William M. Gilroy" <wmgilroy@lucent.com>]

I am shopping for an air compress and I was wondering what kind
of electric circuit I need to run.  If the compressor has the specs of

        4.5 HP
        120 volt/15 amp operation       

Does that mean:
        1) The compressor needs a 15 amp circuit
        2) The compressor draws 15 amps, and then would require a 
           20 amp circuit.

I would think it would be number one but what do other think/know.

Thanks,

Bill Gilroy