Posted for "Christopher Zavatson" <Christopher.Zavatson@udlp.com>:

<< that there is a 3 minute mandatory wait after a heavy
takes off.>>

Brian,
I believe the 3 minute wait after a heavy is mandatory, but 'Heavy' is
defined as 255,000 lb or greater take off weight (exception B-757).  I
think it is pilot's discrection behind anything else.  Any controllers
out there with the details?
Chris