Cable (plenum) questions

["John" <sfsadf>]

My brother and I are installing a DVR-based security system into his
pizzeria. We've got two 60' runs that need to be made out to the two outside
cameras to cover dumpsters and rear parking area. We will be running the
coax and power cables up into a drop ceiling, then 12' over the ceiling,
then out and up to the roof. We do have a/c ducts in the drop ceiling but
they're enclosed. The reason I mention this is because I'm not sure if the
space above the drop ceiling is considered a plenum. Is it, and if so would
we need to run plenum-rated coax -and- power cord? ? Thank you.
--
John