In a hospital, we have all low voltage systems (nurse call, fire alarm, sound, CAT5E teledata, intercom, etc.) run above ceilings on J-hooks. Both the supply and return air are 100% ducted, so the above-ceiling space is not a return air plenum. We are having a bit of a debate whether or not this cabling is permitted to be non-plenum rated. Yes? No? Why or why not?