Is anyone aware of NEC or NFPA code that requires communication cabbling to be in EMT coduit rather that cable trays for the following reasons:
There will be fiber and speaker wires etc. Some of the devices are considered Life savings Devices as speakers and plasma displays that might be used to announce fire threat or evacuation orders.

Ceiling space is a return air plenum
Ceiling is not fire rated
Some devices connected are Life savings devices.
Thanks

Great question! I have always isolated fire/life/safety wiring from everything else, but I don't know the nfpa reference for that practice. I suspect that there might be something in nfpa 72, (National Fire Alarm Code), that might explain how these cabling separations might be required. I don't really know what the situation is in the case you described. It might just come down to a matter of separating class 3 cable from class 2 cable -- NEC 725.