Plenums

[Larry Poole]

I just finished viewing Mike Holt's "Wiring in Plenums Spaces 300.22" on YouTube. I understand the sublety of a physically contructed plenum (duct) vice a plenum space. In the case where a building has no dropped ceiling but has exposed supply and return ducts for environmental air, does the entire area from floor to structural ceiling become a "plenum space"? I would think that in this case the entire room would become an environmental air space. Thanks for your help

 

[GoldDigger]

I just finished viewing Mike Holt's "Wiring in Plenums Spaces 300.22" on YouTube. I understand the sublety of a physically contructed plenum (duct) vice a plenum space. In the case where a building has no dropped ceiling but has exposed supply and return ducts for environmental air, does the entire area from floor to structural ceiling become a "plenum space"? I would think that in this case the entire room would become an environmental air space. Thanks for your help

Once you go past the final supply or return grille you are in the conditioned space. Neither a plenum nor an environmental air space.
One of the features which result in a plenum or e vironmental air space is a separation from the conditioned space itself.