However some drop ceiling designs create a.
Above ceiling plenum box.
The plenum barriers block noise that would otherwise transmit through the ceiling and over the top of partition.
These boxes are available with and without an option for mounting a projector.
A plenum is any space duct or above ceiling or in a stud space that is used to convey environmental air air that you and i will breathe in our environment other than the actual room area.
In these areas metal wiring methods are required per nec 300 22 c.
The way i interpret that is while the plenum edge can have exposed wood wood framing can t extend into the plenum such as a partition wall extending above the ceiling to the lid with the drywall stopping just above the ceiling.
A plenum space is a part of a building that can facilitate air circulation for heating and air conditioning systems by providing pathways for either heated conditioned or return airflows usually at greater than atmospheric pressure.
You cannot put any combustible materials in these spaces unless they are listed for the application.
View from below the acoustical ceiling with some ceiling panels removed to show the plenum barriers above partitions that terminate at ceiling height.
The receptacle should not be permitted in this location.
Typically ships in 1 day s 09 28 2020 the cms492 conceals av equipment above a 2 x 2 ceiling tile to provide a clean professional look for classrooms and conference rooms.
They offer localized mounting for a v and technology equipment in a plenum approved enclosure.
2 x 2 above suspended ceiling storage box.
If the return air for the above ceiling hvac unit is not ducted directly to the grid ceiling and it is pulled through a ceiling register with no duct work then the space is being used as a plenum or for environmental air.
Space between the structural ceiling and the dropped ceiling or under a raised floor is typically considered plenum.
602 2 of imc would allow plenum enclosure to be made of wood in this case because the building can be constructed with exposed wood framing.