I couldn't think of a better group to ask this question to so...
It's basically related to quieting air circulation in a room.
The room is a classroom in a school. It's an L-shaped, fairly large room that underwent a renovation years ago and so the air ducts are a bit screwy right now.
There is one air duct pulling in fresh air and two ducts pulling out the return air. For some reason the two return air ducts in this room are very noisy. In other classrooms you can't hear them at all.
I'm trying to find a way to silence or greatly reduce the noise level coming from the ducts for just one period per day (80 minutes). This would be a temporary fix (just for a few months). Going through the 'proper channels' is not an option. I have to do this one myself.
For the air return at the front of the class I took a piece of cardboard, cut it to shape and size and then just covered the duct completely, then stapled the bottom part to the wall. This worked well. It is now completely silent.
The tricky part with these ducts is that they are at least ten feet high on the wall, making it difficult to access.
I could use some advice on what to do with the *second duct*. If I covered it up completely like the first I'd need a way to access it quickly at the start of the period (covering it up then) and then removing the cover at the end of the period to let the air flow properly again until the next day at the same time.
I'm thinking about some mechanism whereby I can use a pole and reach up to open/close a cover. Would a porous cover be better than a non-porous one? How about some curtain material? Or a type of blinds? A pourous material would allow some air flow but would also be noisier. Whatever it is, I should be able to access it fairly readily at the start and end of the class.
Thanks in advance!