Classroom Humidity Help!

[Tenore76]

Looking for ideas, especially if anyone has some experience with HVAC...

I'm a middle-school teacher that's lucky enough to have a lot of really nice instruments in my program (perhaps too nice, as you'll see...). For example, we have 30 solid mahogany Mainland ukuleles for students to use, as well as 25 solid-top Fender guitars. (Plus a whole lot of laminate instruments in addition, but those aren't really the focus of this question...)

The problem is that in the past couple of years, I was moved into a classroom that the humidity has become enough of an issue that I've had 6 ukes and 3 guitars crack just from hanging on the walls. For example, when I was gone for our Thanksgiving break, and the custodians didn't fill the humidifiers, the room humidity was less than 20% when I returned.

The school's trying to help; we have 2 whole-house humidifiers that are running non-stop. Each is rated for 3600 sq ft, and the room is 1400 sq ft. The custodians are now filling the humidifiers over the weekends, and each instrument has a little DIY humidifier that I designed a few years back. (Little plastic test-tubes with water beads in them...work quite well...) The instrument humidifiers, though, can only do so much when not sealed in a case with the instrument. The room has no windows, and maybe a 10 foot ceiling.)

In spite of these two big humidifiers (and now a third, smaller one) running non-stop, the best we've been able to raise the room humidity to is 32%. And, if the custodians are away for a day and can't re-fill the tanks (each one uses at least 6 gallons of water a day...), then the room humidity is back down to 20% or below.

I know cases might work better, but it's not a great solution for the circumstance. Regardless, my question for anyone out there is more about what might be getting in the way of getting the room humidity up to a decent level? I'm trying to brainstorm ideas with the school admin, and I'm puzzled with why it's not higher than it is when there's several humidifiers going strong...

Thank you!

 

[Poul Hansen]

1. It is difficult to humidify that room, if, as I expect, the ceiling is just hung up and not airtight. Then you'll have to humidify the room above as well.
So lay plastic sheets on top, just as in a normal house.

2. If you use radiatores for heating, place a lot of veranda flower boxes with water on top of them.

3. A toilet is filled automatically, so you could use the principle of the cistern to replenish the humidifiers or an automatic watering system from a greenhouse.

4. Build a (glass?) wall along the walls. Then you only have to humidify the room behind the wall

 

[rainbow21]

Can you comfortably lower the temperature of the room? (set the thermostat lower, and even turn it way down on weekends and breaks)

A lower room temperature will result in a higher relative humidity.

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ADDED: Using google to find an online calculator... https://www.markusweimar.de/en/humidity-calculator/

Plugging in numbers: a room at 75*F with a RH of 30% will increase its RH to 38% if you lower the temperature to 68*F. If you lower the temperature to 58*F (like nights, weekends, breaks...), the RH will increase to 54%. This will happen without additional humidification.

 

[Wiggy]

With the instruments you have, are there any twisted necks, cracks, or separation of the top/back from the sides? It's good that the room doesn't seem to have windows where direct sunlight could cause rapid temperature changes which might damage things.

 

[merlin666]

Congratulations on your class room setup and instrument collection. Your students are lucky. But your problem is considerable. It is not clear if you live in an arid region where this is a permanent issue or if low humidity is seasonal and associated with heating. If it was seasonal then there may be potential modifications to the heating system. If this was permanent then an insulated climate controlled storage area/cabinet may be a good approach.

 

[Tenore76]

I'm in the Midwest, near Chicago, so it's definitely seasonal.

I've got one instrument that the top has started to separate a bit, but for the most part the cracks are along the grain of the tops of the instruments. I have had some bridge separation due to the glue drying out, as well, but that's more easily repaired than cracks.

I'm definitely thinking the fix needs to happen at the HVAC level, especially since it's likely pumping dry air in every time it kicks in. The ceiling is a dropped ceiling that they left the tiles out of because they thought it would be better for acoustics. (It's not, really...) The ceiling is the roof in this part of the building, so there's no second floor above me.

I'm thinking along the same lines as Merlin, at least over the upcoming Winter Break. I'll be sealing them all in a storage closet I have with the humidifiers running in there. If they don't have to humidify as large of a space, I think it'll be able to maintain the humidity even if not refilled for that long...

 

[don_b]

I have worked in many classrooms and that is the absolute nicest school music room and absolute nicest school ukulele and guitar selection I have ever seen, you must be over the moon

 

[Tenore76]

I have worked in many classrooms and that is the absolute nicest school music room and absolute nicest school ukulele and guitar selection I have ever seen, you must be over the moon

I'm very lucky to be teaching in this community. I definitely have frustrations, but having the materials to be able to teach is not one of them! Even better, the guitars are probably about 15 years old, and the oldest of the ukes are close to 10, and the students have been amazing at helping me keep them looking almost new! That's probably the biggest frustration with the damage being caused by the environment - it's not the kids doing it!

 

[EDW]

The ceiling is a dropped ceiling that they left the tiles out of because they thought it would be better for acoustics. (It's not, really...) The ceiling is the roof in this part of the building, so there's no second floor above me.

In a local school where I have done some playing, they did the same, removing the acoustic tiles. I thought it sounded worse (not that it sounds good either way) and removing all the white tiles made it really dim and cave-like.

 

[bbkobabe]

If your school is like mine, the heating&A/C fan has been wired to run ALL THE TIME to flush Covid virus out of the room... there is no way to turn the fan off anymore so the room is steadily dried out all the time with all this moving air.

You could try seeing if someone can undo this if that's the case for you too...