Reinforce drywall panels

[c_olsson]

If there is space, you can build silencers that the fan can pull through and for the return air.

Probably no silencer is needed if the fan faces the garage. If you use compressed air in the garage, it's noisy anyway, so the compressor will hardly be noticed.

I assume the airflow direction is towards the garage (less suitable to pump air from the garage into the basement). You also need a check valve for it to be approved so that exhaust gases cannot enter the compressor room.

 

[Keexet]

Build the frame from OSB and line the inside with plasterboard + some absorbent material, such as speaker insulation. Plasterboard is cheap, you can add several layers. It's weight you're after if you want to achieve sound insulation. MDF is quite heavy and can also be used while plywood doesn't insulate sound significantly.

I already built the box six months ago, so that part is already done. But it was done according to the same recipe you suggested. Plywood/OSB on the outside and then "lined" with plasterboard inside. The sound insulation turned out very well, and I got better usability of the space, but now a new problem has arisen, the heat generation from air-consuming tools becomes too great simply. At least in the summer.

That's why I "lifted" the thread.

 

[Keexet]

Probably no need for a muffler if you have the fan towards the garage. If you use compressed air in the garage, it makes noise anyway, so the compressor might hardly be noticed.

I assume the airflow is towards the garage (less advisable to pump air from the garage into the basement). You also need a check valve for it to be approved so that exhaust gases cannot intrude into the compressor room.

It's correct that the airflow will be from the compressor to the garage. It would have been easier to place the fan in one of the box's walls, but that would counteract much of the box's soundproofing function. It doesn't matter much if it's noisy in the garage, especially if you're working with ear muffs as you often do when using a grinder.

The notion of "approved" was an interesting point. This is not a process industry, and no combustion engines are ever run longer than a second or so in this otherwise poorly ventilated garage. Do you mean that it's a requirement for us cottage owners to comply with these directives as well?

Otherwise, I could consider a check valve of the "cold draft guard" type, mainly to avoid having an open hole leading directly into the compressor to protect it a little from dust and noise when the fan is not running. Another point is that the compressor wouldn't draw in air that way (when it's running and needs to "breathe"), thereby counteracting the fan's function.

However, I'm unsure if such a valve would fit inside the pipe since it's just barely long enough to house the fan, or if I would need to make some "unsightly" compromise to fit it. Feel free to elaborate on your thoughts.

 

[Keexet]

If you run continuously, the ventilation requirement is about 100 liters/second per kW of power output in the compressor. A bathroom fan handles around 50 liters/second and should be sufficient for a regular small 1kW compressor if you don't run continuously all the time (which you rarely do if you're alone; the recommendations mainly apply to industries with multiple users per compressor).

That was an interesting analysis and getting some numbers on the whole thing. I imagine an "invisible" figure in the calculations of how much ventilation the compressor gets is the ventilating effect of the intake air. I noted last winter that the intake air effectively lowered the temperature in the cabinet so that the temperature actually dropped during operation. However, the net temperature change was positive and increased the temperature for a while after the compressor shut off.

My thought on how to circumvent the problem of a simple fan not being sufficient is to install another one, but I take one thing at a time and test as I go. It's an advantage not to have too much "open" when the lesser air-demanding tools are used, so it's like everything, a consideration.

 

[Lostmoose]

What I envisioned when I suggested silencers was that they would sit in the unused space above the box and take the air from there.

 

[Keexet]

The air is drawn into the box from the space above. However, this space is not unused but used for storage. At the back of the top of the box, I have drilled several holes that function as an "intake." This intake is led through a double wall at the back of the box, which is soundproofed. The air "finds its way" into the bottom of the box. The result with the soundproof double wall was fully satisfactory in terms of sound volume, and as far as I can judge, a fully sufficient flow for the compressor's "breathing" as well.

If one were to reason according to passive principles for ventilation, that warm air rises, it would be smart to vent excess heat upward, but the box is not built that way, and requiring too extensive renovations, I might have to completely reconsider the box's design. As mentioned, it is fully adequate for less air-demanding jobs such as blow cleaning, painting, and even nut driving. Therefore, I think it just needs "a little help" with ventilation for the most demanding tasks, when the compressor is running for an entire afternoon, working to power sanders and perhaps in the future also blasting.