How do I determine CFM needed to ventilate a "bedroom" workshop?

[SLK001]

You're in Kansas, so I think you're talking about the two months a year where you can actually bring outside air into the house that isn't freezing. As has been said, you not only need an exhaust path, but also an intake path. Most fans are rated in their CFM capacity, so it's not going to be difficult to find one to meet your needs. If you can afford one, get an air-to-air heat exchanger so you won't loose much room heat or cooling. An enterprising individual who is good with tools could even make an a2a exchanger himself. Add a fan and you're good to go.

 

[Dhal22]

A bit of a non-answer but you need a strong enough fan to make sure your room has a slight underpressure compared to the rest of the house.
I.e. some kind of exhaust ventilation that will pull air through the house, through the workshop and exhaust it outside.
This will generally keep any smells from going 'back' into the house.
How big of a fan this requires is very hard to say since a lot of factors play into it like:
-already existing ventilation system in the house
-how the wind generally hits the house
-how volatile the substances is etc.

Not sure how the climate is in kansas but exhausting all this air means more air needs to get in somewhere, and if it's cold outside this is going to cost quite a bit too.
Might be an idea to look into activated charcoal filters and recirculate/filter the rooms air or similar solutions.

The weather in Wichita is windy. Now, tomorrow, tonight, last year, next year, BC, AD, 2023, 2123. Any day, anytime. Just convert the state to a wind farm and the world's power problem is solved.....

 

[Chewy]

You need to be a little more specific about what you re doing and how much/long you have the chemicals exposed. If you re wiping something down is a lot different from a tub of chemical sitting open. I have all sorts of ventilation systems in my house, shop and at my wife's place of work.
In my basement, my wife used to do lampwork glass. I used a stove overhead fan, vented to the outside. At her work, I made a two station paint booth out of plywood, lined with aluminum. It is down draft with two bathroom fans, one under each paint area. I use 12 X 12 filters to catch the over-spray, It is heated with two heat lamps in between shielded from over-spray. The aluminum makes for easy scraping of paint residue, about once a year. We go through about 4-5 cans of Krylon in about two hours. The mechanisms are then transferred to a heat booth. It uses an electric heater at the bottom and a bathroom fan at the top to vent the out gasses to the outside. This system has been in use for about 7 years. No smell at all in the shop, a 10x 20 building with an electric heater and an window A/C.

Bathroom fans are are rated at CFM,so you can figured room changes, say when taking a shower for 10 minutes. Mine are wired 3 speed so I can select what I need. Just leave the door to the room cracked open and vent to the outside. You can make a flexible hood to place near where your working. Example, where kerosene is used as a cutting lubricant on a lathe or mill and stinks when gets hot.

 

[JerryCordova]

Hi Doug, it's great that you're thinking about ventilation for your shop. Proper ventilation is important for any workspace, especially one where you're using flammable substances like kerosene and acetone.
One option is to install a ventilation system that will draw air out of your shop and replace it with fresh air. You can use a high-powered fan, like a centrifugal or axial fan, to create negative pressure that will suck air out of your shop. You'll also need to install ductwork to direct the air outside, and possibly an intake vent to bring fresh air in.
Another option is to install a downdraft table, which is a table with a built-in ventilation system that draws air down and away from your work surface. This can be a good option if you're primarily working on smaller projects.
If you're not comfortable installing a ventilation system yourself, you may want to consider hiring a professional to do the job for you. They can assess your space and recommend the best type of system for your needs.
In the meantime, you could consider using a respirator when working with kerosene, acetone, or other chemicals that produce strong fumes. This will help protect your lungs and reduce the impact of the fumes on your wife.
I hope this helps, and good luck with your shop!

 

[Headhunter Pipe Co]

These last forever, buy the speed controller , They are always on craigs list for about 50.00$ a piece
Super quiet

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[Dhal22]

Hi Doug, it's great that you're thinking about ventilation for your shop. Proper ventilation is important for any workspace, especially one where you're using flammable substances like kerosene and acetone.
One option is to install a ventilation system that will draw air out of your shop and replace it with fresh air. You can use a high-powered fan, like a centrifugal or axial fan, to create negative pressure that will suck air out of your shop. You'll also need to install ductwork to direct the air outside, and possibly an intake vent to bring fresh air in.
Another option is to install a downdraft table, which is a table with a built-in ventilation system that draws air down and away from your work surface. This can be a good option if you're primarily working on smaller projects.
If you're not comfortable installing a ventilation system yourself, you may want to consider hiring a professional to do the job for you. They can assess your space and recommend the best type of system for your needs.
In the meantime, you could consider using a respirator when working with kerosene, acetone, or other chemicals that produce strong fumes. This will help protect your lungs and reduce the impact of the fumes on your wife.
I hope this helps, and good luck with your shop!

Of course remember to include the big explosion when you draw those flammable vapors across the non explosion proof motor. The more vapors the more fun the explosion!!