Ventilation?

[Shane]

Hi,
New here, new to lampworking. My wife and I are in the process of building a studio. I had a 180 CFM duct fan that I placed in the wall about 6 inches above and maybe a couple inches away from where the torch will be. The work area will be 30" deep and wall to wall. The "studio" is approx 6' wide by 9' long. It has a 40" window on the right hand side and a door at the opposite end of the work area. 4 outlets (one for AC/Heat, window AC & small ceramic heater on the floor), 2 under the work area, 1 on the opposite wall from the window. 2 light switches working independent, 1 for track lighting and 1 for fan. My concern is ventilation. I'm not done with the room yet so she hasn't been making anything. I plan on punching a hole through the wall under the bench to run a hose to a propane tank for now (HH torch). I've spend quite a bit on this project already and want to make sure before it's completed that it's done properly and safely. I've attached some pictures to give you a better idea about size and space of the studio. I tested to make sure it was pulling/blowing air out and it seemed to be doing pretty good. Being as close as it is and no ducting we assumed it should work properly but the blades are plastic. Any suggestions would be greatly appreciated.

[Dale M.]

From the get-go, 180CFM is probably not going to be enough...

First question is how big is the hood you are going to use... Need "face opening" dimensions... Is it 24x30 or ???x???... CFM is usually determined by a simple formula..

"Width" x "Depth" divided by "144" equals "Square Feet" times 125 = CFM

Width is width of hood.
Depth is depth of hood.
144 is inched in square foot.
Square Feet is calculated square feet opening of hood.(square inches divided by 144)
125 is CFM of flow acceptable per square foot of face opening...

Lets use a 24 x 30 inch hood...

24 x 30 = 720 / 144 = 5 x 125 = 625

So for a 24 x 30 hood "face opening" requires a 625 CFM fan to get proper air flow through work station area..

Also door or window has to be open enough to flow equal amount of "make up" air (625 cfm) for ventilation to function...

Dale

[Shane]

To be honest there's no hood planned. The torch will almost be going directly into the fan. The silver you see in the picture is the 8 inch end cap. I have more pictures if they would help. I had a 1320 gable fan but for a space that size everyone said it would be hard to heat and cool. It is an insulated space but not very air tight. The original structure was taken down to the studs and rebuilt in a hurry. My main concern at that point was water getting in one side...there was no footer. So for a space 6X9ish I still need a hood and a larger fan? I want it to be comfortable enough to use year round.

Also can someone please explain the need for a hood? What I'm thinking is that it's more about the size of the room, building, etc that would determine ventilation right? What I'm saying is I don't need a gable fan that moves 1320CFM in a space 6'X9'. That's designed for an entire attic. This is rather confusing. I liked someone elses common sense approach "bad air out, good air in".

[Dale M.]

I suggest you go back and read the thousands of words written on the many sites that deal with ventilation for lampwork....

Dale

[Shane]

I've done that. I've seen everything from a few fans pointed at windows to $3000 setups. I'm just trying to figure out what works in my space. I went middle of the road. I'm still confused as to the need for a hood though. I do have another way to add makeup air to the space (by adding a couple of vents above the door leading to fresh air above the carport) which should help.

[Elleth]

I am building a studio as well, it will be 12 x 16 and have decided not to do a hood but to use this funnel system. My only question is about the cfm of the fan recommended, I'm not sure it will be enough for my space, perhaps Dale can chime back in with his opinion?

Make sure you research your ventilation system well because it's really not something you want to get wrong!

Good luck and have fun

Edit to say: Ok, I just read the funnel vs hood thread, if I am reading it correctly the 275 cfm fan referenced in the above link is probably not strong enough.