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Old 2016-05-17, 7:42am
dragonglassllc dragonglassllc is offline
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Join Date: May 12, 2016
Posts: 2
Angry Ventilation HELP PLEASE

Okay, I am finally going to bite the bullet and just ask my questions. I am fairly new to lampworking and am very addicted. I recently got a Phantom and decided to make a new double workbench with much better ventilation. I will have a Phantom on one side and my RedMax on the other. I would like to be able to do some fuming in the future and want to make sure my family and I are safe.

I have read every thread, post, and journal I can find on the subject and I am more confused than I was when I started. My work station is in the third car portion of my three car garage. My bench is 36" deep by 8' wide and there is 80" from the top of my bench to the ceiling. We will be cutting a hole through the ceiling into the attic and then out the side of the house. I cannot go straight outside because my home has a brick façade up to about the attic height.

I have decided to go with two funnel vents, one for each torch, but beyond that I am stuck. I was originally going to have one fan for both vents and tie them together with ducting, but I have spoken with some people that said that would cut down on the CFMs dramatically, so I will have two separate fans one for each vent and then maybe tie the ducting together after the fans in the attic so I only have to put one vent on the outside of the house.

I know we don't want flex tubing, at least most threads say that is bad, even though you see pictures of it everywhere, so smooth ducting it is. I was thinking 8" because I have read some people are actually changing out their 6" to 8" and anything higher seems to be harder to find.

My biggest problem here seems to be the fan(s) I need. I have read to take the square footage of your opening and multiply that by 125 to get the CFMs you need. The opening of my funnel will probably be 10-12" but 125 CFM I know is not enough. I have also read you should at least have a 850 CFM fan but then some people seem to have 300-500 and say it works fine. I was looking on Grainger's website for fans that have about 850 CFM and then there is the issue of Static Pressure.

Not all of the fans show what the CFMs are when you add in Static Pressure so then I am not even sure if 850 CFM will be enough because my fan will be at least 7 1/2' from the funnel opening. I found a calculator online for Static Pressure but I cannot figure out how to use it.

I am just so confused at this point and feel I will never get this bench built. Can someone please just tell me the best fan type and CFM I need for my scenario?
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