Dying for vent/fan help

[Lub]

Hey guys, sorry for not being too active these past couple months. Life's been pretty crazy to say the least. I'm to the point that I'm setting up a second station for my buddy "n00bonfire" to work at, as well as for lessons/colabs/whatever. It's going to be one 8-10 foot worktable, along a wall, directly in front of a pretty big window. We are going to use two separate hoods, one fan, and basically just connecting the two hoods with a T connector, then connecting that to the fan, then out the window. Our only problem, and the reason its not built yet, is the fan. I've been on here researching, been on grainger, been calling HVACR people, little to no help. We need a fan that can clear 2 workstations in a 1300 cubic foot room, and must be duct able. I don't mind making a box to hold the fan, but if it was easy to just pop a duct on, I'd be thrilled.

I've seen the 70 dollar gable fans, but they aren't very duct able. I've seen the 300 dollar vortex fans, but they don't move enough for what you pay for. I'm begging for help. Just got my first Dewar today and need to start working before it tries venting on me. Money is not as issue, so long as its an incredible fan that enables me to breathe fresh air. Any ideas are welcome and appreciated. "n00bonfire" is gonna post up pics and diagrams soon, so visual aids are coming.....thanks again.

[p.j.]

if you are in front of a window, why do you need to duct it?

i have one of those vortex's btw

[drewspuppet]

Look at direct drive centrifugal exhaust fans. U can prob get one for about $500 but they are worth it and will last. I think I got mine, have 2 from industrialfansdirect.com - I have the 33 + 55 downblast models

[drewspuppet]

Edit I have the upblast models, wall mounted

[Lub]

P.J. Thats kinda what I thought. Pictures are about to be added, but we just felt hoods are more "up and away" as opposed to pulling through a single window in the center of our two torches, lots of dead space in the corners and what not, we figured, but again, nothing is bought yet and we are open to suggestions.

[LTD]

Putting walls from the ends of the bench to the ceiling and a lip down from the ceiling across the front will help a ton. A high CFM gable fan should do the trick.

[Lub]

drew can you maybe send me a link to your exact model ? cant find it.

[Lub]

yeah luke dats what i was thinking a little.

[Sketchball]

EDIT: Here be those visuals.


Putting walls from the ends of the bench to the ceiling and a lip down from the ceiling across the front will help a ton. A high CFM gable fan should do the trick.

I was the one kind of resisting the attic fans. I could understand if it were still practical even with the torch at the far end of the table if it's moving that much air. Tell me what you guys think.


Here is a picture of the old station at the wall that we want to use.
http://i863.photobucket.com/albums/ab191/Lub_Glass/IMG_0360.jpg

This first drawing is just a mock up in MS Paint, no real size reference, from a couple months ago. (Kiln is much smaller than that lol)
http://i863.photobucket.com/albums/ab191/Lub_Glass/revised-2.png

Here is the overall dimensions of the room, to-scale.
http://i863.photobucket.com/albums/ab191/Lub_Glass/SmallDems.jpg

Finally the dimensions of the wall and window, and window gap... also to-scale.
http://i863.photobucket.com/albums/ab191/Lub_Glass/smallWall.jpg

[Lub]

thanks dog. So yes, let the brain juices flow gentlemen, any help is much appreciated and will be repped. I need this table up SOON so I can tear into this dewar full force

[p.j.]

Putting walls from the ends of the bench to the ceiling and a lip down from the ceiling across the front will help a ton. A high CFM gable fan should do the trick.

i think this is the best idea so far. one fan on either side of the window for even draw. have one hood that runs the length of the table. put some fans behind you for some extra air flow

[LTD]

No hoods. just build a lip as low as you are comfortable. and at an angle like you had the old one. You can also build sides on the bench tilted inwards a little. One good high CFM gable fan in the top of the window should be fine. A 45deg lip coming from a foot in to the bench from the wall would also help, but most likely would just take up space. Get the thing knocked together and start burning the O2!!! Only thing I can think of that might help to maximize yer exhaust would be pulling the window out all together and replacing it with a piece of plywood and putting two fans in side by side with a divider coming out about two feet....

[drewspuppet]

floaire.com-fans (http://www.floaire.com/catalog/FanPartSelection.asp?blnSizeFan=0&nFanTypeId=1&efantypeid=10&eFantypeDescr=Centrifugal+Upblast+Direct+Drive+Fan s&sfantypeid=0&sFantypeDescr=&CFMspec=0&SPspec=0&ReturnSPspec=0&IntakeSPspec=0&BTUspec=0&Tempspec=70&PhaseSpec=0&HertzSpec=0&MotorTypeIdspec=0&Catalogid=105&SvoltoptSpec=0&CoilPhase=0)

The DU50H is variable speed up to 2181 cfm - $615 - there are others on this site too. Same fans I have

[LifeGlass]

[/QUOTE]
The DU50H is variable speed up to 2181 cfm - $615 - there are others on this site too. Same fans I have[/QUOTE]


I always wondered about those fans, that is the type used in Restaurants correct? You can point them straight up, and no water will leak in, they are baffled?

[drewspuppet]

Yea, I'm not sure I have mine wall mounted, but I know you can do a roof mount with those too.

[Adapt]

Dude! You must be stoked on getting liquid! If you guys go the attic fan route make sure to angle your torches to the fans if possible. It sounds awkward, but makes a difference.

I had a Max Air Can Fan 14" at an old shop with tons of duct, it was a beast, but probably overkill for your situation. Here's a link just for kicks, maybe a smaller one is good for your set up.

http://www.canfilters.com/documents/MaxFan-Information.pdf

[elad65]

You have done a lot of guessing about what size fan.

You have done some really nice graphics on room size and lay out (which mean nothing).

You HAVE NOT done any calculations on face opening of fume cabinets/Hoods. I don't see any information on duct size. I don't see any actual duct lengths/routes measured, I do not see seen and duct velocity calculations or static pressure calculations.

At best you are just wild ass guessing.

You intentions are good, you research is lacking a lot of facts.

Elad.

[coloringdan]

I am a wild ass guesser too. I have a very similar setup and I put a used furnace blower right in the window and it is more air flow than I even really want or need. $20 bucks on craigslist

[jahglass]

This is a really good article about ventilation http://mikeaurelius.wordpress.com/ventilation-primer/

I recently went to my local HVAC supply house and asked them to put the word out to some of their contractors to save the blower unit next time they do a furnace replacement job, they usually just throw em out or scrap them. Within 2 days, I got myself a sweet squirrel cage fan for free!

[LTD]

You have done a lot of guessing about what size fan.

You have done some really nice graphics on room size and lay out (which mean nothing).

You HAVE NOT done any calculations on face opening of fume cabinets/Hoods. I don't see any information on duct size. I don't see any actual duct lengths/routes measured, I do not see seen and duct velocity calculations or static pressure calculations.

At best you are just wild ass guessing.

You intentions are good, you research is lacking a lot of facts.

Elad.

Room size and lay out actually makes a big difference in ventilation.... say you have a tiny room and a fan with massive CFM and a very small window for make up air. Would you have good ventilation?

[elad65]

Its about CFM at face opening of hood where glass artist stands and works. NOT about total space.

Its a guaranteed fresh air source from behind artist coming over his shoulders and around his head to insure he/she is breathing clean air.

Elad

[LTD]

If the make up air is not sufficient bench face opening size does not matter. If you are exhausting more air than you can reasonably make up you get a very windy shop and the wind will mess with your flame quality. Total space does play a significant role in proper ventilation. As does available make up air.

[elad65]

You are correct on one point, makeup air must meet or exceed the capabilities of exhaust system.

Elad

[LTD]

How many shops have you built? I have been doing this a long time and have built quite a number of benches, with and with out hoods, in tiny rooms and huge warehouses. Every bench I have built has had excellent ventilation.

[elad65]

I have built several studios and have been helping others figure out (calculate ) proper air flow at face opening of fume cabinets or hood, duct size and fan sizes for proper face velocity and duct velocity and over coming static pressure in systems for about 7 years.

Just because you have built a system or two does not mean you understand or know proper design criteria to have proper functioning system. If you do this on paper first, there is no guess work when purchasing fan or ducting and hood parts.

Also there is a ton of information on this site and a lot of other lampwork sites that support calculating a design before implementing it.

Elad

[LTD]

Just because you have built a system or two does not mean you understand or know proper design criteria to have proper functioning system.
Elad

Your assumptions are pretty rude, Let's get back to helping Lub get his shop set up. None of your suggestions or rather judgments have actually answered any of his questions. He actually listed the width of the bench, the height of the bench , the height of the ceiling and the width of the room. If you take that in to account he has given the area of the face opening of the bench. He was asking What would be the proper way to vent the space given those dimensions. Bagging on him and others for not giving enough info when he actually has in not helping the situation at all.
Lub, if building the bench the way I suggested does not give you proper ventilation, I would be amazed. I hope you get your studio set up and running A.S.A.P. Good luck. Let me know how it works out.

[LTD]

Oh, the face of the space is 5feet 4inches by 12feet.

[elad65]

You are actually going to build a single hood to that dimension?...

64 in X 144 in = 9,216 sq inch opening.

9,216 /144 = 64sq-ft

64 sq-ft X 100 CFM = 6400 CFM fan

Suggest reducing size to two independent fume cabinets about 30 x48 inches (each) .

30 in x 48 in =1,440 sq in.

1,440 / 144 = 10 sq ft hood opening.

10 sq-ft X 100 CFM - 1,000 CFM.

Two hoods at a 1000 cfm (each) is one hell of a lots less air to move than one hood at 6400 CFM

But again to get flow correct you also have to consider duct diameter and length and number of turns to keep up duct velocity so any left over particles from fuming or frit work or just plain combustion by products do not drop out of air flow and allow the contamination to remain in duct work .


Elad

[elad65]

Update. Going on premise that it will take 10 feet of duct and 2 90° turn to get vent duct from hood to fan. This is for one hood.

7 inch duct with the two mentioned turns has a Loss Factor of 0.3208 IW (for the 10 ft) and when coupled with a 1000 cfm fan will give a ducts velocity 0f 3741 FPM which is well above the recommended 2500-3000 FPM recommended by most heath and safety organizations who regulate these systems.

Elad.

[Shatner]

I use a 1250cfm 12" inline CanFan ducted to a lightbulb hood a buddy tossed down to me.

It exhausts two stations and the whole garage very nicely.:chilling:

[elad65]

But what are you using for hood(s) and ducting and how many turns. Its all relevant. What is source of makeup air.

Elad

[LTD]

Hey LUB, You get it figured out?

[Shatner]

But what are you using for hood(s) and ducting and how many turns. Its all relevant. What is source of makeup air.

Elad

Hood is a hand me down grow hood, 1 45* bend and makeup air comes from having the garage door opened.

[elad65]

And the size of the front opening and the diameter of the duct and the length of the duct run?

Elad

[Lub]

hey guys, sorry for abandoning this for a few days, my girl was in town from cali....priorities.

[elad65]

IF you are interested in the fume hood concept here is some reading that may help you find your way.

http://ateam.lbl.gov/Design-Guide/DGHtm/exhaustdevices.htm

Elad