Building Studio, Vent Help Please

InsanityBeader · #1 2007-07-12, 7:24pm

Hi all, I need some knowledgeable help. Try as I have, I can't really figure out the right vent system to have installed and I have read the various threads on it. My blondeness is really coming out in that I can't really understand technical jargon or the math. My dear hubby is anti-handy so he really isn't much help though he tries to be. We are contracting to build an 8ftx8ft room in the back of the garage to become my workspace with a carpenter and electrician. One wall will have an A/C on it, I have a door to the outside with a window and they will be hardwiring in the vent system that will vent to the attic space above the garage that has out vents all around it. Today we were at Home Depot and looked at vent hoods and honestly could not figure out what I should get. Could someone please reccommend something. We begin construction on Thursday, July 19th and I need to have the hood for the electrician by that Saturday. The guy at home depot said we shouldn't consider the "range" cooktop hoods but instead took us over to look at the big fans over by the lumber and said we should have that installed in the ceiling. I want to do this right the first time!!

Dale M. · #2 2007-07-12, 9:22pm

Stay a way from ceiling fans.... Salesman does not have a clue to your needs....

Yes you need a hood or a fume cabinet (hood with sides)...

Do not take ventilation into attic and expect it to flow (vent) out through attic vents (at eves). This will contaminate whole attic space with the very contaminates you want out of your work space. Go directly outside with vent exhaust....

Dale

bhhco · #3 2007-07-13, 6:11am

Do not get the hood yet. The hood should not be hardwired in, so it is not needed at this point. Instead, provide a 15A, duplex outlet within 4' of where you plan to have the torch located - dedicated for the hood fan. Later, the hood will be addressed and a proper ventilation set-up can be suggested.

Me

InsanityBeader · #4 2007-07-13, 6:20am

Allright, where do I go to purchase the proper vent set up? Hubby says that my stuido space is approximately 512 cubic feet. SO how strong of a vent should I be looking at? Is a cook space hood set up going to be appropriate for me?

One more thing I wanted to add.. hubby informed me that when he spoke with the contractor, the current idea was to tap into the dryer vent and add a "flap" that will prevent the venting from traveling back towards the dryer.

Dale M. · #5 2007-07-13, 8:19am

Quote:

Originally Posted by InsanityBeader

....SNIP.....

One more thing I wanted to add.. hubby informed me that when he spoke with the contractor, the current idea was to tap into the dryer vent and add a "flap" that will prevent the venting from traveling back towards the dryer.

NO-NO-NO-NO----

Vent must be stand alone system that vents directly outside... Besides dryer vent duct is TOO SMALL to carry volume of air you need to move for proper ventilation... CONTRACTOR is in same category as BIG BOX store SALESMEN... Clueless to what is required to create proper ventilation....

Do not consider any vent duct smaller than 6 inch and 8 inch is the better choice!.. Do not consider any vent system that does not take its own dedicated path directly outside....

If you have to run out and buy ventilation TODAY.... Go get a range hood with at least 300 cfm capacity and direct vent it outside, if it seems a little anemic put side baffles from hood down to bench top to improve air channeling.... A 300-350 cfm hood wil change out full room air about once every two minutes... Get hood as low as possible to be as effective as possible....

Check out ventilation basics here...

http://www.artglassanswers.com/forum...opic.php?t=150

Dale

bhhco · #6 2007-07-13, 9:58am

Dale is absolutely correct and he types faster than me

. And your DH has the cubic foot right on!

What else? As Dale said... use 6" or 8" duct... the larger duct cost is only pennies more than the smaller duct (and it will work later with larger fans, if/when you upgrade).

Vent the exhaust separately, and as directly as possible, to the outside. Venting the exhaust straight up, through the roof directly over the vent hood, is the best and least restrictive thermal flow path.

If you know where the torch will be, then have the contractor install a roof vent on the garage roof directly above that point and install a galvanized 8" duct from the roof vent down through the sheetrock ceiling. Then, later you can hang your hood/fan and connect to that ceiling/roof vent duct. If a separate exhaust fan is used, it will be connected to the ceiling duct, then the hood connected to that fan.

Assuming you are using minor torch and one 5 lpm oxycon, you will very likely find the combo hood/fan is more than sufficient, but if not, then place a larger fan at the ceiling, attached to the duct.

All this assumes adequate make-up air supply... perhaps the most overlooked element of the system. There must be a hole large enough to let in the same amount of air as is being exhausted, or all will be for naught. It will matter little how large the duct work is, or how strong the fan is, if the room cannot be supplied with the same volume of air that needs to be exhausted. The make-up air requirement can be a considerable challenge... especially to a room's 'AC system', and to the flame stability.

Me

Diane (clarus) · #7 2007-07-13, 12:19pm

Dale and bhhco are right on with their advice. Basically what you need is some kind of enclosure around your torch where the fumes can collect and be sucked up into the exhaust pipe with a blower. I made my own enclosure - see my post from last week in the Studio section. I made it out of sheets of steel from Home Depot. You should be able to use a squirrel cage fan that you can get at Grainger; they have locations all over the country. I was told to use one that's based on 100-125 CFM per square foot of face opening. Think of looking at a box on its side and you're looking at the opening only. An example - mine is approximately 3' wide by 2' tall, so it's 6 square feet. I use a 747 CFM fan, 6 times 125 CFM. Your hood may be different. I think you do understand the importance of doing this right; you're doing the right thing asking questions here before you do anything else! Good luck and keep us posted.

Also don't forget to use smooth duct; the flexible duct will reduce the air flow and reduce the effectiveness of your fan.

-Diane

InsanityBeader · #8 2007-07-13, 1:53pm

Thank you Thank you! This has been such good information and I'm so glad I could come here to be set straight. I will be passing this info on to my contractor and we may be reorganizing where I set upthe torch in the room to accomodate a direct vent out. I will keep you guys posted and eventually show pictures of the set up!

Diane, I checked out your set up, very nice!

beadgirl · #9 2007-07-18, 7:06am

Diane,
How are you doing with your studio?
sending positive thoughts to you. If you need a pic of the electric in my attic. I can post them for you before we close up our ceiling. MarieAnn

bhhco · #10 2007-07-18, 8:06am

Quote:

Originally Posted by beadgirl

Diane,
How are you doing with your studio?
sending positive thoughts to you. If you need a pic of the electric in my attic. I can post them for you before we close up our ceiling. MarieAnn

MarieAnn,

Before you close up your ceiling... the absolute best exhaust path is straight up through the roof. A 8" duct is sufficient for all except the very largest torches. Leave a 'attic access' opening framed in if you can, regardless of if you exhaust through the roof, or not.

Me

Diane (clarus) · #11 2007-07-18, 8:34am

MarieAnn, my ventilation setup is fantastic. Everything goes up the vent, even the bugs

. I still use an N-100 respirator mask when I do silver, or when I get around to using my enamels, but for everything else just having the fan on seems to be sufficient. I was a little concerned that it would suck up things I didn't want it to; I can even work with silver leaf in the area directly below the torch and it doesn't move. Only the stuff in the air.

You saw the photos, but to give you a better idea of how the exhaust is set up, here we go. DH didn't want to cut a hole in the roof of the garage, so from the hood it goes straight up, makes one 90 degree turn, and runs 10 feet out to the back wall of the garage.

Only thing I need to do now is get the electrical upgraded, which I'm working on today. Then I get to use my new kiln!

-Diane

InsanityBeader · #12 2007-07-20, 6:36am

UPDATE!!
They started putting up walls yesterday. Hubby and I decided to buy the highest CFM hood we could at Home Depot which ended up being a CFM 440 for about $360.oo. My handy guy started doing research and actually had scrapped the dryer vent idea before I had to tell him no to that. It will be venting directly outside. I'm getting just a Liiiiiiiiiiiiiiiiiiiiittle bit exicted!!!!! Just a little bit!

beadgirl · #13 2007-07-20, 12:10pm

Hey Wait .. Check out www.Graniger.com
Orlando location Phone # 407-843-3220
1TDT4 805 CFM Dayton $178.25
1TDT9 Dayton 794 CFM $ 205.00

2C946 Dayton 815 CFM $ 165.38 Discountinued But may be avaible to bring in from another location
Do not go up thru ceiling you are asking for problems with leaks.
No affilation to them. Best luck to you, MarieAnn

Diane (clarus) · #14 2007-07-20, 1:18pm

MarieAnn is correct - you are going to need a stronger fan. You'll also need to increase the size of the ventilation duct to 8". If you use the fan you describe, by the time you buy it, remove the existing fan and cut out a bigger hole for the larger duct, you might as well just buy the materials at Home Depot and make the hood yourself (or have the contractor make it.)

We're just trying to help you to be safe.

-Diane, also a crazy mom

InsanityBeader · #15 2007-07-21, 5:36am

Oh dear.. this is not what I wanted to hear. I was sure the 440 was going to be sufficient for my little room. The plan is to run the vent hose up through the cieling and then over to the soffets (sp?) that run along easement and vent directly out. Not cut the roof in any way. I told our contractor that 6" to 8" was the requirement. 8" being preferrable.

Is that the right website? I got something that doens't appear to deal with ventilation.

InsanityBeader · #16 2007-07-21, 5:48am

I did find a site that was Grainger.com but if I have to try to find peices parts to build something then I am completely over my head.

beadgirl · #17 2007-07-21, 8:42am

Hey Insanity Beads, Size of room has noting do with this. PM'd you MarieAnn

Diane (clarus) · #18 2007-07-21, 9:01am

MarieAnn, I'm Diane, a FELLOW crazy mom. I don't know what InsanityMom's name is. But you should check out her web site - pretty beads!

-Diane

beadgirl · #19 2007-07-21, 9:06am

Opps, so sorry to the both of you. And yes her beads are very pretty.
MarieAnn

InsanityBeader · #20 2007-07-21, 11:52am

Thank you for the compliments on my work! I really appreciate them

I think at this point I am pretty much committed to the 440 hood. However, if we find it's not being sufficient we could go into the attic space and add in a fan/blower to the duct work that would up the cfm.. correct? I currently work on one oxycon and a minor bench burner. Mostly stay with soft glasses. I dont forsee a change in the near future from that set up. I'm still going to continue to do more research and bug more people for more info.

Diane (clarus) · #21 2007-07-21, 12:40pm

That sounds great. A couple of things to do right now are to have it lower above your bench - 24 inches instead of 30, and to put some side baffles - partitions that go from the lower sides of your hood down to the bench top. These things will help contain the fumes and allow them to get sucked up the vent more easily. I have steel baffles on mine, but I've seen other setups that have plexiglass. I can't vouch for the safety of that, but if you look in the studio section there are several enclosures that use it.

When/if you decide to upgrade the fan, I think standard procedure is to remove the fan from your existing hood and put the new blower somewhere in the duct line; in your attic would be fine.

I don't claim to be a ventilation expert, but I've learned so much from everyone over the past year and want to help others as a result.

Good luck and keep up the great work. I especially loved your grape necklace.

-Diane