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CarolinaDreamDesigns
2005-09-15, 6:01pm
OK - I've been playing on a hothead for the past year off and on and NC is losing it's MAPP gas so I'm looking to upgrade. I have been torching in my garden shed - in the door way or at one side. I can't figure out how I can add ventilation especially with a movable table.

Standing in the door of the shed you're in the door on the left and just inside the shed is a long bench/storage made out of 2x4s and attached so it can't be moved. Above the bench is the only window. My kiln is up on bricks on the top of the bench along with various frit, tools, rod rests, junk. The bench is too thick to attach a torch to, too short to stand and torch on, too tall to sit and torch on. So my BF made me stands that a movable tabletop can fit on different stands so I can choose to stand and torch or sit and torch. What I am doing most nights is opening the door, window, setting up my table where I show it - sideways to the end of the bench and door way - or directly in front of the open door. Most nights being in the open door won't work and isn't useful for letting me use the bench top for my glass, kiln, etc. I don't work with powders, metals, or fine frit for now but want to torch in the winter and work with other items so I will need to make this area workable for ventilation. The back wall and half of the side wall is built in shelves and glass storage.

I can't figure out how to do what is safe in this shed - add in the fact that I want OUT of this house and city in the next year and I can't see doing much in terms of remodeling this shed - it's a temporary situation. It's been suggested to torch in my spare bedroom for now and over the winter but even with a concentrator, I do NOT want to have a propane tank inside - add in flying glass and chips and carpet - I'm not sure that wouldn't be just as bad as the shed dilemmna.

What to do??? Any and all suggestions would be welcome?

Thank you!!!! Martha

door window
[------}----------{------}------|
| | Kiln frit, etc |
| | bench |
| |___________________ |
|x TT tabletop |
|x TT @ chair XX|
|x TT XX|
|x XX|
|shelf XX|
|XXXXX glass storage/ shelvesXX|
|XXXXX XXXXXXXXXXXXXXXXX|
--------------------------------|

Dale M.
2005-09-15, 7:18pm
First thing is not to make it to complicated. Simply build a hood or "barley box" (fume hood) style work area, calculate face opening, and apply formula of about 100cfm per each sqft of hood/box opening. There have been figures of anywhere from 80 to 125cfm being put out lately but the 100cfm figure will probably be good enough for most applications. Shed/room shape is not an issue, but air flow is. If you are moving (for example) 600cfm of air through hood (2x3ft face opening), you need a make up air source that is capable of flowing the same 600cfm or slightly more into studio. Ideally make up air needs to be put into area between you and torch... So if it comes from each side or from behind you, you will probably be ok.... The open door of shed is probably best source of make up air. If you manufacture a fume hood or barley box style work station its probably best to vent it out through window. BUT if window is real close to door you may get a air flow from window to door and be drawing contaminated air with what you expect to be fresh air... There should be at least 10 feet between ventilation exhaust and your fresh make up air for minimum dissolution of exhaust gasses.

Working out physical locations for hood and ducting is pretty simple, once you understand the concept's and pitfalls of ventilation....

If you can cut a hole in any wall, place fume hood at any place that is convenient for you and route ventilation duct our through the hole as far from make up air source as practical...

Keep in mind, the even if you do not use frits or do not do fuming, the colorants in glass are usually heavy metal compounds so there is toxic metals along carbon monoxide and nitrogen oxides gasses from torch combustion.

http://adm.monash.edu/ohse/documents/information-sheets/exhaust-ventilation.html
http://www.energyusernews.com/CDA/Article_Information/Fundamentals_Item/0,2637,22007,00.html

Dale

MikeAurelius
2005-09-16, 4:45am
For a bench mounted hood, use 80 CFM per square foot of hood coverage. Using more than this, especially in a small shed will be way overkill and probably start affecting your torch flame.

Sheds are fairly loosely built so you will certainly have some air leakage, but be sure the door is open when the fan is running to provide fresh air.

CarolinaDreamDesigns
2005-09-16, 5:43am
Well I can see my cruddy picture didn't survive the posting. I have my movable table in the middle of the floor next to the bench that is unusable for torching due to positioning. I guess I could "suggest" a vent system that works with flexible ducts that could be pulled over where I'm working. Have to think about this more.

I greatly appreciate the help and information given to me by everyone in the glass community. If it wasn't for the sharing and freely given help and support, I never would have expanded my life to try such an insane thing: "Playing with fire and hot glass - imagine a fuddy-duddy old lady doing something nuts like THAT?!"

If you don't have the sharing, the giving, the cool cool people who offer so much openly .... what's the point? Thank you BOTH for your comments. I lovveeeeee glass people!

=D>

Martha

Dale M.
2005-09-16, 5:52am
Unfortunately movable tables and hoods and flex tubing is really not really ideal situation for studio... IF shed is yours to do with what you want, I suggest a bit of redesign to accommodate a more practical arrangement of studio apparatus...

It was never clear in your first message if shed is on rental property and you can not modify it or that you choose to just work around the configuration as it is. A few hours with hammer and saw is not a total remodel, and may yield a more practical arrangement till you can move to your new location.

Dale M.

CarolinaDreamDesigns
2005-09-16, 6:20am
It's not rental property but if I hear one more time, you'll never sell that house unless you get rid of this or do that and what were you thinking??!! The problem is the bench and storage that is built into the shed - in front of my only window - is a plus factor for selling. Other people will use it. I was told that cutting extra holes in the shed or tearing up the useful bench and shelving would detract from the shed, the property, my possibility of selling it. Anything out of the ordinary would be bad according to the realtors.

That's why I was trying to figure out a way to work with what I had with pieces and parts and setups I have that can be moved with me. :::sigh::: NOT the best of situations - I guess I can keep dodging the wind and torch in open door?

Thank you -

Martha

MikeAurelius
2005-09-16, 6:31am
Dale is correct - flex vent ducting is the absolute worst thing you can use. Not only is the diameter normally too small to provide sufficient air flow through the duct, but the corrigations add turbulence to the air stream, which further reduces the efficiency of the air flow.

Corrigated ducting also tends to sag and bend where you don't necessarily want it to. Air needs to move in a straight line at all times. Any deviation from a straight line causes an increase in back pressure. Too much back pressure and the fan no longer functions as it was designed for, and far too much back pressure and the fan will actually stop moving air due to too much resistance.

Always use smooth sided ducting designed for moving air. It is available in a variety of sizes from 4" up to 12" and can be found in most home improvement stores.

Keep the number of bends to a minimum, use only what is required to get the job done.

Keep the total run of the duct as short as possible as well.

Additionally, do not change the size of the duct at any point in its run. The only time a duct size can/should change is right at the fan, before the run starts - usually the reason is that a large size duct adapter is required to fit the exhaust port on the fan - so the builder will use a 10" adapter, but then immediately add a 10" to 8" or 10" to 6" duct adapter. This very short run of decreasing size does not greatly affect the flow of air, usually only by 0.01 or 0.02 inches of static pressure. However, decreasing the duct size halfway down the run can and does increase static pressure by as much as a factor of 10.

Once the duct is through the wall, be sure that the air flow does not dump the exhaust fumes on a high traffic area - remember that there may be glass particulates in the air stream. Use an additional 90 to duct the air stream down towards the ground. I've seem some folks actually duct further and dump the air into a 50 gallon drum to catch any glass trash, but that may be a bit overkill for a small studio.

Put some 1" window screen on the duct end to keep birds and small critters out of the vent.

A simple flap damper installed in the duct run will prevent backflow of air when the exhaust system is not in use.

And finally, be sure that the exhaust is at least 10 linear feet from any source of fresh air to the studio. This ensures that no combustion by-products will be sucked back into the studio.

Jacinthe
2005-09-16, 6:33am
you two always have good words of wisdom and advice.

Some day I plan on getting a garden shed like this

http://www.mholf.nl/media/029.jpg

And I plan to have this layout... someday

3582

MikeAurelius
2005-09-16, 6:38am
Are you a 'lefty' (left handed), Sarah? The reason I ask is that I see your kiln and glass storage all on the left side.

As a 'righty', I've messed around with different layouts and have found that certain things sort of always need to be on my right side or I get seriously cranked off - the kiln is right behind me on another bench, but my glass selection is on the right, my tools (for the most part) are on the right.

(Sorry to hijack the thread LOL)

Jacinthe
2005-09-16, 6:45am
Are you a 'lefty' (left handed), Sarah? The reason I ask is that I see your kiln and glass storage all on the left side.

As a 'righty', I've messed around with different layouts and have found that certain things sort of always need to be on my right side or I get seriously cranked off - the kiln is right behind me on another bench, but my glass selection is on the right, my tools (for the most part) are on the right.

(Sorry to hijack the thread LOL)
Nah I'm righty... the layout could be switched, cause actually I have my glass now on my windowsill on my right side... but I have my flowerpot of vermiculite on my left so if I were ever to get a digital controller, I would put my kiln on my left like that... which actually might be easier to do...
The only thing I"m then worried about is that venting out thing, cause if I put the vent on the left side of the shed, then I'd be venting in the direction of my neighbour's yard, I don't like them, but I don't think they would much care for glass particles all over their back patio... the way I have it plotted now would vent up over my bike shed that is now in my backyard, which is part of the rental house.

Does it make sense and does it look like a good safe setup?

MikeAurelius
2005-09-16, 6:46am
Actually yes it does, Sarah. It looks very good.

Jacinthe
2005-09-16, 6:51am
thanks Mike :D

I plan on running my propane hose through the window so my propane will be outside like it is now... sometimes it gets COLD though with the window open ;)

MikeAurelius
2005-09-16, 7:32am
Use styofoam sheets to cut the opening down to just what is needed for the hose. If you can get some 2" construction grade foam (it's usually yellow, at least here in the states), cut it to snugly fit, with a notch in the corner for the hose. Fit in place, then use paper or cloth towel to close the rest of the gaps.

This is what one of my students did in her bedroom studio (no sleeping, just glass). Corner bedroom of a house, ventilation goes out one window, fresh air duct and hoses in the other window on the other wall. Double hung windows are great!

CarolinaDreamDesigns
2005-09-22, 3:42pm
Sarah - I NEED that Shed!!!! It's gorgeous!

Right now I can't do much of anything. My rescue Mama dog and her pup are in the side yard with the shed and I'm terrified of torching and somehow sending hot glass out the door where the pup is sitting - she'd probably try and catch it!

;-(

Martha