Phoebe3 Posted February 5, 2017 Report Share Posted February 5, 2017 I've been through several pages in this forum and looked at kiln manufacturers' websites, but can't find an answer. How close to a wood ceiling can a kiln be? I want to fire in my basement, but the clearance from the concrete floor to the joists of the floor above is only about 6 feet. I'm trying to decide how small my kiln needs to be in order to fire safely. Would this change if I used a down-vent? What if I suspended a large metal hood under the joists? Thanks in advance. Link to comment Share on other sites More sharing options...
Mark C. Posted February 6, 2017 Report Share Posted February 6, 2017 How many feet from the kiln lid to ceiling is the question??? Tthe downdraft vent evens kiln temps out and removes burn out fumes more than any cooling effects. Link to comment Share on other sites More sharing options...
neilestrick Posted February 6, 2017 Report Share Posted February 6, 2017 A downdraft vent won't have any effect on heat coming off the kiln. It only vents fumes. Even in a basement with 'low' ceilings, the clearance between the kiln and ceiling is not an issue from a safety standpoint. If you can stand up in the basement, then it's fine. The bigger issue is heat radiating through to the floor above. Depending on the size of the kiln, the room above the kiln can be noticeably warmer from the heat of the kiln. To help that, you can put a layer of cement board on the ceiling above the kiln to help block the heat, and also keep some fresh air moving through the space with a fan. The best solution to deal with kiln heat is a vented hood above the kiln, like those made by Vent-A- Kiln. The hood also vents fumes. They're pretty easy to install, but more expensive than a downdraft vent. If you have a window near the kiln, a fan in the window can do a good job of pulling out heat. Link to comment Share on other sites More sharing options...
JohnnyK Posted February 6, 2017 Report Share Posted February 6, 2017 A downdraft vent won't have any effect on heat coming off the kiln. It only vents fumes. Even in a basement with 'low' ceilings, the clearance between the kiln and ceiling is not an issue from a safety standpoint. If you can stand up in the basement, then it's fine. The bigger issue is heat radiating through to the floor above. Depending on the size of the kiln, the room above the kiln can be noticeably warmer from the heat of the kiln. To help that, you can put a layer of cement board on the ceiling above the kiln to help block the heat, and also keep some fresh air moving through the space with a fan. The best solution to deal with kiln heat is a vented hood above the kiln, like those made by Vent-A- Kiln. The hood also vents fumes. They're pretty easy to install, but more expensive than a downdraft vent. If you have a window near the kiln, a fan in the window can do a good job of pulling out heat. The cement board works even better if you install 1" spacers between the board and the wood joists. Link to comment Share on other sites More sharing options...
Phoebe3 Posted February 6, 2017 Author Report Share Posted February 6, 2017 Thanks! I didn't think about using cement board and I can certainly put in spacers. The basement door opens to the outside (it's more of a root cellar than a real basement) so I can leave the door open and put in a fan, but there aren't any windows. The kiln I currently have is an old Skutt 2727. Probably a little bigger than I need so I could have looked for a smaller version if the top had to be farther from the ceiling - glad i don't have to buy another kiln! I hadn't thought about the heat in the room above. We don't have cooling and it gets pretty hot here in the summer. I don't make a lot of work so I could probably arrange to just fire in the winter. As long as the basement door is open and I'm using a fan, do I need to also use a kiln vent? The room is never occupied, but the furnace is down there (return vent is from the house so not much basement air gets in it, I don't think). Thanks again for your help! Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted February 6, 2017 Report Share Posted February 6, 2017 To get good ventilation to a space, you must have an entry and an exit, one is for bringing the fresh air in and the other is for getting the non-fresh air out. You will not get ventilation from only one opening, even if that opening has a fan! LT Link to comment Share on other sites More sharing options...
neilestrick Posted February 6, 2017 Report Share Posted February 6, 2017 Whether or not the fan system is adequate will depend on the power of the fan in the door, and what you're firing in your kiln. You can always try the fan and add a kiln vent later if needed. Link to comment Share on other sites More sharing options...
neilestrick Posted February 6, 2017 Report Share Posted February 6, 2017 To get good ventilation to a space, you must have an entry and an exit, one is for bringing the fresh air in and the other is for getting the non-fresh air out. You will not get ventilation from only one opening, even if that opening has a fan! LT It depends on how tight the space is. In an open basement studio there's often enough air being pulled in from the rest of the house that you don't necessarily need two openings in the same room. But if it's a closed room, it's always good to have an intake, too. Link to comment Share on other sites More sharing options...
Pugaboo Posted February 7, 2017 Report Share Posted February 7, 2017 Aren't we talking about 2 different things? Venting the room and venting the kiln itself? You want to vent the room to remove heat, fumes, toxins, etc. You want to vent the inside of the kiln to even out the temperature from top to bottom, remove toxins and fumes from the interior or the kiln, etc. I've always understood that a vent in a room would do nothing to improve the quality of the firing inside the kiln but a vent on the kiln does improve the quality of the air in a room as well improve the quality of the firing inside the kiln. Am I mistaken? T Link to comment Share on other sites More sharing options...
glazenerd Posted February 7, 2017 Report Share Posted February 7, 2017 The term you are looking for is: "make up air." The amount of air being exhausted from the room, is being replaced "made up" by a supply air source. There is another way to tackle this beast: basement with no windows... Install a thru wall fan; many models are only 8" in diameter, so they can easily be installed between floor joists. Relatively inexpensive; would recommend the 270 CFM model. http://www.homedepot.com/s/thru%2520wall%2520fan?NCNI-5 Nerd Link to comment Share on other sites More sharing options...
neilestrick Posted February 7, 2017 Report Share Posted February 7, 2017 Aren't we talking about 2 different things? Venting the room and venting the kiln itself? You want to vent the room to remove heat, fumes, toxins, etc. You want to vent the inside of the kiln to even out the temperature from top to bottom, remove toxins and fumes from the interior or the kiln, etc. I've always understood that a vent in a room would do nothing to improve the quality of the firing inside the kiln but a vent on the kiln does improve the quality of the air in a room as well improve the quality of the firing inside the kiln. Am I mistaken? T To get rid of fumes, you can either vent the kiln or vent the room. To get rid of heat coming off the kiln, you need to vent the room. A good room vent, placed near the kiln, will handle the fumes and heat. In basements, it's best to vent the room, since the heat will affect the temperature of the room above. If you've got the budget, a downdraft vent and a room vent would be ideal, but if you've got to choose one, choose the room vent. Downdraft vents don't do much to even out temperature. They may help a little bit, but if your kiln is firing unevenly a vent isn't going to fix the problem. They do improve the air quality inside a kiln, though, and can make a noticeable difference in some glazes. Link to comment Share on other sites More sharing options...
Phoebe3 Posted February 7, 2017 Author Report Share Posted February 7, 2017 Thanks again for the insights! Our basement is pretty leaky - there are places where you can see daylight between the exterior siding boards, plus there are several vent openings so I'm not really concerned about intake air. I'll put a CO2 detector a few feet from the kiln and it sets off, I'll definitely install a vent fan. When you say that glazes are affected by the use of a downdraft kiln vent, could you elaborate on that? Which types of glazes and how are they affected? If you don't want to take the time to answer, just direct me where to look. Thanks again! Link to comment Share on other sites More sharing options...
dhPotter Posted February 7, 2017 Report Share Posted February 7, 2017 Here is an example of the same glaze being fired in the same kiln. Unvented on the left. Then the kiln got an Orton vent. Pic on the right. If you are firing in oxidation that means Oxygen. The piece on the right has brighter colors, not dull like the unvented pieces. Link to comment Share on other sites More sharing options...
neilestrick Posted February 8, 2017 Report Share Posted February 8, 2017 Exactly. A cleaner atmosphere in the kiln can give brighter colors. Some touchy glazes (like low fire reds) will do better since they like oxygen and are less likely to be affected by fumes coming off of neighboring pots. Link to comment Share on other sites More sharing options...
Phoebe3 Posted February 8, 2017 Author Report Share Posted February 8, 2017 Thanks again everyone! I'll post again when I've got results. Really, really appreciate your help! Link to comment Share on other sites More sharing options...
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