Indoor Kitchen and WFO

[tdibratt]

Hi, I am toying with building an oven inside my basement kitchen. I was thinking that I doubt very much building inspectors have any specific code for WFO and likley wood buring fireplace codes would prevail. Well here in Ontario a wood buring fireplace requires a fresh air duct and vent leading to the fireplace opening. Anyone have any experience with building a WFO inside and whether or not we can get away without the fresh air vent? I suppose if it is mandatory I would run it up to the WFO vent landing area just before the door seal under the chmney. Thoughts?

Thx

[splatgirl]

Re: Indoor Kitchen and WFO

This guy is building an indoor oven, or I guess technically the oven is outside and the landing is inside. IIRC, there is a bit in the thread about how he addressed the fresh air intake:
http://www.fornobravo.com/forum/f21/...nity-8365.html

I agree that code requirements for fireplaces would prevail but it never hurts to call your inspections office and talk to someone. I don't think ventilation and air supply is is something you should guess about, as it seems like at the very least it would be a real drag to spend the time building a WFO indoors only to have it smoke up your whole house every time you use it because it doesn't have adequate draw not to mention the safety issues.

Keep us posted on your plans and build. I built my outdoor WFO this summer and love it so much that I'm planning to do either another one or a cooking fireplace indoors next...

[tschaefges]

Re: Indoor Kitchen and WFO

We have an indoor oven (Wood-Burning Oven - a set on Flickr) and you definitely need a fresh air source, especially when starting the fire. When it's really cold outside there isn't enough draft to pull all the initial smoke up the chimney and you can get some in the room. Once the fire gets started, though, it's fine. Our oven is on the main floor, so I just crack open a nearby window, but if it were in the basement a supply duct will be necessary.

[dmun]

Re: Indoor Kitchen and WFO

A hint from the rumford.com site is to put your fresh air vent behind the refrigerator. The heat coming from the fridge will pre-warm the intake air, and there won't be any light leaks. They make specific vent blocks for this purpose, and some of them have dampers that close when you're not firing.

I'd worry about putting the vent right at the oven opening. You don't want drafts blowing ash on top of your pizza. If you do put it there, be sure to use metal vent pipe so a falling cinder won't melt through PVC.

[tdibratt]

Re: Indoor Kitchen and WFO

tschaefges, where is your frsh air vent located? Did not see it in the pics.

Nice oven by the way!

[tschaefges]

Re: Indoor Kitchen and WFO

I just crack open a patio door that's just to the left of the oven. Since we're on the main floor we didn't bother with a separate supply duct.

[david s]

Re: Indoor Kitchen and WFO

We have reached the point where the heat and humidity is so oppressive that we shut the house up tight and run the aircon. Leaving a door open is a no no. The only way I can work comfortably is get an hour or two in before breakfast and the same before sundown.

[tdibratt]

Re: Indoor Kitchen and WFO

I spoke to my insurance company yesterday and they reccomended that I get the plans/design approved by a WETT (Wood Energy Technical Training) certified professional and of course the building permits and inspections. So I am in the process of finding someone who is WETT certified to see if I can get some assistance here. I spoke to the building permits dept and they told me to submit the plans and they will review and get back to me. I told them what I was building and the person I was speaking to was not concerned about this being built ground up and not part of some UL approved kit (or at least I did not think so).

Not sure they will accept a window being opened. I can try that and see what feedback I get. There is a window right next to where I plan to build it.

[dmun]

Re: Indoor Kitchen and WFO

they reccomended that I get the plans/design approved by a WETT (Wood Energy Technical Training) certified professional

This seems to be a Canadian professional association of chimney sweeps. Since wood fired ovens don't accumulate creosote in any appreciable quantities, this seems to be an odd request.

[splatgirl]

Re: Indoor Kitchen and WFO

But SO typical of local building inspections! They don't know the answer so giving you some BS and sending you on a wild goose chase is how they deal.

I can tell you that U.S. code, or at least in MN, requires an air supply as part of the fireplace, so I agree that it's unlikely they're going to accept just opening a window. Sounds like you're on the right track at least. I'd maybe try talking to a fireplace builder or contractor or someone in the business of fireplaces (did I say this already?).

[Fish Wheels]

Re: Indoor Kitchen and WFO

You may get some information from these builders
STOVEMASTER - Custom Design and Construction of Masonry Heaters

Rod

[dmun]

Re: Indoor Kitchen and WFO

Masonry heaters have a very clever closed loop system, with both the outside air input and flue tightly closed off after the wood is burned off to conserve the heat in the masonry unit. I'm not sure how that would work in a WFO.

[splatgirl]

Re: Indoor Kitchen and WFO

As far as your options for incorporating an air intake, google "outside air kit" and you'll find lots of good info and options for units that could probably be repurposed or retrofit for a WFO application...

[dmun]

Re: Indoor Kitchen and WFO

Here's a very interesting article from woodheat.org It's about masonry fireplaces, but remember, from a building code perspective, a WFO is a masonry fireplace.

The money quote:

Makeup Air
While improper design and location is a major cause of poor fireplace performance, tighter house construction and powerful exhaust fans must share some of the blame. By installing vapor barriers and using doors and windows that have sealing gaskets, builders commonly reduce air leakage by more than 75% compared with the standard construction of 20 years ago. And homes are now commonly equipped with high-volume exhaust fans, such as those in downdraft kitchen ranges, which can move air out of the house at a rate of 600 cubic feet per minute (cfm) or more. Because tightly sealed house walls will not allow this much air back into the house through leakage, these powerful fans create negative pressure that can cause a chimney to backdraft and fill a house with smoke (Figure 4).
One standard fix for smoky fireplaces has been to install a supply of outdoor air in the belief that air starvation is the root cause. While lack of combustion air may be a problem in some cases, supplying outdoor air to the fireplace through a duct is certainly not the cure. Two research studies, one conducted in Canada on a series of factory-built fireplaces and one done in the U.S. on a masonry fireplace, looked into the behavior of outdoor combustion air supplies. In both studies, the fireplaces were installed within chambers that could be depressurized continuously after a fire was lit. As the fires died down to charcoal, technicians monitored carbon monoxide readings in the chamber to see when exhaust began to spill from the fireplaces. Tests were done with and without combustion air supplied from outside the depressurized chamber. No consistent difference in spillage timing or amount could be found whether or not outdoor air was supplied.

Here's the link to the Rumford.com article I referred to earlier in the thread.

[tdibratt]

Re: Indoor Kitchen and WFO

Thanks DMUN. Interestingly enough I had contacted John Gulland (author of that WOODHEAT.ORG). He got back to me and advised against putting an oven in the house. My situation of running the oven in my basement kitchen would have 2 x 90 degree elbows (top of oven back to wall to exterior chimney and then up) and he suggests with the amount of smoke oven's create on start up, that it would likely fail. He suggested a power exhaust fan on the chimney might make it work (additional $1500). The Chimney and exhaust fan will likely be around $6,000 alone (I arrived at this figure using the online Sentinal Chimney configurator and added the $1500). He speaks form experience as he too has an outdoor oven but would not consider one indoors. He also suggested that a WETT certified professional would not be able to pass judgement on the design because an oven is beyond that of a fireplace and chimney and there are no relevant code provisions and suggested I contact the building dept and get more guidance before proceeding.

All in all, his advice is very useful. I expected to have some hurdles to get over on this one since ovens are not typical and people may not know how to deal with them (i.e Building Dept). I did contact several WETT certified professionals and not one got back to me. Not sure if they are too busy or just do not want to get involved because of what I am trying to do.

At this point the whole idea is somewhat of a turn off for me. Given the cost of the chimney alone and hurdles I need to rethink this and see whether or not I want to pursue. It was a challenging project for me which I was looking forward to.

I will keep any additional feedback or progress (if any) posted on this site. Many thanks to DMUN and others for feedback and comments.

Regards