Skutt Envirovent still allows fumes

[Bill Kielb]

@MochiFriend Just to add a drawing for clarity

 

 

Edited December 3, 2023 by Bill Kielb

[MochiFriend]

3 hours ago, Bill Kielb said:

Just to add a drawing for clarity

Amazing thank you! 

It turns out that my partner has a fan for this purpose already, he uses it with his laser cutter (which is also why we have a piece of wood with a circle cut out for our window). So all I need to do is just get some ducting from Home Depot.

Do you recommend attaching any kind of "capture device" on the end of the duct that is in the kiln room, eg. some kind of lightweight hood or umbrella-looking thing? Or just the end of the tube sitting there near the kiln is fine for the purposes of testing this out? 

Best,

Ali

[Bill Kielb]

1 hour ago, MochiFriend said:

Do you recommend attaching any kind of "capture device" on the end of the duct that is in the kiln room, eg. some kind of lightweight hood or umbrella-looking thing? Or just the end of the tube sitting there near the kiln is fine for the purposes of testing this out? 

 

Any hood is great, higher inlet better than low is good but really if you get it in the room, the room is small and to keep the odor from exiting the room, near the kiln much better than you are doing now. Keep in mind, the kiln vent is capturing many, just not all.

Edited December 3, 2023 by Bill Kielb

[Hulk]

I'd re-used a propane patio heater hood - large diameter, light weight - for overhead system on previous kiln.

[MochiFriend]

Hello everyone, I just wanted to give an update and say thanks for the advice so far. I've set up the additional venting to match the exact diagram that @Bill Kielb sent over in his latest message. I'm going to do a glaze fire tomorrow and have a pm 2.5 + voc reader in the room to monitor.

I'm curious if you guys think that having the one window open is necessary for intake airflow. I understand that the two outflow vents require a source of intake air, however would the intake air come from around the house as the room is not a perfect vacuum? Anyway, I will be leaving the window open as planned for now, but this is something that my partner and I debated about. Many thanks. 

[Bill Kielb]

7 hours ago, MochiFriend said:

I'm curious if you guys think that having the one window open is necessary for intake airflow. I understand that the two outflow vents require a source of intake air, however would the intake air come from around the house as the room is not a perfect vacuum?

When you run the dryer it exhausts 200 cfm, window open or not, so no, air  will be drawn in from the many minor  openings in the house. Opening the window even a very small amount will help ensure that you do not suck fumes back down the flue of a gas fired appliance though. Most old codes allow exhaust by volume …. if there is sufficient home volume to draw from. Most homes have leakage on the order of 5 air charges per hour or more.

I would suggest you put your pm2.5 in the adjacent room(s) to get a pretty good idea if you are succeeding in exhausting all the particles generated by the kiln from the kiln room. Maybe confirm by noting the reading in the room vs the reading in other rooms. If the fan is large enough exhaust then the other rooms will remain at or near their baseline and change proportional to the activity in the other rooms as well as the pm2.5 outdoors. If you are a smoker, the counts will be crazy high maybe up to 1000 µg/m3 or more especially when you first light up.

outdoor air will generally be in the single digit range for pm2.5 but can rise very high due to fires for which air filtration became one of the only ways to lower this count indoors. Your local weather station likely posts AQI and maybe Pm2.5 daily. For my location today, at this point they have measured in the last hour AQI of 29 and pm2.5 of 8  µg/m3 See below accuweather prediction for my location.

Edited December 8, 2023 by Bill Kielb

[MochiFriend]

6 hours ago, Bill Kielb said:

11 hours ago, MochiFriend said:

 

When you run the dryer it exhausts 200 cfm, window open or not, so no, air  will be drawn in from the many minor  openings in the house. Opening the window even a very small amount will help ensure that you do not suck fumes back down the flue of a gas fired appliance though. Most old codes allow exhaust by volume …. if there is sufficient home volume to draw from. Most homes have leakage on the order of 5 air charges per hour or more.

 

Thank you Bill, that is good to know. So just to clarify, is your answer / advice that "yes we should leave the window in the adjacent room open slightly" to ensure that the fumes aren't sent back around thru any gas appliances? 

Since there are two windows in the adjacent room, one of the windows has the new fan venting out of it, and I've propped the other window open slightly. 

I've seen advice on this forum to always ensure that there is a nearby window open to provide air intake source near the kiln when a vent is being used, so am somewhat confused about this advice if that is the case (because wouldn't the same principle apply, that you would just have the air being drawn from the cracks and crevices around the house?). 

Kiln is firing and the PM 2.5 reader is positioned in the upstairs living space, eager to see what the readings show today. 

Thank you! 

[MochiFriend]

A follow up! There's a smell in the kiln room (above + around the kiln), but no smell in the adjacent office room.

Readings:

500F: 
TVOC
Baseline: 0 in all rooms
Living room: 0 
Kiln room: 23 ug/m^3

PM2.5
Baseline: 1 in all rooms
Living room: 1
Kiln room: 1

1200F
TVOC
Living room: 120
Kiln room: 320

We are wondering if we should perhaps close the door to the small kiln room so that the only negative air intake is instead from the leaks around the house. I'm not sure if this would make it spread more or less given that the fan is not venting out all the fumes. (Our stove is electric and furnace intake is from around the house - not near the kiln room). 

I think that given there is still the persistent smell in the kiln room even with the additional fan venting out -- I am considering to move the kiln to be right in the corner between the two windows (health is first..). 

Edited December 8, 2023 by MochiFriend

[Bill Kielb]

3 hours ago, MochiFriend said:

A follow up! There's a smell in the kiln room (above + around the kiln), but no smell in the adjacent office room.

Readings:

500F: 
TVOC
Baseline: 0 in all rooms
Living room: 0 
Kiln room: 23 ug/m^3

PM2.5
Baseline: 1 in all rooms
Living room: 1
Kiln room: 1

1200F
TVOC
Living room: 120
Kiln room: 320

We are wondering if we should perhaps close the door to the small kiln room so that the only negative air intake is instead from the leaks around the house. I'm not sure if this would make it spread more or less given that the fan is not venting out all the fumes. (Our stove is electric and furnace intake is from around the house - not near the kiln room). 

I think that given there is still the persistent smell in the kiln room even with the additional fan venting out -- I am considering to move the kiln to be right in the corner between the two windows (health is first..). 

Sorry for the confusion, as long as you have enough volume in your house the makeup air from all the little cracks etc… likely is fine as you have run the dryer without issue and it sucks about 200cfm out of the room when operating.. So with the window closed maximum draw will occur from all other rooms which will limit the fumes from exfiltrating to the occupied spaces. If later, running the kiln vent, bath fan, stove vent etc… the volume of your house and normal leaks may not be enough and you will begin pulling from your furnace ….. providing your furnace is a natural draft furnace.

Anyway, two competing issues, pure ventilation and combustion appliance makeup air. Always safe to design in makeup air so combustion appliances behave well. So not a one sized fits all and best done by someone with experience and knows all the components of the home else out of safety you will likely see makeup air always suggested. Like most things if someone is viewing these problems as a stream of airflow, technically this is usually a very flawed view. Folks who do it everyday for real are very cognizant of the pressure difference.

Interesting results from the air monitor btw. I see a lot of general assumptions about vents, kilns and working near them, this may be a nice simple way to show folks All the fumes are likely never captured by down draft ventilation. Your pm 2.5 results seem low since outdoor air is generally above zero. Regardless a nice indicator of trend and your monitor does voc.

Edited December 9, 2023 by Bill Kielb

[MochiFriend]

2 hours ago, Bill Kielb said:

Interesting results from the air monitor btw. I see a lot of general assumptions about vents, kilns and working near them, this may be a nice simple way to show folks All the fumes are likely never captured by down draft ventilation. Your pm 2.5 results seem low since outdoor air is generally above zero. Regardless a nice indicator of trend and your monitor does voc.

Thank you Bill as always for your helpful insight. 

We're reaching the end of the firing now, but I am looking forward to pulling the graph from my monitor for the day that shows the TVOC levels. 

PM2.5 levels did not go above 1 both in the kiln room and the house. However, TVOC levels in the kiln room started increasing significantly around the 1800F mark til now (firing to cone 5 - 2150F ish) — they started spiking from 500 ug/m^3 and are now at 2313 ug/m^3 in the kiln room. Indeed it is a helpful reminder of what you said, fumes are not going to be 100% covered by downdraft ventilation and even if like 90% of the fumes are captured, the small % of fumes that are not captured are still pretty bad. Also, I cannot smell anything in the room, but it's a good reminder that smell != fumes as sometimes we can't smell the latter. 

For example, when Skutt says "little to no smells/fumes will leak out of the kiln" — even a small amount of fumes is significant, imo. 

That all said, I've decided that for my own peace of mind I will be relocating the kiln, ideally now to the garage (but this will be determined by if we can get a 240volt outlet routed down there, which will be challenging - contractors coming to quote this week). Another conclusion I've come to from this whole experience is that I also don't think kilns, even small kilns, are suitable to fire in the home. 

[Bill Kielb]

10 hours ago, MochiFriend said:

PM2.5 levels did not go above 1 both in the kiln room and the house

@MochiFriend If this is an older monitor I would definitely check the pm2.5 module. They generally allow gentle cleaning of the optical detector and pathway. It’s really unlikely to have such low readings, especially when outdoor air is usually in solid single or double digit range. 2.5 micron stuff is really small to the point where a reading of approximately 300 would show as very fine dust in a beam of sunlight or laser pointer. Generally Everyone has to dust, even folks with 1 micron hepa air purifiers. So a count of zero or one seems relatively unlikely. Still you have VOC’s so the trend and delta readings super helpful to illustrate the point: it’s hard to completely ventilate a kiln indoors, and to be as effective as practical it’s often really hard for folks to do without some solid formal experience.  

While much advice is well intentioned, it ends up a bit more non intuitive than expected. Picture below of me verifying that no matter how gently one scoops glaze chems out, hundreds if not thousands of very very small particles get displaced and migrate tens of feet or more, nearly instantly. The laser is a nice visual example much like the beam of sunlight.

Finally a personal thanks for sharing, this is a hard subject to address to the level in these threads and yet could help a significant number of potters have a better understanding of the dynamics present.

Edited December 9, 2023 by Bill Kielb

[neilestrick]

12 hours ago, MochiFriend said:

Another conclusion I've come to from this whole experience is that I also don't think kilns, even small kilns, are suitable to fire in the home. 

It all depends on the venting setup.

[Bill Kielb]

On 12/8/2023 at 8:41 PM, MochiFriend said:

That all said, I've decided that for my own peace of mind I will be relocating the kiln, ideally now to the garage

@MochiFriend
Just in case you end up in the garage, years ago we helped with a system (very low cost) that would allow studio users to fire in an enclosed dock. Not totally pertinent here but maybe helpful to look at the intent to intercept the various sources of air without overdrawing them but still ensuring the room was reasonably negative with respect to the studio. The carpet blower was an ideal economical high power blower that needed to be in place and operating during firing. Marcia Grant ( my Marcia) was nice enough to sketch this so it would be more understandable for the folks in the studio.

Anyway - a nice sketch with some well illustrated terminology for the various sources of air, might be useful for perspective for others here or for you if you move to the garage.

 

Edited December 10, 2023 by Bill Kielb