ash and carbon monoxide

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partybob99

Member
Sep 21, 2010
39
NorthWest, OH
I keep reading ash in a fireplace will continue to release carbon monoxide for “days”.. Is this true? And would this only occur if the ash is still warm/hot? I presume ash that’s room temperature will NOT release CO.. Correct?
 
The ash itself doesn't, the little bits of still-hot-enough-to-burn-(albeit not producing enough heat for you to notice much since they're so tiny)-but-not-yet-fully-burned charcoal (remaining embers) does though. Since it's basically mixed in with the ashes, you can't tell them apart easily. Stir the ashes and maybe you'll find a small red-glowing ember here and there, but then you might not. Try pointing an infrared thermometer at it though, that might show you a slight difference in temp. Days is probably a bit pessimistic but I've definitely opened my stove the next day and put my hand almost right on the ashes and noticed they were a little warm ... even when the stove was stone cold.
 
I have a carbon monoxide detecter at both my stove and fireplace and it never goes off, so I'm assuming if there's any CO, it's far too small to worry about.
 
tiber said:
I have a carbon monoxide detecter at both my stove and fireplace and it never goes off, so I'm assuming if there's any CO, it's far too small to worry about.

That's depending on which detector you have, and how old it is.

The UL 2034 standard requires a detector to sound the alarm only after 60 minutes of a CO concentration of 70 PPM. You could be breathing is a lesser concentration indefinitely without the alarm ever sounding because the standard is based on 10% of your serum hemoglobin being bound to CO. My detector won't sound an audible alarm at levels lower than 70 PPM, but if you push a button you will see any spikes that are over 15 PPM. I have had several episodes where I took way too long to clean out and dump the ashes which led to my meter picking up CO spikes of up to 25 PPM, even though the stove is in the basement and the meter is up in the bathroom at the top of the stairs.

Harmful? I dunno. Having up to 10% of my serum hemoglobin inactivated by bound CO may not produce any visible symptoms, but that doesn't mean it's OK in my book. Personally, I don't want to be breathing any of it. Since seeing those numbers flash red on my alarm, I've been much quicker and more thorough about emptying the ashes than I used to be. Put the ashes into a metal container with a lid, put your boots on, and bring them right out to spread on your garden, or at least get them outside of the living space. What's so hard about that?
 
Welcome to the forum partybob99.

Methinks this is another non-issue. It certainly is something we've never been concerned with and probably won't ever be.
 
CO from the ash . . . no.

CO from hot coals . . . yes. In fact, you can commit suicide easily enough by firing up a charcoal grill and then bringing it inside and letting the coals do their thing . . . not that I would recommend doing this . . . ever!!!

That said . . . like Dennis . . . I think this is a non-issue. Unless you're scooping out lots of coals and leaving them in an uncovered bucket on your hearth (instead of placing them in a covered metal bucket and placing this outside on a non-combustible surface) I wouldn't worry about it . . . the only other time I could think where this could be an issue is if there was a set up with a very poor draft and there was a reverse draft situatiion.

Quite honestly, in the 20 years I've been on the job as both a volunteer firefighter and career public education officer in the fire service I cannot recall a single instance where hot coals in the woodstove was the cause of a CO call . . . on the otherhand I can think of many CO calls involving propane and natural gas furnaces along with a handful of calls involving cracked heat exchangers in oil furnaces and bad decision making when folks hauled in gasoline-powered generators into their home or attached garage and at least one call where a guy was using too small of a propane tank to power his propane oven.

Incidentally, here is the latest CO incident in the City of Bangor.

http://www.wabi.tv/news/15341/students-sick-from-carbon-monoxide-and-natural-gas-leak
 
firefighterjake said:
CO from the ash . . . no. CO from hot coals . . . yes.

Well, Jake, I'm sure by now you've already read the other thread that began today regarding this matter.

Pure ashes... no. But that's rarely the case for many folks. I don't have an ash drawer in my stove, so it's pretty hard to get just ashes and no coals with just a shovel. I now take my time and use a deep-fry skimmer to sift the small coals out of my ashes, but I have had a detectable level in my home from a neglected ash bucket before I began to sift out the cinders. Then there was the time... well, just read the other thread.

Look, I'm not a chronic worrier, but chit happens to us all, and sadly, it happens with increasing frequency as we advance in years. Best to be prepared for it. After all, it only takes one time.
 
OK, so the consensus Im getting is when a fire burns out for the night (for those non 24/7 burners) there will be a mix of ashes and coals in the morning.

For me I usually put a small piece of wood on the fire around 10:30pm and then go to bed. By morning the house is cold and the fire is out. Since I work days, I dont bother restarting the fire, so everything just sits until 5:30pm or so when I get home. At that time, I shovel a mix of coals (unburned wood) and ash into the garbage leaving about an inch at the bottom of the woodburner. All the ash and coals (unburned wood) are COLD by this point. (Perhaps calling them coals at this point is not the correct word to use)

So my question is, when the coals are COLD are they still releasing CO? Im presuming the answer is no... CO is a product of the burning process and any pieces of black, charred wood left over cannot release any additonal CO.
 
partybob99 said:
CO is a product of the burning process and any pieces of black, charred wood left over cannot release any additonal CO.

You answered your own question.... but... coals can still be burning for well longer than the time you specify, for days as a matter of fact, so if they are the least bit burning there will be CO2 released.
 
shawneyboy said:
partybob99 said:
CO is a product of the burning process and any pieces of black, charred wood left over cannot release any additonal CO.

You answered your own question.... but... coals can still be burning for well longer than the time you specify, for days as a matter of fact, so if they are the least bit burning there will be CO2 released.

As stated . . . CO is a product of the burning process so dead coal = no CO.

As also noted, coals can still be hot for several days in some cases . . . I'm not sure about releasing carbon dioxide . . . carbon monoxide yes, carbon dioxide I'm not so sure about.
 
firefighterjake said:
As also noted, coals can still be hot for several days in some cases . . . I'm not sure about releasing carbon dioxide . . . carbon monoxide yes, carbon dioxide I'm not so sure about.

Wherever there is oxygen present, there will be some CO2 created as well, but the ignition temperature of CO is pretty high, so I suspect you will generate a lot of CO that never gets burned. Coals won't stay hot just because they are insulated, there has to be some slow combustion going on from oxygen diffusing into the coal bed. This kind of extremely long, slow and low-temp burn will create mostly CO gas.

I don't think there have been too many documented cases of CO-induced fatalities due to wood burning appliances, but I still feel it's possible to have occurrences where you might inhale more than you should. Pays to understand where the risks may lie and to eliminate them IMHO.
 
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