Carbon Monoxide Questions

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Island

New Member
Dec 21, 2008
12
Alaska
I had a quick question with a longer story behind it.

The question is whether CO from a wood stove exists without the smell of smoke in any burn conditions?

This is a relatively new house. Six month old. We run the wood stove (RSF Opel III) for the primary heat source each day for around 10 hours. It is built more air tight than older homes. We only have a wood stove on the lower level, all other appliances/heat are electric.

The story is that our CO alarm (ceiling mounted combo smoke/CO no digital readout) went off yesterday. The stove was burnt down to coals and dampered down. There was one bathroom fan on at times upstairs during the day and one Panasonic ERV downstairs which exchanges heat and brings in fresh air running constantly on low. We have operated the stove in similar conditions every other day. At no time during the day did we smell any smoke.

My wife and I had been feeling a bit under the weather but attributed it to similar symptoms as another family member outside of the household that we spent time with the prior day. Typically fatigued, slight headache and upset stomach. My wife did vomit one time similar to the family member. We felt some symptoms even when we were out of the house prior to the alarm and after. The kids were fine throughout.

There were two open fires within 100 yards of our house burning scrap wood. The smell of that was strong as soon as we stepped out doors. It was a bit of an inversion day.

We did purchase two new detectors w/digital readouts and installed them within an hour after the event on the two levels of the house. Neither has any memory yet of any CO particles.

I regret having opened all the doors and airing out the building. I should have closed it down and called the FD to track any source if there was CO present. Next time I will treat it more seriously and systematic as the concern we have now is bordering on paranoia.

Any ideas or prior experience with CO and wood stoves that can help us ferret out the cause?

Thanks!
 
Yes, CO has no odor.

A cpl thoughts:

Does the existing combined "smoke"/co alarm differently for each type of event, ie is the"smoke" alarm different than the
CO alarm? If no, are you deducting that since there was no "smoke" that the alarm therefor was due to CO?

Depending on where you are in Alaska,... A trip to the local ER can quickly rule out CO toxicity/exposure (as long as nobody in the household smokes tobacco, or anything else), as CO has a relatively long half life and can be detected with a simple blood gas analysis.

And if the new detectors show nothing, then you can hope it was a false alarm.

Test the new CO detectors per mfg instructions (lit cigar etc).

And airing out the building as you did, rather than expose the family trying to figure out the problem was the right thing to do IMHO.
 
Island, does the RSF have an external air source? If not, with a tight house the fans may be able to depressurize the house enough to cause the stove to vent into the living space. Has the HRV,(air exchanger), been properly balanced? The intake and exhaust should be about the same when it is running on regular speed with no other fans operating. Also,how old was the original CO alarm? It may have been due for replacement. Just some thoughts.

Earl
 
Thanks for the replies.

I wasn't sure if CO could exist separate from the smoke smell with air tight wood stoves as it seems if the CO is being pulled back in, so would some of the smoke.

The alarm is different for each. To tell the truth, it was cleared before I had the chance to look up the manual. My wife who was doing the clearing said it sounded like what the CO alarm is supposed to. It did require resetting and the memory indicator was blinking for a smoke alarm. A mystery there.

I will go and see if the hopital can test 20 hours after exposure.

The RSF has an external air source. The ERV is even less sophisitcated than an HRV and has no balancing option. The fan pulls in fresh air while expelling building air and crosses each through a heat exchanger. Very basic. I think I am going to add some makeup air vents equivalent to the exhaust fans to be sure I am not depressurizing the house.

The CO alarm was new.

Thanks for the thoughts.
 
With such a tight house the bathroom fan could surely be enough to bring in co. Its good to have redundant co monitors.
 
When the stove is down to just pure charcoal, there will be very little smell of smoke. That's why you add wet wood chips to the BBQ, because the pure charcoal isn't making any smoke. I never get any smoke (or smokey smell) from my charcoal forge, even when the fire is just smoldering along.

I agree with others here that your fan and a tight house can couple together to bring the air inside the stove into the house.... especially during a temperature inversion.

I'd try to duplicate the conditions without a fire going by running the fan on high and using an incense stick to see how aggressively the smoke gets pulled into the draft opening. If it gets sucked right in with the stove cold, you should have enough draft with a warm stove to keep things going in the right direction, but the laws of convection are complex. That's why the CO detector in the first place... just in case.

I had a peak reading of 10 PPM on Christmas Eve on mine (installed on the bathroom wall at the top of the stairs leading to the basement that contains the wood stove), but I figured it was due to my wife using the gas range and oven all day long. The stove was going pretty intensely all day, so I doubt anything would have made it back in during that time period.

Do you have any other gas or oil devices in the home?
 
Thanks Battenkiller. I can see how the cooling fire with little smoke with the bath fan on could have caused an down draft. I will be installing the passive air vents today.

No other oil or gas appliances and we don't park in the garage.

May be able to try to replicate but since it is an airtight, my guess that any leaks are possibly in the pipe joints hidden in the chase and would be hard to locate.

Definately in an inversion cycle. Fog came down this morning pretty densely.

Thanks again.
 
As others have said, CO is odorless. Smoke detector's can also go off due to smoke that you likely could not see. CO defectors go off at relatively low levels. However, your wife's symptoms could have been from CO poisoning. If there is a next time, I would call the Fire Department. Most have very expensive and accurate 4 gas meters. That way you know exactly what you have. The digital readout on residential detectors are often not very accurate so the FD readings can pin it down a little better. You have done all the right things so far. Just stay alert to the possibility as we all should, regardless of what kind of fossil fuel we are burning. Stay Safe, Steve
 
I have a CO detector in my basement near my wood/coal boiler. I am also a resident landlord, renting two apartments upstairs in the building. The state of Maine just passed a law requiring CO detectors in the bedrooms of all occupied rental units. They're allowing "combination units" a smoke and CO detector in one. I question the use of these, as a former firefighter I know CO is heavier than air and sinks to the lowest point it can, while smoke being lighter than air rises. Putting a CO detector on the ceiling seems almost as bright as putting a smoke detector on the floor.

If the draft in the chimney is not strong enough to actually "lift" the CO out of the basement then it will back into the house, and it might well not result in a concurrent smoke odor.

My CO detector is 4 ft off the floor, about five feet from the boiler. I have been burning one full year and about a week so far this year. The only time there is ever anything on the memory is when I fire the ATV up and drive it out to plow the yard. At no other time have I ever noticed anything but a zero on the memory when I check it. Chimney is about 30 ft high from the cleanout and stainless lined... very strong draft.

With a manual damper, and an inversion, even the strongest chimney would strain to pull the CO up with the smoke. Keeping a hot fire when it is burning would help... outside air might help. Likely making some adjustment on the manual damper when the weather is warmer and the draft is less to allow the chimney's full draft to pull through the stove.

I won't be burning the entire winter, only a couple more weeks... second week in January I am headed to Alaska for work until April, at least. Love to be home to burn, keep the oil man away, but things just don't work out sometimes. I can't be home, then I am going to be someplace I want to be. Alaska.
 
LeonMSPT said:
I have a CO detector in my basement near my wood/coal boiler. I am also a resident landlord, renting two apartments upstairs in the building. The state of Maine just passed a law requiring CO detectors in the bedrooms of all occupied rental units. They're allowing "combination units" a smoke and CO detector in one. I question the use of these, as a former firefighter I know CO is heavier than air and sinks to the lowest point it can, while smoke being lighter than air rises. Putting a CO detector on the ceiling seems almost as bright as putting a smoke detector on the floor.
LeonMSPT, If you check, I think you will find that CO is actually slightly lighter than air.....Specific Gravity of 0.9657 to be exact, air being 1. And it often is carried by heated air and or smoke, so it will rise. Otherwise it mixes fairly evenly with air since its specific gravity is nearly the same. Here is a useful link that discusses placement of CO detectors. http://www.carbonmonoxidekills.com/placement.htm
 
Have some neat "clock outlets" in the apartments, as it's an older building. Look to me like they'd make a great location for CO detectors... smokes are all hardwired and interconnected. If one goes off, they all go off... As the owner, I like it... but until people get used to them it can be challenging explaining to them that this happens when someone burns the beans.

Thanks for the info... left wondering where the previous info came from... :)

tfdchief said:
LeonMSPT said:
I have a CO detector in my basement near my wood/coal boiler. I am also a resident landlord, renting two apartments upstairs in the building. The state of Maine just passed a law requiring CO detectors in the bedrooms of all occupied rental units. They're allowing "combination units" a smoke and CO detector in one. I question the use of these, as a former firefighter I know CO is heavier than air and sinks to the lowest point it can, while smoke being lighter than air rises. Putting a CO detector on the ceiling seems almost as bright as putting a smoke detector on the floor.
LeonMSPT, If you check, I think you will find that CO is actually slightly lighter than air.....Specific Gravity of 0.9657 to be exact, air being 1. And it often is carried by heated air and or smoke, so it will rise. Otherwise it mixes fairly evenly with air since its specific gravity is nearly the same. Here is a useful link that discusses placement of CO detectors. http://www.carbonmonoxidekills.com/placement.htm
 
LeonMSPT said:
Have some neat "clock outlets" in the apartments, as it's an older building. Look to me like they'd make a great location for CO detectors... smokes are all hardwired and interconnected. If one goes off, they all go off... As the owner, I like it... but until people get used to them it can be challenging explaining to them that this happens when someone burns the beans.
LeonMSPT, The clock receps. would be fine. I really like the combination CO/Smoke detectors as opposed to just Smoke on the ceiling. I think they catch more, sooner. But I also like a single CO somewhere else. They are such cheap insurance that having more than one can't hurt. Take care, Steve
 
Frankly, the Co detectors in the upstairs rental units don't really make much sense. The combustion based heating equipment is in the basement, with my floor between the upstairs apartments and the basement. There is absolutely no conceivable source of CO except "possibly" one of the chimneys. They're main house has a double flu, stainless lined chimney that looks about four bricks thick around the liners. The secondary chimney in what used to be the "ell" of the old farmhouse, is an 8 1/2 inch double brick masonry lined chimney with a 6 1/2 inch inside stainless liner... There is an extremely remote possibility that a major failure in one of the chimneys might allow CO to enter one apartment or the other.

You know, as a fire chief, the majority of CO poisoning cases in this part of the country are related to some dummy bringing a generator or combusion heater into "living space" and using it there. "Stupid Hurts", and anybody that stupid is not going to hesitate to unplug a CO or smoke detector and throw it out the window because it's "irritating".

Was a time when people believed in Darwin... :)

tfdchief said:
LeonMSPT said:
Have some neat "clock outlets" in the apartments, as it's an older building. Look to me like they'd make a great location for CO detectors... smokes are all hardwired and interconnected. If one goes off, they all go off... As the owner, I like it... but until people get used to them it can be challenging explaining to them that this happens when someone burns the beans.
LeonMSPT, The clock receps. would be fine. I really like the combination CO/Smoke detectors as opposed to just Smoke on the ceiling. I think they catch more, sooner. But I also like a single CO somewhere else. They are such cheap insurance that having more than one can't hurt. Take care, Steve
 
Interconnection is key. I'm replacing my interconnected ion smokes with photo/ion combos and installing 1 CO detector on each of 3 levels. It's not hard to add an additional CO detector, you just have to cut a round hole in the ceiling not far away from the smoke detector and run a wire. Too bad they don't make three-way combos, but the CO detectors last maybe half as long as smokes.
 
Watch the placement of ion and photo detectors...

Ion detectors are designed to provide faster response to a rapidly growing "incipient" fire. Photoelectric detectors are designed to be sensitive to "smoldering" fires like a cigarette in a couch cushion or an electrical fire in a wall that is growing slowly. The combination types should reflect the benefits of both types of technology, obviously.

Recently, nuisance alarms have come to the attention of the NFPA and various code authorities. Seems that these alarms resulting from cooking, steam from showers in bathrooms, etc... are causing detectors to be disabled by users because they're obviously unpleasant and inconvenient. The result has been that:

"NFPA 72 addresses this problem by requiring that when a smoke alarm is installed within 20 feet of cooking, it should either be photoelectric or have a silencing button."

I believe the standard is ten feet from a bathroom door.

It's your house, you have to live in it... if you install detectors with a "silence" or "hush" feature where you can silence the thing if it's going off because you burned the toast, go ahead and put the ion type wherever you want to. But bear in mind the problems associated with that.

Bedrooms definitely call for the dual type of detector and when I replace mine I will replace them with those. The CO detectors will remain plugged into clock outlets, and be backed up by batteries until I replace the ceiling detectors... I will then wire in CO detectors...

In an apartment building, I believe I will use photo/ion in the bedrooms, photo within ten feet of the bathrooms and twenty feet of the kitchen... just to cut down on the nuisance alarms... so long as the sleeping quarters are covered with dual technology the situation is safe.


velvetfoot said:
Interconnection is key. I'm replacing my interconnected ion smokes with photo/ion combos and installing 1 CO detector on each of 3 levels. It's not hard to add an additional CO detector, you just have to cut a round hole in the ceiling not far away from the smoke detector and run a wire. Too bad they don't make three-way combos, but the CO detectors last maybe half as long as smokes.
 
tfdchief said:
LeonMSPT, If you check, I think you will find that CO is actually slightly lighter than air.....Specific Gravity of 0.9657 to be exact, air being 1. And it often is carried by heated air and or smoke, so it will rise. Otherwise it mixes fairly evenly with air since its specific gravity is nearly the same. Here is a useful link that discusses placement of CO detectors. http://www.carbonmonoxidekills.com/placement.htm

A great book from my childhood was "Alone", the autobiographical account by Admiral Richard Byrd of his time spent alone in a research station in Antarctica. In it, he describes how a gasoline generator exhaust vent got plugged up with ice, poisoning him in his sleep. He awoke just in time to crawl along on the floor (where he was safe from the hot CO fumes) and get the unit turned off. He then had the most hellish month - near death and unable to eat - recovering from the acute effects of the poisoning with not a prayer of rescue during the long Antarctic winter. I always remembered to get low if I suspected CO poisoning.

As I said earlier, my CO detector is at the top of the stairs leading up from the stove. Our nearby bedroom door is always closed, so the detector will go off (hopefully) before I breathe a single molecule. I personally think this is a remote risk, but $38 worth of insurance from Home Depot gives me the extra peace of mind to get a good night sleep.
 
Thanks everyone for the comments. As always, good insight on this board.

Took the following measures:

New Combo CO/Smokies in all the bedrooms and one in the hall; two plug in alarms at floor level; One CD-2002 (boy is that sensitive!!) in the main living area 20' from the stove; two Fresh 80s make up air within 30' of the wood stove; reduced the time and volume of the automatic bath fan kicks on upstairs; set a higher minimum damper setting for the stove to avoid too cool of a fire.

Also got the CO blood test done. The doc said test was valid for 48 hours. It was 22 since our alarm. 0% CO particles attached to my Hb. He said no poisoning occurred as some residual would have shown. His conclusion was the stomach bug which had traveled through some family members days prior.

Looking forward to seeing how the house and stove performs with all the additional data collection and modifications.

Learned to respect CO even more after all I have read.

Thanks again!
 
Had an interesting fire call once, and worked with the college to correct the problem...

Call was "smoke in the building". We responded and investigated, finding an entire community room full of smoke... fairly thick and heavy like a trash can fire. This room is huge with a high sloped ceiling and smoke/fire detectors (rate of rise) on the ceiling. How come they didn't sound? Gee whiz, the smoke was thick enough to choke on.

Turns out, the HVAC system was designed in such a way, and the smoke detectors were located in such a way, that the fresh air/heated air was blowing down the sloped ceiling and across the detectors... preventing the smoke from reaching the detectors. The engineer said I was crazy, the architect said... "Let me look into the prints and come see it, and I'll let you guys know what to do."

They moved the detectors further down the ceiling and put fins in the air outlets pushing the air away from them. The smoke detection system functioned as it was supposed to after that...

Always look for the exception when placing smoke and CO detectors...

Island said:
Thanks everyone for the comments. As always, good insight on this board.

Took the following measures:

New Combo CO/Smokies in all the bedrooms and one in the hall; two plug in alarms at floor level; One CD-2002 (boy is that sensitive!!) in the main living area 20' from the stove; two Fresh 80s make up air within 30' of the wood stove; reduced the time and volume of the automatic bath fan kicks on upstairs; set a higher minimum damper setting for the stove to avoid too cool of a fire.

Also got the CO blood test done. The doc said test was valid for 48 hours. It was 22 since our alarm. 0% CO particles attached to my Hb. He said no poisoning occurred as some residual would have shown. His conclusion was the stomach bug which had traveled through some family members days prior.

Looking forward to seeing how the house and stove performs with all the additional data collection and modifications.

Learned to respect CO even more after all I have read.

Thanks again!
 
Island: no photo-electric smokies for you?

From 2008 Alaska Fire Marshalls publication:
http://alaskafirechiefs.org/assets/dept_1/docs/Fire Flyer January 2008.pdf


Ionization –VS – Photoelectric Smoke Alarms
In light of the recent media and fire service community coverage about the proper selection and use of the different types of smoke
alarms I thought I would clarify our position on the installation of smoke alarms in residential structures.
A study by the National Institute of Standards and Technology concluded that fires in residential structures are more likely to smolder
longer and burn faster than homes occupied when smoke detectors were first introduced decades ago. This has lead some organizations
in the fire service to call for the discontinued use of ionization smoke alarms.
Recommendations:
1. We recommend one smoke alarm be installed on each level of the home including basements and attic spaces and one in each
sleeping room. These are required for all residential housing by AS 18.70.095.
2. We recommend the use of combination alarms (ionization and photoelectric technology) for residential use.
3. Our office has recommended the use of photoelectric smoke alarms for use in smaller houses (less than 1200 sq ft) in rural locations
for many years. This policy was based on research into the high number of nuisance alarms caused by steam from kitchens
and bathrooms when ionization alarms were used.
No matter what type of smoke alarm is used the entire unit should be replaced at least every ten years and many of the new smoke
alarms have an expiration or replacement date on the unit.
National Institute of Standards and Technology study http://smokealarm.nist.gov
Basic Types of Smoke Alarms
Ionization Smoke Alarms react quicker to fast burning fires involving flammable liquids and simple Class A materials such as paper.
Photoelectric Smoke Alarms react quicker to smoldering fires such as those ignited by smoking materials in a couch or chair.
Kitchen Smoke Alarms – Kitchen smoke alarms can be either ionization or photoelectric but they include a button that silences the
alarm for 15 minutes. This reduces the chance that an occupant will remove the batteries if the alarm sounds due to smoke from cooking.
References for more information on this topic:
Alaska Injury Prevention Center’s Original Research on “Ionization and photoelectric smoke alarms in rural Alaskan homes” http://
www.alaska-ipc.org/ionization.pdf
International Association of Fire Chiefs – Fire and Life Safety Section’s position paper http://www.iafc.org/associations/4685/files/
FLSS_Position_Paper_smoke_alarms.pdf
UL’s study on smoke characterization www.nfpa.org/assets/files/PDF/research/SmokeCharacterization.pdf
 
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