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Monoxide death leads to tighter inspection rules


hausdok
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This tragic story involves a boy who died in his family's brand new home when a municipal inspector failed to ensure that a direct-vent furnace was properly configured and installed. This has led to the State of Minnesota changing the training requirements for municipal inspectors.

To access the article, you'll need to register with the Star Tribune, but it's free and it only takes a minute. They'll occasionally send you junk mail advertisements, but I've set up my computer to send them directly to the junk bin so that I never see them.

To read the entire article click here.

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Multiple defects problem.

Thanks for that link.

I wonder how many people here, had they encountered that in the wild, would - like me - have taken all appropriate steps to alert everyone involved to the danger, but at the same would have been thinking to themselves : "real-world, there's little chance that that degree of potential cross-connection at the exterior could admit enough CO to produce a significant concentration...".

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It's hard to believe that could be the cause of death without other factors that affect the quality of combustion. Blue flame technology doesn't make a lot of CO. Maybe it was jetted for natural gas instead of propane.

I can run 80,000 btu's of stove burners all day and not get a peep from a CO detector.

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Originally posted by Chad Fabry

It's hard to believe that could be the cause of death without other factors that affect the quality of combustion. Blue flame technology doesn't make a lot of CO. Maybe it was jetted for natural gas instead of propane.

I can run 80,000 btu's of stove burners all day and not get a peep from a CO detector.

That was pretty much my line of thought as well. I searched the State of MN site referenced in the graphic, but could not find an incident report or analysis.

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Originally posted by Chad Fabry

It's hard to believe that could be the cause of death without other factors that affect the quality of combustion. Blue flame technology doesn't make a lot of CO. Maybe it was jetted for natural gas instead of propane.

The boiler was drawing air for combustion from a very small boiler room and/or a very tight house.

The combustion air in the room was being replaced by the furnace exhaust, which has lower levels of oxygen.

Insufficient oxygen caused incomplete combustion of the "blue flame" appliance, resulting in CO production.

The high level of CO in the exhaust was then drawn back into the home through the disconnected combustion air intake pipe.

I can run 80,000 btu's of stove burners all day and not get a peep from a CO detector.

'Cuz there's an abundance of oxygen to the burners from your big old home. There's also enough air exchange to never deplete the oxygen. Install the stove in a small closet and weatherstrip the door. CO will be rapidly produced.
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I'll buy the theory Bill, but it must have been a very tight house. I feel terrible for the family and the kid but why did the kid's bedroom have such free air communication with the boiler room?

I wish I could see the whole set-up.

'Cuz there's an abundance of oxygen to the burners from your big old home. There's also enough air exchange to never deplete the oxygen. Install the stove in a small closet and weatherstrip the door. CO will be rapidly produced.

Ain't that the truth...my problem is keeping the burners from blowing out.

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Originally posted by Chad Fabry

It's hard to believe that could be the cause of death without other factors that affect the quality of combustion.

I agree. Check out this scenario from last week.

Image Insert:

20081117433_ExhaustGettingSuckedBackIn.jpg

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The 90 + furnace is running; thus, the misty exhaust in the picture. That rusted white vent in the left of the frame is connected to. . .

Image Insert:

20081117525_CombustionIntake.jpg

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This duct that was supposed to be providing combustion air the for the utility room. It doesn't show in the photo, but one could easily see the moisture-laden "steam" of exhaust streaming in to the room through that duct.

Furnace is 10 years old. This setup appears much more egregious than the one in the article and no ond has died in this home. . . yet.

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The incidents I've looked into in detail always had multiple conditions that all came together in a perfect storm of CO production. It's never a single component; it's always a string of specifics that result in disaster.

One of the only near disasters I looked @ was extremely obscure. Some strange air current on the roof drew the combustion gas from the roof discharge back down the roofline, in a soffit vent, and then back to the furnace closet in the attic. The result was approx. 800ppm CO in the attic closet. The whole thing was bizarre, but it made that furnace do all sorts of strange things.

Weird stuff can happen from seemingly little details.

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Exactly. OK, it happened. But looking at that exhaust/intake setup, I would have supposed it unlikely that more than a few percent of the exhaust was being returned to the intake.

Or, looking at Randy's pics, how likely does it seem, "intuitivly", that that much recirculation would would occur given that gap, absent an operating furnace and enough humidity to make the flow visible?

Certainly an eye opener for me, anyway - I've always taken this sort of stuff very seriously, but I'll now report my concerns with a much higher degree of conviction that it might be an actual, as opposed to a theoretical, hazard.

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Originally posted by Chad Fabry

Maybe it was jetted for natural gas instead of propane.

I can run 80,000 btu's of stove burners all day and not get a peep from a CO detector.

Hi,

Well, I didn't go back and reread that article, but I thought that is what the article said - that they were burning propane but that the installer hadn't changed the jets from the installed natural gas jets because someone at the factory allegedly said that he didn't have to in order to burn propane.

That statement alone shows that the installer was an idiot, but it sounds like the inspector still had his head up his butt.

I wonder if the basement "bedroom" was ever a true bedroom. Perhaps it was just a storeroom with a suspended ceiling where the joists above it pass straight through to the mechanical room without any kind of blocking separating the air from that area from the air above the "bedroom."

Guess the only way to know would be to contact the local investigators and ask them for some more details about this mess.

ONE TEAM - ONE FIGHT!!!

Mike

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Even if installations are done correctly, strange things can, and occasionaly do, happen with gas appliances and conditions, creating a deadly CO hazard. I don't know that any inspector can account for all of them, and if they did it would only be good for the short term. There simply is no substitute for a constant CO monitor; a good, low-level one. Please recommend them to your clients who are buying houses with gas appliances, religiously. Someday you might save a life like this one.

Brian G.

Protection, Not Post-Mortems [:-thumbu]

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I agree with Bill's theory and Kurt's "perfect storm" comments.

Factor 1: appliance was not properly converted from natural gas to propane

Factor 2: insufficient intake & exhaust vent separation

Factor 3: missing section of intake duct

Factor 4: tight house (assumed, because it was new construction)

Factor 5: no CO monitors

Factor 1 and poor combustion air quality (due to exhaust being drawn back into the home near the intake for the boiler) probably resulted in high production of CO.

Factors 2, 3, and 4 combined to draw high levels of exhaust back into the home. The missing section of intake duct meant that the appliance was drawing combustion air from inside of the house instead of from the exterior. Assuming this was a tight house (it was new construction), then the disconnected intake duct became the intake vent to replace all air that was exhausted from the house (boiler, kitchen, other fireplaces, bathrooms, water heater). Factor 2 meant that much of the air that was being exhausted by the boiler was being drawn right back into the house.

All five factors lead to the boy's death and the rest of the family becoming ill. It's a horrible tragedy and I'm very sorry for this family's loss.

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Well, I didn't go back and reread that article, but I thought that is what the article said - that they were burning propane but that the installer hadn't changed the jets from the installed natural gas jets because someone at the factory allegedly said that he didn't have to in order to burn propane.

Oh.

I just followed the link in mthomas1's post. I didn't sign up to read the article.

I looked at a boiler that was jetted for NG and burning propane. It was sootier than an oil burner gets after years of service.

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It's not difficult to learn about the causes of carbon monoxide in a home. But amazingly enough, even with all the publicity, it's still widely misunderstood. Kurt is correct, there's usually some combination in place to cause the trouble. And that's the problem, proper investigation procedures are not used.

I've stopped testing for CO simply because I got sick & tired of arguing with HVAC contractors and fire departments when they come in and say the problem I reported does not exist. While more education for muni inspectors may be needed I think the bigger issue is the time element. Inspectors simply do not have the time to properly go through construction projects to perform an adequate evaluation.

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