propane poisoning???

Bob Harper

I hope this works:
http://www.bemidjipioneer.com/Main.asp?SectionID=3&SubSectionID=83&ArticleID=22574

Mark, I agree with you and made most of those points either here or on that other site where I saw this. It kills me when we run our B-vented Fps through the ANSI tests, we have to block the flue 100% and the unit must continue to operate, venting out the draft hood. Therefore, B-vented fireplaces have much higher clearances to combustibles that a comparable direct vent.

I just wonder how many more yrs we have to deal with Cat.1 appliances and draft hoods?

Is there an ANSI Standard for Flue Squirrels or does that come under GAMA?

Bob Harper

case in Mn they claim killed by propane fumes!

I read on HVAC-talk.com about a case in Mn this week where an elderly couple died from supposedly propane poisoning when a squirrel blocked the furnace vent pipe. First of all, propane itself is not poisonous but displaces O2 so it could act as a simple asphyxiant. Second, NO mention of testing or CO readings, even though gas company responded with fire dept.
The problem with these stories is after the initial news story it is very hard to find out exactly just what was proven in court as the proximate cause. Even if a squirrel died in the chimney, was there a cleanout for him to fall down into, or was it full from lack of maintenance or did Rocky actually die inside the vent connector?
If he did actually block the vent connector, why didn't the high limit or pressure switch cut off the furnace?
Was the switch bypassed because of lousy chimney draft?
Was the duct work leaking enough to cause backdrafting?
How about MUA requirements?
Was the furnace firing or in lockout?
Was there a water heater connected too? If so, was it operating ok?
Lots of unanswered questions but I still think the "propane" they smelled was aldehydes from a blocked flue.

Thoughts? Mark?

S Ebels

I would call the writer of the article and say

Pardon me sir, but your ignorance is hanging out all over.

I have never heard of propane fumes killing anyone. I don't think they ever have. A propane explosion, yes more than a few. A house about 10 miles from me blew up last winter, severly burning both the occupants. It took windows out of neighboring houses over 200 yards away. Many more people are maimed for life or killed each year from the byproduct of propane combustion we all know as Carbon Monoxide.

Bob, I agree with you 100% on all the points you raised. A lot of safeties would have to fail in order for a blocked vent to cause the problem. At least on anything made in the last 35 years.

It's sad but it just goes to show how little 99% of the general population understands about CO poisoning and how it occurs.

Mark Hunt

Hmmmmmmmm

I may have to add this to my key word search as I did not hear of it.

Let's look at this.

One: If anything is able to live long enough to build a nest in a chimney, there is nothing drafting out of it. Even low levels of CO will kill a squirrel or a bird. Remember what the coal miners used to use for detecting poisonous gas?

Two: Get used to the ignorance in news stories about CO deaths. Even if an expert Like Jim Davis or Rudy Leatherman were interviewed, the writer would still screw it up.

3: If this was an atmospheric vented appliance, there is no pressure switch and the only high limit control is located on the furnace in or near the heat excahnger. A "draft diverter" or "Draft Hood" disconnects the atmospheric appliance from the chimney so that it can continue to fire in the event of a blocked flue. That is PRECISELY what it was designed to do. So in this case, if this is an atmospheric applaince, the draft hood functioned properly according to GAMA and ASHRAE. It allowed the furnace to fire and vent with a blocked chimney.

4: If this was a fan assisted furnace commonly vented with an atmospheric water heater, then I refer you back to #3. In this scenario, the "draft diverter" on the water heater would then act as the relief for the flue gases produced by the fan assisted furnace in the event of a blocked chimney. So no pressure switch would have seen a blocked chimney situation and the unit would continue to fire. It would vent out of the "draft diverter" of the water heater. GAMA and ASHRAE have no issue with the water heater gases spilling out of the "draft diverter", but they may have a few complaints about gases produced by other appliances useing the water heaters "draft diverter".

5: No-one will test this furnace since it is obvious that the culprit here was a faulty squirrel. Once it was removed, situation normal. It may very well be that someone else is going to die in that house. Something similar happened a while back. Person was killed in their house by CO. Relatives staying there for the funeral were killed as well. A heating contractor, I believe, stated that the equipment was repaired. Guess not.

How did I do?

Mark H

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Bob W._3

Bob, can you give me a link on that? Can't find it in any of the local MN web sites.