Odd Carbon Monoxide reading

[GILow]

Hi all,

A few years ago, after reading of a tragedy onboard a boat where the occupants died due to Carbon Monoxide poisoning, I fitted a Carbon Monoxide alarm to the boat.

It's a pretty basic device, but it does have a LCD display to show the current CO level, plus a history system that keeps a record of the highest historical concentration detected.

Like a lot of new boat "toys", I would check on it daily at first, whenever I was running the engine, or cooking on the stove. It always read zero. And like a lot of new boat toys, the fun wore off and I stopped looking at it, probably after a month or two.

Well, I was fiddling with it today and I discovered that at some stage in the time it has been on the boat, it has recorded a peak concentration of 49 ppm, which is just one ppm below the alarm threshold (provided the concentration had been maintained for 60 - 90 minutes).

I had no idea when this happened, but I was curious.

Coincidentally, perhaps, I recently discovered that mixing epoxy resin in the cabin sets off the gas leak detector (THAT was a pucker up moment I must say!)

So, I wondered if maybe the Epoxy Resin had something to do with it, and I did read, from the West System site, that runaway curing epoxy can emit carbon monoxide. In this job I only had one small pot get away from me, and I was up on deck at the time, but it may be related.

Anyway, this is all by way of saying a CO detector on a boat may be a useful thing in unexpected ways. Not sure what I have learned from this discovery, except to learn there is one more thing I don't really understand.

Food for thought perhaps.

Matt

[Wotname]

Might be worthwhile to mix up a small pot of epoxy and let it runaway near your CO detector and see what reading you get.

[GILow]

Originally Posted by Wotname

Might be worthwhile to mix up a small pot of epoxy and let it runaway near your CO detector and see what reading you get.

Tempting... but maybe if I have any leftover at the end of the deck job. That stuff is not cheap

[GILow]

Originally Posted by GILow

Tempting... but maybe if I have any leftover at the end of the deck job. That stuff is not cheap

And the only batch I had run away on me was much bigger than my usual quantity. Around 600 mls.

[a64pilot]

Have a link for the CO device?

[IdoraKeeper]

Me thinks it's worth looking at the list of things that your detectors actually detect. The propane alarm on Idora thinks cooking spray is a propane leak and alarms accordingly. Annoying for sure. Battery gases may also accumulate when the boat is closed up for extended periods.. Plenty of perfectly normal things can set these detectors off.

[Fiveslide]

I don't have a display like your alarm, but anytime I spray aerosol products near mine, it will go off. Sunscreen, bug spray, things such as that. One particular bug spray actually ruined one detector and I had to pull the fuse and go get a replacement cause it would not shut up.

[a64pilot]

Originally Posted by IdoraKeeper

Me thinks it's worth looking at the list of things that your detectors actually detect. The propane alarm on Idora thinks cooking spray is a propane leak and alarms accordingly. off.

It could be Propane, it’s my understanding that since CFCs were outlawed that Propane is often used as a propellant. I don’t know about food stuff, but think paint and deodorant etc sometimes has propane propellant.

[IdoraKeeper]

True that. A good excuse to buy expensive Olive oil and ditch the spray.

[thinwater]

Yes, PAM uses propane as propellant. The detector should go off.


If you have enough of any flammable gas to se it off, there is a problem worth investigating. If you have that much hydrogen in the cabin something is seriously wrong.



Chemistry class was important.

[TTWHTD]

Great post. Here is what's going on. It is called Cross Sensitivity (CS). (I am a Haz-Mat Tech for a large urban Fire Department and see this with our professionial sensors often) Not to mention, we use this CS to our advantage when looking for a known gas and don't have a meter/sensor for that gas.



For instance, the CO cross sensitivity to Acetylene is 1ppm CO = 250ppm Acetylene. So if we have a known acetylene leak and need to determine the concentration we may use a CO detector to sample. If our reading is 20ppm CO (even though zero CO is actually present) our Acetylene concentration is 2,500ppm. (ppm = parts per million). We have to use supplied air percautions at 2500ppm so we would mask up and ventilate at that number!

This short article best explains CS but google it and you will find a ton more technical info on it as well. www.indsci.com/docs/press/monitoringarticle.pdf


Your specific brand of detector may have different actual data for the specific calculations but the Cross Sensitivities are the same.


CO may have been present, however, I beleive there is a CS being emitted by the resin and therefore picked up by the CO sensor.



Hopefully after reading the short article it is more clear and I didnt muddy the water?

[Midnight Son]

I maintain gas monitors as well. CO sensors, unless they state so, are also cross sensitive to Hydrogen gas, given off when charging lead acid batteries. Another thing to think of.


Cheers

[TTWHTD]

Originally Posted by Midnight Son

I maintain gas monitors as well. CO sensors, unless they state so, are also cross sensitive to Hydrogen gas, given off when charging lead acid batteries. Another thing to think of.


Cheers

Exactly! The main point is to bring light to the fact that just because it’s sold and calibrated to detect CO, they will detect many other gases as well and with a good CO Cross Sensitivity chart they can be used for other known gases as well. Too bad the manufacturers don’t include this info but I suppose it would just confuse the hell out of the regular user.

[Rorzech]

Propane is used as a propellant in lots of aerosol cans. Sets off propane detectors for sure. I took my vent hood off my battery bank one day and the next thing that happened was my CO detector was going off ! I guess that the CO detector, detects Hydrogen gas also. Who new ! These modern day detectors used to fill a whole laboratory and they have shrunk all the equipment down into a tiny little package ! They cost near to nothing compared to the amazing ability they have for saving our lives. I never trust having just one detector of one kind. I always have two detectors for everything I want protection from,like Smoke,Propane & CO especially. Anchor drag alarm & water in bilge alarm , low battery,Low engine oil, High engine, or exhaust temperature . These cheap devices can save us from so much grief. Depth sounders , forward looking sonar, radar can be put in that category also. The list goes on. Safe sailing!

[buzzstar]

Wish I had an answer to the actual cause. I do not. That said, you mention a good practice in your post -a daily check [of all operating instruments, new or not]. Then one should record the information in a log, much like is done for weather and navigation. If you also maintain an activity log [mixing 600 ml epoxy today] you might see a correlation -or not. Just a suggestion, and a p-i-t-a., but well maintained logs have saved lives, vessels, and and lesser, but related difficulties.