LifePO4 chemistry not as important as we thought

[rslifkin]

Originally Posted by wholybee

The marine versions (supposedly) have a different sensitivity profile. Such that a home should have no CO, and poor ventilation. So a home unit will alarm immediately at the presence of any CO. But, a boat has sources of CO, and ventilation, so a small amount present doesn't necessarily indicate a danger. (Supposedly) the marine versions consider both the level of CO, and the duration, so a high CO level will alarm sooner than a low CO level. Externally, they would look the same.

I can't recall where I read that, but I was confused at the difference when I was outfitting my boat, and that was the conclusion of my research.

Many of the newer home versions work on that time weighted exposure method as well, but not all of them do. The biggest difference I've seen is that the marine units spec a wider temperature range (and come with a much higher price tag).

[sailorboy1]

yes the special marine CO

[tanglewood]

Originally Posted by s/v Jedi

24.7.1.1 and 24.7.1.2 are not in the 7/15 revision that circulates and newer ones are behind paywalls

You are quite right. I was looking at an old version. The current version says:

24.6.1 Carbon monoxide detectors shall be installed on all boats with an enclosed accommodation compartment(s)

The exceptions have been removed.

[s/v Jedi]

Originally Posted by tanglewood

You are quite right. I was looking at an old version. The current version says:


[/FONT]


The exceptions have been removed.

Ah so it’s the other way around. Still strange because this would require us to have the sensor even though we have no source of CO at all.

[rslifkin]

Originally Posted by s/v Jedi

Ah so it’s the other way around. Still strange because this would require us to have the sensor even though we have no source of CO at all.

Diesels still produce CO, just much less of it. But there are still other sources of CO. For example, you've gone to a marina and end up downwind of one of those boaters that feels the need to warm up their engines for 20 minutes before leaving the dock. Depending on distance, wind strength, and the boat in question, that can easily put a harmful amount of CO into your boat.

[crayiii]

Originally Posted by rslifkin

Diesels still produce CO, just much less of it. But there are still other sources of CO. For example, you've gone to a marina and end up downwind of one of those boaters that feels the need to warm up their engines for 20 minutes before leaving the dock. Depending on distance, wind strength, and the boat in question, that can easily put a harmful amount of CO into your boat.

We were woken up by our alarms in this exact situation!

[Chotu]

Or one I was a bit shocked at.

Same as the idling neighbor boat but a car!

[rslifkin]

Originally Posted by Chotu

Or one I was a bit shocked at.

Same as the idling neighbor boat but a car!

That one is definitely more surprising, considering most modern-ish cars don't put out much CO once they've been running for a couple of minutes and the catalysts warm up. But the right set of conditions and a car that was just started cold could do it.

[s/v Jedi]

Originally Posted by rslifkin

Diesels still produce CO, just much less of it. But there are still other sources of CO. For example, you've gone to a marina and end up downwind of one of those boaters that feels the need to warm up their engines for 20 minutes before leaving the dock. Depending on distance, wind strength, and the boat in question, that can easily put a harmful amount of CO into your boat.

That’s the thing, we don’t have a diesel in our interior space. Also, when CO ingress from the outside is dangerous, then logic dictates that it’s more dangerous outside than inside. The detector should be outside.

I know Dutch law enforces placement of the detector close to the potential source, which is the correct way of doing this. It allows a much earlier detection.

[GordMay]

Originally Posted by rslifkin

That one is definitely more surprising, considering most modern-ish cars don't put out much CO once they've been running for a couple of minutes and the catalysts warm up. But the right set of conditions and a car that was just started cold could do it.

Carbon Monoxide poisoning severity is related to, both, the CO level, and the duration of exposure.
As CO levels increase [and remain] above 70 ppm, symptoms become more noticeable and can include headache, fatigue and nausea.
At sustained CO concentrations above 150 to 200 ppm, disorientation, unconsciousness, and death are possible.
The typical catalytic converter combines oxygen with carbon monoxide, to form non-poisonous carbon dioxide (CO2), reducing the high concentrations in the exhaust manifold (typically 30,000 ppm or more), to low concentrations, typically below 1,000 ppm, after the catalytic converter.

[tanglewood]

Originally Posted by s/v Jedi

Ah so it’s the other way around. Still strange because this would require us to have the sensor even though we have no source of CO at all.

Apparently. I haven't been involved with any of that so don't know how it came about. But I suspect it's due to an earlier comment about how the source of CO doesn't have to be YOUR boat. There have been instances where one boat gasses out a neighboring boat.

[s/v Jedi]

Originally Posted by tanglewood

Apparently. I haven't been involved with any of that so don't know how it came about. But I suspect it's due to an earlier comment about how the source of CO doesn't have to be YOUR boat. There have been instances where one boat gasses out a neighboring boat.

Yes, I’ve heard of that as well. Horrible.

[rslifkin]

Originally Posted by GordMay

Carbon Monoxide poisoning severity is related to, both, the CO level, and the duration of exposure.
As CO levels increase [and remain] above 70 ppm, symptoms become more noticeable and can include headache, fatigue and nausea.
At sustained CO concentrations above 150 to 200 ppm, disorientation, unconsciousness, and death are possible.
The typical catalytic converter combines oxygen with carbon monoxide, to form non-poisonous carbon dioxide (CO2), reducing the high concentrations in the exhaust manifold (typically 30,000 ppm or more), to low concentrations, typically below 1,000 ppm, after the catalytic converter.

Actual levels are typically far lower than that for modern-ish (last 20 years or so) cars in good condition. Plus, a car is only going to be so close to a hatch or something on a boat, so there will be at least some dilution. This test showed 30 ppm for a 2003-vintage car run in an enclosed garage for 20 minutes: https://pubmed.ncbi.nlm.nih.gov/28768080/

[s/v Jedi]

By far the biggest problem is people putting their portable generators too close to, or even completely indoors. I just bought a new Honda and it has a label stating you can’t buy these in California. I guess people there manage to kill themselves with these even though there is a CO detector right on the generator itself which switches it off!

[sailingharry]

Originally Posted by rslifkin

Many of the newer home versions work on that time weighted exposure method as well, but not all of them do. The biggest difference I've seen is that the marine units spec a wider temperature range (and come with a much higher price tag).

My understanding of the time weighted delay of a marine unit is that it will prevent spurious alarms with a waft of CO passing by. So, the argument is "a home unit is too sensitive, we need to make a less sensitive marine unit." In other words, a home unit is too sensitive. If that somehow makes sense..... But if that's the case, I'm happy to have one that provides earlier warning. Especially since in the 4 years it's been installed, I've never had an alarm (false or otherwise), so I'm not suffering from alarm fatique.


As far as temperature, my boat is arguably not as subject to the high temperatures than cabins, RV's, and similar unconditioned spaces that a home-style CO detector is subject to.


But all of this conjecture is exactly the problem with hiding the standard behind a fee structure. ABYC says "trust, me, you really do need to pay twice as much for a marine unit that lasts half as long (5 years vs 10) and does't include a fire alarm because, well, we know what you are too dumb to understand." And given that there are VERY few makers of marine CO detectors, and ABYC is by its nature run by industry insiders, it makes it especially hard to not think that there is a financial incentive here (I normally strongly resist this argument). ABYC could go a long way if they included some background reasoning in the standard.