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What are some of the best CO detectors for low level CO detection? Ones that can detect to low poison levels that just make you feel lousy over time.

Bacharach said during a CE class years ago that current CO detection technology was unable to detect low levels of CO (under 50 ppm) without frequent nuisance alarms. 50 ppm can kill in less than a night as I recall.

Marc

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I've always used Nighthawk in my home, it's also the same we have in all our fire stations. Has a digital readout and also saves peak readings. Has gotten good reviews in the past. They do read low levels, but have a sliding scale for when they alarm. You could probably google it and find it, but basically high levels alarm faster than low levels.

On our rigs for responding to 911 calls regarding CO, we carry ITX and Rae. We don't mask up unless it's over 100ppm by policy, and call out gas company for anything over 9ppm unless it's an obvious cause.

50ppm won't kill you overnight, but it shouldn't be there just the same. OSHA sets 50ppm as the max for an 8hr. workday, and NIOSH sets the ceiling to not be exceeded at any time at 200ppm.

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  • 2 years later...

If you want a fixed single gas CO alarm to meet the codes, it must be listed to UL2034 or 2075 (battery vs. hard-wired station monitored). However, ALL CO alarms listed to these standards do NOT provide adequate protection and in fact mislead people with a false sense of security. They are designed such that they will not alert until your carboxyhemoglobin (COHb) level reaches 10%, which is the medical definition of CO poisoning. Therefore, a properly working listed alarm does NOT protect against poisoning but only death. That's when they work. Many are crap and fail miserably.

Now, to the OP's request, there are only two low level unlisted CO monitors available in the US for fixed installation that do not require a 4-20mA output signal to a DCS, PLC or other control system: CO Experts and the NSI3000. Both are very similar in alert levels, quality and reliability. Anyone can buy the CO Experts from George Kerr right off his website. The NSI3000 can only be sold and installed by professionals trained and certified by the National Comfort Institute. There should be one monitor on each floor level, one within 15 LF of each sleeping room and they should be installed between knee and face heights where your mouth is breathing whether standing or sleeping. CO will slowly rise through the house so usually the highest readings are at the top of the house--not down low. That just goes to show whomever wrote that code doesn't know about CO.

If your UL listed POS alarm goes off, get everyone out immediately, call 911 and get medical attn: because it only alerts once you've been poisoned-----------when they work.

Now, there are many excellent personal CO alarms made to wear or carry. Everyone should have one on them. Take when you travel. Keep it in your vehicle's cab as you drive. Wear it anywhere out in public but especially in commercial buildings of any type. BTW, I was asked to turn mine off on a plane because it was alerting to the high ambient CO levels. Yes, airports are horrible for air quality. A home inspector really should wear a multi-gas alarm for LEL, O2, CO and H2S. You should also wear a PASS like firefighters wear and tell the Realtor to listen for it alerting should you become incapacitated or gone for awhile.

HTH

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. . . and they should be installed between knee and face heights where your mouth is breathing whether standing or sleeping. CO will slowly rise through the house so usually the highest readings are at the top of the house--not down low. . . .

I disagree. Air has a specific gravity of 1.0, while carbon monoxide is .96 - the same as nitrogen. Gases that have such close weights don't stratify in a typical household environment. If they did, carbon dioxide, which has a specific gravity of 1.5, would pool on the floor and we'd suffocate if we were to lie there.

Carbon monoxide tends to rise initially, only because it's typically produced by combustion and it's hot at first. After a short time, it effectively disburses throughout the space.

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Well Jim, if you take a CO certification course you would learn otherwise. Besides, with CO being essentially neutral buoyancy, the stack effect causes warm air to rise up carrying CO with it. This has been proven time and time again by researchers and combustion analysis practitioners. There is a case proving this from Japan called "Suicide in Sendai". A guy in a high rise tried to kill himself in the basement using CO. It failed but did rise up many floors killing an old lady many floors up. It is also my general experience.

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Well Jim, if you take a CO certification course you would learn otherwise. Besides, with CO being essentially neutral buoyancy, the stack effect causes warm air to rise up carrying CO with it. This has been proven time and time again by researchers and combustion analysis practitioners. There is a case proving this from Japan called "Suicide in Sendai". A guy in a high rise tried to kill himself in the basement using CO. It failed but did rise up many floors killing an old lady many floors up. It is also my general experience.

Yeah, but you also know that gas appliances that depend on natural draft need gas vents with a minimum height to function properly. A high rise has more height than a house.

So, in different ways, you're both right.

Marc

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Well Jim, if you take a CO certification course you would learn otherwise. Besides, with CO being essentially neutral buoyancy, the stack effect causes warm air to rise up carrying CO with it. This has been proven time and time again by researchers and combustion analysis practitioners. There is a case proving this from Japan called "Suicide in Sendai". A guy in a high rise tried to kill himself in the basement using CO. It failed but did rise up many floors killing an old lady many floors up. It is also my general experience.

I agree entirely about CO having neutral buoyancy and the stack effect when CO is warm and said as much in my post. I hope that there's no question about the fact that warm gases rise and that, when first produced, CO readings will be higher in the upper parts of a house.

My point is that, as it cools, CO dissipates and with time the stack effect becomes irrelevant. Once mixed in the indoor air, the CO does not settle out again.

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Are you proposing that folks wear multiple gasses monitoring equipment all the time in any restricted or interior environment? Do you always wear a full tilt PASS system when you're working?

Do you do that? (directed to Hearthman)

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Well, it was in English, and it sure sounds like he's proposing what I asked him.....and it's not really any of my business......but it's so ridiculous I had to ask to make sure he was being serious.

(Personal and belligerent comments deleted by moderator.)

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May be prickly but seems to be pretty knowledgeable about those subjects he chooses to chime in on.

Perhaps no more idiotic than some of the things most of us have proposed a time or two. Though I won't be digging back to find any of my or anyone else's idiocies.

And you won't find me wearing all those alarms!

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I did some pruning of this thread to remove personal and belligerent comments. Please keep it civil, folks. This isn't IN.

If Hearthman's barb "As for what I'm proposing I thought I typed in English" is okay, why ain't the others?

I thought what he proposed was idiotic, and way over-the-top - and didn't say so until he took a stab at Kurt. I can't say that here? Heck, is this turning into an ASHI forum?

Yes, Erby, I have made idiotic comments before on this and other forums. I will go to confession and do my penance; cross my fingers and hope to die. I will also accept and learn, and have accepted and learned from, any/all criticisms here.

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I did some pruning of this thread to remove personal and belligerent comments. Please keep it civil, folks. This isn't IN.

If Hearthman's barb "As for what I'm proposing I thought I typed in English" is okay, why ain't the others?

I thought what he proposed was idiotic, and way over-the-top - and didn't say so until he took a stab at Kurt. I can't say that here? Heck, is this turning into an ASHI forum?

Yes, Erby, I have made idiotic comments before on this and other forums. I will go to confession and do my penance; cross my fingers and hope to die. I will also accept and learn, and have accepted and learned from, any/all criticisms here.

There's a line between prickly and belligerent. I let the prickly sarcastic comment remain because it was part of his answer to Kurt's reasonable question.

I trim things when they become personal and tedious or when they devolve into chest thumping.

Disagreements and debate are welcome and encouraged, just don't make it personal.

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