Need a recommendation for a good CO readout

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  #1  
Old 01-24-14, 08:41 AM
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Need a recommendation for a good CO readout

I don't trust the one I've had for years because
1- I've had it many years & I've been told they should be thrown away after 10.
2- It always reads "0"

The replacement can be a plug-in monitor or a hand-held meter--doesn't matter for my needs. Hopefully a reliable detector that can read down to the lowest levels won't break the bank.

I may be hyper-sensitive to CO. I get a mild headache whenever I use my wood burner in the shop but my digital detector says there's no problem.
 
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  #2  
Old 01-24-14, 10:18 AM
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What a coincidence!

Because my wife and I are occasionally running two 36 year old furnaces, last week I checked the operation of our 13 year old CO monitor/alarm.

There is a "test" button on the thing that you press and lights flash and the alarm speaker blasts away, but now I understand that this test does not indicate that the actual CO sensor itself is still detecting CO, so I thought I'd get right to the heart of the matter and stuck the thing in front of our vehicle's exhaust and after a couple of minutes the thing was still silent.

I then did more research about CO detectors and discovered that the typical CO detector takes many many minutes to sound an alarm, even in pretty high concentrations of CO. Take a look at the owner's manual at the "response time" of your CO monitor/alarm. Not only that, but these detectors may last only 5 years!

You see on most CO detector labels that the unit is "UL approved" or "meets UL specifications". These phrases refer to UL2034, some of whose requirements are here:
http://www.ul.com/global/documents/o...xideAlarms.pdf
and whose specific requirements are detailed here:
Carbon monoxide detector standards
and, a bit more biased, here:
Carbon Monoxide Poisoning - Carbon Monoxide Myths

As far as I can tell, the response time of a CO detector is directly related to its price. The faster the response time, the more expensive the detector.

I ran into the following video when searching for a fast CO detector:
TGS 5042 Figaro carbon monoxide sensor testing - RoadTest - YouTube

Here is the electrochemical CO sensor element that apperas in that video:
http://www.figarosensor.com/products/5042pdf.pdf
As far as I can tell, just the bare-bone sensor costs around $20 apiece, so you know that any commercial detector that contains it is going to be expensive.

So I searched for a CO detector in the marketplace that has that element and here's the only on-the-wall one I could find:
Defender LL6070 Low Level Carbon Monoxide Monitor
Within the "product features" section you can see a link to its "electrochemical sensor", which just happens to be that Figaro sensor. The only thing I don't like about the unit is the batteries that are "soldered in place". I suppose one could determine what they are and replace them anyway, but that's going to be a hassle. Why not put replaceable batteries in there?

There are a pile of hand-held CO detectors on the market. Because they are more or less "survey" type detectors, they have to be very fast responding and are, therefore, expensive compared to units intended to sit on the wall of a residence.

You have to decide what you want in a CO detector as far as speed of detction and the concentration of CO that you want the detector to detect (that is, the concentration of CO that you are willing to breathe).

I want to have a low-level, fast-responding detector so that I know what the people in our home are breathing all the time, at any moment, but that's just me. You might be prefectly happy with an inexpensive "plug-in" unit that does what the UL standard requires.

One feature that many hand-held, survey detctors have is "auto-off", which means that to conserve battery life, the unit automatically turns itself off after a certain number of minutes or seconds. If you want continuous monitoring of CO levels, these units are probably not appropriate.

Here is a unit I found that I am seriously considering:
Carbon Monoxide Detectors - Portable, fast, and accurate CO detectors for general or industrial use
It can serve multiple purposes and, if you want, it stays on all the time and the easily replaceable battery lasts a couple of years in continuous use. It also has an adjustable alarm for whatever CO level you want. The only questions I have about the unit are how long its sensor lasts and how do you deal with that built-in re-calibration requirement.

Whatever unit you get, I think that it has to be REALLY tested beyond pressing a button. That is, it should be put in some CO for say over an hour and see if it actually alarms, or, if it has a digital display of concentration, the display begins to show a rising level of CO.

Hope this helps a bit.

For you pros out there, are there any other hand-held units that don't have the auto off feature and would you recommend them?
 

Last edited by Darwin's Child; 01-24-14 at 11:50 AM.
  #3  
Old 01-24-14, 03:28 PM
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Just ran across this:
National Ambient Air Quality Standards (NAAQS) | Air and Radiation | US EPA

You can see for yourself how this compares (or doesn't) with the UL standard for CO residential monitoring devices.
 
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Old 01-28-14, 09:21 AM
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Last week I wrote a message to Sensorcon about their detectors and received a reply yesterday. Below in blue is the exchange with their reply on top and my original on the bottom. (The names have been changed to protect the innocent.) The potential buyer has to decide whether the 2-4 year expected life, the accuracy, the portability and point-source detection capabilites of their units justify their price. (I must admit that I would like to be able to determine the CO being emitted by our old furnaces in the flue, plenum, etc.)

There are some $40 wall units that have digital displays. They supposedly display CO concentration below 10ppm, but do not actually emit an alarm until the UL time/concentration specifications are met. Most, if not all, of these units have a built-in "replace by" date that starts a clock as soon as the unit is first energized. When the clock hits the pre-determined time-from-first-start interval, the unit begins to emit an audible signal that indicates that the unit should be replaced and that CO detection has ceased. In the case of that rather expensive Defender wall unit I linked above, it is 5 years.

In the case of the $40 unit with digital display that I'm considering (Kidde model 900-0146), 7 years.

If the Kidde's accuracy from 0-30 ppm CO is reasonable (which is an important unanswered question, IMO), then it's 7 year lifetime and low price make it an attractive alternative to the higher-priced units. Like the Defender unit above, it also has an electrochemical sensor, but I don't believe that it is the Figaro.

Again, each buyer has to decide what they want in a detector before they buy one.

Below is the exchange I had with Sensorcon.

xxxx,

The alarm rate is programmed into the unit and so there is no way to change that level. It is not likely that the level would go that high from exhaust outside however it is dependent on a number of factors such as where the exhaust is located in relation to household vents, how long it is running, age of the vehicle etc. Also, keep in mind that people have different sensitivity levels to CO. The sensor should last between 2-4 years with average use but could last longer. It does come with a built in countdown of 180 days. We do recommend it be calibrated for accuracy every 6 months to retain the +-2 accuracy. If there are any other questions I can answer please let me know.

Thank you,
xxxxxxx

Sensorcon, Inc
150 N Airport Dr.
Buffalo, NY 14225
716-566-2728


On Fri, Jan 24, 2014 at 11:26 PM, xxxxx wrote:

Hello, my name is xxxxxx and I've very interested in using your CO detector in our home -- particularly at night on a nightstand. I have just a couple of questions about it that are not in your FAQ section.

1. Is it possible to disable the alarm at 30 ppm and set an alarm point higher than that? In that regard, how likely is the CO concentration in a home to get up to 30 ppm if there is no fireplace or gas-fired furnace or water-heater (or anything else I haven't mentioned) burning fuel? What if there is just heavy vehicular traffic nearby outside? Could that drive CO concentration inside our home to 30 ppm?

2. I don't want to have to spend $150 plus shipping every two years in order to measure and alarm for CO in our home. How long does the sensor in your instrument remain sensitive to CO? (Can we get at least 5 years of gentle use out of the instrument?)

Thanks very much for the information.

Sincerely,
xxxxx
 
  #5  
Old 01-28-14, 10:06 AM
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I was liking the Sensorcon until I read that...
 
  #6  
Old 02-01-14, 01:18 PM
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My wife and I bought the following detector:

It is a Garrison brand, model 46-0309-0, but I believe it is a re-brand of the Kidde KN-COPP-B-LPM shown on the following link:
Kidde KN-COPP-B-LPM Battery-Operated Carbon Monoxide Alarm with Digital Display (CO Alarms) - By Kidde
The one significant difference is that Canadian Tire's "Garrision" re-brand has a 10-year warranty, versus the Kidde's 7-year, so it is possible that the Garrison is a completely different unit even though it looks indentical to the Kidde, but I doubt it.

We've had the thing for a few days and the display hasn't budged from a reading of zero, so because I'm skeptical about almost everything except the inevitabilty of death, this morning I tested the unit in exactly the same way that the guy in that Youtube video tested the Figaro sensor.

I put a flaming ball of paper in an old transparent mayonnaise jar, put the cover on to snuff out the fire, then put the detector in the jar and put the lid back on.

Sure enough, within just a few seconds the display began to show CO and within just a few more seconds it started alarming like crazy. I was amazed.

How accurate it is at low levels I don't know, but it definitely responds very rapidly and at some point rapidly alarms to high levels of CO. I suppose I could do variations of the experiment that might involve allowing some air into the jar, etc, but I'm not going to bother.

All I wanted to know was whether it would actually detect CO and now I know that it does. For that reason I recommend this unit as an amazingly inexpensive solution to detecting CO in the air in which it sits.

But I would still advise anyone buying any detector of any type to perform the same simple test as above to verify that the thing actually does what it's supposed to.
 
  #7  
Old 02-01-14, 07:46 PM
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An UL approved alarm with a digital display will only start displaying a level at 30ppm.

Below that on some you can push a button and get a reading down to 11ppm.

---------
This thread had some excellent info and really needs to be pinned/stickied.
 
  #8  
Old 02-01-14, 10:46 PM
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Our detector meets CAN/CSA-6.19-01
(CAN/CSA-6.19-01 (R2011) | Accessories | ShopCSA)
and no mention is made anywhere of meeting UL standards, so there may be electronic differences between it and the Kidde.

But from here:
http://www.home-inspectors.com/Carbon_monoxide.pdf
we have the following:

"Detector sensitivity issues

The standards organizations of Canada (CSA) and the United States (Underwriters Laboratories or UL) have coordinated the writing of CO standards and product testing. The standards as of 2010 prohibit showing CO levels of less than 30 ppm on digital displays. The most recent standards also require the alarm to sound at higher levels of CO than with previous editions of the standard. The reasoning behind these changes is to reduce calls to fire stations, utilities and emergency response teams when the levels of CO are not life threatening. This change will also reduce the number of calls to these agencies due to detector inaccuracy or the presence of other gases. Consequently, new alarms will not sound at CO concentrations up to 70 ppm. Note that these concentrations are significantly in excess of the Canadian health guidelines.

Detectors with a digital display and a “history” option can provide the true CO concentrations in a house. A low-level display would be useful for people with existing respiratory problems or for those who like to spot evolving problems, rather than having to wait for the situation to become serious. Low-level CO detection products are becoming commercially available. They will not be certified to CSA or UL standards, as these standards currently prohibit low-level displays."


Our unit's operator's manual states that the unit displays CO concentration from 11 to 999 ppm, but it will never alarm for concentrations below 70 ppm. It also states that although the unit does not alarm below 70 ppm, one should still take action to ascertain from where displayed concentrations below that originate.

I now notice that in the Kidde's description on the above link that its display will not show concentrations below 30 ppm, but, as Muggle said, when you press the "peak reading" button, it will display a previous peak concentration down to 11 ppm.

There is definitely politics in play when it comes to the CSA and UL standards for CO detectors for homes. When you compare the level of alarm in those standards to the recommended levels of exposure to CO, there is quite a "disconnect". For example, the new standard requires that there be no alarm below 70 ppm, but the US National Ambient Air Quality Standards for CO exposure are 9 ppm for an 8-hour average exposure and 35 ppm for a 1-hour average, both "not to be exceeded more than once per year". As the section in blue above states -- "the reasoning behind these changes is to reduce calls to fire stations, utilities and emergency response teams when the levels of CO are not life threatening.

Therefore, it appears that whether or not people are being harmed by CO concentrations below "life threatening" is either of no concern to the people at UL or CSA, or, after a cost-benefit analysis, the harm from that level of CO is of lesser impotance than the "nuisance" it causes responders.

After educating him/herself of all the above, the buyer of a CO detector will no doubt ask him/herself the following question (which I am now asking myself). "Do I really want a CO detector that has all of the restrictions of the CSA/UL, or do I want one that detects and displays CO concentrations right down to zero and I can set where I want the alarm to sound automatically myself?" Those people who have unexplained periods of headaches may very well choose to kill two birds with one stone and buy the latter in order to eliminate low-level CO as a possible cause of their headaches. Got a headache? Step 1 - look at the low-level CO detector.

The above photo of our unit verifies that our unit displays "0". Tomorrow I'll try to verify whether or not it displays concentrations between 0 and 30 ppm by sticking it back in the jar and observing what is the very first number displayed above zero.
 
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Old 02-02-14, 11:15 AM
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I just finished testing our unit in the jar.

Because the manual states that the CO reading is displayed (and maybe CO is only sampled) every 15 seconds, and I can't know exactly where the timer is at any moment, I only kept the unit in the jar for about 15 seconds.

In about 10 seconds the display went from 0 instantly up to 350 ppm. (Again, this is an amazingly fast response to CO, IMO.)

I removed the unit from the jar as fast as I could. The next reading was 641 ppm and held steady for a bit, then readings started to drop. At first the reading dropped in large intervals, but below 100 ppm the invervals decreased rapidly to shorter and shorter amounts. At the end of the process, the reading went from 57 to 45 to 35 and then right to zero. If the unit read below 30 ppm, I believe the next reading after 35 would have been around 25 ppm.

After the test I pressed the peak level button and 641 was displayed.

Therefore, I believe that the lowest concentration that our unit is allowed to display continuously is 30 ppm, which is according to present CSA and UL specifications. But at least concentrations above 30 ppm will be displayed continuously, which is nice, but I'd still prefer it if it continuously displayed concentrations lower than that.

I have reset the peak reading to zero, so when I want to know the highest level seen by the detector since the last push of the "peak level" button, I'm going to have to press that button. Because I have to get fairly close to the unit to read the display, I guess I can handle the additional onerous task of pushing the button. Should a significant peak show up, I can reset the peak, press the peak button after some time, reset, etc. more and more frequently to try to nail down when CO concentration goes up, if it is a periodic phenomenon. I'll start off by pressing the peak button once a week and then either expand or contract the interval depending on what the display shows. I'm keeping the unit on the night-stand next to my side of the bed, so I'll try to make it a habit that when I turn in I first press the button.

Anyway, I'd still like to at least borrow a detector that can do what that sensorcon unit can. I'd like to poke the sampling probe in various places to observe what's what within some of our hot air registers, flues, etc. If I can find a similar unit whose sensor lasts as long as the one in our Garrison unit, or has a cheap replaceable sensor, I might spring for it. In the meantime, we're "covered".
 
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Old 02-02-14, 04:25 PM
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I really wanted to like that Sensorcon meter. It looked like a pro instrument for a reasonable $149 but I can't bring myself to invest that much for a meter that has a lifespan of only 4 years...and the sensor can't be replaced by the user.
But that looks like the price of admission for a reasonably accurate meter that responds fast and displays all the way down to zero.

I think I'll talk work into buying one...then I'll borrow it a lot
 
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Old 02-03-14, 09:53 AM
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What follows in blue is another email exchange I had with Sensorcon.

==
xxxxx,

The sensor can be replaced. Currently the cost is about $100.

Thank you,
xxxxx

xxxxxx

Sensorcon, Inc
150 N Airport Dr.
Buffalo, NY 14225
716-566-2728


On Sun, Feb 2, 2014 at 7:08 PM, xxxxxxxxxx wrote:

Hi, xxxx.

Just one final question. When the internal CO sensor fails "2-4 years" down the road, can the unit be sent back to you to have just the CO sensor replaced and, if so, what would the charge be for doing that?

Thanks for the information.

Sincerely,
xxx


=====
And if Sensorcon can replace the sensor, as long as the sensor itself is mass-produced, has a model number on it and is not proprietary, so too could anyone who knows how to use a small soldering iron. Again, I very much doubt if the sensor itself costs more than $20.

Now all we need is for "someone" to buy one and either take it apart immediately to observe any sensor part number, or wait til the thing stops measuring CO in a few years and then do it.
 
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Old 02-03-14, 10:18 AM
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One possibility is buy the ones pilots use: CO Detectors from Aircraft Spruce

I saw one demonstrated and it could detect a burned out match about 1 inch in front of the detector.

Alternatively you could look on ebay or elsewere for a combustion analysis device that pros use, which can be calibrated by the manufacturer.

CO
 
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Old 02-03-14, 06:26 PM
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Sensorcon makes the sensor themselves so you'll need to ask if they will sell it direct.
 
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Old 02-03-14, 09:03 PM
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Although they supposedly "manufacture" the whole unit, I very much doubt if they manufacture all the bare-bone parts -- circuit board, resistors, capacitors, LCD display, case, or CO sensor. They are probably more "assemblers" in the same way that many north american auto manufacturers are assemblers using parts that are manufactured by various automotive parts manufacturers located all over the world.

If I decide to buy that sampling kit for $180 - $200 plus shipping and taxes (quite possibly 1/4 the cost of a new furnace!), I will tell them that I will buy only if they either include a spare sensor or, at the very least, tell me the make and model number of the bare-bone sensor and how to replace it. If they won''t do that, I'll keep my $200. In that latter case, which one of us will be financially worse off?
 
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Old 02-04-14, 10:22 AM
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Part of their email response to my questions about lifespan and maintain-ability:
We make our own sensors and have transitioned to a assembly technique that doesn't use a sensor connector for both cost and reliability considerations.
The sensor used to plug in but now it's soldered in place. If they did that to keep users from maintaining their own units then it's unlikely they will sell the sensor.
 
  #16  
Old 02-23-14, 12:10 PM
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One dead and 27 hospitalised after suspected carbon monoxide leak at a New York mall - Americas - World - The Independent

After reading the above I tested our CO detector/alarm today. This time I held the mayonnaise jar in front of our vehicle's exhaust pipe for a few seconds and quickly screwed on the lid. Then I brought the jar back in the house and, as quick as possible, I stuck the detector in there and put the lid back on. Within about 20 seconds, the display started to show CO, so I immediately removed the detector from the jar. Readings then began to drop to 30 something then stepped to zero. I pressed the peak button and 77 was displayed. I then reset the peak to zero.

I highly recommend that folks who have CO detectors test them frequently. If you do the simple test I've described above, even using a plastic bread bag or whatever as a container, your detector should either display CO ppm or, after a longer wait, start alarming like crazy.
 
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Old 03-17-14, 06:53 PM
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Notice the part of the following article that I've made bold and underlined. I've made comments after the article.

Carbon monoxide poisoning leaves family 'devastated' - Toronto - CBC News

Police believe carbon monoxide caused the deaths of three members of the same Brampton, Ont., family early Monday when propane heaters were brought into the home after the furnace stopped working in frigid conditions.

"It's just a tragedy … a terrible situation," Peel Regional Police Const. Fiona Thivierge told reporters Monday.

Just before 2 a.m. Monday, emergency services were called to a house on Linden Crescent, in the Dixie Road and Queen Street area. The 911 call was made by Jerry Pitamber, 29, who arrived home to find carbon monoxide detectors activated and members of his family unconscious.

Five people inside the home were taken to hospital, where three were pronounced dead. Two others were treated in hospital and have since been released.

The victims are members of an extended family that owns and operates two popular Guyanese-Chinese restaurants in Brampton.

Police say a man arrived home at this Brampton, Ont., house to find carbon monoxide alarms ringing and five members of his family unconscious. Three were pronounced dead in hospital, two are expected to survive. Police say propane heaters were in use in the home after the furnace stopped working on Sunday.

Dead are Peter Pitamber, 60, owner of Calypso Hut on Queen Street and his wife Seeta Pitamber, 59. The couple's 36-year-old son Terry Pitamber also died.

Also in the home was Paul Rampersaud, 56, Peter's brother (who took a different last name) and owner of the second Calypso Hut location. Paul was taken to hospital but was later released. Another man, a friend of the family's, was also released after being treated in hospital

At the time of the incident, the family had gathered at the Pitamber home to mourn the recent death of Paul and Peter's mother.

Paul Rampersaud issued a statement Monday on behalf of the family.

"Today has been an unimaginable and horrific day for our family," it reads. "The past few weeks have been extremely difficult, as we have been grieving the death of my mother who passed a few weeks ago.

"My brother, Peter Pitamber, came to this country from Guyana over three decades ago. From humble beginnings he became a respected businessman and active member of the Brampton community. Peter built a strong home for his family, and we ask that you now pray for his surviving son, Jerry.

"We are currently in the process of making funeral arrangements and would ask that the media kindly respect our privacy during this devastating time."

Police believe the family's furnace stopped working Sunday, and at some point, propane heaters were brought inside to heat the home. Overnight temperatures Sunday dipped to the –15 C range with the windchill making it feel like it was mid–20s.

Police said those who died were in the upper level of the home, while the survivors were on the lower level.

"We would caution people to not bring propane heaters into their house," said Thivierge. "It's a very dangerous situation."

Shortly after 9 a.m. Monday, Brampton Fire and Emergency Services issued a warning on Twitter about the dangers of carbon monoxide poisoning.

"This tragedy shows that you should never use propane appliances in the home," said the tweet. "If your furnace goes out, call for repair."
===============

The issue I'd like to raise is whether the UL requirements that home CO detectors NOT to alarm early on for low levels of CO had any bearing on this fatal outcome. That is, would a detector that started alarming at a CO concentration of say 10 ppm have prevented this human tragedy?
 
  #18  
Old 03-18-14, 05:15 PM
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Unfortunately, this is not an uncommon tragedy, especially during power outages when people may run a gas generator in their attached garage.

The article does state that the home had CO alarms, but doesn't make it clear whether any were installed on the upper level. CO is slightly lighter than air at room temperature, and becomes lighter as the temperature rises.

Besides installing CO and smoke alarms on every level of the home, you should look for CO and smoke alarms with non-removable lifetime batteries. Up to 25% of existing smoke alarms are inoperable due to dead or missing batteries.

Maryland, currently, and California, this July, require most battery operated smoke detectors sold within their State to have non-removable lithium batteries.
 

Last edited by fixit joe; 03-18-14 at 06:18 PM.
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Old 03-18-14, 05:37 PM
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Still doesn't address the FACT that CO and smoke alarms have a somewhat limited life AND that CO alarms for residential usage are PURPOSELY made not to alarm until the situation is past critical.
 
  #20  
Old 03-18-14, 07:18 PM
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It is true that the UL Standard does not permit Listed CO detectors to "automatically" activate an alarm signal below 30 ppm.

Some UL Listed 10-year CO alarms, like the Defender CA6150, do enable you to "manually" monitor the current and peak CO levels as low as 10 ppm, and the peak duration in minutes. This is a link to the operation instructions.

The Defender LL6070 Low Level CO Monitor is not UL Listed, alerts at 10 ppm, alarms at 15 ppm, and offers the best overall "automatic" protection, but does require replacement every three years in order to maintain the monitor's accuracy at low CO levels. These are the operation instructions.
 
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Old 03-18-14, 07:20 PM
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Furd:
"Still doesn't address the FACT that CO and smoke alarms have a somewhat limited life AND that CO alarms for residential usage are PURPOSELY made not to alarm until the situation is past critical."
=============

Yes, this is the point I was trying to make. I'll quote from any earlier post in this thread:

"The standards organizations of Canada (CSA) and the United States (Underwriters Laboratories or UL) have coordinated the writing of CO standards and product testing. The standards as of 2010 prohibit showing CO levels of less than 30 ppm on digital displays. The most recent standards also require the alarm to sound at higher levels of CO than with previous editions of the standard. The reasoning behind these changes is to reduce calls to fire stations, utilities and emergency response teams when the levels of CO are not life threatening. This change will also reduce the number of calls to these agencies due to detector inaccuracy or the presence of other gases. Consequently, new alarms will not sound at CO concentrations up to 70 ppm. Note that these concentrations are significantly in excess of the Canadian health guidelines."


Again, if the detectors in that home had been NON UL approved and alarmed at say 10 or 20 ppm, would that have saved people's lives? For example, assuming that it alarmed at 10 ppm, IMO there's a very good chance it would have alarmed very soon after the propane heaters were intially fired up. Perhaps even while the person who started them was standing right there, but certainly shortly thereafter. Personally, I think a little responder-nuiscance is worth it to save a few lives, or even one life.

The real irony here is that a consumer looking at a detector on the retailer's shelf is going to see that UL or CSA approval and think that that is a "better" unit than one that is NOT approved. The perhaps fatal irony is that the non UL spec unit may very well provide betteer protection than one that "meets UL specifications".
 
  #22  
Old 03-18-14, 07:45 PM
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The UL 2034 Standard requires that a Listed "Carbon Monoxide Alarm" activate an alarm signal at or below 70 ppm in no less than 60 minutes but no longer than 240 minutes; and, not activate an alarm signal below 30 ppm within 30 days.

A "Low Level CO Monitor" is not UL Listed, and will typically activate an alert signal at 10 ppm and an alarm signal at 15 ppm.

For the best protection against CO poisoning, and to avoid these types of tragedies, all families, especially those with infants or elderly persons, should install a Low Level CO Monitor on every level of the home and near or within every sleeping area.
 

Last edited by fixit joe; 03-18-14 at 08:15 PM.
  #23  
Old 03-19-14, 01:20 AM
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I used to install, calibrate and otherwise maintain CO monitors on industrial compressed air systems that were used for breathing air. I even designed a few using commercially available sensor cells. What I found was that CO is not the easiest gas to test for and that the sensors have a fairly high rate of "drift" needing re-calibration on a regular basis. The best sensor cells I used required calibration about every thirty days to keep them accurate within +/- 10 percent of the full scale span, which in this case was 0 to 50 ppm CO. These alarms would go off at the 10 ppm level. My monitors were so sensitive (even the lousiest models) that the meter would go up 2-3 ppm during the afternoon commute due to the increased CO in the ambient air.
 
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Old 03-19-14, 09:25 AM
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Again, I think that what might have been important in the tragic case above is that a low level alarming detector with a digital display would have likely alarmed shortly after those heaters were fired up. The detector's display would then have been looked at by someone -- at least to figure out how to turn it off.

IMO, the coincidence of the alarm, higher than normal readings that continued to increase, along with the fact that these heaters had just been fired up would have been conclusive proof that those heaters were causing the concentration of CO to rise.

After that unavoidable conclusion had been reached, the problem for the family would have been what to do to get some heat into the building. Some electric heaters were probably the only safe option.
 
  #25  
Old 03-19-14, 01:29 PM
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"Police say propane heaters were in use in the home after the furnace stopped working on Sunday.

Read more: http://www.doityourself.com/forum/ga...#ixzz2wREVI2iD
"

There's no cure for stupid.

But you're right about UL approved CO alarms.

While we're on the topic of UL, their approved ionization smoke alarms don't provide an early warning in smoldering fires. (https://www.youtube.com/watch?v=hdaUXkGoSik)
 
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Old 03-19-14, 02:57 PM
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I would say ignorant rather than stupid, and there IS a cure for ignorace. You can be sure the surviors learned it, the hard way.

Did anyone else catch this sad irony?

"At the time of the incident, the family had gathered at the Pitamber home to mourn the recent death of Paul and Peter's mother."
 
  #27  
Old 03-19-14, 09:54 PM
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I agree, ignorance is a far better term than stupid. Most people have no idea of what constitutes a "safe" level or CO or that the effect of a low concentration is cumulative. That does not make these people stupid just uninformed.

I would suggest that every home have a UL-listed CO monitor and any home that has, or might at some point have, a fuel-burning appliance inside should ALSO have a low-level CO detector. The UL listed model for normal monitoring and the low-level model for use whenever the fuel-burning appliance is in use. Both need to be replaced according the manufacturer's instructions, generally a five year maximum schedule.
 
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