CO Analysers

[RayfromTX]

I recently spent 6 months on Cozumel. I got most of my tanks(around 500) from one fill station where I hold an account. About a month ago I started noticing 3 ppm of CO and days later it went to 5 ppm. I alerted the filler but dove the tanks. It was the same the next day. I went by with my tanks and tester after the dive and showed them. They have a continuous monitor but I don't believe it was calibrated correctly. It turns out it was only on their nitrox. The next day they messaged me with gratitude and said they had found the problem and fixed it. I only read 0ppm on every tank after that. I will not name the blender. There are many on the island. I have tested positive amounts of CO from each of them at one time or another. One of the others was the one where I once tested in excess of 30ppm. I don't know how high it was because above 30ppm the cootwo that I use just flashes TOO HIGH. None of the other tanks on that boat read above 0ppm.

For reference, a smoker that isn't smoking at the time is constantly off gassing CO and will exhale about 17ppm continuously. The CO reading is important for what it may indicate is in the gas that you aren't testing for. It is a sign that indicates the health of the compressor and the condition at the time of pumping and may indicate combustion during the compressor operation which could indicate toxic byproducts.

 

[Scuba-Lad]

Gap in the market it seems (no CO and O2 combo tester available) and huuuge risk being taken by a lot of divers by not testing in this part of the world. I've ordered a separate CO tester, pretty much the only one available here:
View attachment 665298

Thought I'd chime back into this thread in case it helps someone. Since purchasing, I've been using the CO tester on all tanks I've been diving with. Found a few contaminated tanks, one which read around 30ppm on my reader. Whilst the reader might not be the most accurate, the fact that it is detecting something is what I am counting on, so if I test a tank and it registers anything at all on my CO tester, I give it back and swap for one that reads 0. Since buying the tester I've been able to dive air again for quite some time now without having any CO poisoning symptoms afterwards. It would seem to be doing it's job based on this. The reader is small, takes 3 AAA batteries to power it, and has a timer of 120 seconds (bypassable) from the point of switching it on to then being able to test. I set it to the "max" function so that the display shows the max value read since the last power on. It also has a screen light function that flashes if the readout is above about 15ppm (I forget exactly without checking the manual), as well as an audio alarm, which can be switched off. The only slight issue is that the power button is not recessed meaning it regularly gets switched on by things in my bag bumping into it.

Interesting to see heads turn when I test a scuba tank and the CO alarm goes off.....
I also attached it to the handle bars on my motorbike and drove through a busy city to test it, the results were quite shocking

 

[DandyDon]

Thought I'd chime back into this thread in case it helps someone. Since purchasing, I've been using the CO tester on all tanks I've been diving with. Found a few contaminated tanks, one which read around 30ppm on my reader. Whilst the reader might not be the most accurate, the fact that it is detecting something is what I am counting on, so if I test a tank and it registers anything at all on my CO tester, I give it back and swap for one that reads 0. Since buying the tester I've been able to dive air again for quite some time now without having any CO poisoning symptoms afterwards. It would seem to be doing it's job based on this. The reader is small, takes 3 AAA batteries to power it, and has a timer of 120 seconds (bypassable) from the point of switching it on to then being able to test. I set it to the "max" function so that the display shows the max value read since the last power on. It also has a screen light function that flashes if the readout is above about 15ppm (I forget exactly without checking the manual), as well as an audio alarm, which can be switched off.

Ok, I am glad that it's working well for you. I have looked at that unit before and was leery. Another member and I discussed it yesterday after he found it on Amazon for $50 USD. I found it additionally there from other sellers for $40 and even $30 USD. Here are the views I shared with him...

"That's an unbranded product sold by a Chinese resell company. The same product is offered by another Chinese resell company and is listed in the Compare with similar items area on the same page for $10 less. Based on their claims, the one weakness for our use is listed in the Product description Accuracy: CO: +-5% or +-10PPM. So a test could show zero when the tank has 10 ppm, or show 10 ppm when it really has 20. But then we have no way of knowing if it's really that good as there is no information about the manufacturer. And then there is the unanswered sensor drift issue. In my opinion, not trustworthy."​

But then, the prices are great, so if it's all one can get locally or can afford, it's probably better than nothing. I think you could get it to bump-test to see if it's responding at all by asking a smoker to blow into it - not while smoking, as smokers exhale a few digits of CO all day. Nonsmokers actually exhale a lessor amount of CO as everyone produces some in that it may actually serve some purpose in the human body at very low rates, but too low to register on many units and I am getting off point here.

We just cannot determine much about it. It's sold by many Chinese resellers, but there is no real information on the actual manufacturer, the sensor used, how much sensor drift may occur in time, etc. So many unanswered questions.

The only slight issue is that the power button is not recessed meaning it regularly gets switched on by things in my bag bumping into it.

And with AAA batteries that would be a major problem. AAAs are a pet peeve of mine as they store so little power, leaving me to wonder why a unit that runs on 3 AAAs could not have been designed to run on 2 AAs instead. We're not going to get any answers to that tho, so get a dry box big enough to carry it in, maybe even cut a piece of tubing large enough to encircle the buttons and thick enough to work and glue it inside the box with some other glued inserts to hold it in place. Except it might be easier to just carry a dozen AAAs in the dry box for replacements.

Interesting to see heads turn when I test a scuba tank and the CO alarm goes off.

Ha, I bet it does!

I also attached it to the handle bars on my motorbike and drove through a busy city to test it, the results were quite shocking

I wear my Sensorcon hung from a cargo pocket almost everywhere, and it is interesting to observe the reactions, maybe more so in your country with fewer air controls, but I've never been there so I'm guessing.

I have an older Sensorcon that's been on 24/7 for over three years and once went thru a complete washing machine cycle, and it still works fine actually.

 

[John C. Ratliff]

I have been holding off writing here as I am a retired Certified Industrial Hygienist, and have a bit different perspective on testing for CO. For work in professional industrial hygiene, we use certified instruments that can be field calibrated to ensure their accuracy, or we use detector tubes which have been tested and are sealed at the factory. Usually, when we test atmospheres, we calibrate the instrument before and after our field work. This ensures that our instrument is accurate. Companies where we buy these unstruments have “bump gas” for testing to see how the instrument is performing.

Detector tubes are perhaps the easiest to use, but they are quite expensive. And, you need a hand pump to use them. So there is an initial investment that needs to be made.
Gastec Color Detector Grab Sample Tubes | View Our Gastec Color Detector Grab Sample Tubes at SKC, Inc.

Here is the Gastec pump:
GV110 Piston Pump | View Our GV110 Piston Pump at SKC, Inc.

Here are examples of sampling pumps:
Air Sampling Pumps to 5 L/min | View Our Air Sampling Pumps to 5 L/min at SKC, Inc.
These are usually made for sampling the atmosphere that workers work in, but can be used for sampling an air cylinder’s CO level with some training and a filled sample bag.

The reason I’m bringing this up is that these are the types of sampling equipment which will hold up in court if something bad has happened, and someone decides to sample for CO (or other gases). The commercially available samplers that are described before in this thread would suffer in court unless a highly trained IH had done the calibration checks necessary to ensure the sampling was giving an accurate assessment of the actual atmosphere being breathed.

By the way, there are several manufacturers, and I’ve only shown one above for brevity.

SeaRat
John C. Ratliff, CSP(Retired), CIH(2006-2017),* MSPH
*CSP = Certified Safety Professional; CIH = Certified Industrial Hygienist

 

[squid509]

are those tubes also hazardous waste (HAZMAT) after use?

 

[John C. Ratliff]

are those tubes also hazardous waste (HAZMAT) after use?

To my knowledge, the tubes are not hazardous waste after usage. They are very small, and would not contribute much to the environmental waste problems.

GASTEC gas detector tubes are considered to be an "article" as defined in 29CFR 1910.1200(c) and exempt from SDS (Safety Data Sheet) requirements in the Hazardous Communication Standard because; GASTEC gas detector tubes are formed to a specific shape or design during manufacture; have end use function(s) dependent in whole or in part upon its shape or design during end use; under normal conditions of use does not release a hazardous chemical, and does not pose a physical hazard or health risk to employees. Thus an SDS is not required for GASTEC gas detector tubes...
https://www.lab-shop.co.uk/downloads/manuals/450583_Gastec Tubes SDS.pdf

SeaRat
John C. Ratliff, CSP(Retired), CIH(2006-2017),* MSPH
*CSP = Certified Safety Professional; CIH = Certified Industrial Hygienist

 

[grf88]

For divers like me what we are looking for is a go/no go method of testing not an accurate gas analysis.

 

[kelemvor]

I have been holding off writing here as I am a retired Certified Industrial Hygienist, and have a bit different perspective on testing for CO. For work in professional industrial hygiene, we use certified instruments that can be field calibrated to ensure their accuracy, or we use detector tubes which have been tested and are sealed at the factory. Usually, when we test atmospheres, we calibrate the instrument before and after our field work. This ensures that our instrument is accurate. Companies where we buy these unstruments have “bump gas” for testing to see how the instrument is performing.

Detector tubes are perhaps the easiest to use, but they are quite expensive. And, you need a hand pump to use them. So there is an initial investment that needs to be made.
Gastec Color Detector Grab Sample Tubes | View Our Gastec Color Detector Grab Sample Tubes at SKC, Inc.

Here is the Gastec pump:
GV110 Piston Pump | View Our GV110 Piston Pump at SKC, Inc.

Here are examples of sampling pumps:
Air Sampling Pumps to 5 L/min | View Our Air Sampling Pumps to 5 L/min at SKC, Inc.
These are usually made for sampling the atmosphere that workers work in, but can be used for sampling an air cylinder’s CO level with some training and a filled sample bag.

The reason I’m bringing this up is that these are the types of sampling equipment which will hold up in court if something bad has happened, and someone decides to sample for CO (or other gases). The commercially available samplers that are described before in this thread would suffer in court unless a highly trained IH had done the calibration checks necessary to ensure the sampling was giving an accurate assessment of the actual atmosphere being breathed.

By the way, there are several manufacturers, and I’ve only shown one above for brevity.

SeaRat
John C. Ratliff, CSP(Retired), CIH(2006-2017),* MSPH
*CSP = Certified Safety Professional; CIH = Certified Industrial Hygienist

I think the handheld analyzers we're discussing are good for a diver to decide whether or not to dive a tank. If there's an incident requiring litigation, the tank can be sent off to a lab for proper analysis.

Divers struggle to justify the ~$300.00 and 20 seconds needed to analyze their gas as is. I don't think many will be buying an aircheck pump. They don't list the prices on that site, so I assume I can't afford them.

 

[Miyaru]

I'm surprised. A CO analyzer can be built for less than $30 in material costs and it will tell you if there is 1ppm CO present.
And it has been documented on the board here in the DIY section.

 

[kelemvor]

I'm kind of surprised nobody in China has taken the idea and put up CO analyzers on aliexpress for $50. I think most divers just don't understand the risk and so aren't interested in testing their gas. Especially if it's someone who "just dives air" and doesn't test for oxygen content either.