This is why I own a CO Monitor..

[Superlyte27]

I don't believe there is a good place. I hate breathing off of petroleum powered compressors. Probably why I don't do it anymore. Fortunately, (or unfortunately) when you're working as a commercial diver, the air filtration isn't that great, so if the exhaust starts blowing into the intake, you can taste it pretty quickly. So you can call over the comms to the tender top side to fix the positioning of the intake/exhaust.

I still hated it though.

 

[Suzuki416]

Running too long or getting too hot really has nothing to do with CO levels.

Carbon monoxide (CO) is a gas that is present in the exhaust gas of internal combustion engines, including those often used to drive compressors. It also comes from the breakdown of lubricating oil when compressors run too hot.

 

[DandyDon]

Running too long or getting too hot really has nothing to do with CO levels. However, if the intake is west of the petrel exhaust and the wind is blowing east to west, this would put CO into the compressor. There are a few ways to get CO produced in a compressor. Runtime isn't one of them. As a commercial diver, usually all of the gas pumped down to us is via a diesel fed or gas fed compressor. These compressors sometimes run non-stop for days at a time feeding us breathing gas. We are always very careful to put the intake for the compressor far away from the exhaust of the engine.

Damn! :shocked2: Yes, I know you are an expert, but that is just wrong - and so illustrative of why we can't fix this ongoing problem.

I guess you didn't know that an electric powered compressor can produce dangerous CO levels internally?

Carbon monoxide (CO) is a gas that is present in the exhaust gas of internal combustion engines, including those often used to drive compressors. It also comes from the breakdown of lubricating oil when compressors run too hot.

Yep. Thank you.

 

[kelemvor]

Aren't there special lubricants which are supposed to mitigate the risk of oils breaking down into co2?

 

[DandyDon]

Aren't there special lubricants which are supposed to mitigate the risk of oils breaking down into co2?

Yes, except the diver never knows what was used, how the compressor was maintained, etc. unless he happens to also be the compressor operator. There is only one way to know if a tank is safe, by testing the gas in the tank. Every tank used, even if the other hundred off the same compressor were ok.

 

[Superlyte27]

Carbon monoxide (CO) is a gas that is present in the exhaust gas of internal combustion engines, including those often used to drive compressors. It also comes from the breakdown of lubricating oil when compressors run too hot.

You are using either the wrong oil, or the compressor is not operating properly. The right compressor should be able to run all day without overheating if you are inclined to run it all day. If the compressor is running properly but overheating, you've got the wrong compressor with the wrong service rating.

 

[swamp diver]

Running too long or getting too hot really has nothing to do with CO levels.

Unfortunately that is not the case. There are numerous examples of electric-motor driven compressors which have produced carbon monoxide internally. The most famous one is likely the Montreal fire service compressor that would reliably produce CO only 3 hours into a run when the compressor reached a temperature hot enough to autoignite the compressor oil. Carbon monoxide levels as high as 250 ppm were found in the SCBA tanks.
Carbon monoxide and water vapor con... [J Toxicol Environ Health. 1997] - PubMed - NCBI

Poorly installed compressors with little to no ventilation and running mineral oils will reach temperatures which can ignite the lubricating oil. If there is no catalyst in the purifier the CO will go straight into the tank or storage banks.

DAN has published two articles now over the last decade on the rate of CO contamination in dive air and the laboratories (TRI and Lawrence Factor) report a failure rate of 3 percent at 10 ppm. The bulk of compressors out there are electrically powered so the large majority of those failures are from electric and not gas-powered compressors.

Here is a CO poisoning incident which was from an electrically driven compressor where the final stage malfunctioned (personal communication).
August 2008 Volume 18 Number 8

 

[Superlyte27]

Damn! :shocked2: Yes, I know you are an expert, but that is just wrong - and so illustrative of why we can't fix this ongoing problem.

I guess you didn't know that an electric powered compressor can produce dangerous CO levels internally?


Yep. Thank you.

I repeat! If you are using the proper oil, and you are using the proper compressor for the job at hand, it should never overheat. If you have a compressor with a 2 hours service rating, and you are trying to run it 12 hours, you are using the wrong compressor. This isn't the compressor's fault. It's also not the oil's fault. It's your fault for using the wrong tool for the job.

If you need a compressor that will run 20 hours straight, without overheating, there are a ton of them out there. I can take pictures of ours if you like. It can run for 20 hours and the temperature doesn't climb even a degree.

Now, if you are running a compressor that hasn't been serviced, needs a valve job, ring job, has wrong oil in it, or only has a short service rating and it starts to overheat, well, then yah, you MAY get incomplete combustion of the oil causing CO. But who's fault is that?

---------- Post added July 3rd, 2013 at 07:06 PM ----------

Aren't there special lubricants which are supposed to mitigate the risk of oils breaking down into co2?

Yes, it's very hard to get the proper oils to burn. We used Monolich(sp) for years. I'm told there's better stuff out now.

---------- Post added July 3rd, 2013 at 07:09 PM ----------

Yes, except the diver never knows what was used, how the compressor was maintained, etc. unless he happens to also be the compressor operator. There is only one way to know if a tank is safe, by testing the gas in the tank. Every tank used, even if the other hundred off the same compressor were ok.

The oil we use is readily available. The service interval is on a placard right on the compressor with last service and next service date, the air quality report is in plain sight. However, unless people know what they are supposed to be looking for, none of this information tells the general public a single thing. They don't know what's acceptable for oil. They don't know how often that oil should be changed, or how often the compressor gets a valve job or what grade of air they should be breathing.

Education, like what is available on a lot of SB, helps.

---------- Post added July 3rd, 2013 at 07:14 PM ----------

Unfortunately that is not the case. There are numerous examples of electric-motor driven compressors which have produced carbon monoxide internally. The most famous one is likely the Montreal fire service compressor that would reliably produce CO only 3 hours into a run when the compressor reached a temperature hot enough to autoignite the compressor oil. Carbon monoxide levels as high as 250 ppm were found in the SCBA tanks.
Carbon monoxide and water vapor con... [J Toxicol Environ Health. 1997] - PubMed - NCBI

Poorly installed compressors with little to no ventilation and running mineral oils will reach temperatures which can ignite the lubricating oil. If there is no catalyst in the purifier the CO will go straight into the tank or storage banks.

DAN has published two articles now over the last decade on the rate of CO contamination in dive air and the laboratories (TRI and Lawrence Factor) report a failure rate of 3 percent at 10 ppm. The bulk of compressors out there are electrically powered so the large majority of those failures are from electric and not gas-powered compressors.

Here is a CO poisoning incident which was from an electrically driven compressor where the final stage malfunctioned (personal communication).
August 2008 Volume 18 Number 8

I think you guys are missing my point. A properly functioning compressor should not produce CO due to overheating. YES GIVEN HIGH ENOUGH TEMPS EVEN THE BEST OIL CAN START TO BURN...

My point, which clearly wasn't stated clearly (based on all the responses) is that a compressor shouldn't be overheating. Why is the compressor overheating? It shouldn't be overheating just because it's running long is my question and point. Even then... lets say a compressor is overheating, how hot is it getting? Why is it getting hot? Bad oil, wrong oil, bad valves, mechanical issues, consumer model instead of commercial model trying to run all day. What's the greater issue?

---------- Post added July 3rd, 2013 at 07:21 PM ----------

I can't find the flashpoint of Del1 Synthetic Oil anywhere. Anyone know what it is? Just wondering when it starts to break down.

 

[DandyDon]

I think you guys are missing my point. A properly functioning compressor should not produce CO due to overheating. YES GIVEN HIGH ENOUGH TEMPS EVEN THE BEST OIL CAN START TO BURN...

My point, which clearly wasn't stated clearly (based on all the responses) is that a compressor shouldn't be overheating. Why is the compressor overheating? It shouldn't be overheating just because it's running long is my question and point. Even then... lets say a compressor is overheating, how hot is it getting? Why is it getting hot? Bad oil, wrong oil, bad valves, mechanical issues, consumer model instead of commercial model trying to run all day. What's the greater issue?

Nope, I was just replying your blanket claim: "Running too long or getting too hot really has nothing to do with CO levels." which standing alone is totally wrong. Thank you for taking time to explain fully and correcting.

" However, if the intake..." is only part of the problem. The other part is hidden.

 

[swamp diver]

I think you guys are missing my point. A properly functioning compressor should not produce CO due to overheating. YES GIVEN HIGH ENOUGH TEMPS EVEN THE BEST OIL CAN START TO BURN...

My point, which clearly wasn't stated clearly (based on all the responses) is that a compressor shouldn't be overheating. Why is the compressor overheating? It shouldn't be overheating just because it's running long is my question and point. Even then... lets say a compressor is overheating, how hot is it getting? Why is it getting hot? Bad oil, wrong oil, bad valves, mechanical issues, consumer model instead of commercial model trying to run all day. What's the greater issue?

On the surface I agree with you. In an ideal world with the right compressor install, adequate ventilation, synthetic oil, large-bore remote intake, catalyst bed, and proper maintenance there should be no CO in our dive air.

Unfortunately in the sport diving world this is not the case. The bad economy has lead to lengthened service intervals for filters, oils, valves, etc., and lack of operator education leads to poor installs, oil choices, and a general lack of awareness regarding the important equipment and safety issues you highlight.

After the Montreal fire incident many of the fire services across Canada and the USA took a hard look at these air quality issues which resulted in upgraded equipment and operator training. The results have paid off because the rate of CO failure for fire service air is one-tenth that of dive air.

Until the dive industry lowers that 3 percent failure rate for CO we will continue to see injuries and fatalities from CO. The fire fighters have guidance and oversight of these issues through the NFPA and OSHA. In the commercial dive industry you have IMCA and ADC International providing guidance on air quality and OSHA often enforcing those guidelines when there is an accident within US waters.

There is no longer any oversight in the recreational dive industry with respect to breathing air quality (except in the state of Florida) so divers need to carry a CO analyzer to protect themselves especially when offshore in the tropics. Once PADI got out of providing guidance on compressed air testing for its affiliates in 2009 there is very little to no oversight of compressed breathing air quality in the sport diving industry.