Yay, advanced C-card

[pufferfish]

Steve, I think you misunderstand what I am saying - look at the Z180.1 standard. Fill stations that conform to Z180.1 and have regular testing I would consider to be clean air, but the standard still allows for 1 mg/cubic meter of oil/particulates and still be considered clean (IANTD allows for 0.1 mg/m3). My supposition is that depending on the type of oil/particulates that makes it O2 compatible or not.

I never said that bad lubricants are not a bad air problem - I believe in high enough concentrations they are. But in the amounts allowed by the standard, according to the standard, they are not.

Warren I don't think the type of compressor lubricant has any bearing on whether the air is oxygen compatible (OCA) or not other than I suppose one might be more likely to have problems with the non-synthetic oil (mineral oil) IF the fill station manager doesn't change the oil at the prescribed interval which is more frequent with the mineral oil than synthetic. The mineral oil also has a lower operating temperature so if you are running the compressor on those days here with temps in the low thirties and the compressor is in a small space with poor ventilation sucking air through a thirty foot, two inch intake 'straw' you will be more likely to get persisant vaporization of the oil or worse some silent combustion of the lubricating oil with CO production. Basically mineral oil is cheaper but requires more freqent changes which don't always get done.

The particulates can come from two sources. One is smog, pollens, dust, etc. entrained in the intake air. Particulates less than 10 microns have been identified as having both cardiac and respiratory effects especially the fine portion. Remember with any of the contaminants their toxic effects follow the same partial pressure rules as the other gas components. Message here is don't bank air on smog alert days. The other source of particulates comes within the compressor and can be from oil leaking around bad piston rings or filter media that has escaped into the air stream,etc.

OCA air is basically air where the oil and particulates, CO2, and CO allowable maximums have been lowered. Oil and partics because of the explosion hazard and CO2 as elevated levels of CO2 dilate the cerebral arteries and raise not only the risk of ox tox but also potentiates CO toxicity.

Actually what is OCA air depends on who you talk to and there is a Navy, IANTD, and ANDI standard but they are all quite close with regard to the above contaminants.
Oil and partics .1 mg/m3
CO2 500 ppm
CO 2 ppm

With our Canadian CSA Z180.1 standard you may or may not have OCA air. You will have to check the cert itself for the above three contaminant levels as CSA allows 1 mg/m3 of oil and partics and 5 ppm CO. The CO2 allowed level is the same.

I don't want to get into another raging debate of air quality standards suffice it to say the quality of air in Ontario probably ranges from 'Perrier to Walkerton' depending where you are. If a shop is only testing once a year using an unaccredited lab then buyer beware. There are just too many things to go wrong with a compressor or filtration to assume that yearly testing is of any use to the diver.

As far as where to get your Nitrox around the GTA I don't think there are many options to begin with. I'd scratch off any shop that is only testing annually or is using an unaccredited lab. Then look for ones testing to the current CSA Z180.1-00 standard. That should knock off a few more shops. If the cert is more than six months old a few more shops can be eliminated. Figuring out the two remaining shops is not very difficult.

Here is a good link on some of this stuff from Global. It is a bit dated and the CO2 should be listed as 500 ppm.
http://www.gmcscuba.com/engineering_nitrox.htm

OCA air is also known as 'modified Grade E' as shown on this NAUI page.
http://www.naui.org/ethics/NAUIAffiliateCodeOfEthics.html#GradeE

 

[nauidiver2004]

Congrats. I'm enrolled in advanced now

 

[pufferfish]

As you say, you never know, as the diver, what it is you're breathing (purity wise). I'm hoping, with my CO analyzer to maybe catch (some) of those fringe problems before they become real life and death ones.

It's given me cause to pause and wonder about how I'm going to handle the "Here's your tank, now get in the water" type of situations while diving abroad.

Any thoughts? Other than making everyone and their dog wait while anal Steve analyzes the crap out of each and every tank he uses next time he's in Coz!

We did it again........This is about D/Rat's Adv course isn't it?

That always amazes me and moreso my non-diving friends that we just strap on a tank, often a rental one, and just start sucking away not knowing anything about the quality of air within. As a non-diver said to me that is about as wise as saying yah just give me that pint of blood but don't bother testing it before transfusion to see what nasties are in it.

Those two deaths in Mexico from contaminated air were very tragic and highlight the dangers of not questioning the quality of one's air source. Have a look at last month's DAN Alert Diver article on CO contamination in the US. A three percent failure rate is far too high.

Using the field CO detector especially when at unknown fill stations is the only way to ensure air purity just before you head down to 8 atm on trimix.

If you get the BC flow restriction device and sensor cap from Patrick at Oxycheq for I think $35 and drill a hole in the sensor cover you can test your fill in about a minute or two.
Here is a link as to how to do this.
http://www.denninger.net/diving/co-analyzer.htm

CO is the one contaminant that has the potential to kill you with little warning and is odourless and tasteless. Using a field detector is well worth the time involved and $100 for the device.

Drowned Rat just consider this supplemental material for your advanced and future nitrox course :biggrin:

 

[Tom R]

lets not start on the air standards in Ontario yet again, we have one of the highest in the world already.

 

[Warren_L]

Warren I don't think the type of compressor lubricant has any bearing on whether the air is oxygen compatible (OCA) or not other than I suppose one might be more likely to have problems with the non-synthetic oil (mineral oil) IF the fill station manager doesn't change the oil at the prescribed interval which is more frequent with the mineral oil than synthetic. The mineral oil also has a lower operating temperature so if you are running the compressor on those days here with temps in the low thirties and the compressor is in a small space with poor ventilation sucking air through a thirty foot, two inch intake 'straw' you will be more likely to get persisant vaporization of the oil or worse some silent combustion of the lubricating oil with CO production. Basically mineral oil is cheaper but requires more freqent changes which don't always get done.

Hmmm... I took the CSA approved compressed air course through my LDS which was required for anyone using the fill station. There was something mentioned about the type of lubricants used, but I can't recall specifically.....

 

[artw]

Most AOW divers still don't have fundamental control over buoyancy and need to work on this
Pat

shouldn't divers have this under control beforethe advanced course level? .....shouldn't divers have this under control shortly after OW checkouts?

 

[Tom R]

shouldn't divers have this under control beforethe advanced course level? .....shouldn't divers have this under control shortly after OW checkouts?

One would think so, but not a prereq for 99% of the training out there so deemed unimportant by most agencies and instructors.

 

[DrownedRat]

Jesus, those were some big fish eh? I've never seen so many in one dive!

Jeeez I'm getting all choked up here, LOL! Thanks for thinking of me 'Rat! Now I feel bad about all those rocks I was rolling at you on our safety stop last night...

And at least one of those kids was pretty far from wonderful tonight, yeesh!

It's mutual- You're not getting any younger, someone's gotta watch out for ya. I've got my eye on you, and Octo & Knife at the ready to defend you from charging Carp.
Matt.

 

[pufferfish]

Hmmm... I took the CSA approved compressed air course through my LDS which was required for anyone using the fill station. There was something mentioned about the type of lubricants used, but I can't recall specifically.....

I'd be interested in hearing what the specifics of that was. New info is always welcome. You can PM me so we don't bore the locals to death

 

[DrownedRat]

Couldn't agree more. Perhaps it was just the dive company I was keeping, but trim and bouyance control (I won't even start on proper weighting) has been impressed on me as being a critical basic skill. I've sort of starting thinking of is as a root process. From good bouyancy/trim comes comfort, then relaxation, then all the many benifets that stem from that including but no limited to better air consumption. This leads to longer and more enjoyable dives. Then of cours is the ease with which you can now accomplish nessissary skills once the trim/bouyance issues are taken care of.
I'm reminded of a dive several week ago out in Morrisburg (Airmiser can back me up on this one). We are doing the pumphouse station on the top of lock 23. He and I are enjoying ourselves, tooling around checking out the scenery, basically enjoying a nice peaceful dive. Now enter the rescue divers in training... We knew about them as we were chatting with them on the shore before entry. I don't usually like saying nasty things about people, but jeepers.. No courtesy at all. THey were all scrambling around trying to all be the first to whatever they wanted to see ( thought they were supposed to be in a class!). Kicking up silt everywhere. At one point instead of competing with these folks for a raised exit, I let one go ahead of me. Instead of using his hand to pull himself up and over (it was a stone wall)
he proceedes to get himself vertical and kick up. This of course caused a complete silt out for those of us waiting not to mention kicking me in the face. Losing my mask in a silt out is not my idea of a good time and after seeing this performance I did not want these guys rescuing me.

shouldn't divers have this under control beforethe advanced course level? .....shouldn't divers have this under control shortly after OW checkouts?