Testing for bad air

[rstofer]

Being that you said this was Buddy C's first dive since putting the tanks up, and it sounds like you also had the fills at the same time, and that you guys did not exibit the same effects, is there a chance that the cause wasn't the cylinders, but the regs?

The idea of something growing in the regulator is a very real possibility. Something to think about...

Richard

 

[JDMerk]

If the CO level did go up in that study then something else was going on in that cylinder other than just rust, or the testing procedure was faulty.
On the other hand this pdf on breathing air (grade D not grade E) stated that the acceptable limit for CO is 10ppm. Now I know grade E is different but it is very similar to grade D air and the CO level in that study still falls within the acceptable limit for grade D breathing air.

http://www.intecweb.com/_05Vdocs/a33.pdf

 

[Graeme Tolton]

C0 is elevated because carbon is one of the ingredients in steel. This is covered in a previous thread. This is worsened with higher nitrox blends.

 

[Doc Harry]

One other thing to keep in mind is that the analysis is not an 'apples-to-apples' comparison between shops. It's open to variation depending on how the shop owner or manager happens to take the sample. There is no defined procedure for doing that.

In one fill station I worked in, they would come in, replace the filters, run the compressor for 10-15 minutes and then take the sample directly off the output of the compressor. Amongst other things this completely bypassed the storage bank so this analysis was in no way representative of what came out of the whips when we filled tanks.

Good point.

This year I decided to test my air before my annual compressor servicing and filter changes. After the compressor warmed up for an hour, I took one sample directly off the compressor and a second sample from the fill whip (downstream from the filter stacks).

Now I'm going to clean my system and replace the filters and then get another air sample from the fill whip.

I am interested to see what kind of results i'm going to get.

 

[JDMerk]

C0 is elevated because carbon is one of the ingredients in steel. This is covered in a previous thread. This is worsened with higher nitrox blends.

If that is the case, im wondering if the problem exists for both 3A (Carbon steel) AND 3AA (chromoly steel) or if it primarilly effects 3A (Carbon steel) cylinders. Any idea which cylinders were tested in this study?

If the study only effects 3A tanks then its pretty irrelevent since they arent produced any more.

 

[Doc Harry]

If that is the case, im wondering if the problem exists for both 3A (Carbon steel) AND 3AA (chromoly steel) or if it primarilly effects 3A (Carbon steel) cylinders. Any idea which cylinders were tested in this study?

If the study only effects 3A tanks then its pretty irrelevent since they arent produced any more.

The study that I quoted above used new 3AA steel cylinders.

 

[ilikediiiiving]

Just learned from Buddy B that a friend of his (heck, let's call him D) was also out for his first dive of the season last week and also got a fill from this same dive shop. He surfaced and also started rebooting. I think a pattern is developing...

I'm going to take my tanks to the one dive shop (about 30 minutes away) that seems to take pride in their compressor/fills (which one would presume to be the lifeblood of any dive shop?!) and have a vis performed, albeit four months early, to see if there is water in my tank as well--if so, that either means that all four of us, with a mix of aluminum, HP and LP Steel, yoke and DIN, new and older tanks are either all doing something drastically wrong, or the fill procedure/compressor system at this shop needs improvement.

Thanks again.

 

[james croft]

A good rule of thumb is to change filters whenever the canary dies.