Testing for bad air

[ilikediiiiving]

Long time listener; first time caller.

Had an interesting occurence that I would like your feedback on.

After the last dive of the season last November, my buddy and I brought our two sets of tanks (A&B), as well as our third buddy's (C) tanks for fills.

My buddy and I (A&B) always get our fills at this shop.
My buddy's (B) tanks have less than 5 fills on them--always clear and dry them after a dive/cleaning.

Our third buddy's tank (C) needed a visual--when it was opened, the shop noticed some water and rust. They cleaned and dried the tank and refilled it. It was stored (vertically) all winter.

This past week we went out for their first dives of the season; my second.

I had my tanks filled.
My buddy's (B) and our third buddy's tanks were topped off.

After surfacing from the first dive, the third buddy stated that he felt nauseous--started vomiting on the surface. We got him into shore and got him some food and water. He does get seasick easily, but the tide was mild--one-two foot seas max. Given that we were only at ~30 feet for less than 30 minutes, no risk of deco, the though of bad air crossed our minds, but since his condition didn't improve later in the evening when we checked in with him, we attributed it to coincidence and that he was likely coming down with something anyway.

We went to a different (closer to the dive site) shop to get refills for our second dive of the day and my buddy's (B) tanks just went out of visual, so they did the visual for him while we got lunch. When we returned, the owner said that she removed a decent amount of rusty water from the tank, but it was otherwise fine.

This got us thinking that there might be an issue with the compressor, at the very least with moisture, as my buddy (B) has never gotten fills anywhere but the LDS. As I was doing some research on possible causes for this on the boards, I noticed that I've come down with a nasty cough since the dives, which I attributed to breathing 3 tanks of dry air--my buddy(B) just called me and has the same cough.

Now we're starting to wonder if this is no longer a coincidence, but something up with the compressor at the LDS.

Is there an inspection requirement for the LDS compressors?
Does an inspection sticker need to be displayed near the station?
or is this up to the owner's discretion?

Is there some way we can test the "known good" sample of the third buddy's (C) air for contaminants?
Can any other LDS owners comment on a way to approach the shop about this?

Two things I don't want to have to deal with--water in new tanks and bad air--and ticking off the local shop if this is all coincidental.

 

[Doc Harry]

Is there an inspection requirement for the LDS compressors?

Nope. There are no regulations.

Does an inspection sticker need to be displayed near the station?

Nope. There are no regulations. A good compressor station will have their compressor's air analyzed by a lab such as Analytical Chemists and will be happy to provide you with a copy of the air analysis report on request.

Is there some way we can test the "known good" sample of the third buddy's (C) air for contaminants?

Yes, call a lab such as Analytical Chemists and request an air sampling kit with the necessary attachments to sample a cylinder.

You can also purchase a carbon monoxide analyzer to check your cylinders yourself every time they are filled. Bad air can and does happen.

Can any other LDS owners comment on a way to approach the shop about this?

I'm not an LDS owner, but I would just bring it up with the compressor station and ask to see their latest air analysis report. You can also ask them to check the cylinder for carbon monoxide if they have a CO analyzer (which they should). If they refuse, find another fill station.

Other questions come to mind:

Steel or aluminum cylinders? Corrosion in an aluminum cylinder is much less likely to affect the breathing gas than a steel cylinder. Corrosion in steel cylinders has been demonstrated to reduce oxygen content and increase carbon monoxide content in the gas. (original reference and summary write-up)

Was there a funny smell to the breathing gas? If not, the symptoms you describe (n/v) are similar to the symptoms one would get from mild carbon monoxide poisoning.

Your description of water in the cylinders is testament to the fact that water can and does get into cylinders. Many people assert that they don't need to properly inspect and maintain cylinders because "water isn't supposed to be in my scuba tanks."

The water in the tanks may not be the fault of the fill station. There's no way to tell if it's their fault or yours. As someone who has his own private fill station, I would say that the water in your cylinders is more likely to result from your handling of the cylinders rather than the fill station's.

 

[Web Monkey]

Is there an inspection requirement for the LDS compressors?
Does an inspection sticker need to be displayed near the station?
or is this up to the owner's discretion?

I don't think there's any compressor inspection requirement, but there is an air testing requirement at least in in NY State (not sure if it's state, federal or an insurance company requirement).

Considering what lab analysis costs, your shop should be proud to post the lab results. We put ours on the wall where the divers pickup their tanks.

After a few bad fills at various dive sites, I stopped getting outside fills where I wasn't 100% certain about the air quality.

You can test for CO with a small pocket tester, and you can test for really gross contamination with a white cloth, however there are all sorts of nasty things that won't show up with either of these tests, so I decided to just be really careful where I get air.

Terry

 

[deepstops]

Long time listener; first time caller.

Had an interesting occurence that I would like your feedback on.

After the last dive of the season last November, my buddy and I brought our two sets of tanks (A&B), as well as our third buddy's (C) tanks for fills.

My buddy and I (A&B) always get our fills at this shop.
My buddy's (B) tanks have less than 5 fills on them--always clear and dry them after a dive/cleaning.

Our third buddy's tank (C) needed a visual--when it was opened, the shop noticed some water and rust. They cleaned and dried the tank and refilled it. It was stored (vertically) all winter.

This past week we went out for their first dives of the season; my second.

I had my tanks filled.
My buddy's (B) and our third buddy's tanks were topped off.

After surfacing from the first dive, the third buddy stated that he felt nauseous--started vomiting on the surface. We got him into shore and got him some food and water. He does get seasick easily, but the tide was mild--one-two foot seas max. Given that we were only at ~30 feet for less than 30 minutes, no risk of deco, the though of bad air crossed our minds, but since his condition didn't improve later in the evening when we checked in with him, we attributed it to coincidence and that he was likely coming down with something anyway.

We went to a different (closer to the dive site) shop to get refills for our second dive of the day and my buddy's (B) tanks just went out of visual, so they did the visual for him while we got lunch. When we returned, the owner said that she removed a decent amount of rusty water from the tank, but it was otherwise fine.

This got us thinking that there might be an issue with the compressor, at the very least with moisture, as my buddy (B) has never gotten fills anywhere but the LDS. As I was doing some research on possible causes for this on the boards, I noticed that I've come down with a nasty cough since the dives, which I attributed to breathing 3 tanks of dry air--my buddy(B) just called me and has the same cough.

Now we're starting to wonder if this is no longer a coincidence, but something up with the compressor at the LDS.

Is there an inspection requirement for the LDS compressors?
Does an inspection sticker need to be displayed near the station?
or is this up to the owner's discretion?

Is there some way we can test the "known good" sample of the third buddy's (C) air for contaminants?
Can any other LDS owners comment on a way to approach the shop about this?

Two things I don't want to have to deal with--water in new tanks and bad air--and ticking off the local shop if this is all coincidental.

Florida has a law in place that sets the standard for scuba air quality: Compressed Air Standards for Recreational Diving

My LDS is rather proud of the gas they sell and posts their test results quarterly: http://www.fillexpress.com/library/testresults.pdf

Your description of water in the cylinders is testament to the fact that water can and does get into cylinders. Many people assert that they don't need to properly inspect and maintain cylinders because "water isn't supposed to be in my scuba tanks."

The water in the tanks may not be the fault of the fill station. There's no way to tell if it's their fault or yours. As someone who has his own private fill station, I would say that the water in your cylinders is more likely to result from your handling of the cylinders rather than the fill station's.

Water usually gets in the tank at the start of the fill process because of water in the valve orifice. Doing the fills dry and cracking the valve open for a second or two prior to filling will pretty much eliminate the possibility.

 

[JDMerk]

Other questions come to mind:

Steel or aluminum cylinders? Corrosion in an aluminum cylinder is much less likely to affect the breathing gas than a steel cylinder. Corrosion in steel cylinders has been demonstrated to reduce oxygen content and increase carbon monoxide content in the gas. (original reference and summary write-up)

Rust has nothing to do with the production of carbon monoxide.
4 Fe+ 3O2 + 6 H2O= 4 Fe(OH)3
Notice there is no carbon in that equation...however it can reduce the oxygen content but by in large that is a lesser concern due to hemoglobin's affinity for CO being 200X than for O2.
Carbon monoxide is a byproduct of incomplete combustion, if the compressor was detonating due to high heat/hydrocarbons...then yes carbon monoxide may very possibly be present...and thats a big deal.
A good fill station should have their air tested regularly and have a CO/moisture detector, as well as standard breathing air filters and possibly hyper filters. If all their ducks are in a row they should have no problem showing you their setup.

 

[Doc Harry]

Rust has nothing to do with the production of carbon monoxide.
4 Fe+ 3O2 + 6 H2O= 4 Fe(OH)3
Notice there is no carbon in that equation....

Again, the quoted study revealed increased levels of CO in highly corroded cylinders, but not in control cylinders filled at the same time. I can't explain it, I'm just repeating the study data.

Actual data: (gas analysis after induced corrosion period)

Highly-corroded steel cylinder:
oxygen 15.0%
carbon monoxide 10 ppm
carbon dioxide 0.01%

Two matched aluminum cylinders (filled at the same time):
oxygen 20.9% (in both cylinders)
carbon monoxide 3.0 ppm and 3.5 ppm
carbon dioxide 0.03% (in both cylinders)

Go figure.

 

[ilikediiiiving]

Doc,

Thanks for the informative response.
I'll request a copy of their analysis and look into the CO detector you referenced.

To answer your questions:

My (A) Steel LP85 tanks, purchased last October with approximately 12 dives on them--they aren't due for visual again until October, but I think it might be worth my while to have a look inside to mitigate any water penetration, as occurred with my buddy's (B) steel HP100s purchased last summer with about the same amount of dives as mine.

The third buddy (C) who got sick had older aluminum tanks that were just inspected and cleaned last fall--this was his first dive of the season on them--visual, initial fill and topping off all done at this same shop.

Thanks again.

 

[ilikediiiiving]

Thanks everyone for your insightful and well-referenced responses.
I haven't seen any certificates or analyses posted at any of my LDSs.

I'll inquire about their practice and let them know what happened on our dive and see if it gets me anywhere; else, I'll start driving somewhere that I trust.

Thank you again.

 

[Goindrinkn]

I'd like to toss in something that happened to my wife and I when we were newer divers - after not diving for a few weeks, we were at a beach site and began the dive, a few minutes in she signaled an issue, and we surfaced. She said she was feeling sick and that she thought the air was a little "funny". ---I took a few breaths off the reg and sure enough there was something a little odd about the "taste". So we swam back and swapped her over to one of my tanks that was filled at a different time. It got better but there was still a bit of a funny taste for a few minutes and we thought it might have blown something into the line etc. Long story short, after testing the gas in the orignal cylinder it was fine. The manager at our LDS was concerned enough that he hooked it up and breathed the gas for a few minutes after testing just to see if it was anything. Turns out that when she went to store it after the previous dive she inadvertantly trapped some water in the second stage. It had gone nasty and grew a little something that became rehydrated when she put it in the water, but eventully flushed out.

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? esp if they had been put up for awhile. And the rust might be a coinsidence. I'd probably have them looked at..

Anyone have a similar experience?

 

[Cave Bum]

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.