Bad air?

[Ryan Nelson]

I just received two hp fills at a shop and when I hooked up my regulator and ran thru my checks I noticed a funny aftertaste kind of like something burnt. My girlfriends tank was the same way. Breathed thru both octo and reg same results then switched to backup reg and still the same. Also had a bitter aftertaste and burning on the throat.

I called the dive shop I got the air from and he assured me that he only uses vegetable oil in his compressor and that if there was any issue it would certainly be non toxic. I didn't feel comfortable taking his word for it so I bled the tanks in my van. The van subsequently filled with somke...

My questions-
Is this guy full of ****?

Did I ruin my tanks? Should they be cleaned as a precaution?

Am I over reacting?

 

[Brandon]

Yes, he's full of crap. Clean the tanks and switch shops.

 

[kwinter]

You should have borrowed a CO detector and tested it right in front of him. Then made him breathe the tank empty after signing the ownership of the shop over to you.

 

[Ryan Nelson]

When you say clean, do you mean tumble or o2?

We left the shop as they were closing, didn't realize the air until we were at the dive site.

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[swamp diver]

I agree you should have tested the tank air for carbon monoxide before dumping them.

I have only seen "vegetable oil" used once in a compressor in the Caribbean and this was discovered after two divers had died of CO poisoning. If he is truly using a vegetable oil he must have gone to the supermarket and purchased sunflower, canola, or rapeseed oil. None of these oils have the properties required such as sufficient flash point to safely lubricate a high pressure breathing air compressor so eventually these oils will auto-ignite and produce CO.

More often when an uneducated compressor operator says he is using a vegetable oil it turns out to be a "food-grade" oil which is typically a polyalphaolefin (PAO), a synthetic hydrocarbon oil. Whether or not they are any safer than the typical synthetic ester oil used in most HP compressors is open for debate and most knowledgeable industry persons will say to choose the ester over a PAO compressor oil for high pressure use because the ester has greater thermal and oxidative resistance.

If you can detect any oil mist residue in your tanks or if you detect an odor imparted to the inner tank wall I'd send them in for O2 cleaning. And find another dive shop.

Just curious what country are you in?

 

[Ryan Nelson]

Thanks for the info. This was a shop in Santa Barbra, CA. I've got air from them one time before with no noticeable issues.

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---------- Post added July 6th, 2014 at 07:51 PM ----------

I bled the tanks solely because of the fear of saturation in the tank walls.

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[NAM001]

There is no threat of wall saturation..... Perhap the shop would hve cleaned them for you. second thought naaa

Thanks for the info. This was a shop in Santa Barbra, CA. I've got air from them one time before with no noticeable issues.

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---------- Post added July 6th, 2014 at 07:51 PM ----------

I bled the tanks solely because of the fear of saturation in the tank walls.

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[Ryan Nelson]

I was just denied a fill at a shop after explaining the situation to them. They said I needed to have tank re hydroed and viz to make sure it's still ok. I understand this is bs, but his logic was there is still bad air left in the tank even after its been completely bled out, maybe it's true but it can be enough to make a difference right?

Anyway I had them filled at another shop and the air has no noticeable taste...The shop I filled mine at only had a meter for oxygen.

Thoughts?

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[Dsix36]

Getting another hydro is unnecessary since the "bad air" will not effect the tank integrity. The fact that there was "bad air" in those tanks does indicate that they need to be cleaned though. If they are not going to be cleaned, then at the very least another VIP with an inspection for hydrocarbons needs to be done. Just because you can not taste or smell anything now does not mean that there is not oil residue left inside the tank.

 

[Scubadude_LA]

Did you breath gas from those exact tanks on the fills prior to the bad ones?
If so and the problem is new to the recent fills, I assume the bad gas came from the last fill you received, in which case the shop is the culprit.

- Vegetable Oil, alarm bell #1
- Hydros are good for 5 years and have absolutely nothing to do with air quality, that is alarm bell #2.
- Vis could be justified, maybe.
- CO is odorless and tasteless, you would not have detected it if it was present without an analyzer.
- If it's as bad as you say, I doubt you were the only victim.
- you did the right thing by bleeding the tanks (except for having a sample)
- good reason to spend $170 on a CO analyzer.

Compressor intakes should NEVER be positioned downwind of operators that ate beans the night before. Methane is serious at higher partial pressures!