Non-O2 Clean Air in Nitrox tanks?

[Sonic04GT]

Haha I will read over the hijack later.

But yeah, the main thing is, I have dived steel tanks pretty much since I got certified a few years ago, and I love them. I avoid using AL80s whenever possible, or even renting tanks period, since I paid $700 for the pair, I need to use them. The buoyancy characteristics are GREAT, and the capacity/physical size of course.

I guess some people missed the point that I will be getting them VIP'd at the end of the month and they will not contain nitox until then. The question was, I of course want the O2 clean rating, so during every VIP do they clean the tanks anyway and slap a new O2 compatible sticker on? As I thought this was mainly a "visual inspection" how do they actually clean for O2?

The fill station has been providing air for years, it's one of the better known dive spots in central TX, so if there was an issue with air quality itself it probably would have surfaced by now. Their fill station definitely looks interesting though. I believe they told me a year or 2 ago that they are actually using missile silos out of an old submarine converted to hold air, then they just slapped a compressor on that haha.

Windy Point Park

As for a little background on WHY I came to TX to dive, from FL

I was stationed at Fort Hood, with my dive buddy, in the Army for a year and a half. I met my girlfriend here, and he met his girlfriend here. We got out of the military last year. He came to stay with me in FL for a little while, did some lobstering and some ocean dives, and once he found out he didnt get into commercial dive school, he went back to TX to be with his girlfriend before she deploys soon. Well, during that time, my girl and his girl got open water certified together, so, well, here I am diving TX again for a couple weeks. Threw all the gear in the car and drove out here before I start school soon.

Let me tell you, IT SUCKS, but at least the 4 of us are together. Camping there tonight, doing a night dive, then diving in the morning. There's a shop 15 mins away that can fill the tanks but they'll be closed by the time we finish our first dive, and they won't re-open until after we are scheduled to leave the next morning.

I miss FL, where you can't have enough dive shops haha

 

[FWADIVER]

Pete, hate to further the hijack, but oxidation of carbon containing compounds (ie oil) produces co2, it only produces co in rare cases of hypoxic environments, which is not most definitly not the case during a partial pressure o2 fill. I still find it very unlikely its possible to get co poisoning from a oil contaminated tank and pressurized o2 the chemistry doesn't add up. You might convince me that diesel fumes plus pressurized o2 = co, that reaction is more plausible given my quick back of napkin stoichiometry here. Claiming what you are is how ideas like "you will get bent breathing nitrox" becomes common knowledge.

 

[The Chairman]

Pete, hate to further the hijack, but oxidation of carbon containing compounds (ie oil) produces co2

You should tell the automakers this. How in the WORLD do their auto engines produce CO??? Why do they need those catalytic converters? This is especially true since they tend to run mixtures very lean. Combustion is rarely perfect or complete and CO is one of the many by-products of the process.

CO is the result of an incomplete oxidation of a hydrocarbon. This can happen from a lack of oxygen or insufficient heat. We obviously have a lot of O₂ in a Scuba Tank. At 3,000 air has a PPO₂ of over 42 ATM. 600 psi of O₂ would be right at 40 ATM. As the hot O2 starts the combustion process, the relatively cool tank wall quenches it, producing more CO than CO₂.

it only produces co in rare cases of hypoxic environments,

Contrary to your former protestation otherwise, it would appear that your understanding of combustion seems to be lacking. Combustion WITHOUT producing any CO is a rare event. Combustion with CO is so common that its a given.

Claiming what you are is how ideas like "you will get bent breathing nitrox" becomes common knowledge.

Again, since you claim to understand all of this more than I do, I ask for a third time: Why bother with Modified E grade air, when you maintain that E grade is more than sufficient? Are you suggesting that this is merely hype generated by people who also claim that breathing NirtrOx will get you bent? Why the rule if there are no benefits?

Stoichemistry is a wonderful discipline that is often trumped by reality. Reactions are seldom as neat as your paper napkin, since pressure and heat can be real party poopers and throw in some nasty surprises for you.

PS, as you try to get your mind around this, don't forget the effects of thermolysis of hydrocarbons at elevated pressures of O₂.

 

[The Chairman]

The question was, I of course want the O2 clean rating, so during every VIP do they clean the tanks anyway and slap a new O2 compatible sticker on? As I thought this was mainly a "visual inspection" how do they actually clean for O2?

If tanks are filled at the shop where the original cleaning was done, they are usually given a "pass" during VIP. If tanks are commonly filled elsewhere or filled by a shop that only has Grade E, then they will probably charge you for cleaning your tanks. The charge for this varies widely, as does the competency, so check ahead BEFORE you fill them.

PS, I also love the weighting characteristics of steel tanks. Fill Express offers banked NitrOx as do other shops. Getting your tanks filled there obviates the need for O₂ cleaned tanks.

 

[Teljkon]

Haha I will read over the hijack later.

so during every VIP do they clean the tanks anyway and slap a new O2 compatible sticker on? As I thought this was mainly a "visual inspection" how do they actually clean for O2?

The Real answer is depends on the shops practices you need to talk to the guy or gal at the place doing the vip. Find out if the charg for a vip on a nitrox tank includes a O2 clean.

A O2 clean is not considered to be part of a vip by most shops as stated by net doc. But all vips on nitrox tanks should include a check for hydro carbines with florescent and white light.

Oxygen cleaning simply involves washing all interior parts of the tank in a fomula that can remove hydro carbons as well as other contaminates in the process. Usually this is combined with a mild abrasive that wont harm the interior of the tank walls to removing light rust or oxidation. The tank will actually be tumbled with this inside. Finally the valve and assembly is usually cleaned in a hypersonic cleaner with the same formula. Then every thing is re built with O2 safe O rings and lube and the tank is dried and reasmbled.

Thats just the facts as i know them remeber that there is alot of debate on this its almost like you can ask how saftey conservative are you about O2 cleaning for nitrox. Are you a by the book CGA (compressed Gas association) PSI/PCI guy or are you a laid back Osha guy.

Some may say you need a O2 clean as soon as you pop your valve for a VIP others only if it dosent pass the Florescent section of the vip no matter what kinda machine its been on. So IDK man you opend a can of worms that every diver needs to figure out for them selfs as YOUR ULTIMATLY RESPONSIBLE FOR YOUR SAFTEY.

You should probably rent it could save you a buck at vip.

Fire triangle - Wikipedia, the free encyclopedia

 

[Teljkon]

OMG did I just say laid back and osha in the same sentence

 

[rescue15]

Combustion and oxidation, while similar, are not interchangable. CO is from incomplete COMBUSTION, not incomplete oxidation.

I think you are ignoring probable cause of the posibility of contaminated environment when the compressor was filling the tanks prior to the partial pressure blending (at the previous fill). There is nothing wrong with partial pressure blending.

Steve

 

[The Chairman]

Combustion and oxidation, while similar, are not interchangable.

Perhaps you are ignoring the possibility of ignition for 40 ATM of O2 with an elevated temperature.

I think you are ignoring probable cause of the posibility of contaminated environment

No, I am not ignoring the "probable cause". I know where the intake and the compressor are in that building. There is no chance for an internal combustion engine to get close and the compressor is electric. Also, no one else got sick.

You are free to believe what you want, as am I. While you may think there is no issue filling contaminated tanks, I have found the opposite to be true. Since I have no control on how a shop fills my tank, I am quite wary of PP Blending. I prefer to get my tanks filled from a banked system and I vote with my feet. Here in Key Largo, you can find my tanks being filled by Horizon Divers. Good people, safe system and wonderfully consistent gas.

 

[colint]

Surely this argument is moot as a cylinder is only considered oxygen clean for 15 months after the last clean, even if only filled with modified E grade air.

Colin

 

[RTee]

Renting will probably be cheaper than O cleaning the tanks again. If in doubt rent the darn things, add up the five or six pounds difference and just enjoy the diving and the company.

As to the difference in air between a HP 100 filled at 3000 psi and an 80, it is so minor that at best it may provide you with an additional 5 minutes of diving perhaps, unless you are planning to dive very shallow...

HP will give you extra diving time...let's see. I remember diving with a friend who was using steel 100 HP tanks while I had only 80s at the time. When she said that she wanted to dive with her 100 because of the extra dive time she would get I told her that her tanks would only last as long as my 80...because being my diving buddy, she would have to come up when I did . So we used her 100s on the first dive and then my 80s on the second.