How often do most shops in your area require Nitrox tanks to be O2 cleaned?

[DA Aquamaster]

Its actually the valve that is the most important O2 consideration as scuba valves are not designed for O2 service and come "on" very fast and do not have the worlds smoothest flow paths - both can cause compression and heating due to flow dusturbance.

The tank itself is pretty innocuous even with 100% O2. O2 cleaning reduces fuel, but that is a moot issue without an ignition source.

The general practice now, legal and insurance paranoia aside, is that a tank does not need to be O2 cleaned unless you are using a mix greater than 40% or are transfilling 100% O2 into the tank.

Lets be real here. Many shops mix via a stick running mixes up to 40% through their very non oil free or non 02 compatible compressors and they are not blowing up. At that point asking a diver to O2 clean a tank just to get a banked, membrane or stick fill of 36% is just plain stupid and suggests the motive is profit on the O2 cleaning, not safety.

For mixes over 40% or for partial pressure fills, absolutely a VIP is not enough, they should be O2 cleaned at least annually.

 

[PhilEllis]

All that said, you are right. You should not necessarily have to have your tanks fully O2 cleaned annually. Before taking that step, the shop should inspect the inside of the tank with an ultraviolet light to see if there is any indication of contaminants. If they find none then your tanks don't need to be cleaned...they already are.

You can't use a UV light to inspect for the presence of hydrocarbons at the parts per million level in a scuba cylinder. Now, I don't object to the use of a UV light, any more than I object to the use of a fortune teller, when inspecting cylinders. However, I DO OBJECT to any inference that you can use a UV light (or a fortune teller) to determine if a cylinder is safe for oxygen service.

In the scuba diving industry, THE ONLY WAY we can make a statement as to the cleanliness of a cylinder for oxygen use is through the application of a proven, predictable, and tested cleaning process. Like many things in life, we use the process as proof when making measurements is too difficult or too expensive. Testing for the presence of hydrocarbons in a scuba cylinder would require the application of a milipore weight test, or some other qualitative examination. These methods are too expensive, too time consuming, and not available to scuba stores in the United States or anywhere else in the world.

The repeated introduction, fill after fill, of E grade or modified E grade breathing air still results in the introduction of hydrocarbons into the cylinder. They can accumulate with repeated introductions of "clean" air. It is essential to follow a cleaning process before placing a sticker on a cylinder that says you "certify" or "authorize" the cylinder for oxygen use. Result, cleaning before you place any sticker on a cylinder. I agree with your LDS.

Now, the issue of how much they charge for that service is a store by store issue. If the prices doesn't suit you, look for better prices elsewhere. But, their initial response that cleaning is required is correct. Please remember....my response is based on the assumption that you are approving the cylinder for a filling method or application that first introduces pure oxygen.

Anyway, just my opinion.

Phil Ellis

 

[PhilEllis]

You are wrong. There's no need to clean a tank that is already clean. Whether or not there are contaminants in a tank can be verified adequately with a UV light.

I'm not sure what you mean by "normal" air. However, the quality of the air for any decent shop in the U.S. should be tested on a regular basis and the results of that testing will be posted. If a shop's air is determined to be Grade E then it is basically free of the contaminates contained in the air we breath "normally," and has a very low level of humidity. Grade E air will not contaminate your O2 clean equipment...tanks, valves, regs...that is if it is still Grade E when your tank is filled.

Where, exactly, did you get the wisdom that lead you to these conclusions?

Phil Ellis

 

[mike_s]

You can't use a UV light to inspect for the presence of hydrocarbons at the parts per million level in a scuba cylinder. Now, I don't object to the use of a UV light, any more than I object to the use of a fortune teller, when inspecting cylinders. However, I DO OBJECT to any inference that you can use a UV light (or a fortune teller) to determine if a cylinder is safe for oxygen service.

In the scuba diving industry, THE ONLY WAY we can make a statement as to the cleanliness of a cylinder for oxygen use is through the application of a proven, predictable, and tested cleaning process. Like many things in life, we use the process as proof when making measurements is too difficult or too expensive. Testing for the presence of hydrocarbons in a scuba cylinder would require the application of a milipore weight test, or some other qualitative examination. These methods are too expensive, too time consuming, and not available to scuba stores in the United States or anywhere else in the world.

[snip]

Phil....

I was going to reply to his earlier post with a similar reply but you beat me to it....

A tank is "dirty" (with hydro-carbons) way before you can see it with your naked eye.... even with a UV light..



A tank is only as clean as it was when it was last cleaned... using a set procedure.....

 

[PvilleStang]

Also, if you dive Nitrox with a shop that does partial fill mixing, then you definitely should do it every year. If you don't, it could cause an internal fire in your tank during the O2 adding stage, and your tank would be ruined, to say the least. AND you'd be endangering the life of the shop workers filling the tank. Come to think of it, this could turn out better than expected. DON'T ever O2 clean your tanks, rinse the inside after every dive, but DO NOT allow to dry. </sarcasm>

In all reality, o2 cleaning your tanks is a necessity. BUT, on a different note, I've just got to ask this one:

Faber, when delivered from the factory, is claimed to have O2 cleaned tanks, and seem to be powdercoated on the inside. Is it actually necessary to tumble them (and strip off that paint) in order to clean them?

 

[Mack Diver]

$75 for o2 cleaning is way on the high side for me. but so is $20 bucks for a visual.

I've never heard of a shop charging that high....

I think $75 to O2 clean the tank and valve is a bit on the high side, but not by much. When you look at the time required to drain the tank, clean it, dry it, disassemble, clean and reassemble the valve with new parts, inspect the tank and then fill it, you are talking about a labor intensive process.

Even a regular visual inspection takes time and it is not like you can do other things while you are inspecting the tank. If you compare the hourly rate to what mechanics, plumbers, electricians, etc charge, then it does not seem that out of line.

For the record, anyone who tells you a steel tank is full of rust, without looking inside 1st, should be avoided. As my niece likes to say "Run away bravely".

 

[JessH]

Lots of responses but doesn't look like anyone has answered the actual question that I asked. So does anyone mind letting me know what the policies of some other shops in the area are?

Mack, according to your website it looks like you require some sort of wash but not a full O2 clean on a yearly basis, is this correct? Also the prices on your site look reasonable enough that I would not be as hesitant to do a full O2 clean on a yearly basis. Keep in mind that that $75 I mentioned did not include the $20 for the visual, and I have a feeling they would have charged me extra for a nitrox fill with it. So we are talking about $100/tank. If your shop was closer to me it would have definitely been the first place I stopped, but the distance is kind of a pain especially if its anywhere near "rush hour."

I really wish someone would start banking atleast EAN32 in the area so we wouldn't have to worry about this whole mess. Rumor was that aquasports was going to but now that they're gone that's definitely not going to happen.

~Jess

 

[danktex]

Most shops I have come across require annual cleaning of the tank and the valve. I also agree with Phil that ultraviolet light can not detect small enough amounts of contaminants. It is only good as a gauge in seeing that some exist not that none exist. $70 is high not to include VIP and a nitrox fill.

I clean my tanks and valves every year. It is not that hard and gives me piece of mind. I started doing this after witnessing enough "O2 cleaning" by a shop that sometimes never involved removing the valve only changing stickers. Oh and of course charging for it.

 

[ianr33]

I clean my tanks and valves every year. It is not that hard and gives me piece of mind. I started doing this after witnessing enough "O2 cleaning" by a shop that sometimes never involved removing the valve only changing stickers. Oh and of course charging for it.

But where are you going to get your fills when this shop goes out of business due to you no longer paying for O2 cleaning ?

 

[danktex]

BTW most shops test their air after changing filters........