Nitrox fills

[beeger]

Funny how PSI seems to only enforce regulations that require the diver buying more inspections, more stickers, more tanks, which means more inspections, which means more cylinder inspectors, and ignore the rest. Remember, PSI is a private organization with no "official" status other than being a common denominator that some dive shops/dive operators fall back on. That email was yet another example of something so wrong it isn't worth the effort to try and straighten it out.

[LKunze]

I agree. Bottom line is it really doesn't matter. At least it's not an unavoidable problem since there is only one shop in the state you can't get air (EAN21 ) put into a tank with a nitrox sticker on it.

[ANewHope]

I have a question that probobly sounds stupid to everyone else but me, but is NITROX air more dangerous than "AIR" or not? (Fires, stuff that reacts violently to oxygen and the like) I, not knowing jack about nitrox, would assume that the higher O2 concentration would make the tank more dangerous to be around if lets say, your car was on fire. I wouldnt go near your smoking car to pull you from your car if I saw the nitrox sticker. So in a situation like this I could sorta see the reason for the rule. I know this is a stupid example, but I would think that there must be situations where an "oxidizer" would cause emergancy personel to act/react differently.

If I am wrong about the Nitrox being flamible or dangerous it may just be another way the government likes to protect us from our/my ignorance.

PS: LKunze, why not just have the shop fill your air with 22% OXY?

[LKunze]

Because I didn't feel like spending $9.00 per fill when I didn't need to.

[DanL]

FEDERAL Dept of Transportation regs? So, as long as I don't cross state lines with my 21% "nitrox" in my NITROX labelled tank, I won't be fined or imprisoned? Oops - forgot - MN always finds a way to ahve even more stringent regs than the feds.
Guess I'll carry my tank to the next dive rather than "offer it for transport" in my car.

[jasondbaker]

ANewHope, I would think that any tank of compressed gas would be hazardous in a fire. The tank explosion and resulting fragments may cause more damage than the actual contents of the tank burning.

I suggested to Lonnie that he go with ean22 but I think at that point he was already interested in other options. In hindsight this could have been resolved with a win-win for both parties. The shop could have recommended a ean22 mix at a reduced price to satisfy store policy and Lonnie's needs. Lonnie was not familiar with this store's policy and had driven a long way for some fills. The key is that Lonnie's needs would have been met and he would understand the store requirements in the future. The store would have a satisfied customer who would provide future referals.

[rudolph_medic]

The marking of the vehicle only is necessary when you are carrying over a certain quanity. The dive shop policy is only covering themselves from the DOT requirements- just like the hydro. Just because the tank is out of date for the hydro doesn't mean it will not accept an air fill, or a nitrox fill for that matter!

[rudolph_medic]

We have several dive shops here on the board- what is your opinions on this matter? What are your policies on this, and was the dive shop out of line?

[fantasea]

Honestly, there’s been so much debate (even behind the scenes) for the last decade or more on the use and filling of ‘enriched air’ versus ‘regular air’, and there never seems to be a law or something that stands undisputed or unchanged (like absolutes on DCS – there are no absolutes). As dive operators, even we were told misinformation from other colleagues and industry sources in the past, and now, just when you think you know something, it changes all over again.

Why can’t training agencies and divers all think of air as simply EAN21 or EAN22? We don’t think that this would confuse anyone if training agencies began their teaching curriculums for their beginning Open Water Divers with that simple mindset. This would seem to make transitions over to Enriched Air Nitrox, Tri-Mix, and other mixed gas learning much easier.

DOT standards on the subject may/will change next year, and then change again. Then they’ll change once more. It is hard to comment on their justifications. We don’t wish to knowingly break any laws.

By PADI standards (we cannot speak for other training agency standards), we can say the following:
It is crucial that no one accidentally confuse a tank of enriched air for a tank of normal air. Enriched air tanks are clearly marked to identify them as enriched air tanks. One method for blending enriched air requires putting pure oxygen in the cylinder and adding oxygen compatible air, this is called “partial pressure blending”. Because the tank valve and interior will be in contact with pure oxygen, if partial pressure blending will be used, the cylinder must meet oxygen service standards, even though the final enriched air blend may have less than 40% oxygen. (Standard scuba cylinders don’t typically meet oxygen service requirements until those standards/procedures have been applied.) Enriched air cylinders filled by other blending methods may not have to meet oxygen service standards, depending upon manufacturer recommendations, local law or local practice, but the cylinder must still be dedicated to assure proper markings.

Enriched air cylinders have standardized stickers and/or tags and color-coding generally agreed upon by the international dive community. These markings assure that you can readily identify an enriched air tank, determine its contents, and determine whether the cylinder can be used for partial pressure blending:
1. Yellow cylinders should have a 10cm/4 inch green band around the tank shoulder with yellow or white lettering reading “Enriched Air”, “Enriched Air Nitrox”, “Nitrox”, or similar designation.
2. Non-yellow cylinders should have a 15cm/6 inch band around the tank shoulder. The top and bottom of this band should be a yellow 2.5cm/ 1inch band, with the center 10cm/4 inches green – again with the same lettering/label as above.
3. Enriched air cylinders should have a dated annual visual inspection sticker (decal) stating that the cylinder has been serviced and inspected for enriched air use. The sticker should also indicate if the cylinder does or does not meet oxygen service standards for partial pressure blending.
4. Enriched air cylinders should have a contents sticker (decal) or permanent tag. This sticker/tag should be, at a minimum, list the oxygen content of the blend the cylinder currently holds, the fill date, the maximum depth for the blend, and the name of the person who analyzed the oxygen content to verify the blenders analysis (this should be the diver who will use the tank). Stickers and tags are replaced/rewritten when you have the cylinder refilled by the blender.
5. Besides the markings above, local laws and regulations may require additional or modified markings on enriched air cylinders. Some areas have recommendations or requirements that an enriched air cylinder be used within a given period, such as 30 days, and the cylinder may be marked accordingly.

The use of duct tap in addition to the markings above is a great idea for help in clear and easy identification at the surface and below, especially when staging.

We are in no way saying that this is a perfect system or the only system that should be used for air/enriched air use. We rest assured that as diving continues to develop, many new and useful ways of marking, analyzing, diving, transporting, storing, and maintaining scuba cylinders will continue to develop and improve.

Funny though, in some places we’ve seen outside of the US, the only marking that a tank is enriched air is a green colored valve cap!

[chrisw]

fantasea, tx for your perspective!