77 replies to this topic

[ScubaDrew]

I remember the set up well and less is more and much simpler.

Rental tanks, especially at resorts should be clearly marked unless they are dedicated air tanks, as resort divers could grab the wrong tank, attach their gear and go overboard before anyone knows what happened. On top of that, if a diver surfaces, or is surfaced in distress, knowing that they were breathing something other than air could help in figuring out what went wrong, and then how to treat it, and looking for your own style of sticker, which may actually blend into the color of the tank, may slow down that process. The nice bright bands make it plain it wasn't air.

Of course dedicated tech trips are a different animal, where everybody is on something other than air.

Personally I never learned why the yellow/green band is so offensive to so many in the first place, most people use dedicated tanks for air or nitrox anyway...

[PerroneFord]

Personally I never learned why the yellow/green band is so offensive to so many in the first place, most people use dedicated tanks for air or nitrox anyway...

I think there is a disconnect here.

If a shop owns the tanks and are renting them out, and they want a big green and yellow sticker that's just fine. You aren't going to get much argument, even from DIR types. It's when shops want those stickers on customers tanks to get fills, that this becomes an issue.

The yellow and green band isn't offensive. It's simply not helpful. It tells you nothing about what is in the tanks. Could be nitrox (but what blend??), could be air. It causes people to make assumptions about the breathing gas that may or may not be true.

Why would a person use dedicated tanks for nitrox or air? I sure don't. But then I don't dive air very often. I keep air in my bailout bottle but that's just because I don't know what depth I'll use it to. When I get mix trained I'll change it to 18/55 instead.

So if it's the shops tanks, put anything on there you want. The rental 108s I use have the big yellow and green stickers on them. My tanks are clean. Or at least, cleaner.

[shadragon]

I ensure I have 5 things listed as a minimum for my NITROX tanks:

- My name
- Analysis date
- % mix (XX.X format)
- 1.4 depth in feet
- 1.6 depth in feet

I consider the 1.4 depth my max depth for that dive plan (and realistically I would try to stay well above that depth). The 1.6 value is only for contingency or emergency. I would not violate the 1.6 depth for any reason and I usually set that depth minus 10 feet (90 - 10 = 80, for example) as my DC depth alarm value. The 1.4 depth value in feet I have on the tank should match the 1.4 depth value in feet on my DC with the mix % entered. If it does not agree within +/- 1 foot, then I double check everything.

If there is a label I use that space, or I use a piece of masking tape. In Grenada the tanks were bare metal with just a green cap to indicate it was NITROX. There was no tape so I wrote onto the tank neck directly with a pencil.

[netmage]

Wow... three pages.... Air is for tires....

-Tim

[ScubaDadMiami]

Not even for tires anymore. My tires are filled with Nitrogen.

[netmage]

Personally I never learned why the yellow/green band is so offensive to so many in the first place, most people use dedicated tanks for air or nitrox anyway...

..
The yellow and green band isn't offensive. It's simply not helpful. It tells you nothing about what is in the tanks. Could be nitrox (but what blend??), could be air. It causes people to make assumptions about the breathing gas that may or may not be true.

Why would a person use dedicated tanks for nitrox or air? I sure don't. But then I don't dive air very often. I keep air in my bailout bottle but that's just because I don't know what depth I'll use it to. When I get mix trained I'll change it to 18/55 instead.

Wait a second... I am offended...

What's offensive? Well, there are a few different ways to make nitrox; I'll stick to the 3 mainstream, and for purposes of this discussion, recreational mixes 40% and below. And the mainstream industry still (by their continuous practice) uses the most dangerous and customer costly method of mixing. Me thinks in yet another effort to generate revenue for the shop.

1. Membrane - does not require customer equipment to be O2 serviced. Significantly more expensive, typically pre banked.
2. Nitrox Stick - does not require customer equipment to be O2 serviced. Very cheap. Also pre-banked.
3. Partial Pressure - requires EVERYTHING coming in contact w/ 100% O2 to be O2 serviced, very labor intensive, requires trained and competant fill personnel to do algebra. Slow.....

Don't get me started on shops requiring O2 cleaning every VIP, dedicated Nitrox Band stickers, ANDI tags.

My tanks get a single sticker at the neck w/ a number on them... That is the F02.
Every tank that walks out of my LDS gets analyzed.
Recreatioanlly I top-off with two mixes..., 32% for anything under 80' and 40% for anything above.
So, sometimes a tank has 40% and it gets topped off w/ 32%, tada.. 35% for that dive. Sometimes I go 'crazy' and use 36%, but thats rare, and I'm spoiled w/ Fill Express being 5 miles away.

Generally deeper than 120' and there will usually be helium involved... but thats another item.
1.4 - 1.6, well to me, it's a guideline. I don't bring a shovel when I dive, and I don't dig into the sand. Even at 1.6, (barring any aversion of higher PP02's) NOAA limits are like 45mins for single dive exposure... So, 3 minutes checking out the props isn't suddenly going to spiral me down the rathole.

-Tim

[shadragon]

1.4 - 1.6, well to me, it's a guideline. I don't bring a shovel when I dive, and I don't dig into the sand. Even at 1.6, (barring any aversion of higher PP02's) NOAA limits are like 45mins for single dive exposure... So, 3 minutes checking out the props isn't suddenly going to spiral me down the rathole.

You are absolutely correct there Tim. You can go faster than the speed limit and most of the time there are no consequences. A few minutes of >1.6 exposure is the same, probably nothing bad will happen. However, if you respect the limits then the odds are certainly on your side.

When I lived in Germany the majority of the Autobahn system had no speed limit. However, if you got in an accident and it was proven you were going faster than 130 KM/h (which is the recommended speed on the Autobahn unless otherwise posted) then your insurance did not cover you.

The British fella in Marsa Alam who racked up a £40,000 ($72,000 USD) bill for his chamber ride is always on my mind. He was refused insurance coverage because he went to 49.5 M which is deeper than the 30 M max depth that his policy specified. I am sure there are similar clauses about exceeding other training limits and safe dive practices in those policies as well. We all know how insurance companies look out for our best interests... One thing is for sure; insurance will get more restrictive in the future not less.

If I wanted to check out the props and they were below my 1.4 max depth then I would get a lighter % mix and drop the max depth a few feet so I could go there and stay within accepted profiles. If the gas was pre-mixed and I was forced to take it then I would respect the 1.4 depth limit and go take a look at the bridge or cargo hold instead.

Every diver has to set their personal limits based on their training, experience and level of risk they are willing to accept. If I ever saw an 1849 Spanish gold doubloon 10 feet deeper than my max depth then I probably would go for it.

[netmage]

Different strokes for different folks....

[giantstride]

There are a couple of issues here: First, you state that if you drop the tanks off at the dive shop, they will never know you used the tanks with Nitrox. Remember that all tanks used with enriched air must be marked as such; typically with the large yellow and green sticker that denotes enriched air. You never refill an enriched air cylinder with air, because then you have no idea what you mix is. A dive shop that fills air cylinders is not following proper protocol.

[PerroneFord]

There are a couple of issues here: First, you state that if you drop the tanks off at the dive shop, they will never know you used the tanks with Nitrox. Remember that all tanks used with enriched air must be marked as such; typically with the large yellow and green sticker that denotes enriched air. You never refill an enriched air cylinder with air, because then you have no idea what you mix is. A dive shop that fills air cylinders is not following proper protocol.

I think you've missed some pertinent parts of the discussion. Here's a recap:

1. Your assertion that you never fill an enriched air cylinder with air is false. Happens all the time. And safely. Filling an enriched cylinder with air is not a problem at all. Filling a cylinder with impure air, then later filling that cylinder with enriched air using partial pressure blending is VERY dangerous.

2. The Green and Yellow bands are at best useless, and at worst, give misinformation about the contents of the tanks.

3. Regarding "proper protocol" in terms of filling cylinders, please reference the protocol of which you speak. Is it a CGA protocol? Is it OSHA? I certainly don't remember reading it. When I blend, I have to make a decision as to whether I think a cylinder is safe for PP blending. How the tank is marked tells me a lot about it's owner. I would refuse PP blend any tank with a big nitrox band on it without putting a UV light inside.

[Walter]

I would refuse PP blend any tank with a big nitrox band on it without putting a UV light inside.

And some fill stations will refuse nitrox unless the tank is so marked. While I agree with the general concept that the nitrox bands give no useful information, they are sometimes necessary to get a nitrox fill.

[PerroneFord]

And some fill stations will refuse nitrox unless the tank is so marked.

And therein lies the problem. The tank is already marked. It's denoted by the VIP sticker already on the cylinder. If the cylinder has been prepared for oxygen service, the VIP will reflect it. Which do you think should carry more weight? The tank wraps, or the VIP sticker?

Any clown can put a tank wrap on a tank. Hopefully, obtaining a real VIP sticker would be much harder. Frankly, I trust the VIP sticker a LOT more than I'd trust the wrap.

So here's a question for the blenders among us.

Which tank would you be more likely to do a PP fill in:

A. A tank with an o2 clean VIP sticker and no tank wrap
B. A tank with an Air service VIP but with a nitrox tank wrap

[ScubaDrew]

A. A tank with an o2 clean VIP sticker and no tank wrap
B. A tank with an Air service VIP but with a nitrox tank wrap

If it has both, are you still gonna VIP it because it also has a band?

Im not a blender, but I thought you have to have the tank O2 cleaned before you could pump O2 into it, so I would say without the O2 VIP it wouldn't get a PP blend at all.

If I brought my tank in, and it had a wrap, it would also have an O2 VIP, and if that was still valid I would'nt pay for the re-inspection, nor would I be happy with any additional wait time.

Just my .02$

[PerroneFord]

If it has both, are you still gonna VIP it because it also has a band?

Depends on my gut feeling about the tank.

Im not a blender, but I thought you have to have the tank O2 cleaned before you could pump O2 into it, so I would say without the O2 VIP it wouldn't get a PP blend at all.

You do have to have the tank o2 cleaned before you pump oxygen into it. But a single fill afterward could contaminate it. So my decision to "trust" it, is my own. If the tank is sloppy, with lots of garbage on it, dubious markings, etc., I'd still want to VIP it before putting oxygen in it.

If I brought my tank in, and it had a wrap, it would also have an O2 VIP, and if that was still valid I would'nt pay for the re-inspection, nor would I be happy with any additional wait time.

I wouldn't charge for a re-inspection either. I'd be doing it for my personal satisfaction. I also wouldn't charge for the gas I had to drain from the tank and refill afterwards. As to the wait time, custom blends are not usually done while you wait. Or if they are, it's a convenience. Most shops I know do custom blending as a drop-off service. You can't accurately determine the mix until things settle down in the tank anyway. And that could take hours.

If you would be upset with additional wait time, I would be happy to direct you to other local shops. My life comes before any customer's convenience as far as I am concerned.

Mind you, I inspect my OWN tanks after getting fills where I am not sure about them. I'll spin off the valve when I get home, and check the tank with UV to make sure they are still clean. So this is not just something I throw at customers.

[Walter]

And some fill stations will refuse nitrox unless the tank is so marked.

And therein lies the problem. The tank is already marked. It's denoted by the VIP sticker already on the cylinder. If the cylinder has been prepared for oxygen service, the VIP will reflect it.

Agreed.

Which do you think should carry more weight? The tank wraps, or the VIP sticker?

Perrone, I don't have my own compressor nor do I store O2, so I have to get fills at fill stations. Some will put banked nitrox in any tank, some require the green and yellow nitrox bands. I've never tried it, but I hope no one pumps O2 in a tank that's not been marked for O2 service. I'm guessing that those fill stations who will not put nitrox in tanks that don't have nitrox bands do it in an attempt to make divers who haven't been nitrox certified aware that they shouldn't take that tank. It doesn't matter what I think about the wraps, if I want nitrox fills at some stations, they are required.

Any clown can put a tank wrap on a tank. Hopefully, obtaining a real VIP sticker would be much harder. Frankly, I trust the VIP sticker a LOT more than I'd trust the wrap.

I doubt anyone will disagree with you. OTOH, the two different stickers are communicating different messages. The visual sticker communicates the tank has or has not been cleaned to accept O2. The nitrox sticker communicates the tank is filled with nitrox. A tank doesn't have to be O2 cleaned to have nitrox.

So here's a question for the blenders among us.

Which tank would you be more likely to do a PP fill in:

A. A tank with an o2 clean VIP sticker and no tank wrap
B. A tank with an Air service VIP but with a nitrox tank wrap

That's not even close to the question. It's not an either/or situation. If you trust the visual sticker that says the tank has been O2 cleaned, the nitrox sticker should not be an issue.