UW Sports Seattle - Requiring 6" Nitrox Sticker ---ARRRGH!

[Damselfish]

I think the issue is more people that haven't taken a Nitrox class. I think they should cover some basic information in OW class, but that still wouldn't cover all the people out there that are already certified.

 

[diver12345]

You absolutly cannot put air into a nitrox tank with the big green stickers on it per the law because it is a different classification of gas than air. Ask any well educated PSI inspector. PSI also just requires that the tanks be labeled.

 

[Doc Intrepid]

"You absolutly cannot put air into a nitrox tank with the big green stickers on it per the law because it is a different classification of gas than air."

Are you sure?

 

[vbcoachchris]

Are you sure?

CGA classifies Nitrox as at least 23.5% O2 (Only some of the SCUBA industry says 21% is still nitrox) and it IS a different classification of gas than air. So diver12345 is ABSOLUTLY correct it is Illegal to put air in a nitrox tank unless the resulting mix has more than 23.5% O2. It is also recommended to remove the valve EVERY time you change the classification of gas that goes into a cylinder. DOT and the US courts use CGA guidelines for case law, so it does hold up in court if it ever comes to it.

It is also illegal to overfill a tank by even 1 psi and this includes overfilling and letting it cool to the proper pressure, but again this is rarely followed. CGA requires ALL cylinders to be marked with there contents. A piece of masking or duct tape fulfills these requirements. It does not have to be a permanent label, it does not have to be yellow and green and it does not have to be 6’’. That is a NOAA standard and ONLY needs to be followed for NOAA projects. As far as an agency or industry standard, there is NO such book. Some agencies like PADI and NAUI suggest it, and some agencies like GUE absolutely REJECT it. It might be a great idea for shop rental tanks as they might be used by multiple people and helps store employees quickly identify tanks, but for a private individuals tank it not necessary.

Anyone who dives ANY tank without analyzing it first is playing Russian roulette. Even if you always dive air, do you think there is a chance that the person filling your cylinder might make a mistake? I did a dive with someone once and I asked him what was in his tank. He said “air”. I said “are you sure?” He said “I always dive air.” I said “can I analyze it?” He said “if you want”. I did and it was 25%. Somewhere someone put some O2 is his tank. If the shop you use, fills Trimix or nitrox it CAN happen. Everyone should analyze before you dive it. With all this being said, EVERY shop has the right to refuse to fill a cylinder for any reason, if you don’t like their policies don’t go there. I do know I do not want ANYONE filling my tank who honestly thinks it needs a 6’’ band, so I avoid those shops.

 

[adelman]

CGA classifies Nitrox as at least 23% O2 (Only some of the SCUBA industry says 21% is still nitrox) and it IS a different classification of gas than air. So diver12345 is ABSOLUTLY correct it is Illegal to put air in a nitrox tank unless the resulting mix has more than 23% O2. It is also recommended to remove the valve EVERY time you change the classification of gas that goes into a cylinder. DOT and the US courts use CGA guidelines for case law, so it does hold up in court if it ever comes to it.

Could you give a specific reference to the law to which you are refering?

Let's assume for the purpose of the discussion that the shop either verifies that any gas left in the cylinder is air or dumps the cylinder before filling, and that it also removes any EAN contents label (indicating a specific blend) and add a contents label which says "contains air" (which would be good practice when handling any cylinder that has a larger Nitrox-band on it).

It is also illegal to overfill a tank by even 1 psi and this includes overfilling and letting it cool to the proper pressure, but again this is rarely followed.

Catagorically not true, and one of my pet peeves is dive shops that "overfill", while explaining that although it is "illegal", it is an "industry standard practice", as if they are willing to break the law just for you. The other is dive shops that claim they can't "overfill" and if you want your cylinders "full", you'll need to come back tomorrow after they cool. The law that governs filling tanks is 49 CFR Part 173 Subpart G Section 173.301:

173.301a:

(c) Cylinder pressure at 21C (70F). The pressure in a cylinder at 21C (70F) may not exceed the service pressure for which the cylinder is marked or designated, except as provided in Section 173.302a(b). [...]

Section 173.302a(b) refers to filling "+" rated cylinders 10% over the marked pressure.

There is no law that says the pressure in the cylinder can't ever exceed the marked service pressure. It is perfectly legal to fill cylinders above their service pressure, provided that if they are cooled to 70F, they would not exceed their service pressure. Very simple to use an IR temperature gun after waiting for a few minutes for the temperature to stabilize, calculate the temperature-adjusted pressure and top-off. If you're filling them in the Arctic, it is probably cold enough that it would be illegal to fill them to the rated service pressure!

 

[vbcoachchris]

Could you give a specific reference to the law to which you are refering?

Let's assume for the purpose of the discussion that the shop either verifies that any gas left in the cylinder is air or dumps the cylinder before filling, and that it also removes any EAN contents label (indicating a specific blend) and add a contents label which says "contains air" (which would be good practice when handling any cylinder that has a larger Nitrox-band on it).

I believe compressed air is class 2 and nitrox is class 3 (not sure), but if you check the CGA handbook of compressed gases, you will see the ARE different. There are also set protocols for changing the classification of a cylinder and it MUST be done PRIOR to filling the cylinder with the new class of gas, Again CGA handbook of compressed gases. US courts FOLLOW CGA guidelines. CGA actually classifies Nitrox as 23.5 % not 23%, so I did misspeak in my first post.


After my PSI and NAUI cylinder and O2 service classes I did not believe this either. It just didn’t make sense to me. After a little research on this matter outside of class, I found out they were indeed correct and that the main reason is that CGA just has not caught up to what we need in the scuba industry. Case in point putting 100% oxygen in an Al 40 or using a scuba regulator for any kind on it

And you know as well as I do, that no a shop is going to drain the tank and remove a 6'' Nitrox sticker from your tank if you say you want air in it instead of Nitrox.

Catagorically not true, and one of my pet peeves is dive shops that "overfill", while explaining that although it is "illegal", it is an "industry standard practice", as if they are willing to break the law just for you. The other is dive shops that claim they can't "overfill" and if you want your cylinders "full", you'll need to come back tomorrow after they cool. The law that governs filling tanks is 49 CFR Part 173 Subpart G Section 173.301:

173.301a:

(c) Cylinder pressure at 21C (70F). The pressure in a cylinder at 21C (70F) may not exceed the service pressure for which the cylinder is marked or designated, except as provided in Section 173.302a(b). [...]

Section 173.302a(b) refers to filling "+" rated cylinders 10% over the marked pressure.

There is no law that says the pressure in the cylinder can't ever exceed the marked service pressure. It is perfectly legal to fill cylinders above their service pressure, provided that if they are cooled to 70F, they would not exceed their service pressure. Very simple to use an IR temperature gun after waiting for a few minutes for the temperature to stabilize, calculate the temperature-adjusted pressure and top-off. If you're filling them in the Arctic, it is probably cold enough that it would be illegal to fill them to the rated service pressure!

I am not sure you are completely correct here, because there is actually case law that says it is illegal. Do a search on overfilling cylinders. You will see that failing to follow "manufacture recommendations" that result in injury leave that person liable even if it was 1 psi over the recommended pressure when the accident ocurrs. It might be impossible to determine if it would have cooled to the service pressure. The recommended fill rate is 300-600 psi per minute to avoid the situation you list above. Have you ever seen anyone DO the procedure you list with a IR temp gun? I imagine the 10% overfill would be fine, only if the manufacture says it is. We may both be correct. This would not be the first time in history laws conflicted.

Personally I am just sick of all the conflicting information and I am putting a Trimix station in the garage. It was worth the $14K to not have to deal with this anymore (or at least locally)

 

[Mark Vlahos]

Tyler,

...

I'm curious regarding whether this policy also applies to doubles?

(In my case the owner of the shop refused to fill a set of E8-130s with EAN30 because my sets of doubles do not have 6" decals. He wanted me to purchase two decals and put one on each tank. I declined to acquiesce. I no longer patronize his establishment...)

In my humble opinion a diver who cannot recognize a set of E8-130s as "not his/her gas" has issues far beyond the capacity of a decal to resolve, and is an obvious candidate for a Darwin Award.

Therefore I'm curious as to whether your store's policy also applies to sets of large steels, or whether it only applies to single tanks.

Thanks,

Doc

Doc,

As it happens I was in the shop last Friday with my double E8-130's and asked for a top off.

No can do! The discussion started and ended when they said that without the large bands they would not fill them. The fact that the cylinders just got cleaned and stickered for Oxygen service two weeks ago did not even come in to play.

I do think that even a novice diver would notice the difference in weight between a single aluminum 80 and double steel 130's, and the DIN manifold might make their regulator a bit of a difficult fit.

I had been planning on just getting my cylinders filled at the shop that Lynne reccomended, but since my dive buddies had rented gear from this shop I figured that I could get topped off while I was there.

I had similar experiences when I lived in Virginia with the silly bands.

Some things just make me scratch my head.

Mark Vlahos

 

[adelman]

I believe compressed air is class 2 and nitrox is class 3 (not sure), but if you check the CGA handbook of compressed gases, you will see the ARE different.

I will try to borrow a handbook Monday. I haven't made the sizable investment in a copy of my own. Considering the price, it could be a legal document .

US courts FOLLOW CGA guidelines.

Pointer to a law or case?

And you know as well as I do, that no a shop is going to drain the tank and remove a 6'' Nitrox sticker from your tank if you say you want air in it instead of Nitrox.

I was contemplating whether the replacement of the "small" "contents" label (indicating the current contents of the cylinder) with one indicating air would be sufficient to meet any labeling requirement despite the 6" Nitrox band.

I am not sure you are completely correct here, because there is actually case law that says it is illegal.

Do you have a pointer to the case law you're referring to?

Do a search on overfilling cylinders. You will see that failing to follow "manufacture recommendations" that result in injury leave that person liable even if it was 1 psi over the recommended pressure when the accident ocurrs.

There is nothing in the DOT code on this, so that would be a civil liability, not a criminal liability and "illegal" wouldn't be the right word to describe it.

It might be impossible to determine if it would have cooled to the service pressure. The recommended fill rate is 300-600 psi per minute to avoid the situation you list above. Have you ever seen anyone DO the procedure you list with a IR temp gun?

Actually, it is the job of the burst disc to protect the cylinder from catastrophic failure if the pressure gets too high due to the temperature. The DOT regulations go into great detail about the engineering design, manufacture, and testing of cylinders. They are designed to take rated pressure at 70F and sit around at higher temperatures.

I know of one shop (that I respect) that has the IR gun, but doesn't use it all the time (it isn't necessary to, someone filling a lot of cylinders should be able to predict the pressure needed). I use one when blending gases.

I imagine the 10% overfill would be fine, only if the manufacture says it is. We may both be correct. This would not be the first time in history laws conflicted.

Note that this 10% overfill isn't for this purpose; this is the 10% overfill that you get on "+" rated cylinders and is what makes a LP steel cylinder that is labeled as 2400psi a 2640psi cylinder. The "industry standard" is to size a cylinder in CF at 2640psi, not 2400psi. You get this 10% overfill at 70F, so you get to go over 2640 psi when the temperature is above 70F. It is really a misnomer to call it an "overfill", but the DOT regulation uses this work.

Personally I am just sick of all the conflicting information and I am putting a Trimix station in the garage. It was worth the $14K to not have to deal with this anymore (or at least locally)

I concur!

 

[Mark Vlahos]

How about this for an idea. Gasoline stations requiring 6 inch tall bands to be wrapped around your car indicating the required fuel, RED for gasoline, BROWN for diesel, GREEN and RED for ethanol, GREEN and BROWN for biodeisel, and BLUE for Hybrids.

Without the proper vehicle band your vehicle is deemed unsafe and can never be filled with ANY fuel since it is clearly beyond all recognized safety guidelines. It could be deemed illegal to fill any improperly marked vehicle by virtue of the Triple A deciding that it should be.

Mark Vlahos

P.S. Please excuse the heavy sarcasm, but this thing just pushes my buttons.

 

[JackConnick]

Each shop has it's policies, good or bad.

There are other alternatives.

Starfish Diving does all kinds of fills and is nearby at Northgate & 15th. Randy has a complete membrane system, does air, nitrox, mixed gases, argon and also tank servicing. He also has technical equipment for rent. He works out of his house, but is completely certified and licensed, as well as being one of the best technical instructors around. You do need to call beforehand to see if he's around.

Starfish Diving

Jack