NITROX marked tanks MUST be filled to 24% or greater?

[nadwidny]

JUST informed by my LDS that it's now a DOT REQUIREMENT that tanks marked with a NITROX band must be filled with a minimum of 24%.

That sounds like BS to me.
If it's true, when did this happen and where exactly can I substantiate that specification?

And once again let's repeat the rule-If you heard it from a dive shop, it's wrong.

 

[nadwidny]

This is actually a very common belief. People say frequently that once a tank is a nitrox tank, it is always a nitrox tank and cannot be filled with air. the only difference in this case is the way it was stated, but it means the same thing. Some courses actually teach that nonsense.

Here's why it is nonsense.

The thinking is that normal air is not clean enough, so using it in a nitrox tank can potentially introduce contamination that could cause trouble in a later nitrox filling. the problem is that filling a tank with nitrox that is not banked includes filling it with air, so you are potentially adding contaminants every time you make nitrox unless you are using air with a higher level of filtration than a standard air fill. .

BS. Most compressors meet or exceed the OCA specs without extra filtration

 

[bl6394]

I understand that there is a DOT requirement that containers (such as high pressure cylinders) be accurately marked as to contents.

There is a school of thought that filling a cylinder with air when it is marked "nitrox" is in violation of this, because then the cylinder's markings do not accurately reflect its contents. While I do not subscribe to this way of thinking, I can understand it.

There is no such requirement. You may search Title 29 (Labor or more specifically the OSHA requirements with respect to compressed gas in Part 1910 ) and Title 49 (Transportation - DOT) of the US Code here. Neither the US Code nor the CGA pamphlets they incorporated require portable cylinders containing breathing gas to accurately describe their contents. Look for yourself. Electronic Code of Federal Regulations

 

[KevinNM]

Are O2 caused tank/valve fires ANY kind of a problem, anywhere, ever?
Sure, tanks do blow up, but I can't say I've ever heard of a tank igniting.

They do happen. Not common, but they do happen. I know there was a O2 tank fire in Florida that resulted in a fatal tank explosion and in the town I used to live in there was an O2 fire on an FD ambulance that destroyed the ambulance and badly burned the medic involved. That one helped produce the ban of aluminum O2 regulators for med oxygen.

 

[w3dge]

I understand that there is a DOT requirement that containers (such as high pressure cylinders) be accurately marked as to contents.

There is a school of thought that filling a cylinder with air when it is marked "nitrox" is in violation of this, because then the cylinder's markings do not accurately reflect its contents. While I do not subscribe to this way of thinking, I can understand it.

But air IS Nitrox. Its 21% Nitrox. Whats the difference?

 

[sealark]

It's winter time shops are in the lean money making times some will say anything to make a $$$$
Get your own compressor and a couple ABO O2 bottles and fill your own tanks and save a bunch. You can put anything you want into your cylinders. New tanks are Nitrox certified. If you only dive a few times a year support the local shops. If they wont put air in your nitrox tanks go to another shop.

 

[Jim Lapenta]

What particular shop is this? If they are mistaken about this, what other items of misinformation are they handing out? You could save someone's life by helping them avoid this place. Just saying.......

 

[fmerkel]

But air IS Nitrox. Its 21% Nitrox. Whats the difference?

Point I made exactly.

 

[fmerkel]

Sounds like the LDS wants either of the following: you buy additional cylinders or you pay for nitrox when it may not be necessary, but may also limit your planned dives.

Like others have said, ask them to show you the DOT regulations stating such.

I'm insisting on seeing the exact spec and reading it for myself. The shop guy said he would get it from home and call me with it today.
I told him I have a call in to PSI-PCI; Professional Scuba and Cylinder Inspectors.
[PSI-PCI training is the only training recognized, endorsed and used by USDOT, CGA & Cylinder Manufacturers! ]

He said that was the source of his information and he was surprised himself. He sounded sincere and convinced, so for now I'm cutting him some slack and waiting for more info.

 

[nadwidny]

It's winter time shops are in the lean money making times some will say anything to make a $$$$
Get your own compressor and a couple ABO O2 bottles and fill your own tanks and save a bunch. .

Or get medical or welding grade and save even more.