Nitrox cylinder bands

[Peter69_56]

Deleted

 

[Peter69_56]

Hi Peter,

You made a general statement; how about some specificity?

They are definitely not ignorant. They bank 50% to make it easy to fill 50% deco bottles (at the expense of rec divers). I am in a Tec 40 class and will not use 50% on a normalized basis. I don't know how many deco bottles they fill; it may be a huge business.

So, they are ignorant because:

1. they bank 50%?
2. they make people get O2 cleaning for 50% PP blending?
3. they fill tanks with 50%, tanks that may have been contaminated?
4. they know customers are driving to a different LDS for EANx and are making personal connections with the competition?

As far as tank bands, I use bands when it makes sense for me. I have a pony bottle that I load with 40% and it has a band. My O2 clean tanks have bands. The bands on the other tanks are useless except to promote rust on my beautiful PST 100 E7 tanks.

thanks,
markm

In relation to what you said here, "they dont seem to care". You said "I guess they are sure that the compressors used on the dive boats I dive from produce a very high grade of air...dunn-know..."

I am suggesting another thought, perhaps they just fill in blind ignorance. I have seen fill attendants who take little care and just fill. It would appear either in laziness or blind ignorance of any dangers. Perhaps they dont assume that all your fills are of high grade, perhaps they dont understand fully or blind ignorance.

With high risk, to assume is always dangerous at best

 

[markmud]

Hi Peter,

You wrote (in part):
"I am suggesting another thought, perhaps they just fill in blind ignorance."

I don't think it is blind ignorance. Is the risk that high to fill with a 50% banked blend. It is above the industry standard of 40%. I am asking a serious question for which I don't know the answer. Is it a risky practice to fill an O2 clean tank that may have been contaminated with 50%? I don't know.

markm

 

[Peter69_56]

Mark,

I think in all reality, the risk is quite low. I also think we err on the side of caution regarding filling with 100% oxygen as well. Given so many people use welding gear which is not looked after and subject to all sorts of abuse, and yet we hear of few if any oxygen fires with that gear.

However in saying that I think to err on the side of caution is a safer way to be. In this way if someone is a bit sloppy in their cleanliness the risks one hopes are still somewhat low. If we all didn't give a damn, soon we wouldn't even clean tanks or gear and thus have regular oxygen fires. We have to set some standard and we must always build in a safety factor. Thus 40% rule is there to save us from the idiots. And yes if you contaminate gear with oil, there is a significant risk of a fire if you line up all the holes, high flows, oil, heat and high oxygen.

The base training and expectation is to ensure everything is squeaky clean always. The practicality of it is I perfectly clean my tanks and gear, take it to my LDS and they fill it with normal air thus already contaminating the tank. I know this happens more often than most realise.

Anyway I take your point from your perspective they are probably not doing it in blind ignorance. The problem if 40% is ok into a possibly contaminated tank, then 50% probably wont hurt as its only a bit more. If 50% is ok well probably 70% wont hurt etc etc. So we stop with the assuming and stick to the 40% rule to ensure safety.

Its really up to the filler to decide if they want to take the risk. I don't PP fill any tanks I don't know the history to. I know my tanks are clean and stay clean as I don't let anyone else fill then except myself and one (good) LDS who is clearly set up for Nitrox grade air, and I watch them fill for me. If I have a tank filled by another LDS I know, I will NOT pp fill them. I have already had bad air in the past from that LDS with oil contamination, hence my decision to do my own fills.

 

[markmud]

Mark,

I think in all reality, the risk is quite low. I also think we err on the side of caution regarding filling with 100% oxygen as well. Given so many people use welding gear which is not looked after and subject to all sorts of abuse, and yet we hear of few if any oxygen fires with that gear.

However in saying that I think to err on the side of caution is a safer way to be. In this way if someone is a bit sloppy in their cleanliness the risks one hopes are still somewhat low. If we all didn't give a damn, soon we wouldn't even clean tanks or gear and thus have regular oxygen fires. We have to set some standard and we must always build in a safety factor. Thus 40% rule is there to save us from the idiots. And yes if you contaminate gear with oil, there is a significant risk of a fire if you line up all the holes, high flows, oil, heat and high oxygen.

The base training and expectation is to ensure everything is squeaky clean always. The practicality of it is I perfectly clean my tanks and gear, take it to my LDS and they fill it with normal air thus already contaminating the tank. I know this happens more often than most realise.

Anyway I take your point from your perspective they are probably not doing it in blind ignorance. The problem if 40% is ok into a possibly contaminated tank, then 50% probably wont hurt as its only a bit more. If 50% is ok well probably 70% wont hurt etc etc. So we stop with the assuming and stick to the 40% rule to ensure safety.

Its really up to the filler to decide if they want to take the risk. I don't PP fill any tanks I don't know the history to. I know my tanks are clean and stay clean as I don't let anyone else fill then except myself and one (good) LDS who is clearly set up for Nitrox grade air, and I watch them fill for me. If I have a tank filled by another LDS I know, I will NOT pp fill them. I have already had bad air in the past from that LDS with oil contamination, hence my decision to do my own fills.

Hi Peter,

Thanks for your response. And I agree with you.

markm

 

[DJEdB]

Lets face it, in a busy dive resort environment, where the majority of tanks contain air, nobody is going to analyse every tank. Marking tanks which may contain nitrox, and therefore need to be analysed before use seems obvious to me. I appreciate stickers can trap seawater, encouraging corrosion, but if removed, and the tank properly prepared for anual visual inspection, this effect should be minimal.

 

[AJ]

Lets face it, in a busy dive resort environment, where the majority of tanks contain air, nobody is going to analyse every tank.

Everybodu should analyse his or her own tank before diving.

Marking tanks which may contain nitrox, and therefore need to be analysed before use seems obvious to me.

What if a tank without a sticker is accidentally filled with 100%? A sticker on a tank has no meaning at all but can give a false indication.

 

[DJEdB]

Sorry AJ disagree. I see you are A DIR guy, implying you ard a techie. At current no major recreational training agencey teaches its students to analyise tanks before use in entry level recreational diving. Analysers are not required equipment for these courses and entry level divers are not trained to use them. When and if every diver training agency re writes its training materials,and changes its course standards in every language, then contacts every diver ever qualified of the change, you will have a point. Until then I suggest a label warning that that a cylinder contents could be lethal at recreational depths seems like a good idea to me.

 

[DJEdB]

Everybodu should analyse his or her own tank before diving.


What if a tank without a sticker is accidentally filled with 100%? A sticker on a tank has no meaning at all but can give a false indication.

A qualified compressor operator filling a non marked tank with pure o2 and leaving it unmarked, then it somehow ending up in circulation with recreational scuba tanks, seems a lot less likely than an open water student setting up his equipment on an unmarked nitrox cylinder on a busy dive boat, and not analysing it.

 

[DJEdB]

Everybodu should analyse his or her own tank before diving.


What if a tank without a sticker is accidentally filled with 100%? A sticker on a tank has no meaning at all but can give a false indication.

Technical divers are a small percentage of the overall number of divers in the world. They are obviously more qualified and experienced than the typical holiday maker diver. For me, it seems clear that as tech divers the duty of care is with us, when we bring potentially lethal gas mixes onto a dive boat. I beleive anything other than air should be clearly labled.