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If I have my Faber cylinder o2 cleaned for use with Nitrox can I still use it for regular air fills...??



GM
 

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<font color='#000F22'>Depends what you mean by regular?

If regular means clean air - double filtered etc and up to nitrox standards then yeah

If not then using non-clean air would mean you'd have to get your tins cleaned again.
 

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errrr......

Whats clean air..?? I thought that all breathing air fills are clean or am i being really stupid.
 

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like most things in life there's different levels of "x", so there's 'clean' and there's "clean". Like tap water is clean, but not as "clean" as e.g. Evian
 

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If you're going to take 'normal' air (i.e. compressed air that is 21% O2) from ANY dive centre or shop, ask if the compressor in question 'double filters' the gas as it is transfered into your cylinder.

If the owner/assistant/person filling your cylinder says either they are unsure whether it is double filtered or no, it isn't, then do not let them fill your cylinder, take it elsewhere to be filled, at a shop/centre that can guarantee a double filtered fill.

The above assume that you want to use your cylinder for Nitrox fills too. There are a number of compressors I can think of (the one on the harbourside at Abbs is just one) where I refused to allow them to fill my tanks and Drifty was kind enough to take them back to Edinburgh and get them filled at his local shop where we knew we could get Nitrox and/or double filtered air.

Putting 'unclean', or non-double filtered air (21%) into newly or currently O2-cleaned cylinders will result in you having to have your cylinders O2-cleaned again. Apart from the extra cost of having this done, you have your tanks O2-cleaned for a reason - dirt and higher O2 mixes (as found in Nitrox) do not go together well.......indeed, in certain circumstances they tend to explode!


Hope this helps.
 

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Hi

But you only need to be O2 clean if they are putting more than 40% O2 into them. So if the filling station has pre mixed Nitrox it decants at less than that or one of the compressors like Bristol Scuba? that extracts the required % below 4o%, then normal servicing is sufficient.

If like us they put in a measure of 100% O2 then top up with Air you need that O2 clean and double filtering to keep it current.

Dive Safe

Paul

PS We only charge £2 for a Nitrox fill to 40%, but thats another issue.
 

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Mmmm yet another reason for me to get of my arse and try get some diving in with you guys. £2x2 is way cheaper than £5x2 at simply scuba
 

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Of course, that's the dive industry take.

In reality, it doesn't matter in the slightest if you have a non-clean air fill or two when not using Nitrox, as the contaminants it puts in don't build up fill after fill, they evaporate back out and wind up in you, the diver.

Nigel H on UKRS did the math a while ago and worked out that by the time you've got enough hydrocarbons in a cylinder to be an explosion risk, you've passed the toxic dose that would have killed you breathing off the cylinder. And you'd have heard it sloshing around in the cylinder too...

[b said:
Quote[/b] ]Wooo. Now I begin to think about it would somebody
care to guess how much contamination it takes to
release enough energy to be relevant?

Even a slight mist of oil on the inner surface of
a tank suddenly seems irrelevant compared with the
energy there already. At a rough guess we are
talking well over 100grams of contamination instantly
oxydising to pop a 12L from working to test pressure.
Both steel and Ali are increadibly good at dynamic
loads like that.

Where in the valve could we get a dangerous fire risk
involving, I assume, the internal O-rings as additional
fuel? I'm not sure how pillar valves are constructed.

Aside from having half an inch of oil in the bottom
of the tank is there really a risk? Please somebody
convince me O2 cleaning is not a sham as I'm one of
the guy's who's a mean sticker-checker if I'm working
the blending panel.

----

Revise those numbers....

12L at 230 bar is aprox 1242kJ
12L at 346 bar is aprox 1868kJ
We get 4163kJ/mol burning hexane (eg: petrol)
so (1868-1242)/4163 so 0.15 mols of hexane
at 86gms/mol is 13gms at 0.65gm/cc is 20ccs

Not half an inch in the bottom but not
just *dirty* or *you touched it - it's infected*.

----

Interestingly a toxicology site give 20ccs of petrol
as a lethal dose if inhaled or injected. So a tank
with a deadly level of contamination is not quite
an oxygen fire risk?
 

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[b said:
Quote[/b] (Steve W @ Aug. 13 2003,12:31)]You can get personal filters for about £70 which allows you to double filter your air  yourself
I discussed personal air filters separately with a couple of very knowledgeable techies. Both of them consider a personal air filter to be a very questionable piece of equipment. The risk of chanelling is apparently high (higher than with a proper compressor filter), with a consequent risk of filter failure, and you don't know what's in the "unclean" air and what the filter removes and leaves. They both considered a personal filter to be mostly a question of faith and hope and said that, although it will probably do what it's supposed to do in most cases, you should have your cylinder cleaned again after using one. That said, personal filters are widely used by wreck divers in the Baltic. Personally, I don't know what to think.
 

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Hmmm... interesting, first time I saw a personal filter it was being used by a guy who was a BSAC FCD/AI, very involved in deep and techie stuff, I would have thought from his level of experience he's be fairly well clued up on the downsides of a PF, dunno, maybe it's a courses for horses thing

Chee-az
steve
 
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