Nitrox in uncleaned Cylinders??

[Dave Crampton]

Here is a question I've been wanting answered since I dived at the Farnes in May.

I get my fills from a local dive shop which does both clean air and pure O2 for Nitrox for >40%, and premix 40% and clean air for <40%. I have unclean/unserviced cylinders but the shop will fill my cylinders with <40% using Premix and an air top off. They say they do this as its legally allowed to fill uncleaned/unserviced cylinders with Nitrox premix (at 40%) as the O2 % is not high enough to cause problems. Of course they drain the cylinders fully (and properly) and then fill from empty.

When I went to the Farnes in May with YD the Sovereign dive shop who appeared to have 40% premix said they were only allowed to fill cleaned and serviced cylinders.

Who is right here? Does my local shop have it wrong and is practicing dangerously or were Sovereign missunderstanding the rules governing Nitrox Supply?

Anyone here know for sure?

Dave C

[Mark Powell]

Your dive shop is correct, if they are filling with premix which is less than 40% then there is no need for the cylinder to be O2 clean as there is never a time when your cylinder contains pure O2 or a mix higher than 40%.

On the other hand Sovereign are perfectly within their rights to be overly cautious about this and put their own restrictions. It wont do you any good to argue with them.

[Tim Ingmire]

Yeah wot Mark said.

TBH I look forward to the day when all dive centres use a premix like your LDS - that'll save me a good deal in O2 cleaning costs.

[Dave Crampton]

Cheers Mark, and Tim,

Yes I guess I am lucky in that my LDS has Premix 40%

Incidentally Mark, my BSAC club's name is Divetech.

Dave C

www.divetech.org.uk

[Mark Powell]

Originally Posted by dcrampt

Incidentally Mark, my BSAC club's name is Divetech.

www.divetech.org.uk

Great name!

[Conor]

I was going to reply to this, but then realised that Mark had said exactly what I was about to say, which is a good thing as I did my basic Nitrox course with him