Tank contents

[Lawrence Debono]

I was on divernet and Bren invited me to share some information with you.
I dive in Canada and what I found when I came here was a bit disturbing.
>Tanks are called by the number of Cu feet.
>Some of the cubic feet measurements are actually untrue.
>Most people here refer to a 200bar tank as high pressure.

My two cents worth on this is that it is OK to call tanks by the maximum number of CU feet or liters that a tank can hold, BUT it is very useful to put in the volume measurement as well. A great deal of tanks don't have that.

The second and most disturbing issue is that some years ago the US dot decided to lower the working pressure of a number of old tanks. BUT the people including instructors and even manufacturers kept referring to them with the same figure that they had before. E.g. an old steel 72cu foot tank is actually 65cu foot, because it is a 10Liter at a maximum working pressure of 160 bars. I believe there are others like this.  

The last point about calling a 200 bar tank, high pressure, my opinion is false because 200 is quite common and 232 is common all over Europe. I think 300bar tanks should be called high pressure.

My main reason about this is the danger of those that will come on this side of the pond and rent tanks. I'm set I got my tanks and I know the exact volume measurements and know how much to fill them, but others might walk right into the confusion.

Cheers

Lawrence

[Davey Willo]

Thanks for that Lawrence, those measurements always confuse me, I read a lot of US based dive forums and books and they always talk about cubic foot this or cubic foot that and I don't have a clue if they are on about 10's 12's 15's etc...

You guys can't be getting very long dives if you are using 160bar 10's not unless you bolt them together anyway  ;)

Nice to see we now have a Canadian contingent too, welcome my friend.

regards
Dave.

p.s. Lawrence how do you feel about writing a bit of a report on the sort of diving you do over there, the dive sites inland and sea, the flora,fuana etc, it would be nice to hear what you guys get up to.... do you dive through winter? I imagine your winters will make ours look positively tropical.

[Dr Stevil]

As if it isn't bad enough having to deal with cubic feet folk going to the US will have to contend with psi instead of bar, is that also the case for Canada ?
Hopefully anyone encountering imperial measure tanks for the first time will exercise a bit of caution till they're used to the standards.
Cheers
Steve

[Driftwood]

1 cu.ft. = 28.316846592 litres (remember with say, an ali 80, both working pressure and capacity are important - at 200bar it would be an 11.3l but at 232bar it's 9.8l)

1 bar = 14.5038 psi (reserve typically 50bar or 800psi, WP of 232bar or 3200psi)

HTH

[Dr Stevil]

Glad to see you've surfaced Drifty, was getting a bit worried about your absence - so many forums, so much silence ;)
Chee-az
Steve

[Driftwood]

Nice to know you missed me Steve......

[Jay]

Welcome back Drifty! We have some diving to do soon matey - if you fancy a spin in Capenwray or the Lakes, give me a bell.

Regards

[Driftwood]

Cheers Jay,

Will see how things go - kinda hectic at the mo as Emma's starting her new job on Monday which is shifts as well so it could be a "ships in the night" and more dive time?