Metric and Imperial tanks.

[Leadking]

I'm not sure... if you assume a 12-liter tank = an "80" tank, then a 14-liter tank would be more like a "93." A 15-liter tank would be a "100," unless there's some inaccuracy...

--Marek[/QUOTE]

Metric and US standards are just two different languages. Metric is the internal volume of a tank empty (what good is that) and US is volume filled to stated tank pressure. Let's confuse the dickens out of them and measure our tanks in gallons!

 

[Kim]

Metric is the internal volume of a tank empty (what good is that) and US is volume filled to stated tank pressure. Let's confuse the dickens out of them and measure our tanks in gallons!

What good is that? It's easy. Multiply the internal volume of a tank by the number of atmospheres and it tells you exactly how much volume of gas you have. 1 Bar = 1 atmosphere (nearly ).
FWIW it's worth, I don't know anyone who would try to say that Imperial systems are not intrinsically more complicated and difficult than metric!

 

[Leadking]

What good is that? It's easy. Multiply the internal volume of a tank by the number of atmospheres and it tells you exactly how much volume of gas you have. 1 Bar = 1 atmosphere (nearly ).
FWIW it's worth, I don't know anyone who would try to say that Imperial systems are not intrinsically more complicated and difficult than metric!

And it's just as easy to multiply the % of pressure by the full volume. You say multiply bars time internal volume. Like I said, different language!

 

[Kim]

Like I said, different language!

Which was the whole point of the thread - how to work out the relationships - not knock one system over the other. I'm happy some people have taken the time to explain the Imperial stuff to me - thanks! Hopefully us Metric users have also illuminated a few things too.
If I see a flippant comment like - 'What good is that' - it makes me really question stuff about the author, presuming that they actually read the rest of the thread.

Hopefully this thread has enabled speakers of the 'different languages' to understand each other better.

 

[Leadking]

That's why I added the "laughing face" to say I am just kidding. I mean no disrepect and just wanted to point out it is just a different way of ending up in the same place.

 

[Kim]

That's why I added the "laughing face" to say I am just kidding. I mean no disrepect and just wanted to point out it is just a different way of ending up in the same place.

Fair enough.

 

[derwoodwithasherwood]

FWIW it's worth, I don't know anyone who would try to say that Imperial systems are not intrinsically more complicated and difficult than metric!

First of all, I should preface this by saying I'm an old Canadian. So I've grown up with the Imperial system, the US system and the metric system and I use each almost interchangably. Metric is easier for math, no question.

But there are some instances where the Imperial system is far easier to use than the metric system. In particular, most measurements of length. The metric system arbitrarily created a unit of length supposedly based on the distance from the equator to the pole (they got it wrong originally BTW.) Imperial measurements are based on tangibles that we can see and feel and know. They came into common usage BECAUSE they were convenient and easily understood. The foot, the inch (thumb), the hand. Along the line they were standardized of course, but even if your hand is not exactly a hand wide, you can still quickly conceptualize approximately how big a horse is if I say it's 24 hands tall. ("How tall is a hand?" "About the width of your hand." "Oh, Ok.")

A non-metric person will have great difficulty conceptualizing 192 centimeters. ("How tall is a centimeter?" "Exactly 1/100th of a metre." "Oh. Um, how tall is a meter?" "Exactly 1 ten-millionth of the distance from the equator to the north pole, through Paris." "Oh. Gee. Um, so would that be a big horse or a small horse then?" )

The math may be easier with metric units (quick: how many hands in a furlong?) but that doesn't mean the whole system is "better".

 

[Hoosier]

Metric system has been set up as the world standard a long time ago. However, it hasn't been prevailed in U.S. because of a long traditional usage and a superiority in the science field. So, it is a pre-norm that the first thing when we take an engineering course is to learn the unit conversion. Otherwise, you have to stick yourself only to U.S. market....

Metric tanks/bar is very easy for blending. I recently did Thailand liveboard and watched my 32% fill being done many times. Basically they emptied the tank - filled 64 bar of 100% O2 then topped it up to 200bar.

Kim, what do you mean by that "Metric tanks is very easy for bledning?"
You mean, it is easy because there is a pre-setup blending combination?

 

[Kim]

Kim, what do you mean by that "Metric tanks is very easy for bledning?"
You mean, it is easy because there is a pre-setup blending combination?

LOL - I was wondering when someone was going to catch that! My original statement wasn't quite true I realized some time after I posted. If you followed exactly what I wrote then you'd end up with a mix over 50% - so you are completely correct - I meant they have a marking line on the gauge! I was wondering how long it would take for someone to notice.......it took a lot longer than I expected!!!

 

[Marek K]

But there are some instances where the Imperial system is far easier to use than the metric system. In particular, most measurements of length....

Very, very well put. And this from an objective Canadian!

The inch came from a thumb?? How did they figure that? I have small hands, and every part of my thumb is quite a bit more than an inch. On me, an inch is precisely the distance between the tip of my index finger and the first knuckle.

--Marek