Standard vs Metric

[elan]

As I understand it, outside of America, other countries deal in units of psi called BARs, and of course, meters. When diving abroad, do most foreign countries deal in metric, which would leave Americans converting numbers, or does the dangerous nature of scuba diving convince manufactures to produce products in a universal system of measurement (e.g. if I travel to Greece and rent a tank, will the tank pressure gauge measures pressure in bars) ?

TIA

You have to be more precise about what you mean by America. For many people outside of the US America will often mean 2 continents not just the USA.

i saw imperial mostly in the US and parts of Canada a bit in Mexico. In most other places people used metric.

 

[elan]

What's standard?

In the UK, our distances are in inches, yards & miles, speed in miles per hour, we buy beer in pints

Wieghts are now in grammes and kilos, money is decimalised, we use bar not psi, depth is in metres.

Many more like that. Confused? You will be

To make it more confusing some UK imperial units are different from the US units. Or vice versa to be more precise.

 

[debajo agua]

When I was in elementary school, my teacher told us that we'd be using the metric system by the time we're adults (and we do, to some degree) but tell an American a "meter" and he say, "oh, about 3 feet"; or say "Kilogram" and we think, "oh, 2 pounds for every Kilo"; say Celsius and we know below 20 and it's cool, above 30 and it's hot. A BAR of pressure? I don't have a conversion concept in my head for that one.

We're a stubborn lot. :mooner:

 

[ErikH]

Those differences have caused so many problems... time for all to switch to metric And if the whole world could speak one language, that would be nice as well - preferably Dutch but English is fine too

But a conversion concept for BAR's? It's the factor the gas is compressed to fit in its container. 100 bar in a 11liter/80cuft tank = 1100liter. The other way around: to fit 2200 liters of gas in a 11liter/80cuft cylinder you need to compress it 200 times = 200bar! (Or just multiply/divide by 15 to get psi/bar...)

Semi-off topic: here weight belts are marked in US pounds and people divide by 2 to get kilo's. So anyone diving a 20# belt, and thus thinks he dives with 10 kilo's, is actually diving with only 9 kilo's - not really a problem, but jut another conversion issue..

 

[melanie.]

Canada is big and you are not accurate on this half of my fellow divers in quebec and ontario use metric

Ok I will rephrase my response. In my experience in diving Manitoba, Ontario, and Quebec - I have only seen fellow divers use PSI/feet/farenheit. Doesn't mean that people don't use whatever they want

 

[bleeb]

Ok I will rephrase my response. In my experience in diving Manitoba, Ontario, and Quebec - I have only seen fellow divers use PSI/feet/farenheit. Doesn't mean that people don't use whatever they want

My experience around here has been similar. Few use anything other than Imperial units below the surface, whether it's overheard at the dive site/on the boat or over food and adult beverages afterwards. Especially true with the seemingly more numerous who only dive on vacation in warm water. If anything, hearing someone diving in metres locally tends to draw extra attention just because it's unusual.

 

[FinnMom]

Bar is standard, but it's considered to be 1 atmosphere so all the calculations seem really easy when you think in BARs and meters.

The surface is under 1 bar of air. 10m of water is also 1 bar. So at 20 meters you are under 2 bar of water and 1 bar of air = 3 bar total pressure.

Tanks are in liters and the old standard for a SAC is 30 l/min. So if you have a 15l tank, with a standard 30l/min SAC you will use 2 bar/min at the surface.

Whether you need to gauge your speed in km, need for a jacket vs shorts from Celsius or the expense of the local beer in euros and liters, the good news is that you get a feel for any of these new measurements pretty quick just as soon as you start using it.

 

[dbulmer]

Surface = 1 bar
10 metres = 2 bar
20 metres = 3 bar
30 metres = 4 bar


ie Pressure= (depth in metres/10)+1

An average SAC rate for BSAC for example would be 25 litres per min.
For GUE it would be 20lpm if memory serves me right.

Emergency planning for SAC rate would be 30lpm or higher.

Although I use bar in my diving I determine type pressure in PSI

 

[emoreira]

I live in Argentina and rented gear is normally in BAR, but you can find some instruments in psi/feet. Also new gear is sell only in metric units.
I've bought my spg in psi, because I was in the US and finding a spg in Bar was impossible. However I find a spg in psi better at a first glance. 3000 psi at start, 2000 psi in the middle and 1000 psi to return. Just big numbers.

 

[Sat Diver]

Not sure I understand. Are you talking about Atmospheres? Atmospheres are not strictly a Metric unit. The Metric unit Bar is close to one Atmosphere, but does not equal it.

One Atmosphere equals:
SI/Metric Units

101,325 Pascals
101.325 KPa, Kilo Pascals, or 1000x
0.101325 MPa or Mega Pascals or 1 Million x
1.01325 Bar
10.06275861 Meters of Sea Water*​

Imperial Units

14.69594878 PSI
33.0142999 Feet of Seawater*​

* based on a density of 64.1 Lbs/Ft³

Akimbo - you are scary brainy ... I always feel stupid after reading posts like this from you. A friend of mine that I did a couple of reef boat dives with was shocked that I could set the O2% on my computer . He said " You commercial divers always have some guy doing that S**t for you". I laughed ... but I am not so far from that. I am techno illiterate.