3000psi tanks...why?

[spectrum]

Token,

It comes down to what the cylinder can safety contain, not what the diver wants.

As for your consumptions, settle down and gain experience. My weight is not unlike yours, it's no excuse, I can give those little gals a run for their money and I'm no great specimen. It's all about relaxing and diving with decent form.

Pete

 

[mathauck0814]

I am generalizing here but in Europe and here in South Africa all ALI cylinders are 3000psi (200 bar) All steel start at 3500 (232bar) and some are even over 4000psi (300bar). ALI here are primarily used for stages/deco bottles.

Fill stations will give you 3200psi as standard. Anything less and you where "robbed".

Buy steel! Its a better backgas bottle and will last a lifetime if cared for.

My steel doubles give me 247cubic feet of capacity. Life is awesome!!!!

Are the cylinders themselves rated to 300 bar or the valves? I have several valves that have pressure ratings that far exceed the tanks' service pressure, but I've never seen one with a service pressure that high.

 

[elan]

Is there a reason that a standard tank fill is 3000psi? Most air gauges go to 5000, and obviously, more air means more bottom time.

The reason I ask: On a recent dive, I was by far the biggest person on the boat. I weigh about 220lb, and everybody else was well under 200, including two women that probably weighed not much more than half what I do. As you might expect, I started to run low on air before everybody else, although I did make it through a 45 min dive with a decent safety margin. Would it not make sense to give the biggest guy/people on a dive party a tank with more air to forestall an early end to the dive? Would it be reasonable for me to request a 3500-4000psi tank to increase my bottom time, or is 3000psi an established safety practice?

Your profile indicates 0-24 it is to early to draw any conclusions just dive and get comfortable. I was 205 last fall and I was able to do an 60mins on a shallow reef on al63 with 1100psi still left inthe tank. When I started I could only do 40 mins on about the same depth on al 80. I have the same consumption now as my wife and she had 1.5 as brtter consumption before . She is not diving as much as I do so my consumption improved a lot and hers vert little. So your weight not necessarily mean anything.

 

[boulderjohn]

Before you go on your next dive trip, do a little research on the operators in the area in which you will be diving. You may find that some will offer different sized tanks to their customers, sometimes with an additional price that you may think is very reasonable for the benefit you receive.

Here is a chart showing the different sizes that are available.
Scuba Cylinder Specifications from Tech Diving Limited - 928-855-9400

 

[DivemasterDennis]

I think diveahollc's point is important, and not just because I was going to bring it up. "Fill stations are fairly standardized, too, just like tanks. Compressors output generally does not go directly into a scuba tank. It goes into a "bank" of larger cylinders from which tanks are then filled. Getting a bank up to about 3200 psi is close to the max at our shop. Air consumption varies greatly from individual, and physiology is a big part of it. In shape 2o year old sprinters with little body fat but huge lung capacity will burn through a tank much quicker than my petite 60 year old wife/dive buddy. The key to reducing air consumption regardless of your physiology is to not do things that cause you to work harder and thus breath more rapidly. Proper weighting and buoyancy control is a HUGE factor in air conservation. So is not swimming around like a crazy person during a dive. More slowly, look around and enjoy the sights. Dive time will increase, and soon enough NDL's will control your dive time instead or air consumption rates.

 

[DaleC]

I wonder where the people posting in this thread were when this other debate was going on? Because, apparently, the answer for the OP is to seal off the burst disc on a LP steel tank and pump it up as far as one wants. The ratings mean nothing and it will never blow. http://www.scubaboard.com/forums/ad...410554-over-fill-low-pressure-steel-tank.html

 

[boulderjohn]

I wonder where the people posting in this thread were when this other debate was going on? Because, apparently, the answer for the OP is to seal off the burst disc on a LP steel tank and pump it up as far as one wants. The ratings mean nothing and it will never blow. http://www.scubaboard.com/forums/ad...410554-over-fill-low-pressure-steel-tank.html

I assume your post is meant as a sarcastic response to the trend of other thread.

As I read the OP's post, he is talking about vacation dive spots where the tanks are provided by the operator.

 

[elan]

I assume your post is meant as a sarcastic response to the trend of other thread.

As I read the OP's post, he is talking about vacation dive spots where the tanks are provided by the operator.

A bottle of whiskey has a magic property of being able to morph into a bigger tank when it relocates into the operator hands

 

[ajduplessis]

Are the cylinders themselves rated to 300 bar or the valves? I have several valves that have pressure ratings that far exceed the tanks' service pressure, but I've never seen one with a service pressure that high.

Both cylinder and valve are available in 300 bar. My doubles are 232 and valves 300.

 

[spectrum]

Are the cylinders themselves rated to 300 bar or the valves? I have several valves that have pressure ratings that far exceed the tanks' service pressure, but I've never seen one with a service pressure that high.

The cylinder has a rating, that is the limiting factor.

Each valve is fitted with a burst disk that acts as a fuse should the cylinder be severely overfilled. The disc rating is significantly above that of the cylinder service limit.

Many valves will have a rating in excess of the cylinder pressure which lets them be mass produced for many applications. The burst disk is what matches the valve to the cylinder.