LP vs HP steel tanks

[GrumpyOldGuy]

And I thought that the only difference between LP and HP was the pressure stamped on the tank due to to silly DOT regulations. When in Florida I fill both LP and HP to 4,000 psi unless Wayne is behind in charging up his bank. I may be a little off on some of the numbers, but an LP 85 is basically an HP 100, while an LP 95 is an HP 119. It would sure be easier to just adopt the European standard of actual volume in liters so that the answer to this question would be obvious.

At one time I though HP and LP were the same tanks stamped differently also. I was wrong and corrected by others with more knowledge. The type of steel used is different and the HP tanks are significantly stronger. There is a relationship in the physical dimensions probably due to shared and standardized tooling in the manufacturing process.

 

[oldnotdead]

In cave country where 3600 psi on a low pressure 95 is the norm, the extra 50 cu ft over what you'd get in an X7-100 is important especially when the rest of the team has LP 95s or X8-130s.[/QUOTE]

Is 3600 psi a misprint? The huron scuba chart shows a LP 95 as 2640 psi when +'d. Is it regular to fill more than 900psi over recommended max? What does this practice do to the life expectancy of a tank?
Thanks OND

 

[CaboJim]

I own both, a steel HP & a steel LP. I use the LP only if I'm going to be on a boat that can't fill over 3000psi. No one likes getting a short fill, especially on a boat....

 

[Superlyte27]

the beauty of an LP... every weekend my LP's get filled to 3800 Cold

 

[Superlyte27]

Yet you have visited this thread that at first you questioned 5 times already.

The first visit was for the purpose of telling you guys to quit arguiing about LP vs. HP, Split Fins vs. Force Fins, BP/W over Jacket, blah blah blah...

After that, my visits were to be obnoxious. And each subsequent visit will be to see what reaction I get for being obnoxious.

I work at home now. I get pretty bored sitting at the computer all day. So anything to keep me occupied. The first time I even looked at my post count was yesterday when someone mentioned it. But I guess you can expect it to grow since I peruse these pages 8 hours a day monday through friday.

 

[dburg30]

I get pretty bored sitting at the computer all day. So anything to keep me occupied. The first time I even looked at my post count was yesterday when someone mentioned it. But I guess you can expect it to grow since I peruse these pages 8 hours a day monday through friday.

I can relate.. This time of year we're pretty slow so I tend to pad my count this time of year .

My problem is I tend to get sarcastic / devils adovcate and get myself in trouble that way after seeing the same topic on the front page 4 times

 

[Montana Diver]

In cave country where 3600 psi on a low pressure 95 is the norm, the extra 50 cu ft over what you'd get in an X7-100 is important especially when the rest of the team has LP 95s or X8-130s.

Is 3600 psi a misprint? The huron scuba chart shows a LP 95 as 2640 psi when +'d. Is it regular to fill more than 900psi over recommended max? What does this practice do to the life expectancy of a tank?
Thanks OND[/QUOTE]

So the next time you see a set of used tanks for sale, remember that the scuba police isn't around to restrict the ability to overfill tanks. I have wondered if this type of diver uses these tanks and then sells them to unsuspecting divers claiming they will pass hydro. They probably will pass hydro, however, how much of their usefull like has been reduced. I will continue to buy my tanks new or from trusted dive buddies.

Dennis

 

[Indian Valley Scuba]

Is 3600 psi a misprint? The huron scuba chart shows a LP 95 as 2640 psi when +'d. Is it regular to fill more than 900psi over recommended max? What does this practice do to the life expectancy of a tank?
Thanks OND

The more interesting question to ask is how do you legally defend this practice in the event of an injury or death at the filling station or anywhere else as a result of any failure of tank, valve, etc.

 

[iztok]

LP tanks are actually preferred around here (NW FL / Cave Country). They weigh more than an equivalent HP tank - not a direct comparison, but a LP 95 is heavier than a HP 100 - but you get the point. There seem to be two advantages
1) if a shop only fills tanks to 3K, then you aren't getting a complete fill on an HP tank.
2) if a shop slightly overfills an LP tank, you have oodles of gas.

I bought LP 95s. My buddy dives HP 100s. I'd rather carry his to the boat. He'd rather have mine when they are filled to 3K.

Probably depends on where you are going to dive, and how you will get them filled. Hope that helps.

Comparing LP95 to HP100 is not a proper comparison.

XS Scuba Worthington Steel Cylinder Specifications

LP95 is comparable to HP119.

So when you do that advantages (other than price) of LP95 are gone.

 

[cloudflint]

I have two steel 12 litre cylinders. One has a WP of 232 bar and the other has a WP of 300 bar. Our club compressor only fills to 232 so i just have 232 bar posts on both cylinders. The only difference i notice between the two cylinders is that the high pressure cylinder has a thicker wall and thus is much heavier so i can usually wear 2-4lbs less lead than with the low pressure cylinder.