When is LP HP?

[Clammy]

Exactly at what pressure is it LP and what pressure is it HP?

 

[cmburch]

Comparison XS Scuba Worthington Steel Cylinder Specifications

LP 2400PSI
LP+ 2640PSI
HP 3442 PSI

 

[Clammy]

Comparison XS Scuba Worthington Steel Cylinder Specifications

LP 2400PSI
LP+ 2640PSI
HP 3442 PSI

But that's XS scuba, is there an "official" number or can any manufacturer just pick when it's considered LP or HP?

 

[Beachlover]

I'm not positive on this one, but I think lp is up to 3000, hp is 3000 and above.

 

[mavdog]

I heard 3000 psi was the magic number too.

 

[Clammy]

I see... I had just been going by, 3500 or when you had to switch to DIN... I guess to me it didn't make much of a difference, I just bought my first tank and it's an XS Scuba Steel 100 to 3442 ("HP" 100)

 

[spectrum]

I see... I had just been going by, 3500 or when you had to switch to DIN... I guess to me it didn't make much of a difference, I just bought my first tank and it's an XS Scuba Steel 100 to 3442 ("HP" 100)

I agree that 3500 PSI is the closest thing to a defined boundary due to the DIN factor.

The 3442 pseudo high pressure cylinders shave a few atmospheres and can offer the convertible valve.

In the end it's a trade name and can be colored by the timline. I have seen advertisements for 3000 PSI High Pressure aluminum cylinders. At the time they were when compared to 1800, 2475 or 2640 steels.

 

[DA Aquamaster]

3000 psi used to be "high" pressure when the norm was 2250 psi steel tanks (2475 at the 10% overfill allowed for plus rated 3AA steel tanks.)

2250 psi was in fact sort of high compared to 2015 psi and 1800 psi tansk that used to be commonly used in scuba.

Sherwood scuba marketed a new "high" pressure tank with a 3500 psi service pressure tank certified under and exemption process. They also used a 300 bar DIN connection which led to the misperception that a stronger valve connection was needed at 3500 psi. That's not really the case as the idea of using 200/232 bar versus 300 bar DIN connections is to prevent regulators designed for lower pressures from being connected to a high pressure tank and subsequently be damaged by excessive pressure.

But it's a moot point as most current regs do fine at 300 bar pressures. If anything, the deeper 300 bar valves are too long to fit inside a yoke which prevents a yoke from being used on them in conjunction with an insert and many yokes will not tolerate pressures over 3500 psi.

All that is a long way of saying that anything that can use a 232 bar DIN/K valve and be used with a yoke is low pressure and per the curent industry standard in the US, 3442 psi tanks are allowed to use 232 bar DIN/K valves while a 3500 psi tank cannot.

So...3500 is the current and very arbitrary cutoff between low and high pressure.

 

[cmburch]

But that's XS scuba, is there an "official" number or can any manufacturer just pick when it's considered LP or HP?

Oh right I forgot my Al80's go to 3000 psi. I do not know the exact definition. Sorry.

XS Scuba Luxfer Aluminum Scuba Cylinder Specifications

Some of these Al tanks go up to 4350 psi!

 

[Scared Silly]

This is what I have seen and use.

~2400 Low Pressure
~3000 Mid Pressure
~3500 High Pressure