Hp Lp?

[haneym]

i was told HP tanks are harder on your first stage and cause them to wear out faster. how true is this?

 

[lamont]

So how big of a difference is it. Lets say we use 2 steel 80s one HP and one LP, how much more psi and air volume are we talking here?

You should compare an LP80 and an HP100.

Both tanks are the same size and weight on your back. If you underfill the HP100 to 2640 you get 80 cu ft just like the LP80. More dive shops will fill the HP100 to 3500psi than will fill the LP100 to 3500psi. Also, if you're concerned about your valves you can just use LP fills to be kind to your valve seat, but pump it up to 3500psi for special excursions where you want more bottom time...

IMO, i want the HP100 rather than the LP80. And if I need 100 cu ft of gas and can only get 3000psi fills, I'll go with an HP119 or HP120 rather than an LP104 -- and if the added capacity of the LP104 at 3000psi looks attractive I'll just buy an HP130 instead. if that's not enough, then i'll buy an LP120 and overfill it...

 

[matt_unique]

...
PST and now Worthington produce tanks with a service pressure of 3442 psi and the same 3/4" threads as Al80s and LP tanks....QUOTE]

Common misconception, I thought the same for many years too, but the 3/4 vs. 7/8 reference you read for tanks has only to do with the "thread convention" and not the size of the tank opening.

--Matt

 

[spectrum]

DIN valves are required on most tanks actually referred to as HP.. that's a fill pressure of 3500 psi or more. These tanks usually have smaller threads and you can only find DIN valves with those threads

PST and now Worthington produce tanks with a service pressure of 3442 psi and the same 3/4" threads as Al80s and LP tanks. Yoke valves are available for these tanks, and they come with 200 bar DIN valves with Yoke inserts so you can use any kind of regulator on them.

I've never run into a shop that can't give HP fills.

The PST E series valves are rated for 230 BAR.

As for fills, so far everyone will deliver it as a hot fill. If they aren;t in tune yet with HP they may no be keeping enopugh high bank air and I had to wait :20 today while they built up. He was ready to send me on my way 300 PSI short on warm tanks! Some will take the time to cool and slightly over fill to give full rater pressure/temperature rating.

Pete