H.P Steel tanks in Florida

[Degenerate]

Another interesting thread might be to ask what people with "Multiple Tank Syndrome" do for VIPs. Imagining VIPing 30 tanks/year.

We've had a thread like this before but things might have changed.

I suffer from MTS and so do a bunch of other divers I know, and all of us are extremely happy that there is no requirement for VIPs on tanks every year here, just the 5 year hydro req.
A couple people I know who have their own fill stations at home don't even do that, they just keep on going with most of their tanks and have a select few ones kept in hydro that they bring if they're going away on a trip and can't fill at home.

To answer the OP,
Your HP tanks in US are relatively close to our "LP" tanks of choice here in EU, the 232 bar (3365psi).
They offer a lot of gas and a are decently negative, I almost always get mine filled to 250-270 bar when I'm filling at mates.
Our "HP" tanks are 300 bar and basically anchors, very popular as single tanks because you can take quite a bit of lead off your belt, but as doubles they are a massive pain to haul around and very negative in the water.
I very much prefer the 232 bar tanks with an overfill, every day of the week.

 

[tbone1004]

There is also a considerably greater heating effect if the cylinders are nearly empty, than if they are ~1/3 full.

Some shops around here charge more for HP fills.

obviously, but the shops that I frequent, as well as @uncfnp know things like this, so they fill slow and overfill. The overfills in cave country are "calibrated" for bottles to be around 1500psi when they get hooked up to the whips because that's about what they all come back at. The shops that I use on the coast of NC have theirs "calibrated" for bottles coming back around 500psi and they overfill a bit more. Charging more for HP fills is fine if they actually put it back on the whip, but they should have filled it at 300psi/min per the manufacturers recommendation, and overfilled accordingly based on the tank temperature so it cools to the right pressure. Unfortunately the ignorance at most dive shops won't let them do either of those things.

 

[Boston Breakwater]

How does the situation you described have anything to do with HP or LP? You'd have exactly the same gas volume on a proportionally filled LP120 or an LP85 filled to 3700 or an LP95 filled to 3333.

Hello. "How does the situation you described have anything to do with HP or LP? (It doesn't.) The post is about the benefits of using H.P. bottles.
Thanks for the gas volume class.
Cheers.

 

[grantctobin]

At the end of my O.P.
I left off with.
"What's the advantage and/or scenario in which H.P. Steel would be beneficial?"
So, I may have come into a scenario that could be beneficial.
Cheers.

Was the start of your replied to post. I’m falling to understand your apparent train of thought. You’re welcome for the lesson.

 

[happy-diver]

Some mad scratchings for ONLY steel tanks of course

The High Pressures are printed as an example and not to be replicated attempted or pumped

3L X 182b – 2640 PSI = 546 LITRES
3L X 237b - 3442psi = 711 LITRES
3L X 260b - 3770psi = 780 LITRES
3L X 290b - 4206psi = 870 LITRES

6L X 182b = 1092 LITRES
6L X 280b - 4061psi = 1680 X2 = 3360LITRES
6L X 290b = 1740 X2 = 3480 LITRES

7L X 182b = 1274 L
7L X 237b = 1659 L
7L X 260b = 1820 L
7L X 280b = 1960 X 2 = 3920 LITRES
7L X 290b = 2030 X 2 = 4060LITRES

12.2L X 182b = 2220 L
12.2L X 237b = 2891 L
12.2L X 260b = 3172 L
12.2L X 280b = 3360 L X2=6720!!!

15L X 182b = 2730 L
15L X 237b = 3555 LITRES
15L X 260b = 3900 X2 = 7800 LITRES
15L X 280b =4200L X 2 = 8400
15L X 290b =4350L X2=8700L


I breathe a lot and couldn't even contemplate diving at the first two pressures

Well I don't breathe a lot, but a lot goes in and out

 

[Boston Breakwater]

Was the start of your replied to post. I’m falling to understand your apparent train of thought. You’re welcome for the lesson.

Hello. I can't put it any more simplified for you. The topic is "What benefits are there to owning H.P. Steel tanks.
I would say the (2) primary reasons are...
Less weight. More volume.
Here is a past thread. Naturally, not just for you, but for all current members.
The thread is almost 7 years old to the day. You'll also find postings back then didn't have many flippant responses, and were geared to a more academic, professional manner.
HP Tanks - What's the point?
@Colliam7 made an in depth reply.
(As always.) I hope everyone enjoys this thread, and has a good day.
Cheers.

 

[rjack321]

You might be protecting your investment because you are concerned that the day may come when either heightened regulatory scrutiny or an accident limits the practice of "cave" fills.

Your "hp" exemption tanks are far more likely to not get their exemption renewed than any of these scenarios. Probably not a threat from faber but any other manufacturer this is a concern although still rare. And any 3442psi tank is more likely to get condemned due to a poor quality hydro tester skipping the necessary round out protocols.

Non-exemption 3AA HP tanks are crazy heavy.

 

[2airishuman]

Your "hp" exemption tanks are far more likely to not get their exemption renewed than any of these scenarios. Probably not a threat from faber but any other manufacturer this is a concern although still rare. And any 3442psi tank is more likely to get condemned due to a poor quality hydro tester skipping the necessary round out protocols.

I have read through the entire text of all three of the major HP special permits/exemptions -- PST, Worthington, Faber. PST led the way, Faber was a copy with minor improvements, Worthington was another copy with more minor improvements.

The original PST permit is a modified version of 3AA with a higher maximum authorized wall stress. The steel is limited to a high-specification variant of 4309X which is the most common of the four steels authorized for use in 3AA. To maintain equivalent safety, the permit requires heat treating and a number of additional tests. Some are per design, some are per lot, and some are performed on every cylinder. The permit is constrained to nonflammable, nonliquified gases. There are minimum and maximum size limits that bracket usual primary dive cylinder sizes.

The Faber permit is exactly the same except that the steel composition is tweaked, the units are metric, the maximum tensile strength was dropped 3%, there's an REE, 10-year star service is allowed (for cylinders not in diving service), the use of ultrasound testing is permitted, and there are editorial updates to documents referenced.

The Worthington permit has a tiny difference in steel composition from the Faber one, requires a corrosion resistant treatment on the outer surface, and has been amended to use a hydro test procedure that disregards the inelastic expansion criteria.

I don't believe there is any way that these nearly identical permits will stop being renewed while significant numbers of the cylinders are in service unless there is new evidence that the cylinders are unsafe.

Hydro failures are a concern with PST cylinders, yes. Not a problem with Worthington since there is no longer an inelastic expansion test criteria for these. Not a problem with Faber because the shape of Faber cylinders is stable.

Non-exemption 3AA HP tanks are crazy heavy.

Yes, and crazy negative. Relatively few were made and few remain in service. But they aren't what we're talking about here.

 

[rjack321]

I don't believe there is any way that these nearly identical permits will stop being renewed while significant numbers of the cylinders are in service unless there is new evidence that the cylinders are unsafe.

Norris made exemption series tanks for a few years. The permit wasnt renewed, all those tanks are scrap now. Every few years PST seems to lackadaisically renew their permit because they arent even in the scuba business anymore. DOT has to cajole them into renewing because they dont want 1,000 users hounding them.

Non-renewal is a definite possibility, although not from faber they are the most stable of steel tank manufactures of all