hp steel tank ?

[Cave Bum]

hey guys, very new to the scuba board, but i have a good amount of diving under my belt. I am starting to look at scuba tanks and am leaning towards the hp 100 119 or 130. I thought i had a good understanding of tanks, but today when i went into the scuba shop near my house, and asked for a price on a hp steel tank the guy tried to sell me on lp or al(i knew that part would happen). His reason for lp or al was strange to me and was not something i have ever heard before. He said i would not be able to get a fill on a hp steel b/c no dive shop can pump to 5500psi, he was telling me that working pressure on a hp steel is 3442, but that they should be filled to 5500 psi to get there full advertised volume. Did i just find the one random dive shop guy who didn't know about hp steels, or am i missing something?
thanks for all the help

Yup, another idiot out there! We've run across this in several threads in the last couple of weeks.

Since I've answered some of these threads 'officially correctly' but still have still confused folks somewhat; let me try to do better!

High Pressure Steel Tanks can be filled to their rated pressure: 3442 or 3500 psi depending on their rating...

Aluminum Tanks can only be filled to their rated capacity: 3000 psi.

Low Pressure Steel Tanks, if they have a plus stamp, can be filled to 110% of their rated pressure -ie- for 2400 psi tanks that's 2640 psi and for 2250 tanks (steel 72's) that 2475 psi. Otherwise it's their rated capacity.

Did I get that clearer this time? I hope so....

 

[SandyRobinson]

hey thanks for all the help, i thought he was wrong, cave bum i am in Panama city fl, not sure how far that is from ginnie springs

Call Edd at Cave Adventurers in Marianna. Two of my friends just bought some Worthington HP 120s. They are about the size of an Al 80 but a fraction of an inch taller. They weigh less than my LP Faber 95s. The next time I get a set of tanks, I will be looking at these. If I could hide them from my better half, I would do so today The website is caveadventurers.com - Home His online store does not list tanks but he does sell them. Edd's prices are competitive with anyone else.

 

[ONESPEED]

This may sound like a dumb question (but aren't there only dumb answers!) but is there a good link to a site or forum that explains all the ins and outs of LP/HP/AL, pressure and capacity and weight etc?

This link has quite a bit of good information: How to Select a SCUBA Tank - Dive Gear Express

 

[WD8CDH]

It seems that it would be easier to obtain a proper fill on the LP steel vs. possibly not on HP steel.

So what is the reason to own HP steel? Doesn't LP make more sense and in fact may be able to hold more precious gas.

Let me know so I can decide whether or not I should replace my twin HP 100's with LP 104's
Thanks

The only disadvantage of owning an HP tank of the same PHYSICAL size (not the same air capacity) as an LP tank is cost. The advantages are higher safety at a given fill pressure, greater capacity at a legal fill pressure, easier to find an LDS that will fill them to more than 2640psi and in a few cases slightly lighter weight.

Except for cost, it would be better to replace an HP100 with an HP130 rather than with an LP104.

But personally, I would rather dive small doubles than ANY 8" diameter single. And I would really rather dive small diameter triples than 8" diameter doubles.

You could also go with HP120s if the length doesn't bother you.

 

[Wormzer]

But personally, I would rather dive small doubles than ANY 8" diameter single.

What are your reasons? I am currently deciding on the HP100 or HP130.

 

[divinginn]

I dive the 130hp tank and the 100hp tank and love them both,also 3 smaller lp tanks,plus for the 130 are bocoo amounts of gas,I can do 2 shallower dives on one tank with a safety reserve,the weight is not a problem for me but could be for someone smaller. changing my tank straps back and forth from 7.25 inchs to 8 inchs is a bit of a pain. The hp 100 is a great tank good for up 100+ ft. dives but can only get one dive unless they are very shallow,they are very light weight tanks with plenty of gas. One plus for hp over lp tanks is you do not have to deal with trying to get + hydro when you get it requalifyed,around here I cannot find someone to + hydro my lp tanks thus making them lower capacity tanks than rated my 77 would be a 72+- when rehydroed and my 72s are 65 cubic ft. without the + hydro,that factor alone makes me want the hp tanks as overfills around here are nill,north Fla. around cave country would be a different story as they usually fill lp tanks to 3600+ psi.

 

[Gombessa]

Just to obfuscate things a bit for the heck of it:

High Pressure Steel Tanks can be filled to their rated pressure: 3300, 3442 or 3500 psi depending on their rating...

Aluminum Tanks can only be filled to their rated capacity: 3000 or 3300 psi.

Low Pressure Steel Tanks, if they have a plus stamp, can be filled to 110% of their rated pressure -ie- for 2400 psi tanks that's 2640 psi, for 2250 tanks (steel 72's) that 2475 psi, and for 3180 psi tanks (mid-pressure steels) that's 3498 psi. Otherwise it's their rated capacity.

 

[Puffer Fish]

What are your reasons? I am currently deciding on the HP100 or HP130.

Don't leave out the Faber FX 100, 117, 120, 133,149.

Ok, the 149 is a somewhat silly tank (make a great set of doubles for the serously strong type).

I have the 100s, 117;s and 133's.. and shore diving with the 100's and boat diving with the 117's.

The 133 only get used for special dives...

 

[Splash-X]

The advantages are higher safety at a given fill pressure, greater capacity at a legal fill pressure, easier to find an LDS that will fill them to more than 2640psi and in a few cases slightly lighter weight.

Are you sure about that?

A LP100 rated at 2600PSI has 100cuft of gas when it has 2600PSI. A HP100 rated at 3200PSI has 100cuft of gas when filled to 3200PSI. (give or take some PSI for your exact tank rating)

You wouldn't need to fill a LP tank any greater than 2600PSI to have 100cuft so your point of having a higher legal capacity is moot as far as my knowledge goes (don't call me an expert). 100cuft = 100cuft, the PSI needed to achieve 100cuft is lower in a LP.

If I'm wrong, correct me please.

Give a choice between a LP and a HP I would select a LP as any shop can easily fill to the capacity where you often get short changed on a HP as some banks don't carry the needed pressure for that,

 

[divinginn]

I get just as many short fills on lp tanks as hp tanks,the big advantage on the hp tanks is size and weight. the disadvantage is the price,but that gap has narrowed some lately. my lp 77 is the same size and weight empty as my hp 100. At rated pressure I have right at 25 cf more air,I like the extra air,I usually surface with about 1000-1500 psi left,which would come in handy in a emergency situation. My 77 I usually surface with 500-750 psi. I occasionally get a 3000 psi fill in my 77 which is plenty of air for the diving I do.