steel LP vs HP

[jcollin160]

thats what i thought, the HP will be smaller tank size for the same volume at the rated pressure. I just like to fact/option of being to be able to do a little overfill for more volume with the same tank.

In my area, there are only LP tanks around unless someone has one shipped in special.

 

[Stu S.]

with a LP tank you could do a little overfill

Here, folks bought LP cylinders expecting fills at 3,500 psi. That makes the LP 95 hold air like a 120. A number of dive stores stopped doing overfills. They decided to follow the law on that.

With "bonus fills" less available, the only sure way to get 120 cu. ft. is to have a 120 cu. ft tank. The HP is easier to handle and use for most divers.

That's the reason we use HP's.

 

[liuk3]

Yeah, I use HP tanks because my local dive shops won't substantially overfill my tanks knowingly.

 

[bevansmw]

It seems my dive shop overfills my LP tanks unknowingly sometimes. I have two LP 72's with a service pressure of 2250. I've had a few times where they just assumed the service pressure was 3000 and filled to about 3200. They always do hot fills, so they cool down to about 2800psi when they fill to 3200. One time they filled to 3600, that cooled down to 3000psi, I was a bit iffy about that one but it was ok. I usually try to get them overfilled to around 3000-3200 so I get around 2800psi or so as I dive with someone that rents AL 80's and that gives me about the same amount of air as him.

For the reason of overfills and speaking to someone else on Oahu that has HP tanks who was unable to find a dive shop that could get 3500psi in his tanks easily I'm leaning more toward LP tanks. The 72's are my first two tanks, but if I buy more it'll probably be a larger LP tank like an 85.

 

[ScubaSteve]

For me there is nothing better than checking my computer before a dive and seeing 3400 or 3500 psi

 

[HateCheese]

The advantage in an HP is weight / size. I've got a buddy who dives HP 100s, while I dive LP 95s. The HPs are simply easier to lug around. He has no trouble getting a full fill, so he is happy with them. They do take longer to fill - first fill, allow to cool down, then top off. Also, you want to make sure your reg is rated for the higher pressure, and it is generally recommended to go w/ a din valve instead of yoke.

LPs are easy to get a moderate overfill around here. Nice to have the ability to get a little overfill for certain dives / tournaments / etc. Although I have never used them in this way yet, i also got them so that if i drive somewhere I can be assured that no matter what shop fills them, I will get 95 cubic feet.

 

[mksmith713]

I haven't done the math on mine yet but fills on my HP 120's rated 3442 read 4100psi

Any comments?

I've checked with 4 different spg's..... 4100.

 

[ScubaSteve]

My suggestion is to NOT tap the tank with any object . That is way beyond my comfort zone for an overfill.

 

[elan]

i
Just wanted some clarification why people are using HP.

For me it was because they are smaller and lighter for the same cuf volume

 

[Gombessa]

I have two LP 72's with a service pressure of 2250. I've had a few times where they just assumed the service pressure was 3000 and filled to about 3200. They always do hot fills, so they cool down to about 2800psi when they fill to 3200. One time they filled to 3600, that cooled down to 3000psi

Yikes. Speaking as a big fan of overfills here...there are a few shops in my area who will fill 2640psi LP steels anywhere from 3000-3500 cold. However, all of them steer clear of significantly overfilling the old 2250psi LP72s. I don't know exactly why, but ever since finding out, I haven't overfilled the 72s past 2600.