Overfilling HP100 tanks

[climbr1]

So I have scanned the forum and done all the searched and still want to ask. I have a HP100 and a compressor that will do 6000 psi. With the common practice of overfilling LP bottles to 3800 and over I ask why not HP? At a 10% overfill thats still only 3800.

As I understand it there is a different metal composition? And its more stress on regs but the same reg is used for LP overfilling so is anyone else pushing this envelope? My reg is a DIN Mk17

 

[bwade]

With the common practice of overfilling LP bottles to 3800 and over.

Seriously? I would NOT want to be the shop who would be held Liable if a problem happened ......

Wow...

 

[iztok]

I use HP119 and typically get them filled to 3700/3800psi. They cool down a bit to around 3500/3600.

 

[cbrich]

I have filled my HP tanks to 3,800, but that was a hot fill, they cooled down to 3,200 - 3,300. I have done cold fills up to 3,600, but nothing over that. If you need more gas because your air consumption sucks, then get bigger tanks.

But again you have your own compessor, you can do whatever you want to do. If you want to fill those tanks to 4,000+ psig, and double burst disk them, go right ahead. The only people you are putting in danger is you. The scuba police will not came after you.

 

[Scott L]

They are routinely filled to 3800 psi in this neck of the woods. No one has blow'd-up yet...

 

[oxyhacker]

The high pressure tanks are all "high performance" tanks built under a special permit from the DOT. They are thinner walled than the notoriously rugged and overbuilt LP 3AA tanks, but are made of stronger steel and heat treated differently to compensate for it. However, in real life service, they have turned out to be more delicate than 3A and 3AA tanks. They fail hydro much more frequently and require special handling (and a lower test pressure-to-fill pressure ratio) than the 3AA tanks. So while some people may put a modest overfill in them, to compensate for heating, and maybe a bit extra, the general feeling is that they just aren't up to the sort of massive overfills that the 3AA tanks seem to shrug off without ill effects.

So I have scanned the forum and done all the searched and still want to ask. I have a HP100 and a compressor that will do 6000 psi. With the common practice of overfilling LP bottles to 3800 and over I ask why not HP? At a 10% overfill thats still only 3800.

As I understand it there is a different metal composition? And its more stress on regs but the same reg is used for LP overfilling so is anyone else pushing this envelope? My reg is a DIN Mk17

 

[NeedABiggerBoat]

I was recently down in Nassau diving with the sharks, and the first tank I hooked up to was at 4000 psi. It was an aluminum tank though so I don't know if this helps you any. Apparently one of the fellas over-filled it. The crew on the boat had a good chuckle and I dove it anyway.

 

[climbr1]

I would not expect a shop to do the same, this is mine. I have a SAC of .60 so consumption is not what Im worried about. I try to dive all winter 3-6 times and its common to have my pressure rise to 3700 or so after I hit the water after having tanks sit in the snow awaiting their turn to be filled. They have been fine with that although we try to stop short and let them warm up in the water its always a guessing game. Thinking I can get a consistent bottom time if in the summer I filled them to 3800 to begin with. Im not going to double burst disk them.
Oxyhacker, thats the answer to the question I was wondering. If the composition was the same as a LP then I wouldnt hesitate as history is proving that to be commonplace. But with a more delicate and sensitive tank then I will just stick to the normal procedure.

Scott L, just confirming the tanks are HP tanks they are overfilling to 38?

 

[fdog]

Probabally doesn't fall into the "helpful information" catagory, but if you give a HP cylinder a cave fill (double stacked disks and all), I want to shoot video...with a telephoto lens, of course...


All the best, James

 

[climbr1]

Ya, that would be cool. But Ill pass. I shot a SCBA tank with a .338 lapua a few years back and that was like a small bomb going off with 2200 psi.