Overfilling steel tanks

[drbill]

Northeastwrecks- It WOULD be our business IF what you did re: overfills compromised other diver's safety. I'm not saying what you do is, just IF you did an unsafe overfill.

My HP120 died after just 10 years. I attribute it to hot fills and over fills by one of the two dive shops I use. The cause of the failed hydro was 16% over expansion. I do not want overfills or hot fills... just a nice slow fill to the indicated pressure.

Doc

 

[ScubaDadMiami]

When I wanted more volume, I went out and bought larger tanks. However, I will admit to an occasional overfill of steels in the past: like 3100 for a 2640 tanks. I just don't do it anymore.

 

[DA Aquamaster]

I will push my steel tanks to the 10% overfill to get the advertised capacity, but any more than that is just not worth it. I fill my own tanks so I am the guy who gets reduced to several smaller pieces if it blows up. Ad if I need more air, I use doubles or get larger tanks.

The DOT standards are conservative but that's ok, it ensures a great deal of safety and also means a very, very long tank life. There are steel scuba tanks still in service after 50 years and I have seen steel welding tanks that were 90 years old and still passing hydros.

 

[UWSojourner]

So let me get more specific. It sounds like most of you think filling steel Faber 95 (rated to 2640) to 3000 psi is ok?

 

[OceanusDC]

There is another point to think about. Regardless of whether the tanks can take it or not, the DOT has stamp a max pressure on it for the USA and that opens up a liability issue. For example, imagine you, “ABC Dive Shop” over fills 2 steel cylinders. The tank owner Mr. Diver gladly takes the tanks and puts them in the back of his truck (Car, SUV…whatever) and takes off down the road. He stops at a red light but the person on the cell phone driving the vehicle behind him doesn’t see it and rear ends him. The impact isn’t to bad and certainly not enough to cause serious injuries BUT, one of the two steel tanks hits it’s valve on something and shears it off. The result shoots some material back at the car behind and hits the person causing massive physical damage to the person. Mr. Diver is also hit by flying debris and unfortunately dies. Now, the law suits…..The DOT checks the remaining tank for clues and discovers the overfill. Finding the fill receipt they go to ABC Dive Shop and find out they commonly overfill tanks. Now its thousands of dollars in litigation and who knows what the outcome may be. The liability insurance will most likely try to use the over fill to back out of paying so ABC is left out to dry. The DOT may bring some kind of suit. The injured parties and families will be suing everyone involved. Nobody signs a waver when a tank is filled so I assume (bad word there) that the “professionals” at ABC will be left holding most of the blame. I am not a lawyer but I can see a lot of liability floating around here. I would rather lose a few customers than lose everything I own over a few hundred pounds. Just my 2 cents.

 

[flounderboy]

I have never demanded
but most times I have my lp108s filled to 3500
the tank is rated at 10,000 fills at 4000 pounds

what i dont like is getting them to 4200 pounds :11:
yep it happened

and i let them down to 3500 before i drove off

Dive Safe

Mark s

 

[Ontario Diver]

What I'm wondering about is just where this paritcular bit of information started. If a tank manufacturer in Europe makes tanks for the European and American market, how come the American tanks get a 2400 psi rating but the European ones get a 5000 psi rating? Or does the same manufacturer make two completely different tanks for two different markets?

There is one key reason for this. As I have been told some European tanks (German, Italian) are rated for a specific lifetime. They are set up to have x number of fill cycles over 5 years. DOT and TC rate thier cycles for an umlimited lifetime (until they fail hydro).

The trade off is higher fill pressures mean a lower lifecycle.

I don't know about the US, but in Canada you can get a big whopping fine if TC catches you overfilling a customer's tank. I know of one shop that had a customer come in and ask for a "good fill" on his steel tanks. The fill guy pumped them to 3000...... the customer checked the pressure, produced his Inspector ID and the shop got written up.

 

[FreeFloat]

For us lucky divers in the UK we get our tanks filled to

232 Bar for............. funnily enough for 232 tanks

300 Bar for............. funnily enough for 300 tanks

and the Al tanks are rated to 232 as well

I think :06: in Europe 200 Bar is normal, In the Maldives recently 230 bar was the order of the day!

So, being a metric type person can anybody explain how much of a difference it makes on your side of the pond......

Why, if they are the same tanks, are yours filled to such low pressure.............Yes I know about the goverment screwing up, Same here on a lot of things, But this seems total Bo@@@k's

There has to be a reason :06:

200 Bar = 3000 psi
232 Bar = 3480 psi

 

[kalvyn]

So let me get more specific. It sounds like most of you think filling steel Faber 95 (rated to 2640) to 3000 psi is ok?

Yes, as a matter of fact. I just got one of my Fabers filled this weekend. When I go to use it I'm sure I'll have at least 3000 PSI in it as I'm gearing up. I get my tanks filled at a local shop here in Tacoma/Lakewood, I don't self-fill.

I also have a couple E8-119s, and their last fill was to 4000 PSI in the water. That was probably a little extreme, but I did ask for a "good fill" as I had a cool dive trip booked. The dive was canceled unfortunately but NWGratefulDiver and I got a nice 82 minute dive up at Mukilteo as a consolation.

Jimmie

 

[DA Aquamaster]

So let me get more specific. It sounds like most of you think filling steel Faber 95 (rated to 2640) to 3000 psi is ok?

2640 psi is with the 10% overfill. So 3000 psi is really 600 psi over the 2400 psi service pressure which is a 25% overfill.

Given that steel tanks are normally tested to 5/3rds their service pressure (167% of the service pressure) the tank probably is not going to explode. But it does place more stress on the tank and frequent overfilling to that extent will substantially shorten it's useful life - from 50 plus years to maybe 10-15 years as the odds are pretty good the tank will fail it's 2nd or 3rd hydro.