Discussion in 'Diving and Marine Life' started by culumbinus, Oct 4, 2012.
Its latest hydro is marked 21A2011, what does that mean?
Thanks in advance.
I'm no diver but I would guess that the number says it was last certified for whatever tanks are certified for in 2011. If you are looking to buy it I would make the person go and have it certified (and go with them) by whoever does that here before you bought it. As with any tank that holds pressurized gasses I would check for oxidation and stress fractures in the metal but being that your life is at stake I would have a professional take a look as sometimes stress fractures aren't visible to the naked eye.
Tanks are pressure tested in tank of water. Probably means it was tested April 21, 2011
from a NAUI diver
Sir: I'm suggesting only as on opinion, that you look up Rhoody on this forum and offer him a few ice cold ones (unless he prefers warm beers) in exchange for advice or accompanyment as you check out your tank. Scuba tanks have exploded in the past and it bear some serious consideration. I'm no fear monger. However, I live in Alaska and would love to know that you have not become part of the aquatic environment I have to immerse myself in on my next trip. Safety first. In my humble opinion, if doeable, take Rhoody to lunch or something like that. If he accepts, you're on your way to truth, safety, and adventure. I personally only go what I have read on here and I believe him to be worthy of respect and trust. I don't know him, but I would certainly look to him and/or his opinion on the purchase of your tank...
There are more aspects to consider than the Hydro-test, which has do be done each 5 years with aluminum tanks (unless the local law requirements are different).
I actually have not heard from a hydro-tested tank, being tested in Dumaguete, which actually failed the test. In Puerto Galera and Cebu it was normal that a tank or two out of some hundred failed the test. That can have different reasons, that the operations here are not that old and the tanks not that aged or from a more "relaxed" test.
Tanks require also an annual visual inspection, which should be recorded in a logbook (date, tank-number, inspector)
If you say Tanks, you mean completely with valve? 17 years would be a very long time for a valve.
In general, if a tank is proper maintained, handled, stored, filled with filtered dry air etc, there should be no issue even with an older tank. However, we all know the country we are in and the chances that all of the above has been done accordingly.
I personally would be cautious to buy a used tank here unless I know the seller and his operation very well. A brandnew 80cft tank is around 220$ (w/valve) which is the cheapest of the 4 items mainly responsible for your life (BCD, Reg and yourself being the other 3)
Sound practical wisdom Rhoody, thanks.
BTW, do you know of anyone here in Dumaguete who can fill to 4500psi?
As of my knowledge there is nobody.
Regular Aluminum Scuba Cylinders are rated up to 3000 psi, which is slightly above 200 bar. Most compressors have a switch which automatically switch off at 230 bar to avoid damage as everything after the compressor is usually not set up to a much higher pressure than that.
Some tanks are marked with a "+" sign which allows to fill them 10% above the rated pressure.
As of my knowledge there is no standard Aluminum tank for 300 bar on the market, they are usually steel or composite tanks. You also don't want to have a regular Yoke-Valve on a 300 bar cylinder. It is simply not made for this kind of pressure. HP-Tanks use DIN valves usually with 7 thread long to be screwed in, 200 bar 5 thread long (not sure about the correct english term, I hope you get what I mean)
5 years mandatory for SCUBA tank to be hydro tested if used underwater specially in open sea. how about scuba tanks that used for another purpose? i noticed air rifle now filled with compressed air stored in SCUBA tank instead of carbon dioxide. are these SCUBA tanks also need to be hydrotested after 5 years?
I would think for safety purposes anything carrying gas under high pressure should be tested regularly.
No gas involved, it's compressed air. But a tank that old needs a test. They get stale and dirty inside. Another problem is some Philippine run small dive operations dont even filter the air they put in.