Burst disc for HP tanks

[DiverDan]

Derrick,

Your burst disk should be rated for 5/3 the working pressure of your tank. For example, if you have a 3000psi aluminum, the burst disk should be rated for 5000psi. This is also the hydro pressure of the tank.

And DRE the disks are not put on the valves for your inconvenience, in fact you should not have to even worry about them. The reason for having a burst disk on the tank is to prevent the tank from exploding under extraordinary conditions, such as, a fire or other extreme heat conditions. Fire fighters do not appreciate grenades going off when they are fighting a fire. Check out PSI, Inc. at they have great stats on tank explosions. And by the way, the way for the o-ring to fail is if the valve is ejected with your ss shims in it which were not able to relieve the increased pressure.

Dan

[beeger]

You have to call Extreme Exposure to get the shims. They are not available from their website. Actually they have a lot of products that are not available on their website.

Disks can and will fail; European valves have no burst disk system of any sort; o-rings can and will extrude without the valve being “…ejected with your ss shims in it…”; tanks explode during filling because the tanks have an issue not because the burst disk has an "issue."

[ScubaDiveandTravel]

I think installing shims in your dive tank is your business, but I think it is important to let the dive shop know if they are shimmed. If a shop believes it is dangerous to fill these tanks, that is their right and I don't think it should be kept secret from them. I personally don't have a problem filling tanks without a burst disc, but that's personal preference. Like DiverDan said, the real reason burst discs exist is for extrodinary circumstances such as fire. As for DRE's comment about the O ring failing before the tank will explode, that is innacurate. If that was true, there would never be tank explosions. Unfortunately the burst discs rarely save lives in the dive industry, instead they are a pain in the butt because they often burst at normal working pressures. Just be safe guy's and again, please be honest with your dive shop.

Happy Diving,
Richard

[DRE]

Tanks will only explode if they don't pass a hydrostatic test, ie a bad tank with shims will probably blow before the o-ring goes, but there is a very good chance that same tank will go with a burstdisk installed as well. Obviously you do want to maintain your equipment properly - I don't want to dive with shitty regs, nor do I want to dive with shitty tanks. Annual VIP's and current hydros go a long way to prevent tank damage.

In case of fire - don't you think a rubber o-ring will melt long before your tank will explode?!


In Europe tanks do not have burstdisks and they don't have problems - at the same time (and this is different from country to country) they do require hydrostatic testing more often (annually or bi-annually). And BTW, steel tanks don't explode like a handgrenate, they split - aluminiums will shatter, but then again you should never overfill al's in the first place so it's a moot point anyways...

[fantasea]

Our staff has taken the PSI training course through PSI Instructor Corey Monahan. Corey has always been fair, open to debate, open to new ideas, and genuinely excited when something new comes his way. He bases his information on established standards, regulations, and a known events. To improve safety, knowledge, behavior and guidelines we provide for ourselves and others, we believe that the PSI training we received was an exceptional value, a thorough learning experience, very intuitive, and a valuable resource. For anyone who wishes to make further strives in improving their knowledge and safety when handling, storing and caring of their SCUBA cylinders, we fully endorse participating in a PSI training course – you can only come away with a better understanding and learn something valuable from it. Many of our staff will take PSI refresher training; we find that we can all learn something new, something updated, and something that may have been forgotten in the past.

FantaSea Scuba & Travel uses manufacturer proprietary burst disks assemblies in which the rated service pressure is stamped on the back of the burst disk retainer. Though we are no way experts on individual burst disc properties or other non-manufacturer recommended guidelines, so in pursuit of answers we try to turn to the experts.

We at FantaSea Scuba & Travel believe many answers for some of the more complicated issues on equipment and medical advice, can be easily obtained from industry experts like PSI, DAN (Divers Alert Network), DSAT (Diving Science and Technology) and a host of others. We hope that forums like this will encourage others to learn from the leaders in SCUBA and Freediving research and development for these important safety inquiries and advances.

For more information on cylinders and burst disc safety, check PSI's website at or you can contact Corey about the next PSI training this fall here in Mpls. His email is corey@psicylinders.com