Public Service Announcement Add Helium Carbon fiber tanks

[Wookie]

Carbon fiber scuba cylinders don't get hydro'd either. 15 years and down the road they go.

 

[Kay Dee]

As far as the Military, they require DOT and UW designation for all tanks that can be filled by civilian facilities.

First, thanks for your reply! But it seems my wry sense at humour went right over your head. ;-) That is, I once had an Oz CCR Instructor who was an ex Mk16 EOD guy / Military instructor on same. If he heard you call a scuba 'cylinder' a tank he would reply that only the army (or Marines, whatever) used 'tanks' (as in Sherman, Panzer, M1 Abrams, etc) and a penalty of "drop and give me twenty" would be enjoyed as punishment for using the ground pounder term, when in fact it was 'cylinders' that we were / you are using. (Yes semantics maybe, but.............) And this 'term correction" was kept in force until one stoped using said term, which one soon did. Hence my wry comment / 'advice' in the post you quote of mine. ;-)

Anyway back to the cylinders. Now while I think the rest of what you say is somewhat superfluous to the accident itself, if what you say is correct, and I am not doubting you, but am not hands on 'famliiar' with the unit in question, then if 3L cylinders were what the CCR manufacturer supplied / reccomended for that unit,, and the deceased was only using 2L's instead, well I see a potential problem right there unfortnately, as it could be argued that if 3L's were being used then the O2 supply would not have been exhausted. But I don't have a dog in this kerfufle whatsoever, it is simple arithmetic is all.

 

[Wookie]

I'd love to see the DOT stamp or UW designation for an inconel sphere or even a steel sphere used in a Mk 15 or 16.

I think the OP is making it up.

 

[Diving Dubai]

Carbon fiber scuba cylinders don't get hydro'd either. 15 years and down the road they go.

I don't doubt you, however I did find the fol;lowing which leads me to suspect that they should still be hydro'd periodically but do have a finite life of 15 years

• Hoop-wrapped cylinders should be tested every three years and have a 15-year service life.
• Fully-wrapped fiberglass cylinders should be tested every three years and have a 15-year service life.
• Fully-wrapped Kevlar® cylinders should be tested every three years and have a 15-year service life.
• Fully-wrapped carbon fiber cylinders should be tested every five years and have a 15-year service life.

appreciate this website has info on SCBA Cylinders. This is another website again quoting hydro times on SCBA

Now I'm no expert (well apart from NDT/NDE of carbon and metallic components) but I figure that if you're going to take pressurised cylinders into water you'll want to inspect them

Anyone interested in the Corrosion aspects

Galvanic Corrosion of Metals Connected to Carbon Fiber Reinforced Polymers of CFC

 

[Patoux01]

I don't doubt you, however I did find the fol;lowing which leads me to suspect that they should still be hydro'd periodically but do have a finite life of 15 years

Depends on tank and country then, but carbondive claims no limit (except if 200 years is a limit to you)

 

[Wookie]

I don't doubt you, however I did find the fol;lowing which leads me to suspect that they should still be hydro'd periodically but do have a finite life of 15 years

• Hoop-wrapped cylinders should be tested every three years and have a 15-year service life.
• Fully-wrapped fiberglass cylinders should be tested every three years and have a 15-year service life.
• Fully-wrapped Kevlar® cylinders should be tested every three years and have a 15-year service life.
• Fully-wrapped carbon fiber cylinders should be tested every five years and have a 15-year service life.

appreciate this website has info on SCBA Cylinders. This is another website again quoting hydro times on SCBA

Now I'm no expert (well apart from NDT/NDE of carbon and metallic components) but I figure that if you're going to take pressurised cylinders into water you'll want to inspect them

Anyone interested in the Corrosion aspects

Galvanic Corrosion of Metals Connected to Carbon Fiber Reinforced Polymers of CFC

View attachment 436241

I've been wrong before. Thanks for the education.

 

[Diving Dubai]

Depends on tank and country then, but carbondive claims no limit (except if 200 years is a limit to you)

They still need to be inspected as per their service bulletin
And if you for a minute think they have an indefinite life expectancy then I have a perpetual motion machine I can sell you cheap

Pity they all ignore galvanic corrosion at the material interface, perhaps it's because they don't expect them to last that long in service

 

[Diving Dubai]

I've been wrong before. Thanks for the education.

I hope you didn't think I was calling you out, It wasn't meant that way.

Patoux01's comment about carbondive (worthington) cylinders lead me on a geek search. This service bulletin Gives details on inspection methods and periodicity including US & Canada for their cylinders (I guess this must be a standard for all carbon cylinders?).

You may find it interesting and of information in case people bring carbon cylinders on to your new boat. At least you know what should be done

 

[DEEP BLUE CCR]

First, thanks for your reply! But it seems my wry sense at humour went right over your head. ;-) That is, I once had an Oz CCR Instructor who was an ex Mk16 EOD guy / Military instructor on same. If he heard you call a scuba 'cylinder' a tank he would reply that only the army (or Marines, whatever) used 'tanks' (as in Sherman, Panzer, M1 Abrams, etc) and a penalty of "drop and give me twenty" would be enjoyed as punishment for using the ground pounder term, when in fact it was 'cylinders' that we were / you are using. (Yes semantics maybe, but.............) And this 'term correction" was kept in force until one stoped using said term, which one soon did. Hence my wry comment / 'advice' in the post you quote of mine. ;-)

Anyway back to the cylinders. Now while I think the rest of what you say is somewhat superfluous to the accident itself, if what you say is correct, and I am not doubting you, but am not hands on 'famliiar' with the unit in question, then if 3L cylinders were what the CCR manufacturer supplied / reccomended for that unit,, and the deceased was only using 2L's instead, well I see a potential problem right there unfortnately, as it could be argued that if 3L's were being used then the O2 supply would not have been exhausted. But I don't have a dog in this kerfufle whatsoever, it is simple arithmetic is all.

Your absolutely right regarding the tank and cylinder comment. As you are aware the civilian base dive industry seem to enjoy its generalization. To be quite blunt having a discussion about anything technical especially terminology seem to only invite a variety of internet trolls. Before you know what happen the issue is language not the actually subject matter.

 

[DEEP BLUE CCR]

I'd love to see the DOT stamp or UW designation for an inconel sphere or even a steel sphere used in a Mk 15 or 16.

I think the OP is making it up.

You are very well aware that those spheres do not have stamps. Lets just refer to your tag line.Please do not let the facts of the matter interfere with my discourse on the subject.