Same old VIP stuff.........

[owlbill]

Just wondering what peoples thoughts are about the following text. It is from an email we received. I have removed any names of course. I have also highlighted the parts that I am most curious about with regards to comments from you all.

-----------------------------------

NOTE: DOT issued a safety alert bulletin for tanks made with this Alloy 6351-T6 in 1994. The DOT did not order a mandatory recall, nor did the manufacturers issue a voluntary recall. Annual inspections remove most of of these tanks from service before they have a chance to explode. Some explode anyway.

"Customer name removed", "shop name removed" is Proactive not Reactive. I was trained under the standards set forth by the above agencies. We would not like to see an accident in the store, dive site or any place for that matter. Just because it passed VIP and Hydro doesn't make it safe. There has many cases where SCUBA cylinders have exploded after having current VIP and Hydrostatic testing by Government authorized Hydrostatic Testing Facilities. Please check out this site concerning Walter Kidde cylinders napsd.com
--------------------------------------------

 

[mike_s]

Just wondering what peoples thoughts are about the following text. It is from an email we received. I have removed any names of course. I have also highlighted the parts that I am most curious about with regards to comments from you all.

-----------------------------------

NOTE: DOT issued a safety alert bulletin for tanks made with this Alloy 6351-T6 in 1994. The DOT did not order a mandatory recall, nor did the manufacturers issue a voluntary recall. Annual inspections remove most of of these tanks from service before they have a chance to explode. Some explode anyway.

"Customer name removed", "shop name removed" is Proactive not Reactive. I was trained under the standards set forth by the above agencies. We would not like to see an accident in the store, dive site or any place for that matter. Just because it passed VIP and Hydro doesn't make it safe. There has many cases where SCUBA cylinders have exploded after having current VIP and Hydrostatic testing by Government authorized Hydrostatic Testing Facilities. Please check out this site concerning Walter Kidde cylinders napsd.com
--------------------------------------------

1.) one of the manufacturers did have not really a recall, but an upgrade where you could get that tank replaced. but that offer has expired.

2.) in I think 2006, DOT release further inspection requirements for 6351-T6 cylinders.

3.) Many stores choose not to fill or service these cylinders because of issues with them.


There are several threads on this if you want to read more. some of them very recent.

 

[tc]

PSI has many articles on this topic here-

Library

 

[owlbill]

Thanks guys, but I have read all that. I am PSI trained, we use Visual Plus 3 AND Optical Plus AND light and magnifying mirror.

I was more looking for personal opinions.

Looks to me like ALL aluminum cylinders can crack, so, with some of the arguements, does that make ALL aluminum cylinders unsafe?

 

[bleeb]

Looks to me like ALL aluminum cylinders can crack, so, with some of the arguements, does that make ALL aluminum cylinders unsafe?

I've been reading along about this Al cracking thing for a while, but had understood (perhaps wrongly) that it was only practically an issue for tanks made from 6351 alloy and not 6061. When you say "ALL" are you including 6061 in your statement? If so, can you elaborate? What's sort of failure rate are we talking about?

 

[PhilEllis]

Thanks guys, but I have read all that. I am PSI trained, we use Visual Plus 3 AND Optical Plus AND light and magnifying mirror.

I was more looking for personal opinions.

Looks to me like ALL aluminum cylinders can crack, so, with some of the arguements, does that make ALL aluminum cylinders unsafe?

This is certainly a well-hashed subject. I think it is foolish to have this thread bounce over the the typical "VIP is not law, VIP is a scam" argument. It is also of little value to quote letters, articles, and DOT regulations.

The bottom line is.....many scuba stores, rightly or wrongly, have made a business decision to end the practice of filling these cylinders. Some have done so simply following the pack, some have possibly done so to sell new cylinders, and some have done so as a result of careful evaluation of the available data and risk management. In the end, it is what it is. Few stores will fill those and the email you got simply adds one more to the list.

Phil Ellis

 

[owlbill]

I've been reading along about this Al cracking thing for a while, but had understood (perhaps wrongly) that it was only practically an issue for tanks made from 6351 alloy and not 6061. When you say "ALL" are you including 6061 in your statement? If so, can you elaborate? What's sort of failure rate are we talking about?

From - "Cracking and Ruptures of SCBA and SCUBA Aluminum Cylinders Made from 6351 Alloy" By Bill High, PSI, Inc.

--- The Catalina Tank Company began making 3AL cylinders in 1986 using alloy 6061-T6. Although this alloy is generally not subject to SLC, a very few Catalina cylinders have been found with minor thread area cracks attributed to stress corrosion cracking. Therefore, PSI, Inc. recommends that thread examinations, including a mirror-and-light protocol be performed on all 3AL cylinders. ---

This in not SLC cracking but still cracking.

 

[owlbill]

I think what I was after here was the mention many of "There has many cases where SCUBA cylinders have exploded after having current VIP and Hydrostatic testing by Government authorized Hydrostatic Testing Facilities." Is there anything to back this up? I am just trying to clear up confusion as we have many customers (now our customers) who have been told elsewhere that their tank is "unsafe" even when they are in mint condition visually inside and out.

Do tanks just spontaneously explode without SLC? I think not.

Do all dive shops do proper and thourough visual inspections utilizing the most current available methods and tools? I think not.

Should the dive industry as a whole just step up and say "we are done with 6351 for good" and get rid of them all? I am not sure about this one yet, but I might be inclined to join that brigade, but only if the entire industry gets on board. (I know this is highly improbable)

Phil, I did read about and am aware of the incident at your shop that prompted you to change your policy. I would have posted a link to it but could not find it again.

 

[PhilEllis]

Should the dive industry as a whole just step up and say "we are done with 6351 for good" and get rid of them all? I am not sure about this one yet, but I might be inclined to join that brigade, but only if the entire industry gets on board. (I know this is highly improbable)

Phil, I did read about and am aware of the incident at your shop that prompted you to change your policy. I would have posted a link to it but could not find it again.

As far as the retail part of the industry here in the Eastern United States, they industry almost has said that they are done with these cylinders. If you think about it, there has been more hand-wringing, argument, study, evaluation, government action, and general time wasting on this single subject than almost anything in the scuba industry. When Luxfer offered the "rebate" certificates, providing an economic incentive to get these out of the market, the industry filling of these cylinder should have expired with the certificate offer.

I also have a suspicion that there is more TECHNICALLY to this 6351-T6/SLC issue than has been exposed and is currently known. I know my own skills with cylinder inspection are pretty good, and I apparently completely missed (along with the hydro and eddy current test at the hydro station) a crack.

Phil Ellis

 

[Scared Silly]

I talked to my local hydro operator about 18 months ago and he noted that he had failed "many" Al 6061 cylinders for cracks. He show me one with very visible cracks in the threads.

6351 Advisory:
http://hazmat.dot.gov/pubs/reports/cylinder/3al_advisory.pdf

6351 Requal rules:
http://a257.g.akamaitech.net/7/257/2422/01jan20061800/edocket.access.gpo.gov/2006/pdf/E6-14255.pdf