Scuba Bomb

[tlt]

I have seen this information posted around and I thought it would be useful for dive shops, divers and people in general filling and buying tanks. I've seen tons of old tanks advertised on craigslist. I am posting the site link, and summary here. Perhaps the board operator can clean it up and make it sticky.

List of Scuba Tanks Made From 6351-T6 Alloy

All walter Kidde DOT -3AL, ALL Cliff Impact DOT 3-AL, ALL LUXFER 80 cu. S80 (before January 1988) All other scuba tanks made in the U.S. before 1990 (except Catalina tanks) YOU MAY WANT TO CHECK WITH DOT safety alert bulletin YOU MAY BUY A TANK THAT A SHOP WONT FILL. The list is longer than what I have put on here. These tanks that I have listed are the most common tanks that I am seeing sold at this site. ALL of these tanks listed here will require a visual eddy every year COST around $25.00 extre a year.

I apologize if anyone is put off by this, it just seemed very useful, and people should beware. The link has a great detailed list, and links to victims.

 

[tc]

Thanks for the thought tlt, it has been discussed here quite a few times in other threads as well.

To clarify one point- visual eddy test is only required every 5 years when the hydro is done, not every year.

 

[tc]

PSI has a number of articles on the topic for those that would like additional detail-

Library

 

[rstofer]

I think the last two sentences of the document are an overstatement of the facts. If those statements were true, the DOT would have recalled the tanks decades ago.

Many of these tanks are routinely hydro'd, eddy current tested, viz'd and refilled. Some shops have an issue with refilling, others do not.

Richard

 

[Scared Silly]

Read the originals:

Notice No. 94-7; Safety Advisory; High Pressure Aluminum Seamless and Aluminum Composite Hoop-Wrapped Cylinders

then read the CFRs

Hazardous Materials: Aluminum Cylinders Manufactured of Aluminum Alloy 6351-T6 Used in SCUBA, SCBA, and Oxygen Services--Revised Requalification and Use Criteria | Federal Register Environmental Documents | USEPA

Anything else is hearsay.

 

[tlt]

scientific data, pictures, etc.
How much energy is there in a filled scuba tank

 

[rstofer]

Twelve tanks out of an estimated 25 million have exploded over 40 years, give or take. Those odds are a lot better than driving to work or driving a Ford Crown Victoria (police cars where fuel tanks exploded in rear end collisions).

The suggestion to retire tanks after 10 years is nonsense. It doesn't even differentiate among cylinders. One of my Al 80s is 20 years old, my steel 72 is 30 years old, another Al 80 is 15 years old. All are getting along just fine. Why on earth would I junk them?

Store them empty? Why would I do that? The whole objective of buying tanks is to be ready to go at a moment's notice. Maybe it's next week, maybe next year, maybe several years - so what? An empty tank is about as useless as an empty sidearm. They don't even make good hammers.

Scuba tanks are designed for 100,000 fill cycles. Given that they are filled perhaps 50 times per year for the 'average' diver, they should last 2000 years. Even in fleet service with 3 fills per day, every day of the year, the tank should last about 100 years.

The argument that hydro takes out the defective cylinders overrates the testing. After all, the tank didn't explode between tests. The crack could start the day after hydro and not be caught for 5 years. Yet the tank wouldn't fail. On average, cracks last 2-1/2 years before being detected - if they are not overlooked. And still no explosions.

If 6351 tanks were a problem, they would be exploding every day. Twenty five million is a LOT of tanks. They should be popping like popcorn. But they're not! Twelve are thought to have exploded.

Richard