DOT Expiration date on early Tanks?

[JamesBon92007]

OK, I found it on Luxfer's web site:

Luxfer: Press Releases

This was published in December 1999 so it didn't *appear* out-of-date when I read it:

>>3. Inspection Frequency: Luxfer recommends that all-metal SCBA 6351 cylinders be inspected once every 2.5 years (halfway between requalifications). Hoop-wrapped 6351-alloy cylinders should be inspected every 3 years at the time of the normal requalification. Please note that hoop-wrapped cylinders manufactured before 1985 have expired and are to be condemned.<<

I have three Walter Kidde tanks, one of which I was not even going to bother with due to what appears to be a neck crack. Another made the same year (or close to it) has a "tool mark" that may or may not be a neck crack. Getting eddy tests is intriguing but right now it looks like the money I would have to spend would need to be considered as an entertainment expense.

Now, if only Luxfer would offer another rebate/exchange program--they are within driving distance (I think) so I wouldn't even have to pay the shipping.

Meanwhile there's a guy with an old galvanized steel 72 with a J-Valve and a Calypso IV regulator on Craig's List. I think I'll give him a call.

 

[Delta_P]

Ah, got it. SCBA is Self Contained Breathing Apparatus, used on the surface by firemen, hazmat workers, and others who don't want to breathe the surrounding air for some reason. Scott Air Pacs are the most well known SCBAs. Different service than SCUBA.

 

[captain]

Luxfer: Support

This thread really belongs in the Tanks section not vintage.

 

[duckbill]

Getting eddy tests is intriguing but right now it looks like the money I would have to spend would need to be considered as an entertainment expense.

If you can actually see cracks, the eddy test will not be necessary.

Yes, that info is for SCBA cylinders. You'd think, though, that fire departments would be more likely than divers to keep their cylinders full and ready to use. So, if 2 1/2 years is good for fire departments regarding sustained load cracking, being tested every year at vis seems like it should be more than enough to satisfy even the most pessimistic dive shop owner. Oh, well.

 

[JamesBon92007]

By "Sustained Load" we are talking about leaving a tank filled at maximum rated (or high pressure) for extended periods of time, right? Does sustained load cracking occur if a tank is left sitting with only a few hundred psi?

 

[PhilEllis]

Just as a follow-up, I will post the following "clips" from the Federal Register that relates to the PMHSA thought process for issuing the final ruling that these cylinders CAN stay in service.

"In response to the known susceptibility of cylinders made of
aluminum alloy 6351-T6 to SLC, the NPRM discussed three possible
options, which were evaluated as part of a cost-benefit analysis to
address existing safety concerns: (1) Leaving the cylinder in service
without taking any additional measures to reduce the risk, (2)
immediately removing all cylinders made of aluminum alloy 6351-T6 from
service, or (3) performing a NDE at the time of the cylinder's periodic
requalification and requiring additional operational controls (OC)
during the cylinder filling process. After careful analysis, we
selected the third option.

Several commenters suggest that option (3) does not provide an
adequate level of safety. The commenters state that SLC is a
manufacturing problem, and no level of testing will prevent future
incidents. These commenters assert that the only way to prevent future
SLC incidents is to prohibit the use of all aluminum alloy 6351-T6
cylinders. They also assert that the safety benefits outweigh the costs
involved in removing these cylinders from service and express concern
that the SLC problem will only get worse if the cylinders remain in
service.

We agree. However, the original economic evaluation showed
immediate removal of these cylinders from service would place an undue
economic burden on the affected industries. Although the economic
burden of immediate removal is not justified, a gradual phase out of
these cylinders over time will address the safety issue, and limit the
costs associated with removal of these cylinders. Users of DOT 3AL
cylinders generally replace them with a new one after 45-50 years. We
revised the economic analysis to examine the costs of implementing
option (3) with the addition of a 40-year service life. The economic
analysis showed the addition of a 40-year service life to option (3)
would provide an effective phase-out of these cylinders over time
without imposing significant costs on the affected industries. Since
most of these cylinders were manufactured prior to 1990, total removal
of these cylinders would be accomplished by the year 2030. In this
SNPRM we are proposing the addition of a 40-year service life on
existing DOT 3AL cylinders manufactured of aluminum alloy 6351-T6.
Under this proposal, cylinders would be prohibited from service when
they reach the end of a 40-year service life. We are soliciting
comments on whether a 40-year period from the date of manufacture is an
appropriate service life for these affected cylinders."

"F. Operational Controls for Filling Aluminum Alloy Cylinders

In the NPRM, we proposed to add operational controls during the
filling of cylinders constructed of aluminum alloy 6351-T6. The
proposed operational controls included a provision requiring the
cylinder filler to allow only those individuals essential to the
filling process to be in the vicinity of the cylinder during the
filling process.

Commenters generally support this requirement. One commenter
suggests the term ``vicinity'' is not clearly defined and could lead to
wide interpretation. The commenter requests we clarify the area that is
intended to be covered by the term ``vicinity.''

We recognize the term vicinity could be widely interpreted. The
intent of this requirement is to protect non-essential personnel and
innocent bystanders from injury if a cylinder were to rupture during
filling. For purposes of this requirement, vicinity means a location
near or around the filling operation that would impose an unreasonable
risk of injury to an individual if the cylinder were to rupture during
the filling process. The actual distance could vary broadly depending
upon the type of safety mechanisms in place and the actual square
footage of a particular filling location."

This might be an interesting read. Pay special attention to the fact that they are NOT saying the cylinders are safe. They are mostly saying removing them would have a bad financial impact on the "companies". They also point out that time will remove these cylinders from service, eliminating any risk.

It is also worth noting that 6351T6 cylinders are the ONLY cylinders I can find that have a special "operational recommendation" for filling operations to minimize human damage should an accident occur.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[JamesBon92007]

Man, don't give them any ideas!

I thought it was possible to delete my own posts. Might be a good idea in this case. Anyone know how?

 

[John C. Ratliff]

You can edit and remove the information in a post.

SeaRat

 

[John C. Ratliff]

Information removed.

SeaRat

 

[John C. Ratliff]

Phil,

I'm actively looking at this issue of the tank's age, as I have the set of doubles which are within 4 years of that 40 year date. They also have a current hydro from late last year. But, they may be taken out-of-service because of the information you have provided.

SeaRat