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[Federal Register: October 18, 1999 (Volume 64, Number 200)]
[Page 56243-56244]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Research and Special Programs Administration
[Docket No. RSPA-99-5143 (Notice No. 99-11)]

Safety Advisory; High Pressure Aluminum Seamless and Aluminum 
Composite Hoop-Wrapped Cylinders

AGENCY: Research and Special Programs Administration (RSPA), DOT.

ACTION: Safety advisory notice.


SUMMARY: Recently, a DOT-3AL cylinder made of aluminum alloy 6351-T6 
ruptured while being filled. The purpose of this notice is to alert 
owners, users, and other persons responsible for the maintenance of 
certain cylinders made of aluminum alloy 6351-T6 of potential safety 
problems and to advise them to follow the precautionary measures 
outlined in this notice. Also, RSPA requests information on other 
failures, if any, involving cylinders made of aluminum alloy 6351-T6, 
which may not have been previously reported to the agency.

FOR FURTHER INFORMATION CONTACT: Mark Toughiry or Stanley Staniszewski, 
Office of Hazardous Materials Technology, Research and Special Programs 
Administration, U.S. Department of Transportation, 400 Seventh Street 
SW, Washington DC 20590-0001; telephone number (202) 366-4545; or by E-
mail to ``rules@rspa.dot.gov'' and referring to the Docket and Notice 
numbers set forth above.

SUPPLEMENTARY INFORMATION: RSPA (``we'') has been notified of the 
rupture of a DOT-3AL seamless aluminum cylinder made of aluminum alloy 
6351-T6. The cylinder was manufactured by Luxfer (USA) under exemption 
DOT-E 6498, in June 1977, as part of a self-contained breathing 
apparatus (SCBA) unit. The rupture occurred in Summerfield, North 
Carolina, while the cylinder was being filled to its marked service 
pressure of 2,216 pounds per square inch gauge (psig). We have 
requested that the manufacturer, Luxfer (USA), conduct a detailed 
analysis on this cylinder to determine the cause of the failure.
    To date, we are aware of twelve ruptures within the United States 
involving DOT-3AL cylinders made of aluminum alloy 6351-T6, dating back 
to September 1986. Eleven of the ruptured cylinders failed during 
filling. Analyses have confirmed that most of these cylinders failed 
due to sustained load cracking (SLC) in the neck and shoulder area of 
the cylinder.

[[Page 56244]]

    Cylinder ruptures pose risks of death, serious personal injury, and 
property damage that warrant special attention. We provided 
precautionary measures in an earlier safety advisory notice, entitled 
``High Pressure Aluminum Seamless and Aluminum Composite Hoop-Wrapped 
Cylinders'', (Notice No. 94-7, 59 FR 38028, July 26, 1994) concerning 
cylinders made of aluminum alloy 6351-T6. In this notice, we reiterate 
and supplement those precautionary measures. The cylinders at issue 
were manufactured before 1990 by Luxfer (USA) and others. They are 
identified by serial numbers in Notice No. 94-7.
    Any person who owns, uses, fills, or retests one of these cylinders 
should take the following actions:
    1. Do not fill the cylinder to greater than the marked service 
pressure, except during a hydrostatic test.
    2. Do not fill the cylinder that is beyond its required retest 
    3. Do not use any SCBA or self-contained underwater breathing 
apparatus (SCUBA) cylinder that is beyond its required retest date.
    4. Ensure that any cylinder awaiting an inspection, for any reason, 
undergoes a non-destructive examination (NDE) on the interior of the 
cylinder neck and shoulder area for SLC.
    5. During or between DOT required requalifications, perform 
additional NDE on the interior of the cylinder neck and shoulder area 
for SLC.
    6. Increase the frequency of internal inspections. We recommend 
that internal visual inspections be on an annual basis. Other NDE 
methods may be performed at longer intervals.
    Industry guides, such as those provided by Professional Scuba 
Inspectors, Inc. and Luxfer (USA), contain valuable information 
regarding cylinder inspections and recommended inspection intervals. 
This information and the requirements in 49 CFR 173.34(e) should be 
consulted prior to conducting any cylinder inspection.
    Any evidence of a crack or crack-like defect requires further 
evaluation. Contact the cylinder manufacturer, distributor, or retester 
for the procedure to be used in performing the NDE and for rejection 
criteria. For guidance on inspecting Luxfer (USA) cylinders, contact 
Luxfer Gas Cylinders, Customer Service Department, 3016 Kansas Avenue, 
Riverside, CA 92507, web site at www.luxfercylinders.com, telephone 
(909) 341-2288, fax (909) 781-6598. For additional information on SCUBA 
cylinders, Professional Scuba Inspectors, Inc. may be contacted at 6531 
NE 198th St., Seattle, WA 98155, telephone (425) 486-2252, web site at 
    Any person who is aware of the rupture of any DOT-3AL cylinder, 
domestic or foreign, or any other cylinder manufactured from aluminum 
alloy 6351-T6, regardless of the severity of the incident, is requested 
to contact RSPA, through one of the individuals or E-mail address 
listed under the FOR FURTHER INFORMATION CONTACT caption above, as soon 
as possible.
    This safety advisory and Notice No. 94-7 are available for review 
on the Internet by accessing the HazMat Safety Homepage at http://

    Issued in Washington, DC, on October 8, 1999.
Alan I. Roberts,
Associate Administrator for Hazardous Materials Safety.
[FR Doc. 99-27113 Filed 10-15-99; 8:45 am]


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