[Federal Register Volume 59, Number 142 (Tuesday, July 26, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18192]


[[Page Unknown]]

[Federal Register: July 26, 1994]


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DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
[Notice No. 94-7]

 

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

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

ACTION: Safety advisory notice.

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SUMMARY: RSPA is aware of ruptures involving two DOT-3AL cylinders made 
of aluminum alloy 6351-T6. Cylinder ruptures pose a risk of death, 
serious personal injury, and property damage. The purpose of this 
notice is to advise owners of certain cylinders made of aluminum alloy 
6351-T6 to follow the precautionary measures outlined in this notice. 
RSPA also seeks information on ruptures involving other cylinders made 
of aluminum alloy 6351-T6.

FOR FURTHER INFORMATION CONTACT: Charles H. Hochman or Gopala K. 
Vinjamuri, telephone (202) 366-4545, Office of Hazardous Materials 
Technology, Research and Special Programs Administration, U.S. 
Department of Transportation, 400 Seventh Street SW, Washington, DC 
20590-0001. Office hours are: 8:30 a.m. to 5 p.m., Monday through 
Friday, except holidays.

SUPPLEMENTARY INFORMATION: RSPA has been notified of the rupture of two 
DOT-3AL aluminum cylinders made of aluminum alloy 6351-T6. The first 
cylinder rupture occurred in Deer Park, Texas. This cylinder was 
manufactured in 1977 and was part of a self-contained breathing 
apparatus (SCBA) unit. It ruptured while being filled to its marked 
service pressure of 2216 pounds per square inch gauge (psig). The 
second cylinder rupture occurred in North Miami, Florida. This cylinder 
was manufactured in 1982 and was part of a self-contained underwater 
breathing apparatus (SCUBA) unit. It ruptured while being filled to its 
marked service pressure of 3000 psig. The person filling the SCUBA 
cylinder sustained serious injury. In both ruptures, a piece of the 
cylinder neck separated from the cylinder.
    RSPA estimates that approximately seven million cylinders have been 
manufactured using aluminum alloy 6351-T6. RSPA presently does not know 
which cylinders among this population have the potential for similar 
failure. Cylinders made of aluminum alloy 6351-T6 are known to be 
susceptible to sustained load cracking (SLC) in the neck and shoulder 
area of the cylinder. Extensive research, testing and analysis have 
been performed on cylinders made of aluminum alloy 6351-T6 to determine 
any correlation between SLC and the probability of rupture. Findings 
indicated that cylinders with a marked service pressure below 4000 psig 
failing due to SLC would leak and not rupture. Present data are 
inconclusive as to why the two cylinders noted here ruptured instead of 
leaked. RSPA is continuing to investigate the incidents.
    Aluminum cylinders are widely used in industrial, medical, SCUBA 
and SCBA services. Aluminum alloy 6351-T6 has been used in the 
manufacture of the following DOT high pressure cylinders:
    1. Cylinders (seamless aluminum) marked ``DOT 3AL'', including 
those marked with ``DOT 3AL'' above or near one of the following 
exemption or special permit numbers:

6498
7042
8107
8364
8422

    2. Composite cylinders (aluminum-lined with hoop-wrapped, fiber-
reinforced plastic) marked with one of the following exemption numbers:

7235
8023
8115

    To RSPA's knowledge, no cylinders have been manufactured under the 
exemption or special permit numbers listed above, except DOT-E 7235, 
since 1984. Any cylinder marked with one of these exemption or special 
permit numbers most likely is made of aluminum alloy 6351-T6. (DOT-E 
7235 cylinders are discussed more fully below.) If in doubt, contact 
the cylinder manufacturer or distributor to identify the material of 
construction.
    The primary domestic manufacturers of DOT-3AL cylinders currently 
in service are Luxfer USA; Walter Kidde Co.; Cliff Impact Division of 
Parker Hannifer Corporation; and Catalina Cylinders, a division of 
Aluminum Precision Products Inc. Luxfer USA is the only manufacturer of 
DOT-E 7235 cylinders. Between 1987 and 1989, Luxfer USA discontinued 
using alloy 6351-T6 and changed to alloy 6061-T6 for DOT-3AL cylinders 
and DOT-E 7235 cylinder liners. Cylinders manufactured from alloy 6061-
T6 are not believed to be susceptible to SLC; therefore, they are not 
subject to this advisory notice. According to Luxfer USA data, the 
following types of cylinders stamped as manufactured by Luxfer USA 
before the dates indicated below likely are made from alloy 6351-T6.

----------------------------------------------------------------------------------------------------------------
      DOT                       Service and type cylinder                       Part no.            Date mfd.   
----------------------------------------------------------------------------------------------------------------
                  CO2                                                                                           
                                                                                                                
Spec. 3AL.......  1.2 and 1.5 lb........................................  C1.2, C1.5            1-89            
                                                                                                                
Do..............  2.18 lb...............................................  C2-18                 11-88           
Do..............  10 lb.................................................  C10                   8-88            
Do..............  5 lb..................................................  C5                    6-88            
Do..............  15 lb.................................................  C15                   11-87           
Do..............  20 and 35 lb..........................................  C20, C35              4-88            
Do..............  50 lb.................................................  C50                   2-88            
                                                                                                                
                  SCBA                                                                                          
                                                                                                                
Do..............  7, 8 and 13 cu. ft....................................  L7, L8, L13           9-87            
                                                                                                                
Do..............  13.3 cu. ft...........................................  L13-30                5-88            
Do..............  15 cu. ft.............................................  L15                   1-89            
Do..............  26 cu. ft.............................................  L26                   2-88            
Do..............  45 cu. ft.............................................  L45                   11-87           
                                                                                                                
                  SCUBA                                                                                         
                                                                                                                
Do..............  30 and 63 cu. ft......................................  S30, S63              5-88            
                                                                                                                
Do..............  40 cu. ft.............................................  S40                   6-88            
Do..............  50 and 92 cu. ft......................................  S50, S92              4-88            
Do..............  72 and 100 cu. ft.....................................  S72, S100             8-87            
Do..............  80 cu. ft.............................................  S80                   1-88            
Do..............  80.8 cu. ft...........................................  S80.8                 5-87            
                                                                                                                
                  Medical O1                                                                                    
                                                                                                                
Do..............  C.....................................................  M9                    1-88            
Do..............  D and E...............................................  MD, ME                12-87           
                                                                                                                
                  Industrial                                                                                    
                                                                                                                
Do..............  22 and 150 cu. ft.....................................  N22, N150             5-88            
                                                                                                                
Do..............  33 cu. ft.............................................  N33                   11-88           
Do..............  60 and 122 cu. ft.....................................  N60, N122             12-87           
Do..............  88 cu. ft.............................................  N88                   12-88           
Do..............  Service Pressures 2016 and 3000 psig..................                        8-89            
E-7235..........  Service Pressure 4500 psig............................                        See below.      
                                                                                                                
----------------------------------------------------------------------------------------------------------------

    All Walter Kidde DOT-3AL cylinders, of which production ceased in 
January 1990, are made of alloy 6351-T6. Cliff Impact DOT-3AL cylinders 
were made from alloy 6351-T6 before July 1990, at which time Cliff 
Impact changed to alloy 6061-T6. Catalina Cylinders did not produce any 
DOT-3AL cylinders from alloy 6351-T6; therefore, cylinders manufactured 
by Catalina are not subject to this notice.
    Until determined otherwise, any DOT-3AL or DOT-E 7235 cylinder 
should be assumed to be made of alloy 6351-T6, if it was:
    1. Manufactured by Luxfer USA before the applicable date listed in 
the chart above;
    2. Manufactured by Cliff-Impact before July 1990;
    3. Manufactured by any other company in the United States, 
excluding Catalina, before February 1990; or
    4. Manufactured outside the United States.

For aid in determining whether a cylinder is constructed with alloy 
6351-T6, contact the cylinder manufacturer or distributor. RSPA will 
provide further information as it becomes available.
    Any person who owns, uses, fills or retests an affected cylinder 
should take the following precautions:
    1. Do not fill the cylinder to greater than the marked service 
pressure, except during a hydrostatic test.
    2. Do not fill a cylinder that is beyond its required retest date.
    3. Do not use a SCUBA or SCBA cylinder that is beyond its required 
retest date.
    4. Whenever you remove the cylinder valve, visually inspect the 
interior of the cylinder neck and shoulder area for cracks. Any 
evidence of a crack or crack-like defect may require further 
evaluation. Contact the cylinder retester, distributor or manufacturer 
for the procedure to be used in performing the visual inspection and 
for rejection criteria. For guidance on inspecting Luxfer USA 
cylinders, contact Luxfer USA Limited, Customer Service Department, PO 
Box 5300, Riverside CA 92517, telephone (909) 684-5110.
    RSPA wishes to reiterate two previous advisories it has issued 
regarding DOT-E 7235 cylinders. On August 15, 1985, RSPA published an 
exemption-related notice [Notice 85-4, 50 FR 32944] to alert users that 
any cylinder marked DOT-E 7235, with a service pressure of 4500 psig 
and not equipped with a neckring was required to be removed from 
service by October 1, 1985. On March 24, 1993, RSPA published a safety 
advisory notice [Notice 93-8, 58 FR 15895] after being notified of the 
rupture of a cylinder authorized under DOT-E 7235 that had not been 
fitted with a neckring. Cylinders properly fitted with the required 
neckring are not susceptible to rupture. That notice stated in part:
    Persons finding cylinders without the required neckring should 
immediately take the following precautions.
    1. If a cylinder has been filled, its entire contents should be 
vented in order to relieve internal pressure.
    2. The vented cylinders should be segregated from all other 
cylinders by being placed in a secured area and marked conspicuously 
with a tag bearing the notation ``Do Not Use'' or similar warning.
    3. Under no circumstances should any of the cylinders in question 
be sold or otherwise transferred, filled, refilled or used for any 
purpose.
    Once the above procedures have been taken, persons finding 
cylinders without neckrings should contact the company, or distributor 
from whom they were purchased, for their disposition.
    Any person who is aware of the rupture of any DOT-3AL cylinder or 
any other cylinder manufactured from aluminum alloy 6351-T6, whether 
the incident was domestic or foreign, is requested to contact RSPA as 
soon as possible.

    Issued in Washington, DC on July 20, 1994.
Alan I. Roberts,
Associate Administrator for Hazardous Materials Safety.
[FR Doc. 94-18192 Filed 7-25-94; 8:45 am]
BILLING CODE 4910-60-P