Technical Support Document
Requalification (retesting) of Aluminum Cylinders
June 9, 2010
The requalification of cylinders was formally known as the retesting
of cylinders. Requalification is done to ensure that a cylinder is
still acceptable to continue to be used as a pressure vessel to
transport hazardous material. DOT requalifying of a cylinder and the
marking thereof are to be performed by an approved DOT requalification
facility that has been issued a DOT Requalifiaction Identification
Number (RIN). The requirements for the requalifying of DOT cylinders in
the US are identified in Title 49 of the Code Of Federal Regulations
(CFR) in part 180, "Continuing Qualification and Maintenance Of
Packaging" and any applicable DOT exemption.
The requalifying requirements of any cylinder are specific to the DOT
specification and/or exemption to which the cylinder was manufactured.
The DOT specification and/or exemption number are stamped on the crown
of the cylinder. Cylinders manufactured by Catalina Cylinders are marked
with "M4002" on the crown of the cylinders. Cylinders manufactured by
Catalina Cylinders Cliff Impact Division are marked with "CLIFFDIV" on
the crown of the cylinder.
The most basic of the retesting requirements for cylinders manufactured
by Catalina Cylinders and Catalina Cylinders Cliff Impact Division are
identified below.
DOT-3AL Cylinders (Catalina Cylinders and Catalina Cylinders Cliff Impact Division)
Requalifying required every five (5) years.
Requalifying of a cylinder is to be performed five (5) years, as per
Table 1 "Requalification of Cylinders" in 49CFR 180.209, after the
original manufacturing hydrostatic test date stamped on the crown of the
cylinder. Please note the 12 year requalification cycle notated in
Table 1 is only for "dry" fire extinguishers as noted in 49CFR
180.209(j). In section 180.205 (c) it states that a cylinder that is
filled before the retest date may remain in service until it is emptied
of its charge. In other words, a cylinder that currently has a charge
when the 5 year retest date occurs does not have to be drained of its
charge and retested. The charge can be used and the cylinder retested
after the charge has been used.
The
requalifying specified in part 180 consists of an internal inspection
and hydrostatic retesting of the cylinder at a pressure equivalent to
5/3 the service pressure of the cylinder.
Catalina
Cylinders and Catalina Cylinders Cliff Impact Division are not
requalifiers of cylinders to the general public. If you go to this
website, http://hazmat.dot.gov/sp_app/approvals/hydro/hydro_retesters.htm, you will find a complete list of DOT approved retesters throughout the country.
There
are a few companies that have DOT exemptions to requalify cylinders by
Ultrasonic Examination (UE) of the cylinders instead of visually
inspecting and hydrostatically retesting the cylinders. In some cases
there are benefits to this type of requalifying.
DOT-3AL Cylinders "2 by 2 rule" (Catalina Cylinders Cliff Impact Division only)
Requalification not required
per the note under table 1 in 49CFR part 180.205. The note reads, "Any
cylinder not exceeding two (2) inches in outside diameter and less than
two (2) feet in length is exempt from volumetric expansion testing."
DOT-39 Cylinders (Catalina Cylinders Cliff Impact Division only)
These are non-refillable cylinders and do not require requalifying..
E-7737 (Aluminum DOT-3E) Cylinders (Catalina Cylinders Cliff Impact Division only)
Requalifying is not required.
Eddy
current inspection of the threads in 6061 aluminum cylinders is not
required by the DOT and is not mandated as necessary by Catalina
Cylinders. Cylinders manufactured by Catalina Cylinders and Catalina
Cylinders Cliff Impact Division have only been manufactured from
aluminum alloy 6061, not aluminum alloy 6351, and do not require any
special testing or inspection of the neck, threads or shoulder of the
cylinders.
All cylinders that have been successfully requalified will have the date
of the retest (month and year) stamped in the crown of the cylinder
with the RIN of the DOT approved requalification facility stamped
between the month and year of the retest date.
If you have any questions with regards to the requalifying of cylinders
manufactured by Catalina Cylinders or Cliff Impact please do not
hesitate in contacting us directly.
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