The U.S. Department of
Transportation (DOT) released a new safety precaution notice about DOT 3AL
cylinders made from 6351-T6 alloy.
The Notice states there have
been 12 SCUBA/SCBA 3AL-6351-T6 ruptures in the U.S. dating back to
September, 1986. Eleven occurred during fill. Most of those cylinders
failed due to sustained load cracking (SLC) in the neck and shoulder.
Cylinders at issue were made before 1990 by Luxfer and others.
DOT advises those who own,
fill, use or retest these cylinders to
- Not fill beyond marked
service pressure.
- Do not fill or use beyond
its required retest date.
- Insure any cylinder awaiting
inspection undergo a technical examination on the interior of the neck
and shoulder.
- Between requalifications
(hydro test), perform additional examinations of the interior neck and
shoulder for SLC.
- Increase frequency of
internal inspections. DOT recommends annual internal visual inspection.
DOT also states, the PSI, Inc.
and Luxfer Guides contain valuable information regarding cylinder
inspections and recommended inspection intervals. DOT writes in this
official safety alert, "For additional information on SCUBA cylinders,
PSI, Inc. may be contacted". The PSI address, telephone number and web
site are listed. We at PSI, Inc. are extremely proud that DOT recognizes
our commitment to cylinder safety through visual inspection and safety
awareness.