For more than a decade, Luxfer has actively researched this
matter and participated in detailed deliberations involving DOT, the
Compressed Gas Association (CGA) and other cylinder manufacturers to
obtain a service-life extension. However, DOT declined to approve life
extension for these cylinders. Consequently, Luxfer decided not to
pursue this effort further and to take a different approach to providing
cylinders with longer service life.
In 1996, DOT issued its CCFC-1
standard that established basic requirements for design, manufacture and
performance of cylinders consisting of seamless aluminum liners
over-wrapped with structural layers of filament-wound carbon fiber and
epoxy composite material. At that time, DOT offered the possibility of
extending the 15-year service life of such cylinders "up to a total
service life of 30 years." To obtain an extension, a cylinder
manufacturer was required to submit for DOT approval a "Service Life
Extension Plan" that would meet certain criteria. Soon after CCFC-1 was
issued, Luxfer and other U.S. cylinder manufacturers individually
submitted such life-extension plans to DOT. However, DOT accepted none
of these plans and declined to extend cylinder service life.
In response, cylinder manufacturers attempted an industry-wide
approach to obtain DOT approval under the auspices of a special CGA task
group, but the service life was not extended.
Luxfer's longer-life composite cylinder
Luxfer began developing a new, more robust cylinder designed for a
service life longer than 15 years. This new cylinder was based on ISO
11119, an international design standard. In August 2008, DOT granted
Luxfer special permit 14232 (SP14232), which authorizes the manufacture
of these cylinders for use in the United States.
While cylinders made under SP14232 are designed for service lives as
long as 30 years, the special permit explicitly sets forth certain
testing and validation requirements that must be met before the service
life of any cylinder may be extended beyond 15 years. As of the issue
date of this bulletin, no cylinder manufactured under SP14232 has thus
far been approved for a service life longer than 15 years since these
cylinders have not yet reached the age at which their service life will
be eligible for extension.
For more information, please use the DOT links below or contact Luxfer Gas Cylinders at 951-341-2348.
U.S. Department of Transportation special permits search
DOT-CFFC (Basic requirements for fully-wrapped carbon fiber reinforced aluminum-lined)