DOT Exemption Number |
Cylinder Construction |
Hydro Test Requirements |
Service Life |
DOT-SP 7235 |
Fiber reinforced plastic hoop wrapped aluminum liner |
Retest every 3 years |
15 years |
DOT-SP 9421 |
Steel |
Retest every 5 years |
Unlimited until cylinder fails hydrostatic test |
DOT-SP 8059 |
Fiber reinforced plastic full composite aluminum liner |
Retest every 5 years |
15 years |
DOT-SP 10019 |
Fiber reinforced plastic fully wrapped composite aluminum liner |
Retest every 5 years |
15 years |
DOT-SP 10915 |
Fully wrapped carbon fiber reinforced aluminum liner |
Retested prior to May 11,2001 – 36 months. Retested on or after May 11,2001 – 5 years |
15 years |
DOT-SP 11194 |
Fully wrapped carbon fiber reinforced aluminum liner |
Retested prior to July 1,2001 – 36 months. Retested on or after July 1,2001 – 5 years |
15 years |
DOT-SP 11692 |
Steel |
Retest every 5 years |
Unlimited until cylinder fails hydrostatic test |