SCUBA cylinder information for your safety
How do I know if the person inspecting my scuba diving cylinders is properly trained to do so?
Luxfer recommends taking your cylinder to an authorized Luxfer service center or to an inspector trained by Professional Scuba Inspectors, Inc. (PSI) or the Association of Scuba Service Engineers & Technicians (ASSET).2 It cannot be overemphasized that the quality of inspection is far more important than the frequency of inspection! An untrained or improperly trained inspector can look at a 6351 – alloy cylinder numerous times without detecting SLC, “Sustained – load Cracking”!
How many aluminum cylinders have exhibited SLC?
Out of a total US population of 1,073,000 Luxfer scuba cylinders made of 6351 alloy, only 1.25% have exhibited SLC. That’s Thirteen thousand four hundred twelve cylinders.
LIA Intern scuba diving affiliates have invested $1200.00 in a VISUAL PLUS test set, a nondestructive technology that uses eddy currents to thoroughly inspect the threaded neck region of aluminum cylinders. Luxfer says do not use Luxfer 6351- alloy scuba cylinders that have not been both visually inspected and eddy-current tested and then properly documented.
Catalina Cylinders supports the use of eddy current devices to aid in the inspection of the threads of aluminum cylinders. Eddy current devices have proven themselves valuable in detecting linear defects (i.e. folds, cracks, intergranular corrosion, etc.) in the threads of aluminum cylinders that are hard to detect during visual examination aided by a light source and a 2X dental mirror.
For yours and our safety, LIA Affiliates (For the dive internships) do not fill tanks made from 6351 alloy with out a current eddy current test and visual inspection.
New: Federal Register: July 26, 1994
DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
Notice No. 94-7
Since issuing these advisory notices further work into the nature of sustained load cracking (SLC) has offered new insight into its causes and effects. However, one key factor in preventing further damage from this type of failure has to date been missing: a reliable method of early detection. Several nondestructive testing (NDT) methods of inspection have been developed, but their efficacy has not been established.
In response the RSPA contracted the Nondestructive Testing Information Analysis Center (NTIAC) to quantitatively evaluate three common methods of cylinder inspection:
visual testing (VT), eddy current testing (ET), and ultrasonic testing (UT). Conducting an extensive round-robin testing procedure, NTIAC evaluated the performance of each technique in terms of its accuracy and reliability in detecting flaws in the neck and shoulder region of the cylinder.
Based upon the results compiled by NTIAC as part of this project, our recommendation is to adopt the combined visual and eddy current testing (designated VET) as the standard for inspection of aluminum gas cylinders.
ASSET Technician Links:
- Dive Technician Training Aims
- Scuba Technician Training / ASSET Standards and IDEST Approval
- 10 DAY Dive Industry Technician Training
- Scuba Cylinder Testing Technicians Course (Part 1 & 2)
- Scuba Engineer Assessment
- Dive Technician Packages Outlined
- Scuba Cylinder Tank Information
- Technical Diving Articles