Filling and use of Luxfer AA6351 scuba cylinders in Greece
It has come to Luxfer’s attention that certain dive shops and cylinder testing facilities in Greece have been stating that Luxfer scuba cylinders made of 6351 aluminum alloy (AA6351) have either been recalled, banned from use or declared obsolete. In some cases, dive shops are refusing to fill AA6351 cylinders. In other cases, shops are condemning cylinders and attempting to sell divers new cylinders. The justification for these actions is ostensibly based on an EBETAM noticed published on February 14, 2002, and titled “Re-evaluation of aluminum high pressure vessels made from alloy AA6351.”
Luxfer wishes to state categorically that there has never been a recall of Luxfer AA6351 scuba cylinders anywhere in the world, including Greece. Moreover, the cited EBETAM notice neither condemns AA6351 cylinders, prohibits filling them nor declares them unsafe or obsolete. The purpose of the EBETAM notice is to inform cylinder inspectors that AA6351 scuba cylinders require diligent visual inspection due to a metallurgical phenomenon known as sustained-load cracking (SLC) that has occurred in a very limited number of cylinders. If a proper inspection by a trained inspector does not reveal a crack in a cylinder made from AA6351 (which will be true in the vast majority of cases), the cylinder should be considered safe to fill and use until the next required inspection. Any dive shop or inspector who states otherwise is not properly interpreting the EBETAM notice.
Out of a total global population of approximately 1.1 million scuba cylinders made of AA6351, only about 1.25% have actually exhibited SLC. From this same population, 11 SLC-related ruptures have been investigated by authorities around the world. In most instances, there were clear signs of cylinder abuse or misuse, including repeated over-pressurization. For a detailed discussion of SLC in AA6351 cylinders, as well as Luxfer’s recommended inspection procedures, visit www.luxfercylinders.com and click the “Support” section.
Posted by Luxfer