A susceptibility to sustained load cracking (SLC) has been identified in cylinders manufactured from aluminium alloys of specific grades, manufactured between 1963 and 1995. Sustained load cracking is a metallurgical anomaly occurring in cylinders that have remained pressurised for sustained periods of time.
WorkSafe New Zealand Safety Alert
There have been two recent incidents of serious harm in the Asia-Pacific region caused by the catastrophic failure of self-contained underwater breathing apparatus (SCUBA) cylinders manufactured from aluminium alloy 6351. As a result of these incidents in August 2017 WorkSafe New Zealand issued a Safety Alert entitled "Cylinder design approvals withdrawn".
In its Safety Alert WorkSafe New Zealand announced that it had decided to withdraw approval for SCUBA and self-contained breathing apparatus (SCBA) cylinder designs which used aluminium alloy 6351. The withdrawal came into effect from 31 October 2017.
UK Health and Safety Executive (HSE) Safety Bulletin
On 8 March 2018 the UK HSE issued Safety Bulletin ED 1-2018 entitled "Cylinders manufactured from aluminium alloys HE30/AA6082 and AA6351 and used primarily for gases for underwater breathing apparatus".
The publication of this bulletin was prompted in part by the Asia-Pacific incidents, but also by an incident of serious harm caused by the failure of an HE30/AA6082 cylinder in England in 2017.
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