rstofer
Contributor
The service life of an AL tank is approximately 40 years unless condemned for several issue one of which is SLC that lot's of folks fail to look for when VIP'ing the bottles so as opposed to trusting the last monkey to VIP it they used their monkey to VIP it.
Although 40 years seems like a long time, I don't know where the 'number' comes from. Luxfer rates their tanks for 100,000 cycles and cycles is what exercises the metal.
One hundred thousand cycles at 4 per week, 52 weeks per year is about 480 years.
Even if the tank were filled twice a DAY, 365 days per year the life expectancy would be about 136 years.
I have never seen SLC discussed in the context of 6061 tanks anywhere except on SB.
Luxfer: Sustained-load Cracking FAQ
Note the ultimate sentence on that page (emphasis added):
Only Luxfers proprietary 6061 aluminum alloywhich is not susceptible to sustained-load crackingwas used for Luxfer Australia cylinders.
Richard