Originally Posted by sQuidvision
Can anyone confirm this with a link/primary source? Would this mean HPA tanks stamped DOT-3AL still need hydro testing? I would like to know this once and for all!
Yes, it technically would need to have re-certification done every 5 years (see CFR links above). However, most fields and shops will ignore that, and just follow that "under 2 inch ..." rumor rule. Which is a good thing, imho. Just mind
1) damaging the tank and blowing up yourself and/or others.
2) if you're traveling, or if someone does check your equipment for safety compliance - be aware that you will not pass.