In reading
@Gerry52's comment above, I'd like to clarify something I said in an earlier post, where I said a hydro test is about the worst thing we airgunners can do to our tanks . . . .
Hydro testing has its place. When wrapped SCBA tanks were new and had no history, DOT mandated the 15 year life with a 5 year recert via visual inspection and hydro testing. Given the tough usage the firefighters put tanks through, it was not unreasonable. Now, with all the experience we have, one could argue that the hydro may not be as necessary (or that the life should be longer), but that is not my point here. My point is this: If I were buying a tank of unknown history or with any question at all on its history of fills being free of water, I would want it to have a current hydro certification. After that, who knows - but I would want to know that it is a "good" tank, and the hydro would prove that.
Now, for a new tank used properly by an airgunner (as opposed to fire fighting duty) , I think things are a bit different. For example, I have a 9L tank that I purchased about a year ago that has only seen fully dry air, was filled once from empty to max, and then refilled from maybe 3800 psi back up a couple dozen times (if that). It sits, fully protected in boots and with wrap (and recently also in a case), bungied vertically in a corner near my compressor and has not moved much from there, so it has never been exposed to UV light and has only experienced a temperature swing of very few degrees. The partial top-off fills have been slow from my Shoebox compressor with fully dried air, and that tank has led a great life so far. In summary, it is "living a life" so far below the expectations of the design parameters for it (compared to typical firehouse use) that by comparison to what it was designed for, it is barely being used.
In the case of that specific tank, I won't be hydro testing it (it is a CE tank anyways, but that is a separate discussion). I will empty it and fully visually inspect it inside roughly every five years, but that is the extent of what I'll be doing as I keep on using it for a long time.
Hydro testing has its place, but I personally do not think it is warranted in all airgunning cases. That said, caveat emptor - and do things properly to manage the risks of high pressure air storage and use.
