Skipping Hydro

[holeup]

Did you say making a decision between hydro and buying new tanks, after only 20 refills?
do the math brother

 

[UaVaj]

Did you say making a decision between hydro and buying new tanks, after only 20 refills?
do the math brother

Your answer is in post #62.

 

[Thalassamania]

INTERSTATE HIGHWAYS built with federal $$$ they have the last word. If you want to trasnport pressure vessels on the interstates then hydro is a must.

Could you tell us where you got that information? It flies in the face of what I thought to be the case, as well as:

I usually have pretty good luck getting info direct from the DOT. If it matters, write them and ask for a Letter of Interpretation.

DOT people usually assume when you ask questions that you are asking about things as they are under DOT regulation. So if you say "is this or that tank legal under this or that conditions" they will generally answer whether it is under DOT rules. But if you ask, does this tank even come under DOT regulations, then they may answer quite differently.

Oh, 49 171.1 says

(d) Functions not subject to the requirements of the HMR. The following are examples of activities to which the HMR do not apply:
(6) Transportation of a hazardous material by an individual for non-commercial purposes in a private motor vehicle, including a leased or rented motor vehicle.

Pretty hard to get much clearer than that.

Another thing to keep in mind it that there are no "cylinder cops" going around looking for petty violations of the DOT regs. Yes, the DOT does have an enforcement branch, but you will look long and hard for an instance of them ticketing an individual diver - or a dive shop for that matter! - for filling or transporting and out-of-hydro or overfilled tank.

As far as the DOT goes, if a tank doesn't fall under DOT jurisdiction, then it really doesn't matter whether it is a spec, or a exemption, homemade, or a commie rebreather flask - it just isn't their concern.

 

[oncor23]

If you believe that your tank has been well treated...would doing fewer hydro tests extend the length of the tank? Is there any memory of the last hot fill or hydro test in the tank? If you have a hot fill, don't fill again for x number of days. If you have a hydro test, don't fill the tank for x days. Would it hurt the tank to do a hydro test every 4 years or 3 years? If the tank is used daily, should the hydro be done once a year? Again, does the hydro hurt the tank???

I'm asking because I have no idea.

 

[WD8CDH]

Yes, the hydro stresses your tank but if you have it done every year, it won't effect the life of your tank until your great, great, great, great, great grand-kids want to use it. The hydro doesn't heat your tank like a hot fill and the tank is never subjected to mechanical shocks during the test. Frequency of filling, time stored full, etc. is totally insignificant compared to corrosion from a bad fill.

 

[Gombessa]

Yes, the hydro stresses your tank but if you have it done every year, it won't effect the life of your tank until your great, great, great, great, great grand-kids want to use it.

What's more, I believe some countries (Australia?) actually do require hydrostatic testing of all tanks on an annual basis?