Hydro and 2" tanks

Hydro and 2" tanks

OmniMech
OmniMech

November 27th, 2011, 12:09 am #1

It seems like the more I tell people about having to hydro a tank, the more I hear about the whole 'If its under 2" in diameter, it doesn't need to be hydro'd' line. How did that start, and how is it still relevant when EVERY tank has a hydro date stamped on it?
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Fathom
Fathom

November 27th, 2011, 2:02 am #2

it is DOT standard now that any tank which is under 2" does not need to be re-hydro'd

emphasis on RE. usually the stamps on these smaller tanks are now just from the original testing when said tank was produced.


Happy hunting.
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sniper1rfa
sniper1rfa

November 27th, 2011, 2:11 am #3

is that small tanks do not expand enough to be accurately measured with standardized equipment. since the tanks are small enough to pose relatively little danger it would be pointless to require testing facilities to maintain separate equipment for them.
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Target
Target

November 27th, 2011, 5:15 am #4

It seems like the more I tell people about having to hydro a tank, the more I hear about the whole 'If its under 2" in diameter, it doesn't need to be hydro'd' line. How did that start, and how is it still relevant when EVERY tank has a hydro date stamped on it?
Tanks that are under 2 inches in diameter AND less than 24 inches in length do not need to be re-hydro'd. This is because their small size makes it difficult to measure their expansion.
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THAT guy
THAT guy

November 27th, 2011, 10:34 pm #5

is that small tanks do not expand enough to be accurately measured with standardized equipment. since the tanks are small enough to pose relatively little danger it would be pointless to require testing facilities to maintain separate equipment for them.
http://www.youtube.com/watch?v=4JJUt6s-fB0
Do all tanks require them to measure volume change?
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sniper1rfa
sniper1rfa

November 28th, 2011, 12:09 pm #6

the goal is to measure fatigue. As the tank fatigues it will expand more and more, because the material is weaker, and eventually it will fatigue so much the tank will no longer be strong enough.
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THAT guy
THAT guy

November 30th, 2011, 3:40 pm #7

Since it's based off of volume changes, I wonder why the diameter matters. I mean a 2" diameter by 24" long tank is roughly 75ci. That's more than most paintball tanks over 2".
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sniper1rfa
sniper1rfa

November 30th, 2011, 11:09 pm #8

as the diameter goes down the cross-sectional rigidity goes up. It goes up faster than the diameter goes down.
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THAT guy
THAT guy

December 2nd, 2011, 3:09 am #9

So a smaller diameter tank experiences less of a volume change for the same burst pressure?
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