School Me On Tank Safety and Hydro

[ballofpopculture]

I remember back in the day^(tm) being shown all the gruesome pictures of exploded CO² tanks with related bloody stumps. I saw these during my formative years and continue to have an irrational (rational?) fear that my new hyper-lite tanks are going to explode in a cloud of carbon fiber shrapnel. My understanding is that new HPA tanks are aluminum cored, covered in a carbon fiber wrap, and then dipped—each layer adding to the strength of the tank (though I believe the actual strength of the last layer may be negligible?). Then the tanks are hydro tested well beyond their recommended PSI range and shipped off once they (hopefully) pass. Do I have this right? Is there any concern that initial tank testing, or later 5-year hydros actually weaken the tank by taxing it beyond its normal capabilities?

Bottom line: what are the risks that a properly filled (and not overfilled) HPA tank with no oddities like oil in the valve, or large punctures or scratches will just explode after a normal fill? What should I be looking out for beyond a traditional spot check for tank structure issues?

[iamthelazerviking]

Very low probably and with a regulator that has failsafes in place like burst discs, those will blow and the tank will empty. In extreme circumstances, and you pointed out the factors already, a tank could blow up but it's not something I have ever worried about myself.

[mercpb]

VERY low risk in terms of equipment ---
- regulator stem is slotted so it'll vent if it starts to unscrew (which is unlikely, very hard to do)
- burst discs at both 1.8K and 7.5K

There is still a risk of compression ignition if someone puts oil in the tank.
If you're concerned about what's inside when buying a used tank ---- pop the regulator off, flip it over on a paper towel, shine a flashlight in as well.

all your general notes/assumptions are right.
Carbon fiber tanks aren't considered damaged unless the weave is frayed --- gelcoat damage is considered cosmetic.

[tyronejk]

I think the oil compression combustion thing is not actually possible with paintball oil and paintball tank pressures. I remember being curious and doing some calculations way back in college. That said, if I suspect oil is in a tank, I'll still clean it out before filling it with air.

Another way to be sure a tank is clean and free of contaminants is to just rinse it out with water. You want to make sure it's dry before putting the reg back on just to avoid rust on reg components. Surface rust on non-sealing surfaces should not cause issues though.

The most likely way to get hurt by a paintball tank is dropping it on your toe. This is one of those things that's so tightly regulated by the government as to be safe even for the dumbest user. E.g. elevators and commercial aircraft.

[otar]

Is there any concern that initial tank testing, or later 5-year hydros actually weaken the tank by taxing it beyond its normal capabilities?

Regarding this question - no, there shouldn't be any concern of the testing causing fatigue on the tank. They test the tank beyond it's normal operating pressure, therefore if it was to fail it would fail in the test bay, not on the field.

[tyronejk]

I think the OP is probably referring to cyclic loading fatigue (https://en.wikipedia.org/wiki/Fatigue_(material)) but same answer. The testing loads should not cause noticable fatigue in practice. I don't know what number or magnitude of loads are needed to cause a tank structure to fail but I would not be surprised if it were 10x working pressure with over 1000 cycles.

[Jordan]

Fiber wrapped tanks will rupture - ie: split - rather than grenade into flying shrapnel, from my understanding. I'm pretty sure we're more at danger from the macro fittings and hose that are used in paintball.

[Chappy]

10-15 years ago at EMR a rental player fell into a trench. He landed on his tank and it ruptured. It was under his chest at the time. He was sore, but fine. On the one hand I consider him pretty lucky. On the other hand he literally landed on a rupturing tank and didn’t pop like a blood sausage. Just an anecdote that is the only time I’ve seen it happen in my 30 years.

[StaticShocked]

That is a great reminder that most failures are not as bad as our imagination says they can be.