[EricH]

Originally Posted by 1683cadder

Is it safe to go past operational pressure(150psi)?

Yes and no.

Operational pressure is 125 psi (rated). Burst pressure is 500 psi (rated). (Note: All numbers are for the AM 500 ml plastic tanks.) There is a difference in what each is, what it's designed for, even how it's calculated. I'm going to scratch the surface.

Operational pressure says, quite simply, you can run at this pressure for a long, long time without any issues expected. Burst pressure is the pressure at which you'll have a failure in the event of a sudden high-pressure event. The fact that they're both "rated" pressures means that they can actually take higher pressures, but can't necessarily be counted on above their ratings. If you're going above the rated capacity on anything, check the math a few times to verify you'll be OK.

There is also a safety factor built in, too--but it's built into the rating, so it's not really applicable.

Short version: If your pressure is fairly low, you can probably get away with exceeding the rated pressure--but I wouldn't try using it for FRC use again. Do the math--if you really want to, I'm sure we can step through stress calculations for an AM 500ml cylinder, or try to.