What Mindset Allows Pushing Beyond Training / Experience?

[diveongas]

As long as we're being exact, HP cylinders were rated to 3500psi. No cylinder rated to 3442 ever carried the name "HP."

Quoting from PST Technical Bulletin D-100E, "PST high-pressure (3442 psi) cylinders must be retested in accordance with DOT –E9791 or TC-SU4349-230 and have special test requirements based on their design and the DOT/TC requirements. This bulletin provides the necessary information."

Those are PST's exact words, specifially for the 3442 cylinders, "high-pressure." It's also their words for 3500 cylinders as below.

Also, quoting from PST Technical Bulletin D-100, "PST high pressure (3,500 psi.) cylinders must be retested in accordance with DOT-E9791 or TC-SU4349 and have special test requirements based on their design and the DOT/TC requirements. This bulletin provides the necessary information."

Are you arguing that PST's use of "HP" and "high-pressure" are different things altogether? PST seems to think they're the same thing in both documents for both cylinders.

The old PST Spec sheet also shows 3442 cylinders as E-Series with the corresponding old part "HP" numbers. As you correctly pointed out earlier, the marking 3442 instead of 3500 had to do with yolk valves.

[diveongas]

In the interests of continuing exactness, it pays to know that 3500 cylinders use the "smaller" 7/8 thread while the 3442 cylinders (called E Series just to highlight this difference) use the "larger" 3/4 thread, as implied above with yolk valves discussion.