[Tristan Lall]

I'm inclined to continue using the past interpretation of the rule to resolve the Norgren issue in favour of legality. Since a Norgren R07-100-RNEA regulator can frequently¹ be adjusted above 50 lb/in² (the manufacturer's operating limit²) and even above 60 lb/in² (the R77-I limit) using the provided control knob, and FIRST should know this, I would interpret the "maximum outlet pressure" to mean the maximum non-transient pressure at the outlet given a certain user-adjusted setting, rather than the manufacturer's published operating limits or proof limits. This also permits R75 to be read without conflict: the "working pressure" referenced there should be interpreted in terms of the possible range of input pressures, not the adjustment range of the outlet.

Using that logic, the AutomationDirect valve, the Nitra AR-213 is also legal. For R77-I, you must adjust its outlet to 60 lb/in² or less, and the datasheet states this is possible. For R75, the "working pressure" at the inlet should be no more than 145 lb/in² if like the Norgren, you may operate it in excess of recommendations, or no more than 130 lb/in² if you must stay within the manufacturer's range. Either figure satisfies R75.

Also, for anyone concerned about unsafe failure of the regulator, Nitra conveniently provides proof limits: below 215 lb/in², you should not expect the regulator to fail catastrophically.

For better or worse, guidance provided to LRIs is not inherently a rule, and cannot be enforced.

¹I don't know what the production variation is on the physical limit of adjustment, so perhaps I'm relying on outliers to reach that impression.
² For regular customers at least. I seem to recall, but can't document, a Q&A from the early 2000s alluding to Norgren telling FIRST that operating this regulator up to 60 lb/in² was acceptable.