What is high/ low temprature and pressure ranges for ball valves?

[NDS_21]

For ball valves, What range of temprature and pressure can be called high or low comparatively? For example, Valves opetrating at 80 bars and 300C can be called workking at high temprature & pressure range or not! Like this For ball valve, which temprature range and pressure range can be classified in High, Moderate and low ranges?
Comparison of this classifications are varying from person to person so, want a review for this. So that i can find average ranges of this classification! Thank you for your replies!

 

[gerhardl]

As you state, these definitions will vary, and you will not find anything but an average of different opinions. Better search for a solution for an exact application.

And out of curiosity: what actual practical need do you have for the answer? 'Ball valves' are a common, general description, extending towards the 'horizon' in all directions. My opinion, within very 'loose & floating' boundaries:

Vacuum down to ultrahigh vacuum: Special valves
Low pressure: up to and including 10 bars (125 LB) also including valves that also are able to work down to a not too high vacuum.
Medium pressure: 16 up to 40 bars.
High pressure: 60 bars and upwards

Lower temperatures for liquid gases (down to about) minus 196 degrees C: Special valves
Low and normal temperatures: limited by commonly used materials' limitations varying but limits often put in the range about minus 25 deg C to minus 15 deg C surrounding and up to a bit above 100 deg C.
High temperatures: 100 deg. C up to about 250 deg C.(250 deg. C is dry steam at 40 bar)
Higher: About 300 deg C up to 500 deg C (superheated, high-pressure steam for instance). Special valves exists for temperatures far above this.