I am extremely sorry,
I messed up the units. Actually I meant 400 C (~800F).
@MJCronin,
Can you please explain why do "most piping codes limit carbon steel usage to a maximum continuous service temperature of about 775F (~412C)"?
What type of failure is observed at temperature higher than this?
How is critical piping defined?
How is it differentiated from Non-critical piping?
What code is used for the design of Critical piping?
How are allowable stress values different for these two types?