Conditions of design or Operation consitions

I want to know its opinion with respect to a subject that has a little to me complicated.

When analyses of flexibility of pipes are made, generally conditions of Operation are used, (temperatures and pressures of operation); nevertheless much with other specialists has been discussed who the conditions that would be due to use are those of design, since they are conditions you criticize.

Although all we know that the conditions of design always for being very happened through limit of the real thing (Process men) wanted to know that they think with respect to this

Thanks and I wait for its commentaries

Mr. Shrimp

You can search this Forum (the control is to the right, just above the calendar), and you'll find items like these:

http://www.coade.com/ubbthreads/ubbthrea...h=true#Post8288

and

http://www.coade.com/ubbthreads/ubbthrea...=true#Post10038

and

http://www.coade.com/ubbthreads/ubbthrea...=true#Post11588

thanks Mr. Ay

Estimated
After verifying the information delivered by the Mr. Ay, I wanted to define my personal interpretation of what the B31.3 says

For the sustain Loads it will be compared against the code with the pressures of design, likewise for the expansion loads it will be compared against the code with the temperatures of of design.

Nevertheless (basic loads cases of the Caesar II), for the Operation loads of the system (Load in mouthpieces of Equipments and Supports),the Pressure To using will have to be that of design and the temperature to using will have to be that of operation.

I would like it he was commenting on this interpretation
Thank you