In CAESAR's manuals can be read:

"CAESAR II will automatically suggest load cases as per IGE/TD/12 Appendix 7,
but in order to be correct, the following convention must be adhered to with
respect to specification of the Operating Conditions:"
where or what is IGE/TD/12 Appendix 7?
In the same page:
P1 - MIP
P2 - MOP
What does MIP & MOP stands for?

Thanks in advance,

The IGE/TD/12 code is the British Gas Transmission code.

MIP - Maximum Incidental Pressure - The maximum pressure which a system is permitted to experience under fualt conditions, limited by safey devices.

MOP - Maximum Operating Pressure - The maximum pressure at which a system can be operated continuously under normal conditions.

Please note that this is a very complex piping code. If you plan on working with this code, it is highly recommended that you obtain a copy of this code to insure a complete understanding of its requirements.