What does the most severe combination of pressure and temperature conditions mean?
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What does \"Part 3, most severe pressure and temperature combination conditions\" in 20801 mean?
This depends on the process design; when designing, the highest/lowest pressures/temperatures that may occur in the process units need to be taken into account
It means exactly what it says: it takes into account the highest pressure as well as the highest or lowest temperatures according to the design specifications.
Since the pressure resistance of materials generally decreases as temperature rises. The pressure grades used in the standards are all determined based on the allowable stress at the rated temperature. As the temperature rises, the actual allowable pressure needs to be reduced; therefore, when designing, one should not focus solely on the design pressure, but rather ensure that the allowable pressure at the highest/lowest operating temperatures meets the device’s requirements for maximum/minimum operating pressure. Determine the design pressure once.
Calculations and assessments need to be carried out based on the temperature-pressure combinations that may occur during the manufacturing process, with the set of temperature-pressure data requiring the highest conditions being selected as the design parameters
It’s just the literal meaning, designed for the worst-case scenario
As the temperature rises, the allowable stress of metal pipes decreases; therefore, it is not possible to determine the design pressure of the pipes solely based on the process pressure, and adjusted calculations are required. If it is only the effect of high temperature, corrections can be made by referring to Equation 3.2.1 in the G50316 Metal Pipe Design Code.