Which standard governs MAWP calculations for known materials?

Which standard governs MAWP calculations for known materials?

• A. API 570
• B. ASME B31.1
• C. API 579
• D. ASME B31.3

Answer: (D)

MAWP is determined from the material’s allowable stress at the service temperature and the piping geometry, using the design rules in the governing code. For known material properties in process piping, ASME B31.3 provides the procedures and the material data tables to calculate MAWP. It lays out how to take the published allowable stress values for that material at the operating temperature and apply the code’s formulas to determine the maximum pressure the system can safely carry. The other standards serve different roles—API 570 focuses on in-service inspection and alteration, API 579 on fitness-for-service of damaged components, and ASME B31.1 on power piping—so the process-piping MAWP calculations for known materials are governed by ASME B31.3.

MAWP is determined from the material’s allowable stress at the service temperature and the piping geometry, using the design rules in the governing code. For known material properties in process piping, ASME B31.3 provides the procedures and the material data tables to calculate MAWP. It lays out how to take the published allowable stress values for that material at the operating temperature and apply the code’s formulas to determine the maximum pressure the system can safely carry. The other standards serve different roles—API 570 focuses on in-service inspection and alteration, API 579 on fitness-for-service of damaged components, and ASME B31.1 on power piping—so the process-piping MAWP calculations for known materials are governed by ASME B31.3.