Maximum Allowable Working Pressure [MAWP] vs. Maximum Operating Pressure [MOP]

Asked by rajprasad 4 years, 10 months ago | 2 Answers

What is the difference between Maximum Allowable Working Pressure [MAWP] & Maximum Operating Pressure [MOP].


2 Answers

1
ravi 9 months, 1 week ago
The MAWP is a typical definition used in ASME BPVC (ASME Boiler and Pressure Vessel Code) and a number of other codes which refer to it. The MAWP is the maximum gauge pressure permissible at the top of the equipment in installed operating position and at a designated temperature.

Following is the summary of the MAWP from 46 CFR (Code of Federal Regulations) § 54.10-5:

The maximum allowable working pressure for a vessel is the maximum pressure permissible at the top of the vessel in its normal operating position at the designated coincident temperature specified for that pressure.

It is the least of the values found for maximum allowable working pressure for any of the essential parts of the vessel and adjusted for any difference in static head that may exist between the part considered and the top of the vessel.

In addition, Maximum allowable working pressure may be determined for more than one designated operating temperature, using for each temperature the applicable allowable stress value.

See additional pressure descriptions for comparison.

1
phamus 4 years, 10 months ago

Maximum Allowable Working Pressure (MAWP) is the maximum gauge pressure permissible at the top of a completed vessel in its operating position for a designated temperature.

The pressure is based on calculations for each element in a vessel using nominal thicknesses, which are exclusive of additional metal thicknesses allowed for corrosion and loadings other than pressure.

The maximum allowable working pressure is the basis for the pressure setting of the pressure relief devices that protect the vessel. Whereas Maximum Operating Pressure is the maximum pressure that equipment can be operated at below its high pressure alarm or shutdown, or 95% of MAWP, whichever is lower.

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