Maximum Allowable Working Pressure (MAWP)

The COMPRESS Rating Mode takes your pressure vessel or heat exchanger and determines its MAWP, MAEP and MDMT.  Rating Mode is often used when performing post construction calculations such as de-rating in-service pressure vessels and heat exchangers.  Some pressure vessel designers like to use it to input different pressure / temperature combinations and let COMPRESS tell them where the ASME® Code errors are.  COMPRESS also offers a true Design Mode where you input design data and COMPRESS selects component thicknesses, sizes, placements and optionally also determines MAWP, MAEP and MDMT.  You can switch between Rating and Design Modes in COMPRESS at any time.

  • In Rating Mode COMPRESS calculates the maximum allowable working pressure (MAWP) and maximum allowable external pressure (MAEP) for the given temperatures, materials, equipment geometry, liquid level and other UG-22 loadings.

  • The minimum design metal temperature (MDMT) is determined per the rules of UCS-66 or UHA-51.

  • If the data entered does not meet ASME code requirements, COMPRESS will display the appropriate errors in the deficiencies dialog and identify the affected component(s).  In other selected circumstances warnings and good engineering practice reminders are presented.

  • Some programs refer to this input mode as “analysis” because the software takes your input data and analyses but does not change it.

COMPRESS Pressure Vessel Design Highlights