Q. Show Maximum Allowable Working Pressure?
The MAWP to be marked on the Section VIII nameplate is defined as the maximum gauge pressure permissible at the top of a completed vessel in its normal operating position at the designated coincident metal temperature for that pressure. (See Section VIII Appendix 3 for definitions of MAWP and design pressure.) This MAWP may be determined from the design pressure or from calculations, based on the specified nominal component thicknesses, reduced by the specified corrosion allowances. The maximum permissible set-to-operate pressure of a single safety relief device cannot be higher than the MAWP.