Definition(s)
Rerating
A change in the design temperature, design pressure or the maximum allowable working pressure of a piping system (sometimes called rating).
- NOTE: A rerating may consist of an increase, a decrease, or a combination of both. Derating below original design conditions is a means to provide increased corrosion allowance.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global Standards
Rerating
A change in either the design temperature rating, the MDMT or the MAWP rating of a vessel. The design temperature and MAWP of a vessel may be increased or decreased because of a rerating. Derating below original design conditions is a permissible way to provide for additional corrosion allowance.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards
Rerating
A change in either the design temperature rating, the MDMT or the MA WP rating of a vessel. The design temperature and maximum allowable working pressure of a vessel may be increased or decreased because of a rerating. Derating below original design conditions is a permissible way to provide for additional corrosion allowance.
Source: API 510, Pressure Vessel Inspection Code: In-Service Inspection, Rating, Repair, and Alteration Downstream Segment, Ninth Edition, June 2006. Global Standards