Project Overview

This project was to rerate to increase the registered design conditions for an air filter. The filter was built to design conditions of 460ºF, and 165psig. The operating temperatures could reach 460ºF, so a re-rated higher design temperature was requested of the Client.

Rerate Design Conditions of Air Filter main Rerate Design Conditions of Air Filter first Rerate Design Conditions of Air Filter second

Scope of Work

Rally performed a technical analysis to verify design conditions could be increased to one the following conditions: (1) 550ºF and 175psig; (2) 550ºF and 165psig; (3) 525ºF and 175psig; and (4) 525ºF and 165psig. There were no registration or design records available for the previous flange alteration before the recent head replacement.


Field checks were completed to check out the flanges which were discovered to be the limiting components to the design conditions of 460ºF and 165psig. It was discovered that it was not feasible to rerate the FL202 to a higher design condition without major vessel modifications and replacements.

Proposed Solutions:
Stop further related rerate design analysis work on FL 202, and seek for Clients directions on one of the following options:

  • (1) Purchasing a new filter to the new design conditions.
  • (2) Replacing the existing filter with a new head, body flanges, and partial of the shell to reduce the risk of installation misalignment. It was highlighted that a construction risk exists due to no fabrication information of the existing filter internal attachment inside the vessel.

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