Project Overview

Rally was requested to complete the design of the manway for entering Suction Knockout Drum. A 24” manway was the preferred size if feasible. If this design was not feasible, Rally was asked to proceed with 20” manway. “Stub on” would be used instead of “stub in” design.

Manway Addition main Manway Addition first Manway Addition second

Scope of Work

The Suction Knockout Drum had internals that were welded into the upper half of the vessel. Access to the lower half of the vessel was through the existing top manway, up to the top section of the bundle across from that manway, and down through the internal bundle manway, which was only a few feet below the top head.

This arrangement made it challenging for personnel to navigate, and impossible to fit materials into the lower section of the D407 shell.

Rally prepared and submitted ABSA registration for vessel rerate.


  • Detail design calculations for the manway addition on the knockout drum.
  • Reviewed and verified existing general arrangement drawing, detailing the new manway and davit, and modification of drawings.
  • Reviewed codes, ABSA, and Client specification requirements. Reviewed specification of internal and external coating repairs.
  • Drafted, assembled, submitted, and stewarded the design package for ABSA.
  • Mechanical CWP detailing the work required to install and inspect the new manway, including:
    • Details for the welds and post weld heat treatment.
    • Minimum pressure testing and non-destructive examination.

    • Bill of materials, nozzle, manhole, and cover details.
    • New nozzle details general arrangement drawings.
    • Scope for coating repairs around new manway area.

    • Davit arm details.
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