Tank, Vessel & Pressure Equipment Fabrication worked example

Rework Allowance with approved welding hours budgeted for the vessel of 63 units: a worked example in tank, vessel & pressure equipment fabrication

This worked example runs the rework allowance numbers for a tougher week than the baseline: approved welding hours budgeted for the vessel of 63 units instead of the typical 125 units. Rework Allowance measures how much of your fabrication buffer is still available before a tank or pressure vessel job goes over budget on weld repairs.

The inputs for this scenario

  • Approved welding hours budgeted for the vessel: 63 units (the input this scenario stresses; the baseline uses 125)
  • Welding hours actually consumed to date: 100 units (held at the documented default)
  • Baseline shop welding hours for this vessel class: 100 units (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Rework Allowance margin = available value - required value.
  • Margin works out to -37 % at these inputs, and this is the headline figure for the scenario.
  • Absolute margin works out to -37 value at these inputs.
  • Available amount works out to 63 value at these inputs.
  • Required amount works out to 100 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where approved welding hours budgeted for the vessel sits at 125 units and the headline result is 25 %, this scenario comes in 248% below the baseline at -37 %.
  • Use it mid-job after each NDE milestone (root pass RT, final RT, hydro) to check how much rework capacity you have left before the job runs red. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Margin: -37 % (headline result)
  • Absolute margin: -37 value
  • Available amount: 63 value
  • Required amount: 100 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Rework Allowance calculator, set approved welding hours budgeted for the vessel to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.