System Costs

The System Costs worksheet for simulation diagrams displays the costs that accrued during the simulation time. The values shown are averages of the results of all of the simulations.

For each of the four classes of tasks (i.e., corrective, preventive, on condition and inspection), the following information is presented with regard to costs that accrued during the simulation time:

  • Misc. Costs: The miscellaneous costs associated with the task class. This is based on the cost per task and downtime rate, specified in the Maintenance Task window.
  • Costs for Parts: The cost for spare parts due to tasks of this class. This is based on the direct cost per item as specified in the Spare Part Pool window, as well as any indirect costs (e.g., holding costs, costs associated with restocking, etc.). Note that this value is not available for inspection tasks, as inspections do not use spare parts.
  • Costs for Crews: The cost for crews due to tasks of this class. This is based on the direct cost per unit time and cost per incident, as specified in the Crew window.
  • Total Costs: The total cost for maintenance of this type, based on the miscellaneous costs and costs for spare parts and crews.

In addition, the following values are calculated:

  • Block Consequential Costs
    • Total Block Consequential Costs: The sum of all individual consequential block costs. Consequential costs are specified in the Block Properties window for each failure event, each unit of downtime and each unit of uptime.
  • Indirect Pool Costs
    • Total Pool Holding Costs: The indirect costs of maintaining the spare part in the pool over time. For example, if it costs $20 per month to keep the part available in the pool and the part remains in the pool for 3 months, then $60 of indirect costs have accumulated for the item.
  • Additional System Level Costs
    • System Level Failure Cost (CM): The costs associated with system failure events based on the cost per system failure, as specified on the Analysis Settings page of the diagram control panel.
    • System Level Downtime Costs (CM): The total costs associated with system level downtime events due to corrective tasks only. Downtime due to other non-failure events, such as preventive, inspection or on condition tasks, is not included. This is based on the system downtime rate, as specified on the Analysis Settings page of the diagram control panel.
    • System Level Total Costs (CM): The sum of the System Level Failure Costs (CM) and System Level Downtime Costs (CM).
    • System Level Failure Cost (Total): The costs associated with system downing events based on the cost per system failure, as specified on the Analysis Settings page of the diagram control panel.
    • System Level Downtime Costs (Total): The total costs associated with all system level downtime events. This is based on the system downtime rate, as specified on the Analysis Settings page of the diagram control panel.
    • System Level Total Costs (Total): The sum of the System Level Failure Costs (Total) and System Level Downtime Costs (Total).
  • Total Costs
    • Total Costs: The total cost that accrued during the system simulation time, based on all of the costs shown in the worksheet.
  • Opportunity Costs
    • Opportunity Costs: Potential system revenue lost as a result of downtime. This is based on the lost revenue per hour of uptime plus the lost revenue per unit produced (if a throughput simulation has been run). Both are specified on the Analysis Settings page of the diagram control panel.
  • System Revenue Summary
    • Uptime Revenue: The system revenue based on the revenue per unit of uptime, as specified on the Analysis Settings page of the diagram control panel.
    • Throughput Revenue: The system revenue based on the revenue per unit of throughput (if a throughput simulation has been run), as specified on the Analysis Settings page of the diagram control panel.
    • Total Revenue: The sum of the Uptime Revenue and Throughput Revenue.

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