Maintenance & Reliability worked example

Maintenance Availability at 71% pm execution factor: a worked example

This worked example runs the maintenance availability numbers for a tougher week than the baseline: 71% pm execution factor instead of the typical 98%. Estimate achieved maintenance availability against total calendar time while accounting for preventive work execution and startup recovery.

The inputs for this scenario

  • Available calendar hours after maintenance downtime: 700 hr (held at the documented default)
  • Total calendar hours: 720 hr (held at the documented default)
  • PM execution factor: 71 % (the input this scenario stresses; the baseline uses 98)
  • Startup recovery factor: 97 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base maintenance availability = available calendar hours after maintenance downtime ÷ total calendar hours × 100.
  • Achieved Maintenance Availability works out to 66.96 % at these inputs, and this is the headline figure for the scenario.
  • Calendar-Time Availability works out to 97.22 % at these inputs.
  • PM Execution Factor works out to 71 % at these inputs.
  • Startup Recovery Factor works out to 97 % at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where pm execution factor sits at 98% and the headline result is 92.42 %, this scenario comes in 27.55% below the baseline at 66.96 %.
  • Use it to assess a maintenance program's real availability contribution or to set availability targets against total calendar time. 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

  • Achieved Maintenance Availability: 66.96 % (headline result)
  • Calendar-Time Availability: 97.22 %
  • PM Execution Factor: 71 %
  • Startup Recovery Factor: 97 %

Run it with your numbers

  • To rerun this with your own numbers, open the live Maintenance Availability calculator, set pm execution factor to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.