Industrial Software Integration & APIs worked example

Integration Downtime Exposure at 18% cascading failure allowance: a worked example

This worked example runs the integration downtime exposure numbers for a tougher week than the baseline: 18% cascading failure allowance instead of the typical 25%. Estimate the total downtime exposure from integration failures by combining the number of expected outage events with the average duration per event, plus an allowance for cascading system impacts.

The inputs for this scenario

  • Expected integration outage events per year: 6 events (held at the documented default)
  • Average MTTR per outage: 4 hours / event (held at the documented default)
  • Cascading failure allowance: 18 % (the input this scenario stresses; the baseline uses 25)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base downtime exposure = expected outage events x average MTTR.
  • Total annual downtime exposure (hours) works out to 1.77 hr at these inputs, and this is the headline figure for the scenario.
  • Base downtime from direct outages works out to 1.5 hr at these inputs.
  • Cascading failure hours added works out to 18 % at these inputs.
  • Average MTTR (hours/event) works out to 4 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where cascading failure allowance sits at 25% and the headline result is 1.88 hr, this scenario comes in 5.6% below the baseline at 1.77 hr.
  • Use it when setting integration SLAs, planning resilience investments, or quantifying the case for redundant middleware. 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

  • Total annual downtime exposure (hours): 1.77 hr (headline result)
  • Base downtime from direct outages: 1.5 hr
  • Cascading failure hours added: 18 %
  • Average MTTR (hours/event): 4 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Integration Downtime Exposure calculator, set cascading failure allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.