Defense Electronics & Ruggedized Systems worked example

Environmental Stress Screening Load at 7.2% load, retest, and data-capture allowance: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop load, retest, and data-capture allowance to 7.2%, then walk the calculation through step by step. Estimate ESS chamber hours for thermal cycling, powered burn-in, temperature soak, or humidity screening of rugged electronics.

The inputs for this scenario

  • ESS units or thermal/vibe cycle steps: 120 unit-cycles (held at the documented default)
  • Chamber throughput pace: 12 unit-cycles / hr (held at the documented default)
  • Load, retest, and data-capture allowance: 7.2 % (the input this scenario stresses; the baseline uses 10)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base ESS chamber hours = ESS units or cycle steps รท ESS completion pace.
  • Required ESS chamber hours works out to 10.72 hr at these inputs, and this is the headline figure for the scenario.
  • Base ESS chamber hours works out to 10 hr at these inputs.
  • Load, retest, and data allowance works out to 7.2 % at these inputs.
  • ESS completion pace works out to 12 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where load, retest, and data-capture allowance sits at 10% and the headline result is 11 hr, this scenario comes in 2.55% below the baseline at 10.72 hr.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to load, retest, and data-capture allowance, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes a steady throughput pace; ramp/soak dwell times, ESS escapes that trigger root-cause, and chamber recovery between profiles can push real hours well past the estimate on early lots.

Results at a glance

  • Required ESS chamber hours: 10.72 hr (headline result)
  • Base ESS chamber hours: 10 hr
  • Load, retest, and data allowance: 7.2 %
  • ESS completion pace: 12 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Environmental Stress Screening Load calculator, set load, retest, and data-capture allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.