Cleanroom & Contamination Control worked example

Cleanroom Temperature Excursion Cost at 25% lots expected to require quality disposition: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop lots expected to require quality disposition to 25%, then walk the calculation through step by step. Estimate cost exposure from cleanroom temperature excursions that may trigger quarantine, investigation, retest, scrap, or production delay.

The inputs for this scenario

  • Lots or batches exposed to temperature excursion: 14 lots (held at the documented default)
  • Cost per exposed lot or batch: 18,500 $ / lot (held at the documented default)
  • Lots expected to require quality disposition: 25 % (the input this scenario stresses; the baseline uses 35)
  • Fixed HVAC response, deviation, retest, and recovery cost: 22,000 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Variable excursion exposure cost = lots or batches exposed to temperature excursion × cost per exposed lot or batch × lots expected to require quality disposition.
  • Expected temperature excursion cost works out to 86,750 expected temperature excursion cost at these inputs, and this is the headline figure for the scenario.
  • Temperature excursion cost per exposed lot works out to 6,196 $ / piece at these inputs.
  • Variable excursion exposure cost works out to 64,750 $ at these inputs.
  • Fixed hvac response, deviation, retest, and recovery cost works out to 22,000 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where lots expected to require quality disposition sits at 35% and the headline result is 112,650 expected temperature excursion cost, this scenario comes in 22.99% below the baseline at 86,750 expected temperature excursion cost.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to lots expected to require quality disposition, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. The disposition percentage is a probability estimate, not a confirmed reject rate; actual outcomes depend on product stability data and the QA investigation, so treat the result as expected value, not a guaranteed loss.

Results at a glance

  • Expected temperature excursion cost: 86,750 expected temperature excursion cost (headline result)
  • Temperature excursion cost per exposed lot: 6,196 $ / piece
  • Variable excursion exposure cost: 64,750 $
  • Fixed hvac response, deviation, retest, and recovery cost: 22,000 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Cleanroom Temperature Excursion Cost calculator, set lots expected to require quality disposition to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.