Municipal Waste Sorting Equipment worked example

Screen Efficiency at 99% target screen efficiency: a worked example in municipal waste sorting equipment

What does the result look like when target screen efficiency reaches 99%? The full calculation is worked below with real intermediate numbers. Use it after a composition study on screen overs and unders to decide whether the screen needs cleaning, deck replacement, or feed rate trimming.

The inputs for this scenario

  • Undersize correctly passed to unders: 210 kg (unchanged)
  • Total undersize present in feed: 250 kg (unchanged)
  • Target screen efficiency: 99 % (raised for this scenario; the documented default is 90)

Working through the calculation

  • Applying the documented formula (Screen efficiency = undersize correctly passed / total undersize in feed x 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 84 % for screen efficiency, the number this scenario is built around.
  • At this operating point the engine returns 15 points for gap to target screen efficiency.
  • At this operating point the engine returns 210 count for undersize correctly passed.
  • At this operating point the engine returns 250 count for total undersize in feed.

How this compares with the baseline

  • Against the tool's baseline example, where target screen efficiency sits at 90% and the headline result is 84 %, this scenario lands almost exactly on the baseline at 84 %.
  • A figure at this level is achievable when target screen efficiency is genuinely sustained, not just peaked for a shift. It only measures recovery of undersize to unders; it does not capture misplaced oversize in the unders, so pair it with a misplacement check for a full picture.

Results at a glance

  • Screen efficiency: 84 % (headline result)
  • Gap to target screen efficiency: 15 points
  • Undersize correctly passed: 210 count
  • Total undersize in feed: 250 count

Run it with your numbers

  • Every input above is editable in the live Screen Efficiency calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.