UV Curing worked example

UV Intensity Decay vs New at 54% lamp replacement threshold: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop lamp replacement threshold to 54%, then walk the calculation through step by step. Calculate how much UV irradiance has dropped vs a brand-new lamp baseline, with a verdict against your minimum-acceptable percent.

The inputs for this scenario

  • Today's irradiance reading: 1,380 mW / cm² (held at the documented default)
  • New-lamp baseline irradiance: 2,000 mW / cm² (held at the documented default)
  • Lamp replacement threshold: 54 % of new (the input this scenario stresses; the baseline uses 75)

Working through the calculation

  • The calculation starts from the formula this tool documents: % of new = today's reading ÷ original baseline × 100.
  • % of new (today) works out to 69 % of new at these inputs, and this is the headline figure for the scenario.
  • Headroom over replacement threshold works out to -15 points at these inputs.
  • Today's reading works out to 1,380 mW / cm² at these inputs.
  • Original baseline works out to 2,000 mW / cm² at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where lamp replacement threshold sits at 75% and the headline result is 69 % of new, this scenario lands almost exactly on the baseline at 69 % of new.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to lamp replacement threshold, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. Percent of new only tracks peak irradiance; it does not capture spectral shift or reflector fouling, which can degrade cure even when the number still looks acceptable.

Results at a glance

  • % of new (today): 69 % of new (headline result)
  • Headroom over replacement threshold: -15 points
  • Today's reading: 1,380 mW / cm²
  • Original baseline: 2,000 mW / cm²

Run it with your numbers

  • To rerun this with your own numbers, open the live UV Intensity Decay vs New calculator, set lamp replacement threshold to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.