UV Curing worked example

UV Irradiance at Part at 61% lamp aging derate: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop lamp aging derate to 61%, then walk the calculation through step by step. Estimate the UV irradiance reaching the part from rated lamp output, distance falloff, and reflector / focal-distance efficiency.

The inputs for this scenario

  • Rated peak lamp irradiance: 2,400 mW / cm² (held at the documented default)
  • Focal / reflector efficiency factor: 0.75 x (held at the documented default)
  • Lamp aging derate: 61 % (the input this scenario stresses; the baseline uses 85)

Working through the calculation

  • The calculation starts from the formula this tool documents: Estimated irradiance at part = rated peak × focal/reflector efficiency × aging derate %.
  • Estimated irradiance at part works out to 1,098 mW / cm² at these inputs, and this is the headline figure for the scenario.
  • Rated peak irradiance works out to 1,800 mW / cm² at these inputs.
  • Loss to distance / aging works out to 702 mW / cm² at these inputs.
  • Aging derate works out to 61 % at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where lamp aging derate sits at 85% and the headline result is 1,530 mW / cm², this scenario comes in 28.24% below the baseline at 1,098 mW / cm².
  • The practical read: the gap between this scenario and the baseline is entirely attributable to lamp aging derate, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It is an estimate built on assumed efficiency and aging factors; only a radiometer profiling pass at the part plane gives the true value for a process spec.

Results at a glance

  • Estimated irradiance at part: 1,098 mW / cm² (headline result)
  • Rated peak irradiance: 1,800 mW / cm²
  • Loss to distance / aging: 702 mW / cm²
  • Aging derate: 61 %

Run it with your numbers

  • To rerun this with your own numbers, open the live UV Irradiance at Part calculator, set lamp aging derate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.