UV Curing worked example

UV Operator Safety Exposure Limit at 345% safety factor above bare limit: a worked example

Push safety factor above bare limit up to 345% and the picture changes. This example computes every intermediate figure at that operating point. Use it on safety walkthroughs and PPE decisions when stray UV from cure cells reaches operator areas - to prove you're under the threshold limit value or to size a guard.

The inputs for this scenario

  • Effective UV exposure limit (TLV): 3 mJ / cm² (unchanged)
  • Measured stray irradiance at operator: 0.05 mW / cm² (unchanged)
  • Safety factor above bare limit: 345 % (raised for this scenario; the documented default is 300)

Working through the calculation

  • Applying the documented formula (Base exposure (sec) = exposure limit (mJ/cm²) ÷ measured irradiance (mW/cm²)) to the inputs above produces each figure below.
  • At this operating point the engine returns 267 sec to TLV for permissible operator exposure time, the number this scenario is built around.
  • At this operating point the engine returns 60 sec to TLV for base exposure (no safety multiplier).
  • At this operating point the engine returns 345 % for safety factor applied.
  • At this operating point the engine returns 0.05 mW / cm² for ambient irradiance.

How this compares with the baseline

  • Against the tool's baseline example, where safety factor above bare limit sits at 300% and the headline result is 240 sec to TLV, this scenario comes in 11.25% above the baseline at 267 sec to TLV.
  • It computes the permissible operator exposure time in seconds before the effective UV dose reaches the TLV, given the dose limit, measured stray irradiance, and a safety factor applied on top. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Permissible operator exposure time: 267 sec to TLV (headline result)
  • Base exposure (no safety multiplier): 60 sec to TLV
  • Safety factor applied: 345 %
  • Ambient irradiance: 0.05 mW / cm²

Run it with your numbers

  • Every input above is editable in the live UV Operator Safety Exposure Limit calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.