UV Exposure Limits
Exposure limit of a monochromatic UV source at 180–400 nm: the ICNIRP S(λ)-weighted limit and the UVA eye limit as irradiance, dose and the largest source power for an exposure time.
Educational only — not compliance-grade
These pages implement the published exposure limits for the cases each one states, but they are educational tools: no laser safety officer has signed them off.
- Do not use these results alone for PPE selection, NHZ / NOHD approval, controlled-area sign-off, enclosure/interlock approval, or formal classification.
- Always verify against ANSI Z136.1, IEC 60825-1, your local procedures, and the responsible laser safety officer / CLSO.
Formulas
Actinic: Σ Eλ S(λ) Δλ · t ≤ 3 mJ/cm² within 8 h (ICNIRP 2004, S(λ) from its Table 1)
Emax(t) = 3 mJ/cm² / (S(λ) · t) (single wavelength)
UVA eye, 315–400 nm: E · t ≤ 1 J/cm² unweighted within 8 h, so Emax ≤ 1 J/cm² / t
S(270 nm) = 1 (peak weighting)
Input
Results
S(λ) Weight
0.500
MPE Irradiance
2.08e-7 W/cm²
MPE Energy
6.00e-3 J/cm²
Max Power (source)
2.08e-7 W
The limits apply per 8-hour period; this exposure is 100.0% of it.
Actinic UV Weighting Function S(λ)
Model and references
Exact. The equations are exact within the stated assumptions, or are a standard's tabulated values. The results are as good as the inputs. About the tiers
Monochromatic source: S(λ)-weighted limit of 30 J/m² plus ICNIRP's unweighted UVA limit of 10⁴ J/m² (315–400 nm), within 8 h. ACGIH and IEC relax the UVA limit after 1000 s; ICNIRP, used here, does not.
- ICNIRP (2004). Guidelines on limits of exposure to ultraviolet radiation of wavelengths between 180 nm and 400 nm (incoherent optical radiation). Health Phys. 87(2), 171–186. Table 1 (S(λ) and the exposure limits). doi:10.1097/00004032-200408000-00006
- IEC 62471:2006. Table 4.1 (the same S(λ) values).