Proposal and practicality of an alternative blue-light hazard risk assessment method for high-intensity white-light sources at workplaces

Abstract

Objectives. It is prescribed to determine blue-light hazard (BLH) weighted radiances, $L_{\text{B}}$, for an assessment of spotlights with an angular subtense $\alpha \ge 11\text{mrad}$. The BLH weighted irradiance, $E_{\text{B}}$, can be used alternatively for smaller sources. Appropriate instruments are not common among persons commissioned with risk assessment (RA), and especially $L_{\text{B}}$ measurements may be challenging. Therefore, a practical BLH RA approach is proposed that is based on illuminance, $E_{\text{v}}$, pre-calculated blackbody BLH efficacies of luminous radiation, $K_{\text{B,v}}^{\text{Planck}}$, and solid angle considerations. Methods. The practicality of this method was examined and compared against other RA approaches. Results. To ensure comparability of the applied instruments, measurements were performed close to a radiance standard, showing deviations within the lamp's expanded uncertainties ($<4\%$), whereas the deviations were $\pm 15\%$ for longer distances. Focusing on a complex light-emitting diode (LED) spotlight, all detected values could be converted to $L_{\text{B}}$ by means of the RA methods within $\pm 20\%$. Two field tests with several spotlights yielded maximum permissible exposure durations (MPED) obtained from the different RA approaches that agreed among each other within uncertainties largely below $\pm 30\%$. Conclusion. The general practicality of the proposed $E_{\text{v}}$ method can be concluded for a workplace BLH RA of white-light sources.

Keywords: blue-light hazard; blue-light hazard efficacy of luminous radiation; instrument comparison; occupational safety and health; risk assessment; spotlight; workplace.