This standard specifies the action spectra for assessment of the photobiological and thermal effects of optical radiation. The photobiological effects dealt with concern changes in the chemical structure of the materials and in the formation of organisms. These effects are primarily dependent on the number of absorbed photons, their energy, the structure of the biological object and its radiation exposure geometry. These are accordingly dependent on: - radiation exposure (dose) H (see DIN 5031-1); - irradiance E (see DIN 5031-1); - radiance L (see DIN 5031-1); - spectral energy distribution S(λ) (see DIN 5031-8); - action spectra Abiol(λ); - relative spectral sensitivity of the receptor (see DIN 5031-2) for the considered effect; - duration t of the radiation exposure process. The photobiologically effective radiation is described by effective radiation quantities. The individual different sensitivities and adaption processes remain unobserved in this standard. Decisive for the observed effect is the photobiologically effective radiation exposure (dose), that is the product of the effective irradiance and the duration of the radiation exposure. When using action spectra the validity of the law of linearity (Bunsen Roscoe Law) and the additivity theorem (van Krefeld Law) is presumed; this is however only universally applicable to some effects, such as UV erythema. In order to perform comparable effect estimations, these principles are, however, applied to all effects. With the action spectra, reference quantities for assessment of biological effectiveness of different radiation sources are obtained. Phototherapeutic and photosensitive effects are only partially covered by this standard. This standard does not deal with photometric and colorimetric effects. This standard is not applicable for specifications of assessments and limiting values for exposure at work places. This standard has been prepared by the Lighting Technology Standards Committee (FNL) at DIN, Working Committee NA 058-00-07 AA "Strahlenkunde" ("Radiology").