ISO/CIE DIS 25176:2026

This document specifies procedures a) for characterizing angle-dependent transmittance and reflectance properties of complex fenestration systems (CFS) and b) for generating tabular BSDF data sets from the measured or simulated data for use as input to simulation tools. This document establishes generally applicable methods for tabulated BSDF characterization of CFS for evaluation of performance criteria based on integral radiation quantities (illuminance, solar irradiance) and thus on definitions and specifications for generating “low-resolution” BSDF data. The subsequent derivation of analytical models in order to characterize some systems with a large number of similar variations is not included in this document.