ISO/TR 16312-2:2021 assesses the utility of physical fire models that have been standardized, are commonly used, and/or are cited in national or international standards, for generating fire effluent toxicity data of known accuracy. This is achieved by using the criteria established in ISO 16312-1 and the guidelines established in ISO 19706. The aspects of the models that are considered are: the intended application of the model, the combustion principles it manifests, the fire stage(s) that the model attempts to replicate, the types of data generated, the nature and appropriateness of the combustion conditions to which test specimens are exposed, and the degree of validity established for the model.