To allow the calculation of product degradation rates as extension to the currently used thermotechnical design calculations for heat exchangers, a volume-related, reaction-kinetic approach was developed. Therefore, a model system was selected and the product protection design parameters were determined for a lab-scale heat exchanger with the help of simulations. The validation was demonstrated in an experiment. Additionally, the product-protecting operating parameters for the heat exchanger were calculated with a technically relevant set of compounds.