GB/T 3780.8-2019 specifies the determination method of carbon black heating reduction. It provides detailed instructions on sample selection, equipment preparation, heating operation steps, such as temperature and duration control, and standardizes the result calculation and data processing process. Heating reduction reflects the volatile matter content in carbon black and is a key indicator for measuring carbon black mass. The standard provides a unified detection basis for carbon black production, trade and use enterprises, which helps to accurately evaluate the quality of carbon black, ensure its performance is stable, meet the strict requirements of different industries for carbon black mass, and promote the standardization process of carbon black industry testing.