Sinter is the most preferred metallic burden for modern-day blast furnaces. It is produced by agglomeration of iron ore fines in sinter machine. Sintering process depends on airflow through the sinter bed under high suction. The airflow through the sinter bed is measured by sinter bed permeability and has direct correlation with sinter productivity. Permeability can be determined by different ways. Among these methods, permeability detection by measuring the airflow through granular sinter bed by placing the instrument in the static wind box is very well known. But there is a challenge due to multiphase and turbulent conditions in the wind box.Infrared-based flow measurement technique has been used to measure flow. Therefore, this flow has been used to get permeability in the form of JPU (Japanese Permeability Unit). Productivity increases by 4% in spite of decrease in mean particle size of iron ore by 3.4% for a fixed time duration.