In a refinery, product blending plays a vital role in preparing final products for marketing purposes. It must follow environmental regulations. Product blending ensures optimal use of the final product. Databases keep records of feedstock inventory, availability of tanks, and blended qualities. Information about a tank and feedstock inventory is provided by different integrated subsystems. This topic will discuss blend component data, component quality/cost data, mandatory interfaces, blend tank qualities, blend specifications and heel qualities, component inventory and daily production rates, blend production requirement, interfaces for real-time data, blend tank heel data, daily stock production rates, etc.