This YouTube video by Irfan CFPS demonstrates how to calculate the water demand for in-rack sprinkler systems in warehouses, which are designed to protect commodities stored in racks. The video focuses on calculating the demand based on the storage height, commodity classification, and type of rack. The presenter emphasizes the importance of considering the pressure at the connection point when determining whether to add the demand for ceiling sprinklers to the demand for in-rack sprinklers. The presenter also provides a detailed explanation of how to adjust the in-rack sprinkler demand to match the pressure required by the ceiling sprinklers. Finally, the presenter calculates the total water demand for the entire warehouse by adding the adjusted in-rack sprinkler demand to the ceiling sprinkler demand.