Piping serves as an important pillar in most of the engineering applications while the quantification on the pressure drop due to various factors is always the central issue of efficient piping maintenance and design. In this study, the relationship between the pressure drop and the percentage of blockage in Hagen-Poiseuille flow is investigated. The analysis is executed using CFD commercial software of ANSYS Fluent. Our simulation discovered that the pressure drop will increase in an exponential manner with respect to constant increment of the blockage percentage. In other words, the power waste will increase exponentially too when the clot accumulates.