The Darcy-Weisbach Equation is a fundamental formula used in fluid mechanics to calculate the pressure loss due to friction in a pipe. It relates the pressure drop to the length of the pipe, the flow velocity, the fluid's density, and the pipe's diameter, along with a friction factor that accounts for the roughness of the pipe's interior surface. This equation is expressed as ΔP = f * (L/D) * (ρ * v² / 2), where ΔP is the pressure loss, f is the friction factor, L is the pipe length, D is the diameter, ρ is the fluid density, and v is the flow velocity. Understanding this equation is essential for engineers designing efficient piping systems.