Restriction Orifice Sizing Calculator – for liquids This is a sample of the Restriction Orifice Sizing Calculator. To access the working calculator, please sign up for free membership trial. Restriction Orifice for single phase flow. Mass flowrate kg/hr Density kg/m3 Viscosity cP Pipe size inches Inlet Pressure barg Outlet Pressure barg Flow Coefficient C Orifice diameter mm Orifice area sq. inch Login Username or Email: Password: signup now | forgot password? Remember Me Sign up for free if you are not a member already.