•Formulation of looped pipeline network problem without independent loops selection.•Resolution of pipeline network problems by reduced system of equations.•Simultaneous-modular procedure employed on looped pipeline network problems.•Looped pipeline as part of process simulation problem for industrial design. It is proposed a novel method to solve looped pipeline network problems that seeks to deal with limitations of the available methods The problem is modeled as a nonlinear system of equations formed by equations that cannot be solved sequentially, characterizing the resolution as a simultaneous-modular procedure. The equations of the system are the differences between the final pressure of the pipes that end at the same network nodes and the difference between the specified and calculated design variables. At the solution both Kirchhoff’s laws are met, being the method main advantages the no need of independent loops selection and the formulation of a reduced system of equation. Case studs with a small and a big looped water pipeline network, and an industrial installation with looped pipeline configuration, are solved. The latter shows the method applicability for design process, highlighting its advantages in comparison with the traditional simulation procedures.