Three-dimensional fluid mechanics and heat transfer for viscoplastic flows are described by FVM. The OpenMP approach has been implemented to parallelize the numerical code. Results for the elapsed times, speed-ups and efficiencies are presented. The code was used to describe the natural convection (Ra=104; 106) and the lid driven cavity (Re=100; 1000) processes with Bingham, Casson and Herschel-Bulkley fluids (Bn=0.01; 1.0). Results describing isotherms, velocity distributions and streamtraces, as a function of Ra, Re, Pr and Bn numbers are shown. The grid size analysis shows that different sizes are required to obtain precise results for Nusselt number and friction factor.