Fibre shortening is typically an unwanted morphological change during low consistency refining that degrades pulp. A comminution model parametrization was proposed to assess fibre shortening during the low consistency refining of mechanical pulps. Fibre length distribution data from before and after refining with a variety of pulp types, net-powers, feed flow rates, angular velocities and plate geometries was analyzed. The estimated parameters from the comminution model showed to have correlations with refiner gap: the cutting rate had an inversely proportional power-law relationship with the refiner gap; narrower gaps promoted fibre cutting at the middle of the fibre whereas wider gaps promoted a more uniform cutting. Plate geometry was also demonstrated to have a role in the fibre cutting location. The proposed parametrization was compared to other modeling works using the likelihood ratio test, showing that it is appropriate to describe the results reported. (C) 2018 Elsevier B.V. All rights reserved.