The overall objective of this work is to develop a computational model of particle degradation during dilute-phase pneumatic conveying. A key feature of such a model is the prediction of particle breakage due to particle-wall collisions in pipeline bends. This paper presents a method for calculating particle impact degradation propensity under a range of particle velocities and particle sizes. It is based on interpolation on impact data obtained in a new laboratory-scale degradation tester. The method is tested and validated against experimental results for degradation at 90degrees impact angle of a full-size distribution sample of granulated sugar. In a subsequent work, the calculation of degradation propensity is coupled with a flow model of the solids and gas phases in the pipeline.