Rockfall net fences and drapery meshes constitute two of the most adopted protective structural works against rockfall hazard. During their life, they are subject to ageing, corrosion, and impact loads, with a consequent loss of efficiency or even effectiveness. Due to the variability of the environment and, more in general, to external conditions, a definition of a service life, although not unique but different product by product, is not achievable. A quick-assessment procedure to evaluate the degree of conservation of these works based on a multi-hierarchical assessment of the damages, already proposed by the Authors, is herein enhanced and applied with a particular focus on net fences. The main components of a net fence, considered as a system, are identified, as well as all the potential damages and a check list to be compiled by experts during the periodic survey is prepared within a codified report form. The report form, specifically created by the Authors, allows to collect data related both to the state of conservation and the original characteristics of the barrier, enabling a precise geolocalisation and census of the protective measures. The effects of each potential damage on the overall behaviour are considered through the definition of classes of importance. Combining these lasts with the output of the check list for each potential damage, two qualitative indicators, i.e. the diffusion score and the state of functionality, are calculated and, in turn, merged to obtain a qualitative degree of efficiency and a level of maintenance need. A survey campaign realised in the Valle d’Aosta Region (Italy) is presented and the results highlight interesting aspects and suggestions that should be considered in the risk management procedure.

Keywords: rockfall, net fences, degree of efficiency, management assessment procedure, maintenance.