ONR 24810 Guidelines

What You Need to Know

The “ONR 24810: Technical protection against rockfall – Terms and definitions, actions, design and construction, and monitoring and maintenance” is a comprehensive technical guideline focused on rockfall mitigation measures, which not only includes rockfall catchment fences but also many other forms of mitigation including, stabilization with anchoring and mesh/nets, embankments, and galleries. The latest update of the guideline was published by the Austrian Standards Institute in 2017 in both German and English.

It is being implemented throughout the world as a simple, standardized approach to rockfall mitigation and is a valuable tool for engineers to ensure safe and efficient projects.

Herein, only the sections dealing with rockfall catchment fences are discussed. To help guide new users through the process, a Step-by-Step flow chart can be found on this page. For a more comprehensive tool, please visit: www.therockstopshere.com.


The ONR 24810 guides the reader through the initial site investigation through to the construction and subsequent maintenance of mitigation measures. The major sections include baseline surveys for planning and determining actions; mitigation specific chapters on anchors, nails, netting, rockfall catchment fences, dams and galleries; monitoring and maintenance; and maintenance tasks. Specifically, for rockfall catchment fences, it has sections dedicated to the verification of the superstructure itself, anchor design, corrosion protection, grouting, non-standard actions, construction rules and lifespan.


In Austria, the ONR 24810 must be applied to rockfall related projects which have any of the following aspects:
– deal with hazard assessment;
– planning and implementation of mitigation measures;
– official procedures and expert reports;
– teaching and professional training;
– during the award of public contracts;
– in reference to using other technical standards and guidelines regarding relevant mitigation measures;
– for the allocation of public funding;
– constructions carried out by the Forest Engineering Service in Torrent and Avalanche Control;
– information and public relations.

First Step


ASI (2017) ONR 24810: Technical protection against rockfall – Terms and definitions, effects of actions, design, monitoring and maintenance. Austrian Standards Institute, Vienna, Austria.


  • Consequence Class

    What level of risk is there?
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  • Design Block

    How is a design block selected?
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  • Energy

    What system capacity is sufficient?
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  • Height

    What system height is required?
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  • Anchorage

    How is an anchor verified?
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  • Performance

    What other performance criteria are there?
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  • Constructive Rules

    How can the system be safely adapted to a site?
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  • Maintenance

    What recommended maintenance protocols exist?
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