WLV Guidelines

What You Need to Know

The Austrian Service for Torrent and Avalanche Control (WLV) is a department within the Federal Ministry of Agriculture, Forestry, Environment and Water Management and is responsible for technical competence and construction management for everything to do with natural hazards such as floods, mud/landslides, rockfalls and avalanches that present a high safety risk to the population, their living, housing and economic space and infrastructure. In 2002, the WLV published a document entitled “Guideline for the verification of rockfall catchment fences” which was used as the basis for testing and verification of the systems. The guideline was updated in 2005. These guidelines were used to test the first generation of Trumer barriers. In 2010, a revised version of the guideline was published which addressed the adoption of the ETAG 27 guidelines in Europe.

Structure

The basis of the guideline was to establish the verification of the system capacity following realistic 1:1 scale field tests with the following requirements:

  • An impact with a block impacting a three field system in the middle field
  • The block should be a natural or artificial block of material having a minimum density of 2500 kg/sqm
  • The system is anchored as it would be during application
  • The velocity of the block on impact must be 25 m/sec ( ± 3%)
  • Failure of components (e.g. broken cables in the primary net, bearing, retaining ropes or sewing ropes, broken posts, or broken hinge pins between the post and base plate) are not allowed for systems with a capacity of 1000 kJ or less
  • Failure of individual components for systems exceeding 1000 kJ may be accepted if the independent testing body certifies the system as passed or conditionally passed
  • Plastic deformation is expected and allowable as long as it is documented
  • Testing must be supervised and documented by an independent testing body

Approval Process

Testing for systems according to the WLV guidelines was carried out at the test facilities in Erzberg, Austria. The approval process was administered by an independent testing body within the Montanuniversität Leoben.


References

WLV (2005) Richtlinie für den Eignungsnachweis von Steinschlagschutznetzen, Bundesministerium für Land- und Forst-wirtschaft, Umwelt und Wasserwirtschaft, Innsbruck, Austria

WLV (2010) Richtlinie für den Eignungsnachweis und risikobezogene Zusatzkriterien für Steinschlagschutznetzen, Bundesministerium für Land- und Forst-wirtschaft, Umwelt und Wasserwirtschaft, Innsbruck, Austria