What is ISO 12958‑1 about?
ISO 12958‑1 is the first part in the multi-series of documents that is applicable to the geotextiles and geotextile-related products, for the determination of water flow capacity in their plane.
ISO 12958‑1 specifies a method for determining the constant-head water flow capacity within the plane of a geotextile or geotextile-related product.
ISO 12958‑1 describes the in-plane water flow index test, only applicable to factory-assembled products.
Who is ISO 12958‑1 for?
ISO 12958‑1 on geotextiles and geotextile-related products is relevant to:
- Geotextiles/geotechnical engineers
- Civil engineers
- Public and private contractors
Why should you use ISO 12958‑1?
In recent years, geotextiles have been used extensively as filters for drainage systems. With the index test, ISO 12958‑1 aims to examine the flow of water within the plane of a geotextile or geotextile-related product, which is measured under varying normal compressive stresses, with typical hydraulic gradients and with defined contact surfaces.
When evaluating an equivalent in-plane water flow capacity per unit width of the geocomposite, ISO 12958-1 specifies the contribution of the main layer (i.e. geotextile) and the spacing of the discrete draining elements (i.e. pipe) that must be considered.
If you are a geotechnical engineer, taking into account the methods and assessment recommended by ISO 12958-1, is important to determine porosity, permeability and permittivity of geocomposites, to achieve optimal hydraulic performance of geotextiles.
What’s changed since the last update?
BS EN ISO 12958‑1:2020 together with BS EN ISO 12958‑2:2020, it supersedes BS EN ISO 12958:2010, which will be withdrawn on publication of BS EN ISO 12958‑2:2020. BS EN ISO 12958‑1:2020 includes some technical changes with respect to BS EN ISO 12958:2010. These include:
- Introduction of the concept of index versus performance test
- Permission is given to test using rigid/rigid, soft/soft or soft/rigid boundaries
- Addition of guidance for testing cuspated sheets on a single side and for testing multilinear drainage geocomposites
- Withdrawal of apparatus types b) and c)
- Several cosmetic improvements, in particular terms and definitions, procedure, calculation and reporting
