ISO 11058:2019 PDF

Overview

ISO 11058:2019 - "Geotextiles and geotextile-related products - Determination of water permeability characteristics normal to the plane, without load" specifies two laboratory test methods to measure water permeability through a single layer of geotextile normal to the plane. The standard defines the constant head method and the falling head method, procedures for specimen preparation and handling, measurement and calculation conventions (including temperature correction to 20 °C), and reporting requirements. This is the third edition (2019), replacing ISO 11058:2010.

Key topics and technical requirements

• Test methods
  • Constant head: steady unidirectional flow with several constant heads (including a maximum head ≈ 70 mm).
  • Falling head: unidirectional flow under a falling head (apparatus capable of at least 250 mm head).
• Specimens
  • Samples handled flat, not folded; cut per ISO 9862.
  • Typical test set uses five specimens of suitable dimension for the apparatus.
• Apparatus and measurement
  • Apparatus must allow visual observation of bubbles and have a minimum exposed diameter (≥ 50 mm) with internal diameter accuracy to 0.1 mm.
  • Support grid may be used to avoid deformation; head loss of apparatus alone (with grid) must be