ISO 13061-14:2024

Overview

ISO 13061-14:2024 specifies standardized test methods for determining volumetric shrinkage of wood using small clear specimens. The standard defines two accepted procedures - the stereometric method (linear dimension measurements) and the immersion method (water displacement) - to measure the change in specimen volume from a green or fully saturated state to an oven‑dry state. Results are reported as percentage volumetric shrinkage with prescribed calculation and reporting conventions.

Key topics and technical requirements

• Scope: Methods for determination of volumetric shrinkage of wood from green/fully saturated to oven‑dry condition.
• Two measurement methods:
  • Stereometric method: Volume computed from measured radial, tangential (and optionally longitudinal) dimensions. Linear measuring instruments must read to 0.02 mm.
  • Immersion method: Volume measured by mass of displaced distilled water; balance accuracy 0.001 g (1 mg), volume read to 0.01 cm³.
• Apparatus: Forced convection oven maintained at (103 ± 2) °C, desiccator, vessel with distilled water, balance (0.001 g), and dimension gauges (0.02 mm).
• Specimen preparation and size:
  • Rectangular prisms for stereometric method: at least 20 mm in radial and tangential directions; at least 5 mm along grain if longitudinal shrinkage is neglected; minimum 100 mm length if longitudinal shrinkage is included.
  • Immersion method specimens: any shape with a minimum volume of 4 cm³.
  • Annual ring inclination to tangential faces shall not exceed 10°.
  • Measurement points marked at the center of each surface.
• Moisture conditioning: Initial measurements must be taken at or above the fibre saturation point (FSP). If below FSP, specimens are soaked in distilled water at (20 ± 2) °C until dimensional/volume stability is achieved (checked every 3 days; stability criterion 0.01 mm or 0.01 cm³).
• Drying to constant mass: Oven dry at (103 ± 2) °C, check weight changes every 8 h until successive change ≤ 0.2% (or dimensional change ≤ 0.02 mm). Discard specimens that develop checks.
• Calculations and reporting: Formulas provided for volumetric shrinkage (with and without longitudinal shrinkage). Results expressed to the nearest 0.1%; report mean and standard deviation to 0.1%.

Applications and users

• Practical for wood scientists, material testing laboratories, timber product manufacturers, drying and kiln operators, product certification bodies, and researchers.
• Common uses:
  • Characterizing dimensional stability of wood species and processed wood products.
  • Informing drying schedules, product design tolerances, and quality control.
  • Supporting comparative studies of species, treatments, composites, and engineered wood products.

Related standards

• ISO 3129 - Sampling methods and general requirements for small clear wood specimens.
• ISO 24294 - Timber vocabulary (terms and definitions used by this standard).

Keywords: ISO 13061-14, volumetric shrinkage, wood testing, stereometric method, immersion method, oven-dry, fibre saturation point, timber testing, physical properties of wood.