ISO 13061-5:2020

Overview

ISO 13061-5:2020 is an international standard that specifies a precise test method for determining the strength of wood under compression perpendicular to the grain. This standard is part of the ISO 13061 series, focusing on the physical and mechanical properties of wood through tests on small clear specimens. It provides a reliable procedure applicable to various wood species, enabling consistent assessment of mechanical strength when subjected to loads across the grain direction.

Developed by ISO Technical Committee ISO/TC 218 (Timber), the standard replaces the previous ISO 3132:1975 and introduces technical revisions such as updated specimen dimensions and moisture content adjustments. It ensures conformity and comparability of results essential for material selection, quality control, and research in wood engineering and construction industries.

Key Topics

• Scope and Purpose: Defines the determination method of compressive strength perpendicular to grain using small, defect-free wood specimens.
• Test Specimen Preparation: Instructions on specimen dimensions, moisture content conditions (green or air-dry), and conditioning to ensure accurate and reproducible results.
• Testing Apparatus:
  • A testing machine capable of controlled loading
  • Uniform-loading devices with self-aligning hardened steel plates
  • Precision displacement and dimension measuring instruments
• Test Procedure:
  • Application of a gradually increasing load to the entire surface of the specimen in radial, tangential, or 45° orientation relative to growth rings
  • Measurement of load and deformation to determine the proportional limit from the load-deformation curve
• Calculations:
  • Stress at the proportional limit computed by dividing the corresponding load by the specimen’s bearing area
  • Adjustment of results to a standard 12% moisture content when required, using recognized correction factors
• Reporting Requirements:
  • Details of sampling, specimen dimensions, moisture content, density, loading direction, test speed, and statistical values of results
  • Compliance reference to ISO 13061-5:2020 for traceability and standardization

Applications

ISO 13061-5:2020 is vital for evaluating wood material performance in various fields, including:

• Wood Engineering and Construction: Ensures the safe and reliable design of wooden structures by providing accurate compressive strength data perpendicular to grain, which affects connections, supports, and load-bearing components.
• Material Quality Control: Enables manufacturers and suppliers to verify wood strength properties to meet required standards and optimize product use.
• Research and Development: Serves as a reference for studying wood mechanical behavior, quality assessment, treatment effects, and species comparison.
• Timber Industry Certification: Assists certification bodies in validating timber properties against recognized international standards to support trade and compliance.
• Product Testing Laboratories: Provides standardized methods for consistent measurements, fostering international comparability of test results.

Related Standards

• ISO 13061-1: Determination of moisture content - addresses moisture measurement essential for conditioning specimens in mechanical tests.
• ISO 13061-2: Determination of density - specifies how to measure wood density as part of the characterization process for mechanical testing.
• ISO 3129: Sampling methods and general requirements for physical and mechanical tests - guides specimen sampling and handling to meet test integrity requirements.
• ISO 24294: Timber vocabulary - supplies consistent terminology related to wood and timber properties referenced across ISO 13061 standards.

Adherence to ISO 13061-5:2020 ensures precise evaluation of wood’s compressive strength perpendicular to grain, critical for multiple industrial sectors relying on wood as a structural material. The standard formulates a uniform testing approach that supports sustainable and safe utilization of wood resources worldwide.