Overview - ISO 24322:2024 (Timber structures - Part 1: Wood-based products in bending)
ISO 24322:2024 defines standardized test methods to evaluate the long-term performance of timber and wood-based structural products under bending. The standard covers determination of the duration of load and creep factors at ambient temperatures for a defined reference population of products - for example solid timber, LVL, OSB, plywood, particleboard and I‑beams. It can be used to (a) derive new duration-of-load and creep factors for a product, (b) confirm whether an existing set of factors applies to a tested product, and (c) optionally assess sensitivity of these factors to environmental changes.
Key technical topics and requirements
- Scope and applicability: Applies to wood‑based products used in structural bending where duration-of-load or creep factors are relevant to design. Notes that elevated temperature effects may require additional consideration.
- Reference population & sampling: Defines how to establish a reference population and prescribes sampling methods, matched groups and sample-size considerations to obtain characteristic values.
- Specimen conditioning: Sets requirements for conditioning specimens prior to testing to ensure representative, repeatable results.
- Bending tests:
- Short‑term tests (for strength/stiffness reference and reference loads).
- Long‑term tests (for sustained bending loads to measure creep and time‑dependent deformation).
- Test configuration details include load location, load configuration and deformation measurement methods.
- Evaluation and outputs:
- Methods to calculate duration of load factor and creep factor from test data.
- Criteria for confirmation testing, acceptance and possible retest options.
- Reporting requirements to document test procedures and results.
- Optional environmental sensitivity tests: Informative annex for testing how changes in humidity/conditions affect duration-of-load and creep behavior.
Practical applications and users
Who benefits from ISO 24322:2024:
- Structural engineers and code authorities needing validated duration and creep factors for design calculations.
- Product manufacturers (LVL, OSB, plywood, particleboard, engineered beams) developing new structural products or demonstrating compliance.
- Testing laboratories and research institutions performing bending and long‑term performance tests.
- Certification bodies and quality assurance teams verifying characteristic values used in standards and design codes.
Typical uses:
- Deriving design values for structural timber products.
- Verifying whether existing design factors apply to a production batch or new product variant.
- Supporting product development, durability assessment and conformity assessment.
Related standards
- ISO 12122-1 (Structural timber - Determination of characteristic values - Part 1: Basic principles) - normative reference used for sampling and characteristic value derivation.
- Prepared by ISO/TC 165 (Timber structures).