ISO 22389-1:2010 - Overview
ISO 22389-1:2010 is the international standard for testing, evaluation and characterization of prefabricated wood‑based I‑beams used as structural members in bending applications. Part 1 defines procedures to establish the structural capacities of I‑beams - including shear, bending moment, stiffness, bearing, and flange tension/compression - and lists test and specimen requirements, materials considerations, and end‑use limitations. The standard applies to I‑beams intended for covered conditions (possible temporary moisture exposure) but not for permanent weather exposure. It does not cover manufacturing requirements, fire performance, formaldehyde or biological durability.
Key topics and technical requirements
- Scope and definitions: Applies to prefabricated wood‑based I‑beams using sawn or structural composite lumber flanges and panel webs bonded with moisture‑resistant structural adhesives.
- Materials: Requirements for flange stock (modulus of elasticity, tension/compression properties), web materials and adhesives (conformance to ISO 20152‑1).
- Product evaluation and testing:
- Minimum sample sizes and specimen preparation (specimens representative of production; tested at ambient lab conditions).
- Test accuracy and apparatus calibration (error not exceeding ±2.0%).
- Load application and rate (uniform rate producing failure in not less than 1 minute) and mandatory safety/lateral restraint measures.
- Characteristic values: Definition of characteristic strength and stiffness (population 5th percentile at 75% confidence for strength; mean for bending stiffness when using the specified test).
- Specific tests and procedures: Detailed methods to determine characteristic shear capacity, bearing capacity, bending capacity, bending stiffness/creep, web opening effects, flange and end joint tension tests. Example requirement: minimum of 10 specimens per web‑factor combination per critical depth; mean shear capacities should show linear increase with depth with an r² ≥ 0.90 for regression analyses.
- Data recording: Ultimate loads, failure modes and detailed test setup must be recorded; certain failure types are excluded from analyses.
Practical applications and users
ISO 22389‑1 is used to:
- Derive design values and characteristic capacities for I‑joists and floor/roof joists.
- Support product evaluation, quality control and conformity assessment for manufacturers and testing laboratories.
- Provide consistent, internationally comparable test results for specifiers, structural engineers, code bodies, product certifiers and importers/exporters.
- Inform manufacturer handbooks and variation grouping decisions for flange/web combinations.
Related standards
- ISO 20152‑1 (bond performance of adhesives)
- EN 789 (mechanical properties of wood‑based panels)
- ASTM D5456 (structural composite lumber evaluation)
- ASTM D2915 (evaluating allowable properties for structural lumber)
Keywords: ISO 22389-1:2010, timber structures, I-beams, bending strength, prefabricated wood-based I-beams, shear capacity, bending stiffness, product evaluation, structural testing.
Open preview (PDF)Timber structures — Bending strength of I-beams — Part 1: Testing, evaluation and characterization
