Overview
ISO 18402:2016 - Timber structures - Structural insulated panel roof construction - Test methods specifies laboratory test methods to determine the structural properties of double‑sided load‑bearing structural insulated panels (SIPs) intended for roof use. The standard applies to SIPs with two face layers (at least one wood‑based structural panel) and a thermally insulating core with sufficient shear strength to make the faces act together structurally. ISO 18402 focuses on mechanical performance tests relevant to roof panels rather than factory quality control or conformity assessment.
Key topics and requirements
- Scope and definitions
- Applies to double‑skin SIPs (including slabstock and box‑type with internal framing) used as roof elements.
- Defines terms such as structural insulated panel, bonded, slabstock and core types.
- Conditioning
- Standard conditioning: 65 ± 5% RH and 20 ± 2 °C until constant mass (stabilized moisture content).
- Allows alternative and elevated temperature conditioning (example: 80 °C for some tests).
- Primary test methods
- Tensile test of core and bond - specimen size typically 150 mm × 150 mm; assesses tensile strength of core and adhesion between core and faces.
- Shear test on panel assembly - typical specimen 1 000 mm × 150 mm; measures core shear strength and bond under short‑term loading.
- Out‑of‑plane bending - stiffness and strength tests for uniform, concentrated and combined loads to evaluate roof bending performance.
- In‑plane diaphragm (racking) tests - monotonic racking stiffness and strength for horizontal load resistance.
- Creep testing - long‑term deflection under sustained loads.
- Accelerated ageing / durability testing - assesses long‑term performance (references ASTM methods where applicable).
- Reporting requirements
- Sampling, specimen dimensions, conditioning, test setup, failure modes, measured strengths and mean results must be documented.
Applications and users
ISO 18402 is practical for:
- SIP manufacturers developing and validating roof panel products.
- Independent test laboratories performing structural characterization of SIP roofs.
- Structural and façade engineers who need test‑based data for design or performance verification.
- Building authorities, specifiers and certifiers assessing safety, durability and performance claims for SIP roof systems.
- R&D and material suppliers evaluating adhesive systems, core materials and face panel assemblies.
Typical applications include roof design validation, comparative product evaluation, durability studies and providing input data for structural calculations and design codes.
Related standards
ISO 18402 references and aligns with other standards for SIPs and structural testing, including:
- ISO 22452 (SIP walls - test methods)
- ISO 21581 (shearwalls testing)
- ISO 16670 (mechanical fastener joint testing)
- EN 594, EN 14509 and ASTM standards such as ASTM C480, ASTM D7446, ASTM E72 and ASTM E1803.
Keywords: ISO 18402:2016, structural insulated panels, SIP roof test methods, timber structures, shear test, tensile test, out‑of‑plane bending, creep testing, SIP durability.