Overview
ISO 1209-1:2007 defines a basic bending test for assessing the flexural behaviour of rigid cellular plastics under three-point bending. The standard describes a simple method to determine either the load at a specified deflection (20 mm) or the breaking load for small rectangular specimens. It is intended for rigid cellular plastics of 20 mm thickness or greater and is not suitable for materials that show significant crushing. This method does not produce pure bending and therefore does not permit calculation of flexural strength or apparent flexural modulus - see ISO 1209-2 for those parameters.
Key Topics and Requirements
- Test principle: three-point bending with a loading edge applied midway between two support edges; record force at 20 mm deflection or at break.
- Specimen dimensions: rectangular parallelepiped - length 120 ±1.2 mm, width 25 ±0.25 mm, thickness 20 ±0.20 mm.
- Support and loading edges: cylindrical edges with radius (15 ±1) mm; span between supports = (100 ±1) mm.
- Loading rate: moveable head speed (10 ±2) mm/min.
- Number of specimens: minimum of five per sample; additional sets if anisotropy or single-skin specimens are relevant.
- Conditioning: specimens conditioned for at least 6 hours at test conditions; normal test conditions cited (e.g., 23 ±2 °C, 50 ±10 % RH) and alternative temperatures noted.
- Applicability limits: not for materials showing significant crushing; numerical comparisons valid only for materials of similar properties and dimensions.
- Precision: interlaboratory results indicate ~5% repeatability and ~15% reproducibility (95% confidence).
- Test report: must include reference to ISO 1209-1, material ID, presence of skins, conditioning and test conditions, orientation, individual results, mean and standard deviation, deviations from the method, and date.
Applications and Users
Who uses ISO 1209-1:2007:
- Materials testing laboratories performing routine quality checks on rigid cellular plastics.
- Manufacturers of foam boards, insulation, structural core materials and related rigid cellular plastic products for production control.
- R&D teams evaluating bending behaviour during product development (initial screening).
- Specifiers and procurement professionals requiring standardized measurement of load-deflection behaviour for comparative assessment.
- Regulatory and certification bodies verifying compliance with product performance requirements.
Practical uses:
- Screening foam formulations and process variants for bending resistance.
- Quality control sampling to detect batch-to-batch variation in flexural behaviour.
- Comparative testing when full flexural modulus/strength measurement (ISO 1209-2) is not required.
Related Standards
- ISO 1209-2 - Determination of flexural strength and apparent flexural modulus (for full flexural properties).
- ISO 1923 - Determination of linear dimensions (referenced for specimen measurement).
Keywords: ISO 1209-1:2007, rigid cellular plastics, flexural properties, three-point bending, basic bending test, test specimens, loading rate, support edges, flexural strength, apparent flexural modulus.
Open preview (PDF)Rigid cellular plastics — Determination of flexural properties — Part 1: Basic bending test