Overview
ISO 5979:1982 specifies the flat loop method for characterizing the flexibility of some rubber- or plastics-coated fabrics. The standard defines how to form a flat loop from a rectangular test strip, measure the loop height, and interpret flexibility (loop height is inversely related to flexibility: lower height = greater flexibility). It is not applicable to coated fabrics that roll or spiral when cut to small pieces or to materials too rigid to form a loop.
Key topics and requirements
- Scope: Applies to many rubber or plastics coated fabrics as delivered or after specified treatments; excludes fabrics that roll up or are too rigid to loop.
- Test pieces: Rectangular strips, 600 mm × 100 mm. Use three pieces cut in the longitudinal direction and three in the transverse direction.
- Sampling: Test pieces must be taken at least 100 mm from coated-part edges and not less than 1 000 mm from the ends; avoid folds or defects.
- Apparatus: A flat rectangular board with a perpendicular shoulder, a steel bar (200 mm long, square section 20 mm side), and a rule graduated in millimetres. The board surface is powdered (zinc stearate or French chalk) to prevent sticking.
- Conditioning: Condition test pieces for at least 24 hours in atmosphere A as defined in ISO 2231; avoid deformation during conditioning.
- Procedure: Form a loop by superposing ends against the shoulder, place the steel bar on the overlapped ends and hold for 5 minutes, then measure the maximum heights of the two loop edges relative to the board.
- Expression of results: Record individual measurements, calculate arithmetic means (six values per direction), and report test conditions.
- Timing: Minimum 16 hours between manufacture and testing; guidance on maximum intervals for non-product and product tests (e.g., non-product: up to 4 weeks; product tests ideally within 3 months).
Applications and users
ISO 5979:1982 is useful for:
- Quality control in coated fabrics manufacturing (rubber or plastic coatings)
- Incoming inspection and batch acceptance by buyers and converters
- R&D and material comparison when assessing flexibility after treatments
- Textile and materials testing laboratories preparing conformity reports
Typical users include coated-fabric manufacturers, product designers, procurement teams, and independent testing labs.
Related standards
- ISO 2231 - Fabric coated with rubber or plastics: standard atmospheres for conditioning and testing (referenced for conditioning requirements)
Keywords: ISO 5979:1982, flat loop method, coated fabrics testing, flexibility test, rubber coated fabric, plastics coated fabric, loop height measurement, textile testing.