Overview
ISO 4709:2017 defines a classification system for composition cork intended for use as gasket material in the mechanical industry. The standard provides a common language for specifying or describing key physical and mechanical properties of agglomerated cork gaskets (compressibility, oil and water resistance, etc.), together with requirements for sampling, packaging and marking. It is intended to help designers, suppliers and purchasers select materials that meet specified property ranges, but it does not cover every factor affecting gasket performance.
Key Topics and Requirements
- Classification (line call-out): A six-digit code (e.g. ISO 4709 (220304)) where each numeral describes a characteristic:
- 1st numeral = raw material type (for cork products use 2).
- 2nd numeral = agglomerate type (composition cork, cork+elastomer, cork+cellular rubber, etc.).
- 3rd to 6th numerals = key basic characteristics such as compressibility, thickness increase in ASTM IRM 903 oil, mass increase in oil, and mass increase in water (each mapped to defined percentage ranges).
- Supplementary characteristics: Optional suffix symbols (Table 1) for additional properties such as thickness increase ranges (E), tensile strength (M), binder durability (D) and flexibility (F), with referenced test methods.
- Test methods and applicability: Normative and informative references include ISO 4708 and ISO 7322 for test procedures; Annex A lists applicable test methods by cork type.
- Thickness tolerances: Specified tolerances for nominal thicknesses and different cork types (see Table 2).
- Sampling: Test specimen selection and sampling guidance, with reference to ISO 2859-1 sampling schemes.
- Packaging and marking: Requirements for moisture-resistant packaging and mandatory package marking (reference to ISO 4709, product designation, manufacturer identification and source).
Applications and Who Uses It
ISO 4709 is used by:
- Designers and engineers specifying gasket materials for pumps, valves, engines and mechanical equipment.
- Material suppliers to report product properties consistently.
- Purchasing and quality teams for acceptance criteria and inspection.
- Test laboratories conducting the referenced physical and mechanical tests.
Practical uses include material selection and specification during design, procurement of compliant composition cork gaskets, and quality control of incoming gasket materials.
Related Standards
- ISO 4708 - Composition cork - Gasket material - Test methods (referenced for key tests)
- ISO 7322 - Composition cork - Test methods (supplementary tests)
- ISO 633 - Cork - Vocabulary
- ISO 2859-1 - Sampling procedures for inspection by attributes
Keywords: ISO 4709, composition cork, gasket material, classification system, gasket requirements, sampling, packaging, marking, test methods, ISO 4708.