ISO 2231:1989

Overview

ISO 2231:1989 is an international standard published by the International Organization for Standardization (ISO) that defines standard atmospheres for conditioning and testing rubber- or plastics-coated fabrics. This standard specifies the terminology, requirements, and technical procedures for pre-conditioning and maintaining the test atmospheres essential to obtaining reliable, repeatable results when testing coated textile supports. As a technical revision of the original 1973 edition, ISO 2231:1989 focuses on modernizing the conditioning clauses to reflect advances in testing methodologies.

Proper conditioning of these coated fabrics is critical because their properties-such as moisture content, mass, and mechanical strength-are significantly influenced by atmospheric humidity and temperature. By controlling test atmospheres under defined standard conditions, this ISO standard enables consistency and comparability of test results worldwide.

Key Topics

• Scope and Applicability
  The standard applies to rubber- or plastics-coated textile supports and specifies how to condition samples before testing to ensure consistent moisture equilibrium and temperature control.

• Definitions
  Essential terminology related to atmospheres and conditioning is standardized, including:

  • Atmosphere of reference
  • Normal conditioning atmosphere
  • Conditioned state
  • Hygrometric equilibrium

• Standard Atmospheres
  ISO 2231 defines several standard test atmospheres with specific temperature and relative humidity parameters:

  • Atmosphere A: 20 °C ± 2 °C, 65% ± 5% relative humidity
  • Atmosphere B: 23 °C ± 2 °C, 50% ± 5% relative humidity
  • Atmosphere C (Tropical): 27 °C ± 2 °C, 65% ± 5% relative humidity
  • Atmosphere D: 23 °C ± 2 °C, temperature controlled only, no humidity control
  • Atmosphere E: 27 °C ± 2 °C, temperature controlled only (tropical)

• Preconditioning Methods
  Procedures to achieve moisture equilibrium prior to testing include conditioning samples in controlled atmospheres for specified durations (minimum 16 hours for single-sided coated fabrics, 24 hours for double-sided). Preconditioning may involve exposure to dry atmospheres at elevated temperatures for hygroscopic materials requiring precise control.

• Conditioning Methods
  Conditioning can be achieved through two main methods:

  • Method 1: Exposure to atmospheres A, B, or C until weight equilibrium is reached, verified by successive weighings every 2 hours.
  • Method 2: Exposure to atmospheres D or E for a fixed time of 3 hours.

Applications

ISO 2231:1989 is widely used by manufacturers, testing laboratories, and quality control personnel engaged in the production and certification of rubber- or plastics-coated fabrics. Key practical applications include:

• Quality assurance of coated textiles to ensure batch-to-batch consistency.
• Material research and development, enabling accurate evaluation of physical properties under controlled conditions.
• Performance testing for durability, tensile strength, and dimensional stability influenced by moisture content.
• Standardizing testing procedures to meet international trade and regulatory requirements for coated fabrics in industries such as automotive, aerospace, protective clothing, and industrial liners.

Related Standards

ISO 2231:1989 references and complements other international standards relevant to conditioning and testing atmospheres for materials:

• ISO 554:1976 – Specifies normal atmospheres for conditioning and/or testing including temperature and humidity ranges, serving as a foundational reference for ISO 2231.
• Other ISO/TC 45 standards relating to elastomers and coated textile products that define specific test methods and performance requirements.

Together, these standards create a robust framework enabling manufacturers and testing agencies to reliably compare results and maintain high-quality control levels across global supply chains.

Keywords: ISO 2231, rubber-coated fabrics, plastics-coated fabrics, conditioning atmosphere, test atmosphere, moisture control, textile testing, standard atmosphere, preconditioning methods, coated textile supports, relative humidity, temperature control.