ISO 1421:2016

Overview

ISO 1421:2016 specifies standardized laboratory methods to determine the tensile strength and elongation at break of rubber‑ or plastics‑coated fabrics. It defines two test procedures - the strip test (Method 1) for tensile strength and elongation at break, and the grab test (Method 2) for tensile strength only. Both methods apply to conditioned test pieces and to wet test pieces, and both require a constant rate of extension (CRE) tensile‑testing machine.

Key Topics and Requirements

• Test methods
  • Method 1 - Strip test: measures maximum force, elongation at maximum force and, if required, force and elongation at break.
  • Method 2 - Grab test: measures maximum force (tensile strength) only.
• Apparatus
  • Use a CRE tensile‑testing machine capable of recording force and extension with specified accuracy (machine performance per ISO 7500‑1).
  • Force measurement error: ±1 %; jaw separation error: ±1 mm (as specified).
  • Jaw geometry: strip test jaws not less than specimen width (preferably ≥ 60 mm); grab test jaws include a 25 mm × 25 mm clamping area (±0.5 mm).
  • Optional extensometer for strain measurements; capstan or self‑locking jaws recommended when slippage or jaw breaks are a concern.
• Specimen preparation and conditioning
  • Test pieces cut longitudinally and transversely; minimum sample counts specified (e.g., five per direction).
  • Conditioning in standard atmospheres referenced to ISO 2231:1989 (e.g., recommended exposure times: 16 h for one‑side coated, 24 h for both‑sides coated).
  • Procedures for testing wet specimens, including immersion and use of distilled/deionized water and surfactant.
• Timing
  • Minimum time between manufacture and testing: 16 h; standard limits for comparability and product testing are specified.

Applications and Who Uses It

ISO 1421:2016 is used by:

• Manufacturers of rubber‑ or plastics‑coated fabrics for quality control, batch verification and product development.
• Third‑party testing laboratories and certification bodies to demonstrate compliance with client specifications.
• Specifiers, procurement teams and regulatory bodies that require reproducible mechanical property data for safety, durability and material selection.
• R&D teams assessing coating formulations, substrate compatibility and end‑use performance.

Practical benefits include consistent tensile data for design decisions, reliable comparison between materials and vendors, and defensible test reports for contractual and regulatory purposes.

Related Standards

• ISO 2231:1989 - Standard atmospheres for conditioning and testing
• ISO 7500‑1 - Calibration and verification of tension/compression testing machines
• ISO 2286‑2 - Determination of mass per unit area for coated fabrics

Keywords: ISO 1421:2016, tensile strength, elongation at break, rubber‑coated fabrics, plastics‑coated fabrics, strip test, grab test, CRE tensile‑testing machine, standard atmospheres.