ISO 2551:2020

Overview

ISO 2551:2020 specifies a standardized procedure for determining dimensional changes and distortion out of plane that can occur when textile floor coverings and textile floor coverings in tile form are exposed to varied water and heat conditions. The method applies to all textile floor coverings and tile formats and is intended to provide reproducible data for quality control, compliance assessment and product development.

Key elements of the standard include sampling and specimen preparation, conditioning in a normal test atmosphere, defined heat and water exposures, and precise measurement of planar dimension changes and vertical distortion.

Key Topics

• Scope and applicability: Test method applies to all textile floor coverings and tiles (ISO 2551:2020).
• Sampling: Follow ISO 1957 for selection and sampling of specimens. Minimum: three specimens for each test series.
  • For broadloom coverings: at least three specimens of minimum size 250 mm × 250 mm.
  • For tiles ≤ 500 mm: use at least three tiles as delivered; tiles > 500 mm must be cut to specimens ≤ 500 mm × 500 mm.
• Conditioning: Condition specimens in the normal textile atmosphere per ISO 139 for at least 48 h or until mass is constant.
• Apparatus and accuracy:
  • Planar dimension measurements with instruments accurate to 0.05 mm (e.g., calipers, optical table).
  • Vertical (out-of-plane) measurements with accuracy to 0.5 mm.
  • Support plates, rigid plates and reference points as described to ensure flatness and repeatability.
• Test sequence:
  • Drying in a ventilated oven at 60 °C ± 2 °C for 2 h (and a separate 24 h exposure where required).
  • Immersion in water at 20 °C ± 2 °C for 2 h, with careful blotting before measurement.
  • Reconditioning in the normal atmosphere for 48 h (or until mass constant) and final measurements.
• Results expression: Planar stability is given as the percentage change to 0.1% using the standard percentage formula; results indicate elongation (+) or shrinkage (−). Out-of-plane distortion is reported as the maximum vertical deviation measured after conditioning.

Applications

• Quality control and batch verification for manufacturers and suppliers.
• Product development to compare constructions, backing systems and yarn/treatment effects on stability.
• Installation guidance and dimensional tolerances for specifiers and installers.
• Complaint investigation where dimensional change or edge curl is alleged.

Related Standards

• ISO 139 - Textile conditioning and test atmospheres (referenced for specimen conditioning).
• ISO 1957 - Machine-made textile floor coverings: selection and sampling of specimens (referenced for sampling).
• Developed by ISO/TC 219 (Floor coverings).

This standard provides a practical, repeatable test protocol for measuring dimensional stability and distortion of textile floor coverings and tiles under controlled heat and wetting cycles, supporting conformity assessment and informed product decisions.