ISO 23999:2025

Overview

ISO 23999:2025 - "Resilient floor coverings - Determination of dimensional stability and curling (vertical deformation) after exposure to heat" specifies standardized test methods to assess how resilient flooring (sheets, tiles, panels, planks or rolls) reacts to heat. The standard defines procedures for measuring dimensional stability (linear change) and curling (vertical deformation) after heat exposure and optional reconditioning. It replaces the 2021 edition and includes clarified measurement approaches and new informative annexes for result calculation.

Key technical topics and requirements

• Scope and test principle
  • Measures dimensional change and vertical deformation of resilient floor coverings after heat exposure and reconditioning.
  • Tests use three specimens measured before and after treatment.
• Specimen types
  • Applicable to sheets, rolls, tiles, panels and planks; preparation steps differ by form.
• Apparatus and oven requirements
  • Thermostatically controlled, ventilated oven with uniform temperature ±2 °C.
  • Specimens must be positioned so heating elements do not radiate directly; support plates must sit >50 mm from oven walls and >100 mm from ceiling/base.
• Support plates
  • Metal plates (e.g., aluminium or stainless steel), thickness 2.0 mm ±0.5 mm, smooth and flat.
• Measurement devices and resolution
  • Curling (vertical deformation): devices with minimum resolution ±0.1 mm (laser, optical, tactile gauges).
  • Linear dimensional change: devices with minimum resolution ±0.02 mm (optical bench, callipers, block and dial gauge setups).
  • Includes guidance on scoring marks, rigid steel plate use, and the “block and dial gauge apparatus” for tiles/planks.
• Terminology
  • Defines machine direction (MD) and across machine direction (AMD); MD/AMD can be assigned arbitrarily when unknown.
  • Curling conventions: concave (outer-edge uplift = positive) and convex (centre dome = negative).
• Procedure
  • Initial measurement → heat exposure → reconditioning (if applicable) → final measurement.
  • Annex A and B provide measurement and calculation guidance.

Practical applications and who uses it

ISO 23999:2025 is used by:

• Flooring manufacturers for product development and quality control.
• Independent testing laboratories to provide consistent test data.
• Specifiers, architects, and procurement teams assessing material suitability for heated environments (e.g., commercial fit-outs, underfloor heating situations).
• Installers and compliance officers verifying product claims and conformity to performance requirements.

Benefits include reproducible test results, improved product specification, and reduced installation failures related to thermal distortion.

Related standards and context

• Prepared by ISO/TC 219 (Floor coverings) in collaboration with CEN/TC 134.
• Includes informative Annex A (measurement of dimensional change due to heat) and Annex B (calculation and expression of results).

Keywords: ISO 23999:2025, resilient floor coverings, dimensional stability, curling, vertical deformation, heat exposure, oven requirements, block and dial gauge, optical bench, flooring test methods.