ISO 23999:2021

Overview

ISO 23999:2021 specifies a laboratory test method for assessing dimensional stability and curling of resilient floor coverings (sheets, tiles, planks) after exposure to heat. The method measures linear changes and vertical deformation following a defined heat treatment, enabling manufacturers, test laboratories and specifiers to quantify how products respond to thermal stress.

Key topics and technical requirements

• Scope and principle: Measure relative change in distances or specific locations on a specimen before and after heat exposure; measure vertical deformation (curling) post‑heat.
• Heat exposure: Oven specified to be thermostatically controlled and ventilated, normally at 80 °C ± 2 °C (or other declared setting), with prevention of direct radiant heating.
• Specimen preparation:
  • Sheets: cut three nominal 240 mm square specimens, parallel/transverse to manufacture direction.
  • Tiles/planks: select three specimens from spread-out samples; ensure adequate width for micrometer measurement on planks.
• Apparatus:
  • Support plates (metal, ≥1.5 mm thick), flat and polished.
  • Measuring devices: optical bench (non-contact) or block-and-dial-gauge assembly; required range ≥200 mm and precision typically ±0.02 mm (optical); alternative systems accurate to at least 0.1 mm.
  • Micrometer pillar‑mounted drop gauge, rigid steel plate templates (e.g., 240 mm × 240 mm), square templates (e.g., 610, 508, 305, 229 mm), calibrated shim/spacer blocks and scoring device.
• Test sequence: conditioning → initial measurements (linear and curling) → heat exposure → reconditioning → final measurements.
• Results and reporting: Express curling and dimensional stability as calculated changes; includes procedures for domed material or negative curling (invert specimen and mark accordingly).

Applications and who uses it

• Manufacturers: product development, quality control and conformity assessment for resilient flooring.
• Independent testing laboratories: standardized evaluation for compliance claims and performance comparisons.
• Architects and specifiers: verify thermal performance for installations in heat-prone environments (e.g., sunlit rooms, heated flooring).
• Regulators and procurement: include test criteria in technical specifications and acceptance testing.

Related standards and context

• Prepared by ISO/TC 219 (Floor coverings) in collaboration with CEN/TC 134.
• This third edition (2021) replaces ISO 23999:2018 and includes updated calculation methods and Annex A improvements.

Keywords: ISO 23999:2021, resilient floor coverings, dimensional stability, curling, tiles, planks, sheets, heat exposure, flooring test method, oven 80 °C, block and dial gauge, optical bench.