ISO 18543:2021

Overview

ISO 18543:2021 - "Glass in building - Electrochromic glazings - Accelerated ageing test and requirements" specifies an accelerated ageing test and pass/fail requirements for electrically switchable glazing used in buildings. The standard applies to electrochromic glazings assembled as insulating glass units (IGUs), laminated glass, or combinations, made with inorganic or organic electrochromic materials. It is explicitly not applicable to non‑electrically driven chromogenic products (photochromic or thermochromic).

Key topics and technical requirements

• Objective: Evaluate long‑term durability and optical performance after accelerated cycling and simulated solar exposure.
• Test duration: 5 000 hours of exposure in a temperature‑controlled test chamber under simulated solar irradiation.
• Temperature classes:
  • Class 1: specimen temperature (85 ± 7) °C
  • Class 2: specimen temperature (65 ± 7) °C (for products that cannot switch above 65 °C)
• Cycling:
  • Samples are switched repeatedly between high and low transmission states.
  • Switching must reach at least 85% of the dynamic range (difference between highest and lowest transmission).
  • Maximum of 50 000 switching cycles during the exposure period (adaptations allowed if >50 000 would occur).
• Measurements and equipment:
  • Initial and final optical characterisation (visible transmittance, switching times) using a spectrometer (380–780 nm) and temperature‑controlled oven.
  • Test chamber with simulated solar lamps, electrochromic cycling unit, and optional imaging equipment.
• Performance criteria:
  • Limits on changes in visible light transmittance, switching time differences, and other degradation indicators defined in the standard.
• Reporting: Detailed test report and observations required.

Practical applications and users

ISO 18543:2021 is used to:

• Qualify and compare durability of electrochromic glazing products for windows, doors, skylights, curtain walls and other façade elements exposed to solar radiation.
• Support product development and accelerated reliability testing for R&D teams.
• Provide test methods for independent laboratories performing accelerated ageing tests and certification bodies assessing conformity.
• Aid architects, façade engineers, specifiers and building owners to set performance expectations, procurement criteria, and warranty terms.

Typical users: glass manufacturers, façade consultants, test laboratories, building product certifiers and sustainability/energy performance teams.

Related standards

Normative references cited in ISO 18543:2021 include:

• ISO 9050 - Determination of light and solar transmittance and related glazing factors
• ISO 12543 (all parts) - Laminated glass
• ISO 20492 (all parts) - Insulating glass

Keywords: ISO 18543:2021, electrochromic glazings, accelerated ageing test, glass in building, switching cycles, simulated solar radiation, visible transmittance, durability testing.