IEC 60216-1:2025

Overview

IEC 60216-1:2025 - "Electrical insulating materials - Thermal endurance properties - Part 1: Ageing procedures and evaluation of test results" specifies general ageing conditions and evaluation procedures for deriving thermal endurance characteristics of materials. Originally developed for electrical insulating materials and simple combinations, the procedures are widely used for materials not intended as electrical insulation. The standard assumes an Arrhenius-type relationship (log(time) versus 1/absolute temperature) and requires that no first-order thermal transition occurs in the tested temperature range. This part also gives guidance for using the more detailed instructions in other parts of the IEC 60216 series.

Key topics and requirements

• Ageing procedures and data evaluation: Defines experimental procedures, specimen preparation, exposure temperatures/times, ovens, environmental conditions and methods for establishing initial property values and times-to-endpoint.
• Arrhenius assumption: Assumes a practically linear relationship between log(time) and reciprocal absolute temperature for valid TI (Temperature Index) determination.
• Temperature Index (TI): Updated definition in the 2025 edition; TI remains a single-point characteristic (commonly the temperature in °C at which a selected property reaches a specified end-point at a reference time, e.g., 20 000 h).
• Selection of materials: New requirements for selecting related materials (for example, different colours) to ensure representative test data (clause 5.1.2).
• Thickness sensitivity test: A new test procedure for thickness dependence has been added (clauses 5.5 and 6.6).
• Data analysis and statistics: Methods for numerical analysis, regression, handling censored/incomplete data, dispersion/non-linearity assessment and generation of the thermal endurance graph/TEP.
• Documentation: Specifies required content for test reports and acceptance criteria for data validity (statistical tests and data requirements).

Applications and users

IEC 60216-1:2025 is used for:

• Accelerated ageing and thermal endurance assessment of polymers, varnishes, tapes and other insulating materials.
• Establishing Temperature Index (TI) and Thermal Endurance Profiles (TEP) for material selection and lifetime prediction.
• Material qualification in electrical equipment design, insulation system development, component selection and reliability testing. Primary users:
• Materials scientists and polymer engineers
• Test and certification laboratories
• Product designers and reliability engineers in electrical and electronic industries
• Standards and compliance officers

Related standards

• IEC 60216 series (other parts provide detailed test methods)
• IEC 60493-1:2011 (statistical methods referenced for confidence limits and data handling)

Keywords: IEC 60216-1:2025, thermal endurance, electrical insulating materials, ageing procedures, Temperature Index, TI, Arrhenius, thickness sensitivity, accelerated ageing, thermal endurance profile (TEP).