Overview
IEC 60068-2-14:2023 - Environmental testing - Part 2-14: Tests - Test N: Change of temperature - is the seventh edition (2023) of the international standard that specifies methods to evaluate the effects of ambient temperature changes on specimens. This technical revision updates figures, specimen temperatures, severities and temperature tolerances, and revises standardized test-report requirements for Tests Na and Nb. The standard defines test procedures for rapid and controlled temperature changes to assess thermal robustness and reliability.
Key Topics and Requirements
- Test types: Defines three change-of-temperature methods commonly referenced as Test Na (rapid change with prescribed transfer time), Test Nb (specified rate of change) and Test Nc (two-fluid-bath method).
- Test parameters: Specifies how to select high and low conditioning temperatures, exposure times, rate of change (dT/dt), number of cycles, and transfer time (t) to represent field conditions.
- Severities and tolerances: Provides updated severities and temperature tolerances, and includes Annex C with exemplary tolerance tables for preferred temperature and rate combinations.
- Test equipment and setup: Describes thermal cabinet arrangements (one- or two-chamber methods), mounting/supporting of specimens, and precautions for condensation and thermal gradients.
- Preconditioning and recovery: Specifies preconditioning, recovery intervals, and criteria for initial and final measurements.
- Reporting requirements: Revised standardized requirements for test reports for Tests Na and Nb - detailing the information to be recorded and reported for reproducibility and compliance.
- Informative guidance: Annex A (consequences of improper severities) and Annex B (thermal responsiveness of materials and geometries) aid test selection and interpretation.
Applications
IEC 60068-2-14 is used to evaluate how temperature transients and cycling affect:
- Electronic assemblies, PCBs and components
- Automotive and aerospace systems exposed to rapid temperature changes
- Telecommunications and outdoor equipment subject to diurnal cycles
- Industrial controls, consumer electronics and medical devices for reliability and lifetime prediction
Use this standard to perform temperature cycling, thermal shock, and environmental qualification tests that simulate real-world temperature changes and validate product robustness.
Who should use this standard
- Test engineers and thermal laboratories implementing environmental testing
- R&D and reliability teams designing for thermal stress
- Quality assurance and compliance officers preparing test reports
- Certification bodies and manufacturers seeking consistent, repeatable temperature-change testing
Related standards
Keywords: IEC 60068-2-14, change of temperature test, environmental testing, thermal cycling, Test Na, Test Nb, Test Nc, temperature tolerances, thermal shock, specimen.
