IEC 60068-2-78: Environmental Testing – Part 2-78: Tests – Test Cab: Damp Heat, Steady State

Overview and Purpose

IEC 60068-2-78 is a part of the IEC 60068 environmental testing series, which focuses on the exposure of electronic equipment to steady-state damp heat conditions. This standard is designed to assess the ability of components, equipment, or other items to withstand high humidity combined with elevated temperatures over extended periods. The test aims to simulate conditions that might be encountered in tropical climates or other high-humidity environments, evaluating the effects on the specimen’s physical and chemical stability, as well as its mechanical functionality.

How the Test is Conducted

1. Preparation: Specimens are prepared according to their operational instructions, ensuring they are in the appropriate state for testing. This might involve setting them to a specific operational mode or condition.
2. Exposure to Damp Heat: The specimen is placed in a controlled environment chamber where it is exposed to a constant high level of humidity (up to 95% relative humidity) and temperature (typically between 40°C and 55°C). These conditions are maintained continuously throughout the duration of the test.
3. Duration: The exposure period is determined based on the product’s intended operational environment and the specific objectives of the test. It can range from several days to several weeks, depending on the standard’s requirements and the manufacturer’s specifications.
4. Monitoring and Evaluation: The environmental conditions within the chamber are closely monitored to ensure they remain within the specified parameters. After the exposure period, the specimen is evaluated for any signs of moisture-related damage or degradation in performance, including corrosion, insulation breakdown, or mechanical failures.

Purpose of the Standard

• Moisture and Heat Resistance: Evaluates the specimen’s resistance to prolonged exposure to high humidity and temperature, crucial for ensuring reliability in high-humidity environments.
• Durability Assessment: Helps in assessing the durability of components and equipment under steady-state damp heat conditions, which can accelerate aging and reveal potential failures.
• Design Improvement: Provides feedback for improving product designs to enhance resistance to moisture and temperature, ensuring long-term reliability.
• Quality Assurance: Forms an essential part of quality assurance processes, ensuring that products meet international standards for operation in varying environmental conditions.