IEC 60068-2-78:2012

Overview

IEC 60068-2-78:2012 is an internationally recognized standard developed by the International Electrotechnical Commission (IEC) that specifies a test method for evaluating the resistance of electronic components and equipment to damp heat under steady-state conditions. This standard is essential for assessing product durability when exposed to high humidity environments at constant temperatures without condensation, simulating real-world transportation, storage, and operational conditions.

The standard applies to a wide range of specimens, including small components as well as large equipment, and is suitable for both heat-dissipating and non-heat-dissipating specimens. By replicating sustained high humidity exposure, IEC 60068-2-78 helps manufacturers and test laboratories ensure product reliability and longevity, minimizing failures related to moisture ingress.

Key Topics

• Test Scope
  The test examines how specimens withstand high humidity conditions at a steady temperature, preventing condensation-related damage. It focuses on moisture absorption and diffusion effects over a defined period.

• Test Conditions
  The standard defines severity levels by temperature, relative humidity (RH), and duration. Typical temperature and RH combinations include:

  • 30 ± 2 °C at 85% or 93% RH
  • 40 ± 2 °C at 85% or 93% RH

  Test durations vary from 12 hours to up to 56 days, depending on product specifications.

• Test Chamber Requirements
  The humidity and temperature chamber must conform to IEC 60068-3-6, featuring:

  • Accurate and localized temperature and humidity sensors
  • Prevention of condensation directly on specimens
  • Controlled purity of humidifying water (conductivity ≤ 20 µS/cm)
  • Suitable volume to allow uniform environmental conditions
  • Avoidance of radiant heat exposure to specimens

• Test Procedure

  1. Pre-conditioning specimens if required
  2. Introducing specimens into the chamber in their operating or specified state
  3. Gradually adjusting moisture levels without condensation
  4. Maintaining exposure for the specified duration
  5. Post-test recovery phase before final measurements

• Measurements and Reporting
  The standard mandates initial, optional intermediate, and final evaluations including visual, electrical, and mechanical checks. Test reports must comprehensively document test parameters, environment, specimen details, and results to ensure traceability and reproducibility.

Applications

IEC 60068-2-78:2012 is widely used across industries where electronics and electrical equipment face humid environments, such as:

• Consumer Electronics
  Ensuring reliability for devices exposed to humid climates or storage conditions.

• Automotive and Transportation
  Testing components for moisture resistance during transit and operation.

• Industrial Equipment
  Evaluation of machinery and control units operating in moisture-prone environments.

• Telecommunications
  Qualification of outdoor or sealed equipment to withstand humidity stress.

• Medical Devices
  Verifying device durability under controlled environmental stresses.

This standard supports quality assurance, product development, and compliance with environmental robustness requirements, thereby reducing warranty claims and enhancing customer satisfaction.

Related Standards

• IEC 60068-1: Environmental testing – General and guidance for preparing environmental tests including damp heat tests.
• IEC 60068-3-6: Environmental testing – Guidelines for performance confirmation of temperature and humidity test chambers.
• IEC Guide 104: Preparation of safety publications, including basic safety standards applicable to environmental testing.
• Other IEC 60068 series parts: Covering various environmental tests like vibration, temperature cycling, and cold testing.

Incorporating IEC 60068-2-78 within a comprehensive environmental testing program ensures robust performance verification of electrical and electronic components under humidity stress, integral to meeting international quality and safety standards.