IEC 60068-2-38: Environmental Testing – Part 2-38: Tests – Test Z/AD: Composite Temperature/Humidity Cyclic Test

Overview and Purpose

IEC 60068-2-38 is part of the IEC 60068 series that outlines environmental testing methods for electronic and electrical equipment. This specific part, Test Z/AD, focuses on composite temperature/humidity cyclic tests. It is designed to subject test specimens to cyclic changes in temperature and humidity to simulate the conditions that products might encounter in natural environments. The purpose of this test is to evaluate the ability of components and equipment to withstand composite climatic stresses, which can reveal weaknesses in materials, mechanical structures, and electronic circuits.

How the Test is Conducted

1. Preparation: The specimens are prepared according to the standard’s guidelines, ensuring they are in the appropriate state for testing. This may involve setting them to a specific operational mode or condition.
2. Cyclic Exposure: The test involves exposing the specimen to a series of temperature and humidity cycles. These cycles typically include phases of high temperature with high humidity, followed by a transition to low temperature with low humidity, and vice versa. The specific conditions and duration of each phase are defined by the test parameters.
3. Controlled Environment: The testing is conducted in an environmental chamber capable of accurately controlling temperature and humidity levels. The chamber must also be able to transition between the specified conditions within the time frames outlined in the standard.
4. Monitoring and Evaluation: Throughout the test, the environmental conditions are monitored to ensure compliance with the specified parameters. After the test, the specimen is evaluated for any signs of physical, mechanical, or electrical degradation. This evaluation may include visual inspections, functional testing, and measurements of electrical properties.

Purpose of the Test

• Durability and Reliability Testing: To assess the durability and reliability of electronic components and equipment under fluctuating climatic conditions.
• Design Improvement: Identifies potential design or material weaknesses when exposed to composite temperature and humidity stresses, allowing for necessary design improvements.
• Quality Assurance: Serves as a critical component of the quality assurance process, ensuring products can withstand environmental stresses encountered during shipping, storage, and operation.
• Product Lifespan Estimation: Provides valuable data for estimating the product’s lifespan under varying environmental conditions, aiding in warranty and maintenance planning.