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IEC 60068-2-78 Humidity TestingIEC 60068-2-78 Damp Heat Steady State Compliance Testing

IEC 60068-2-78 evaluates electrical products or equipment for transportation, storage and use under conditions of high, steady humidity. As a certified environmental lab, we realize the importance of IEC 60068-2-78 humidity testing. Meeting the environmental damp heat requirements can be difficult. We understand the challenges and guide companies through the process. 

Keystone provides the peace of mind that all of your needs will be met under one roof. We have a reputation for helping customers achieve their environmental product certifications. Additionally, our accurate test reports are delivered quickly. When products do not meet the requirements, we assist with the troubleshooting process. 

Request a quote to receive testing services tailored to your specific requirements. Have a question about our 60068-2 compliance testing capabilities? Contact us or call (724) 657-9940 and we will determine the best course of action.

Summary of IEC 60068-2 Humidity Damp Heat Testing

This 60068-2-78 test method evaluates the suitability of electrotechnical products under high humidity conditions. This standard is primarily intended to permit the observation of the effect of high humidity over a long period of time.

The test is applicable to small equipment and components as well as large equipment with complex interconnections. The test can also be carried out for specimen with test equipment external to the chamber, requiring a set-up time that prevents the use of preheating and maintenance of conditions. Furthermore, both heat-dissipating and non-heat dissipating specimens can be tested to IEC 60068-2-78.

Test Procedures of IEC 60068-2-78 Humidity Testing


The unit under test is conditioned and introduced into the chamber at a standard ambient temperature. Next, the unit is unpacked, switched off, and in a ready-for-use state. The temperature is adjusted in the chamber to specific severities. The specimen must be allowed to reach temperature stability.

IEC 60068-2-78 may call for measurements during, or at the end of conditioning while the specimen is still in the chamber. If this is the case, measurements and the time when measurements will occur are specified prior to testing. Operating conditions and the period in which operations will take place must be defined.

The humidity is adjusted within a time of no more than 2 hours. Condensation is avoided by not increasing the absolute humidity. 


The test chamber must be such that:

  • Sensing devices can be located in the working space. This will monitor the temperature and humidity.
  • The temperature and relative humidity in the working space can be maintained at the values and within the specified tolerances.
  • Condensed water is continuously drained from the chamber.
  • No condensed water from the walls and roof of the test chamber can fall on the specimen.

For testing heat-dissipating equipment, the volume of the test chamber must be at least five times the total volume of the unit under test.

The test severity is defined by a combination of temperature, relative humidity, and total test duration. Unless otherwise specified, the standard recommends 85 to 93% relative humidity and temperatures of 30 to 40 C.


A passing or failing grade is determined by a visual, electrical, and mechanical inspection. Once the test has concluded, a report of the following information will be documented.

  • Specific mounting structures
  • Test severities and tolerances
  • Initial measurements
  • Conditioning
  • Intermediate measurements
  • Recovery Conditions
  • Final measurements

Expert IEC 60068-2-78 Steady State Humidity Compliance Testing

Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling. In addition to IEC humidity testing, Keystone has a full scope of expertise including vibration, fungus, and IP code. Our team strives to give our customers more time and energy on product development instead of testing.

Ready to get started? We are. Request a quote to see why so many companies work with us to achieve their environmental humidity compliance testing needs.