What Is Damp Heat?
The damp heat test is an accelerated ageing test in which the sample is held for an extended period at high temperature and high relative humidity. It is a standard durability test for electronic and photovoltaic modules.
Purpose of Damp Heat
The purpose is to reveal, in accelerated form, the corrosion, delamination and insulation degradation caused jointly by moisture and heat.
Which Products Is Damp Heat Applied To?
- Photovoltaic modules
- Electronic boards and components
- LED lighting modules
- Battery systems
- Adhesive and lamination joints
In Which Sectors Is Damp Heat Used?
Standards Related to Damp Heat
- IEC 60068-2-78constant moist heat test test
- IEC 60068-2-67series of environmental testing methods test
- IEC 61215
- JEDEC JESD22-A101
Damp Heat Conditions
- Temperature
- Common condition is 85 °C; varies depending on product standard
- Relative humidity
- Common condition 85%
- Time
- Fotovoltaikte 1000 saat; elektronikte 500 veya 1000 saat
- Gerilim
- In some specifications, voltage is applied during the test (biased damp heat).
Equipment for Damp Heat
- High-temperature-humidity chamber
- Humidity and temperature logging
- Voltage supply setup
- Insulation and function measurement instruments
Sample Requirements for Damp Heat
- The sample must be in its typical use configuration
- Initial performance and insulation measurements must be taken
- If voltage is to be applied, the connection setup must be prepared
- The number of specimens is defined in the product standard
Duration of Damp Heat
Typically 500 or 1000 hours; approximately three to six weeks.
Damp Heat Procedure
- 1Initial measurements (performance, insulation) are taken.
- 2The sample is placed in the chamber; voltage is applied if required.
- 3Temperature and humidity are brought to their target values.
- 4The conditions are maintained for the defined duration.
- 5The sample is removed and measurements repeated after stabilisation.
- 6Delamination and corrosion are assessed by visual inspection.
Damp Heat Acceptance Criteria
The acceptance criterion is defined in the product standard. In photovoltaics, the typical criterion is that the drop in power output does not exceed a defined percentage and insulation resistance meets the limit.
Evaluation of Results
Percentage performance loss and visual degradation are assessed together. Electrochemical migration is also examined in tests with voltage applied.
Damp Heat Report
- Standard applied
- Temperature, humidity, duration and voltage condition
- Initial and final performance values
- Insulation-resistance results
- Visual inspection and photographs
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Photovoltaic module standards
- Electronic component specifications
Environmental and Climatic Testing — What Does This Testing Field Cover?
The section below describes the field that the Damp Heat test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Environmental testing shows whether a product withstands ambient factors such as temperature, humidity, pressure, solar radiation, dust, water and corrosive atmospheres. The aim is not to break the product but to bring forward, in ACCELERATED form, the conditions it will meet over its life.
Test profiles are derived from the product's real exposure, and that derivation is the actual engineering work of the field. A device operating in an enclosed office and one mounted on a pole are not tested with the same profile. The IEC 60068 series defines general methods, MIL-STD-810 military profiles, RTCA DO-160 aviation profiles and the ISO 16750 series location-based automotive profiles. A test applied without a profile selection produces both unnecessary cost and false confidence.
Temperature tests simulate three separate phenomena and all three produce different failure modes. Steady high/low temperature tests whether the material can operate at that temperature. Temperature CYCLING creates fatigue at joints between materials with different expansion coefficients — solder cracks appear here. Thermal SHOCK intensifies this effect through an abrupt transition.
There is a distinction in humidity testing too. Steady damp heat shows the diffusion of moisture into the material and its effect on insulation properties. Cyclic damp heat creates condensation: water droplets form on the cooling surface, and this is far more aggressive than dry humidity. Water ingress into enclosures, increased leakage current and corrosion usually appear in the cyclic test.
Dust and water protection is a separate body of work and is expressed by the IP code. The point to note here is that an IP test is not a DURABILITY test: it shows that protection is provided under defined and short-duration conditions, not resistance to long-term immersion or pressure washing.
The most common mistake in this family is translating a test result directly into a LIFE PREDICTION. Accelerated tests are designed for comparison and design verification; a reliable conversion between hours in a chamber and years in the field can only be established with a material-specific acceleration model calibrated against field data.
Functional monitoring determines the value of the test. Keeping a product in a temperature chamber and then switching it on does not show what happened DURING the test. In critical applications the product is operated throughout the test and its parameters are monitored; intermittent faults that appear and disappear can only be caught this way.
Method groups in this field
Temperature
Dry heat, cold, change of temperature and thermal shock; steady and cyclic profiles.
Humidity
Steady damp heat and cyclic damp heat; cycles with condensation are more aggressive.
Water and dust
IP protection tests: dripping, spraying, jets, immersion and dust tightness.
Radiation and ageing
Accelerated ageing by xenon arc and fluorescent UV, solar radiation simulation.
Pressure and altitude
Low pressure (altitude) and rapid pressure change tests.
Corrosive atmosphere
Salt spray, mixed flowing gas corrosion (simulating industrial atmospheres), mould and fungus tests.
Commonly confused in this field
- Test duration cannot be converted into field life; a conversion made without an acceleration model is misleading.
- Temperature cycling and steady temperature produce different failure modes; neither replaces the other.
- If the product is not operated during the test, intermittent faults remain invisible; functional monitoring determines the value of the test.
- IP protection is not evidence of durability; it shows protection under defined and short-duration conditions.
- A test applied without profile selection both increases cost and gives false confidence.
- The mounting and orientation arrangement affects the result; the report must document it.
Which decisions these results support
- Design verification and qualification
- Declaration of the protection class and operating temperature range
- Reproducing field failures in the laboratory and root cause analysis
- Supplier component approval
- Decisions on warranty period and storage conditions
Related Tests
Frequently Asked Questions About Damp Heat
According to which standard is Damp Heat made?
Damp Heat is executed in scope IEC 60068-2-78, IEC 60068-2-67, IEC 61215 and JEDEC JESD22-A101. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Damp Heat apply to?
Mainly applied to Photovoltaic modules, Electronic boards and components, LED lighting modules, Battery systems and Adhesive and lamination joints. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Damp Heat done?
The determining parameters are: Temperature — Common condition is 85 °C; varies depending on product standard, Relative humidity — Common condition 85% and Time — Fotovoltaikte 1000 saat; elektronikte 500 veya 1000 saat. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Damp Heat?
The sample must be in its typical use configuration, Initial performance and insulation measurements must be taken and If voltage is to be applied, the connection setup must be prepared. The number of samples is determined according to the product standard and the scope to be reported.
How long does Damp Heat take?
Typically 500 or 1000 hours; approximately three to six weeks. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Damp Heat result called "appropriate"?
The acceptance criterion is defined in the product standard. In photovoltaics, the typical criterion is that the drop in power output does not exceed a defined percentage and insulation resistance meets the limit.