Humidity and Heat Resistance Testing Service

Humidity and Heat Resistance Testing Service – Accredited ISO/IEC 17025 Environmental Durability and Reliability Assessment for the Croatian Market

Humidity and heat resistance testing is a critical environmental evaluation method used to assess the ability of materials, components, and systems to withstand the combined effects of elevated temperature, high humidity, condensation, and thermal cycling. These environmental stresses are among the most common causes of degradation in electronic devices, automotive components, medical equipment, building materials, packaging, and industrial products, leading to corrosion, delamination, loss of adhesion, electrical failure, dimensional changes, and premature aging. In the Croatian market, where the Hrvatski zavod za norme (HZN), the Ministarstvo gospodarstva i održivog razvoja, the Državni inspektorat, the Ministarstvo graditeljstva i prostornoga uređenja, and the Carinska uprava enforce strict quality, safety, and environmental standards aligned with EU directives and HRN EN (Croatian standards based on European norms), the accurate evaluation of humidity and heat resistance is essential for product certification, supplier qualification, type testing, quality control in manufacturing, and import‑export processes. Our laboratory offers a comprehensive humidity and heat resistance testing service, applying standardized methods such as IEC 60068‑2‑78 (Damp heat, steady state), IEC 60068‑2‑30 (Damp heat, cyclic), ASTM D2247, ISO 6270‑2, HRN EN 60068‑2‑78, and HRN EN 60068‑2‑30 to simulate real‑world tropical, coastal, and industrial environments and to evaluate the performance of products under controlled temperature and humidity conditions. All tests are performed under our ISO/IEC 17025 (CNAS) accreditation, and the resulting reports are fully accepted by Croatian authorities and notified bodies, making them indispensable for regulatory compliance, product validation, and market access in Croatia and the European Union.

Test Samples and Materials We Regularly Examine

Our laboratory receives a wide variety of materials, components, and products for humidity and heat resistance testing. Typical samples include:

• Electronic components and assemblies – PCBs, connectors, sensors, displays, and electronic modules for automotive, industrial, and consumer applications.
• Automotive and transportation components – interior trim, lighting systems, sensors, control units, and wiring harnesses.
• Building and construction materials – insulation materials, sealants, adhesives, wall coverings, floorings, and roofing membranes.
• Coatings and paints – organic coatings, powder coatings, and surface treatments for corrosion protection.
• Medical devices and pharmaceutical packaging – drug‑delivery devices, diagnostic equipment, and packaging materials that must maintain sterility and integrity.
• Consumer goods and appliances – household appliances, power tools, and electronics that may be exposed to humid conditions.
• Packaging materials – flexible packaging, rigid containers, and barrier films for food and pharmaceutical products.
• Prototype and new material formulations – submitted by manufacturers for validation of humidity and heat resistance before series production.
• Field‑retrieved components – for failure analysis and remaining life assessment.

Damp Heat Test – Steady State (IEC 60068‑2‑78) – Evaluating Resistance to Continuous High Humidity

The steady‑state damp heat test exposes the test specimen to a constant elevated temperature and high humidity (typically 40 °C, 93 % RH) for a specified duration (e.g., 48, 96, 240, or 500 hours). This test simulates the conditions of tropical and highly humid environments and is used to evaluate the resistance of materials to moisture absorption, corrosion, and degradation of electrical and mechanical properties.

• Damp heat test – steady state (IEC 60068‑2‑78 / HRN EN 60068‑2‑78 / NTC 5600 – for electronic and electrical components) – we place the test specimen in a temperature‑ and humidity‑controlled chamber and maintain the conditions at 40 °C and 93 % RH for the specified duration (e.g., 48, 96, 240, or 500 hours). After the exposure, the specimen is removed and inspected for visible damage, corrosion, blistering, and loss of adhesion. The electrical performance (e.g., insulation resistance, dielectric strength) is measured before and after the test. We report the test conditions, the duration, the visual condition, and the electrical performance (pass/fail).
• Damp heat test for coatings and paints (ASTM D2247 / NTC 5601 – for the corrosion protection evaluation) – we expose coated panels to a condensing humidity environment (40 °C, 100 % RH) for a specified duration (e.g., 240, 500, or 1000 hours). The panels are inspected for blistering (ASTM D714), corrosion (ASTM D610), and loss of adhesion (ASTM D3359). We report the blistering rating, the corrosion rating, and the adhesion rating.
• Damp heat test for packaging materials (ASTM D4332 / NTC 5602 – for the moisture resistance of packaging) – we expose packaging materials and sealed packages to 40 °C and 90 % RH for a specified duration (e.g., 7 days). The packages are inspected for seal integrity, delamination, and the condition of the contents. We report the condition of the packaging and the contents.
• Damp heat test for medical devices (NTC 5603 – for the device stability and sterility) – we expose medical devices and their packaging to 40 °C and 75 % RH for a specified duration (e.g., 30 days) and then verify the device's functionality, the sterility, and the packaging integrity. We report the functional test results and the sterility status.
• Damp heat test at different temperature‑humidity combinations (NTC 5604 – for the performance mapping) – we expose the specimens to different temperature‑humidity combinations (e.g., 30 °C/80 % RH, 40 °C/93 % RH, 55 °C/95 % RH) to evaluate the material's response to different environmental severity levels. We report the performance at each condition.

Damp Heat Test – Cyclic (IEC 60068‑2‑30) – Evaluating Resistance to Condensation and Temperature Cycling

The cyclic damp heat test subjects the specimen to repeated cycles of high humidity and temperature variation, typically with a 24‑hour cycle that includes a period of high humidity and condensation, followed by a period of drying and lower temperature. This test is more severe than the steady‑state test and better simulates the conditions of real‑world use, where condensation and temperature changes occur daily.

• Cyclic damp heat test (IEC 60068‑2‑30 / HRN EN 60068‑2‑30 / NTC 5610 – for the condensation and cycling effects) – we place the test specimen in a temperature‑ and humidity‑controlled chamber and subject it to a cyclic profile: typically, the temperature is raised to 55 °C at 95 % RH, held for 12 hours, then reduced to 25 °C at 95 % RH, and held for 12 hours. The number of cycles is typically 6, 12, or 24 cycles (corresponding to 6, 12, or 24 days). The specimen is inspected for corrosion, blistering, and electrical failure after the cycles. We report the number of cycles, the visual condition, and the electrical performance (pass/fail).
• Cyclic damp heat test with functional monitoring (NTC 5611 – for the in‑situ performance evaluation) – during the cyclic damp heat test, we monitor the electrical performance of the specimen (e.g., the resistance, the insulation, and the signal integrity) in real time. The test is stopped if a functional failure occurs. We report the time to failure (in cycles) and the failure mode.
• Cyclic damp heat test with condensation measurement (NTC 5612 – for the water film formation) – we place a condensation sensor (or a test plate) next to the specimen to monitor the formation of a water film on the surface. The presence and the duration of the condensation are recorded. We report the condensation pattern and the effect on the specimen.
• Cyclic damp heat test for automotive components (ISO 16750‑4 / NTC 5613 – for the climate‑chamber testing) – we perform the cyclic damp heat test according to the automotive standard (e.g., ISO 16750‑4) which uses a temperature‑humidity profile that simulates the conditions in the passenger compartment and the engine compartment. We report the performance and the compliance with the automotive standard.
• Cyclic damp heat test with electrical load (NTC 5614 – for the combined environmental and electrical stress) – we apply an electrical load (e.g., a supply voltage or a signal) to the specimen during the cyclic damp heat test, to simulate the real‑world operating conditions. The test is used to detect any failure due to the combined stress. We report the performance and the failure mode.

Heat Resistance and Thermal Aging Testing – Evaluating the Performance at Elevated Temperatures

Heat resistance and thermal aging tests evaluate the ability of materials and components to withstand prolonged exposure to elevated temperatures without significant degradation of their mechanical, electrical, or physical properties. These tests are essential for products that are used in hot environments, such as engine compartments, industrial ovens, and solar energy systems.

• Heat resistance test (ASTM D573 / ISO 188 / NTC 5620 – for the thermal stability) – we place the test specimen in an oven at a specified temperature (e.g., 70 °C, 85 °C, 100 °C, 125 °C, 150 °C) for a specified duration (e.g., 7, 14, 28, or 56 days). After the exposure, we measure the changes in the mechanical properties (tensile strength, elongation, hardness), the electrical properties (insulation resistance, dielectric strength), and the dimensions. We report the property retention and the visual condition.
• Thermal aging test (NTC 5621 – for the accelerated aging of polymers) – we age the material at a temperature above the service temperature to accelerate the degradation process. The aging is performed for multiple durations (e.g., 100, 500, 1000, 2000 hours) to construct the degradation curve. The service life is predicted using the Arrhenius model. We report the property retention and the predicted service life.
• Heat resistance test with thermal cycling (NTC 5622 – for the thermal fatigue evaluation) – we subject the specimen to repeated thermal cycles (e.g., from -20 °C to +80 °C, or from 20 °C to +100 °C) with a specified dwell time at each temperature, and for a specified number of cycles (e.g., 100 cycles). The specimen is inspected for cracking, delamination, and loss of properties. We report the number of cycles and the condition of the specimen.
• Heat resistance test for electronic components (JEDEC JESD22‑A108 / NTC 5623 – for the high‑temperature operating life) – we operate the electronic component (e.g., an IC or a transistor) at its maximum operating temperature and voltage for a specified duration (e.g., 1000 hours). The electrical parameters (e.g., the leakage current, the gain, the threshold voltage) are measured at intervals. We report the parameter drift and the pass/fail status.
• Heat resistance test for coatings and paints (ASTM D2485 / NTC 5624 – for the thermal stability of coatings) – we expose coated panels to elevated temperatures (e.g., 100 °C, 150 °C, 200 °C) for a specified duration (e.g., 100 hours). The coatings are inspected for discoloration, cracking, and loss of adhesion. We report the condition of the coating and the adhesion rating.

Combined Humidity and Heat Testing – Simulating Tropical and Coastal Environments

In many real‑world applications, materials and components are exposed to a combination of high humidity and high temperature simultaneously, which can cause synergistic degradation effects (e.g., corrosion accelerated by temperature, or polymer degradation accelerated by moisture). Our combined humidity and heat tests simulate these conditions, providing a more realistic assessment of the product's performance in the diverse Croatian climate (coastal, continental, and mountainous).

• Combined temperature‑humidity test (NTC 5630 – for the tropical climate simulation) – we expose the specimen to a combined stress of high temperature (e.g., 60 °C) and high humidity (e.g., 90 % RH) for a specified duration (e.g., 500 hours). The specimen is inspected for degradation. We report the combined‑stress performance and the degradation mode.
• Combined temperature‑humidity with salt spray (NTC 5631 – for the coastal and marine environment) – we subject the specimen to a cyclic test that includes salt spray (ASTM B117), high humidity (40 °C, 95 % RH), and elevated temperature (60 °C). This test simulates the conditions of the Adriatic coastal region of Croatia. We report the corrosion rating and the condition of the specimen.
• Combined temperature‑humidity with UV exposure (NTC 5632 – for the outdoor application) – we expose the specimen to a combined cycle of UV radiation (ASTM G154), humidity (40 °C, 95 % RH), and temperature (60 °C) to simulate the outdoor environment. This test is used for materials that are exposed to sunlight, such as roofing, cladding, and outdoor furniture. We report the UV resistance, the humidity resistance, and the combined‑stress performance.
• Combined temperature‑humidity with electrical load (NTC 5633 – for the operational reliability) – we apply an electrical load to the specimen during the combined temperature‑humidity test, to simulate the real‑world operating conditions. The test is used to detect any failure due to the combined environmental and electrical stress. We report the performance and the failure mode.
• Combined temperature‑humidity with mechanical stress (NTC 5634 – for the stress‑corrosion evaluation) – we apply a mechanical stress (e.g., a tensile or a bending load) to the specimen during the temperature‑humidity test, to evaluate the susceptibility to stress corrosion cracking (SCC) and environmentally assisted cracking. We report the time to failure and the failure mode.

Performance Monitoring and Failure Analysis – Evaluating the Degradation Mechanisms

To fully understand the degradation mechanisms and to identify the root cause of any failure, we perform a comprehensive performance monitoring and failure analysis during and after the humidity and heat resistance tests. These analyses are essential for design improvement and for certification by the HZN and other Croatian authorities.

• Continuous electrical monitoring (NTC 5640 – for the detection of electrical failures) – we continuously monitor the electrical parameters (e.g., the resistance, the insulation resistance, the leakage current, and the capacitance) of the test specimen during the humidity and heat tests. An abrupt change in the electrical parameters indicates a failure (e.g., a short circuit, a corrosion‑induced open circuit, or a change in the dielectric properties). We report the electrical parameter evolution and the time of failure.
• Periodic functional verification (NTC 5641 – for the functional integrity check) – at regular intervals during the test, we remove the specimen from the chamber and perform a full functional verification (e.g., a performance test, a calibration check, or a safety test). The functional test results are compared with the pre‑test results. We report the functional degradation and the pass/fail status.
• Visual and microscopic inspection (NTC 5642 – for the detection of surface damage) – we inspect the specimen surface for signs of corrosion, blistering, cracking, or delamination using an optical microscope and a scanning electron microscope (SEM). The nature and the extent of the damage are recorded. We report the visual condition and the SEM images.
• Cross‑section analysis (NTC 5643 – for the depth of degradation) – we prepare a cross‑section of the specimen (or the component) and examine it under an optical microscope or a SEM to measure the depth of the corrosion, the diffusion of moisture, or the thickness of the degraded layer. The depth of degradation is reported.
• Chemical analysis of the degradation products (FTIR, XRF – NTC 5644 – for the identification of the corrosion products) – we use Fourier‑transform infrared spectroscopy (FTIR) and X‑ray fluorescence (XRF) to identify the chemical composition of the corrosion products, the degradation products, and the migrated species. The identification helps to understand the degradation mechanism. We report the chemical composition and the degradation mechanism.

Compliance with Environmental and Product Standards – Pass/Fail Criteria

The measured humidity and heat resistance performance is compared with the requirements of the relevant product standards and the environmental specifications to determine the conformity of the product. Our tests provide a clear pass/fail result and a statement of compliance with the applicable standards, including the HRN EN standards and the EU directives.

• Compliance with IEC 60068‑2‑78 (NTC 5650 – for the steady‑state damp heat test) – we compare the electrical and mechanical performance of the specimen after the test with the acceptance criteria specified in the product standard (or the client's specification). The acceptance criteria typically include a minimum insulation resistance, a maximum leakage current, and the absence of visible damage. We report the compliance and the pass/fail status.
• Compliance with IEC 60068‑2‑30 (NTC 5651 – for the cyclic damp heat test) – we compare the specimen's performance after the cyclic test with the acceptance criteria (e.g., the absence of corrosion, the absence of delamination, and the retention of electrical performance). We report the compliance and the pass/fail status.
• Compliance with automotive standards (ISO 16750‑4 / NTC 5652 – for the climate testing) – we perform the humidity and heat tests according to the automotive environmental standard ISO 16750‑4, and we compare the results with the specified requirements. We report the compliance and the pass/fail status.
• Guarantee verification (NTC 5653 – for the contractual purposes) – we test the product to verify that its humidity and heat resistance is within the guaranteed values specified in the purchase order or the design specification. We report the measured performance and the margin relative to the guarantee.
• Environmental compliance for the Croatian market (NTC 5654 – for the EU and Croatian regulations) – we verify that the product meets the environmental durability requirements of the Croatian regulations (based on the HRN EN standards) and the EU directives. The statement of compliance is included in the test report. We report the compliance and the applicable regulations.

Complementary Tests – Material Characterization and Physical Property Evaluation

To provide a comprehensive assessment of the humidity and heat resistance and to correlate it with the material properties, we perform complementary tests, including material characterization and physical property evaluation.

• Water absorption measurement (ASTM D570 / NTC 5660 – for the moisture uptake) – we measure the water absorption (in %) of the material after the humidity exposure, by weighing the specimen before and after the exposure. The water absorption is correlated with the degradation. We report the water absorption and the effect on the properties.
• Dimensional stability measurement (NTC 5661 – for the expansion and contraction) – we measure the dimensions (the length, the width, and the thickness) of the specimen before and after the humidity and heat exposure. The change in the dimensions (in %) is reported. We report the dimensional change and the effect on the fit.
• Adhesion measurement (ASTM D3359 / NTC 5662 – for the coating adhesion) – we measure the adhesion of the coating (or the paint) after the humidity exposure, using the cross‑cut test or the pull‑off test. The adhesion rating is reported. We report the adhesion rating and the loss of adhesion.
• Hardness measurement (ASTM D2240 / NTC 5663 – for the material softening) – we measure the hardness (Shore A, Shore D, or Rockwell) of the specimen before and after the humidity and heat exposure. A decrease in the hardness indicates a softening of the material. We report the hardness change and the softening effect.
• Microstructural examination (ASTM E3 / NTC 5664 – for the changes in the microstructure) – we examine the microstructure of the material (the grain size, the phase distribution, and the presence of voids) using optical microscopy and SEM, before and after the test. The microstructural changes are correlated with the degradation. We report the microstructural changes and the degradation mechanism.

Test Report and Recognition in the Croatian Industrial, Automotive, and Construction Sector

All procedures described are within the scope of our ISO/IEC 17025 accreditation, with equipment calibrated periodically (temperature‑humidity chambers, data loggers, microscopes, and testing machines) and traceability to international standards (NIST, PTB). Our test reports are issued in English (with a Croatian summary available on request) and include:

• Full identification of the test item (product name, model, serial number, material, and intended application).
• Detailed description of the test methods applied (IEC/ISO/ASTM/HRN EN/NTC standards, test conditions, temperature, humidity, and duration).
• Numerical results: insulation resistance (MΩ), leakage current (mA), water absorption (%), dimensional change (%), hardness (Shore/HRC), and adhesion rating (5B to 0B).
• Graphical data: temperature‑humidity vs. time profiles, electrical parameter vs. time curves, and degradation vs. time curves.
• Comparative tables against the values specified by the client or against the limits of the relevant standards (IEC 60068‑2‑78, IEC 60068‑2‑30, ISO 16750‑4, HRN EN 60068‑2‑78, and the requirements of the HZN, Ministarstvo graditeljstva, and Državni inspektorat).
• Photographs and micrographs (SEM) of the test item before and after the test, showing the corrosion, the blistering, the cracking, or the delamination.
• Recommendations for material selection, design improvement, and quality control measures to enhance the humidity and heat resistance.
• Expanded uncertainty (k=2) for all key measurements, calculated according to the ISO/IEC 98‑3 Guide.

These reports are fully accepted by the Hrvatski zavod za norme (HZN) for the verification of product conformity, by the Ministarstvo gospodarstva i održivog razvoja for industrial and energy compliance, by the Državni inspektorat for market surveillance, by the Ministarstvo graditeljstva i prostornoga uređenja for building materials approval, and by the Carinska uprava (Croatian Customs) for tariff classification and quality verification in the import of materials and components. Additionally, we offer consulting services for the selection of materials with high humidity and heat resistance, the design of environmentally robust products, and the implementation of quality control programs for environmental durability, contributing to the reliability, safety, and longevity of products in the diverse and growing Croatian market, from the coastal and maritime industries to the continental manufacturing and construction sectors.