Why Temperature and Humidity Testing Matters
Most product failures don't happen on the factory floor—they surface weeks or months later in the field.
Prolonged exposure to heat, cold, and moisture can gradually weaken materials, accelerate component aging, and create failure mechanisms that are difficult to detect during routine inspections. Connector corrosion, battery degradation, plastic deformation, seal leakage, and adhesive breakdown are just a few examples of issues triggered by environmental stress.
For manufacturers of electronics, automotive components, batteries, and medical devices, identifying these risks before products reach customers is a critical part of product qualification.
This is where IEC 60068 becomes important.
Widely adopted around the world, IEC 60068 provides a standardized framework for evaluating how products respond to environmental conditions they may encounter during transportation, storage, and normal operation.
By uncovering hidden weaknesses early in the development cycle, manufacturers can reduce warranty costs, improve reliability, and strengthen customer confidence.
What Is IEC 60068?
IEC 60068 is a comprehensive series of environmental testing standards developed by the International Electrotechnical Commission (IEC).
Rather than defining a single test, the standard provides a collection of procedures designed to simulate environmental stresses products experience throughout their lifecycle.
The IEC 60068 series covers:
- Low-temperature exposure
- High-temperature exposure
- Humidity and moisture resistance
- Thermal shock
- Vibration and mechanical shock
- Corrosion and salt spray
- Combined environmental stresses
For temperature and humidity evaluation, several sections of the standard are commonly referenced by manufacturers and testing laboratories.
The Most Common IEC 60068 Temperature and Humidity Tests
IEC 60068-2-1: Cold Test
The Cold Test evaluates product performance and material integrity under low-temperature storage or operating conditions.
Testing may be performed on both non-operating specimens and powered equipment depending on the product's intended use.
Typical Test Temperatures:
- -20°C
- -40°C
- -55°C
- -70°C
Common Applications:
- Automotive electronics
- Outdoor communication equipment
- Battery systems
- Industrial control devices
Key Risks Identified:
- Material embrittlement
- Seal failure
- LCD display abnormalities
- Cold-start failures
IEC 60068-2-2: Dry Heat Test
The Dry Heat Test assesses how products perform when exposed to elevated temperatures for extended periods.
Typical Test Temperatures:
- +70°C
- +85°C
- +105°C
- +125°C
Common Applications:
- Industrial electronics
- Power supplies
- Automotive components
- Electronic assemblies
Key Risks Identified:
- Accelerated aging
- Thermal runaway
- Plastic deformation
- Electrical performance drift
IEC 60068-2-30: Damp Heat Cyclic Test
Real-world environments rarely maintain constant humidity levels.
The Damp Heat Cyclic Test simulates changing temperature and humidity conditions that force moisture to repeatedly condense and evaporate inside the equipment under test.
This process helps reveal weaknesses that may not appear under stable laboratory conditions.
Typical Conditions:
- Cyclic temperature changes between 25°C and 55°C (or 65°C)
- Relative humidity above 90%
Key Risks Identified:
- Moisture ingress
- Insulation degradation
- Micro-cracking
- Condensation-related failures
IEC 60068-2-78: Damp Heat Steady-State Test
Unlike cyclic testing, IEC 60068-2-78 exposes products to constant temperature and humidity throughout the test period.
One of the most common test conditions is:
- 40°C
- 93% RH
Exposure durations may range from 48 hours to several weeks depending on product requirements.
Common Applications:
- PCB assemblies
- Connectors
- Sensors
- Electronic control modules
Key Risks Identified:
- Moisture absorption
- Corrosion
- Material degradation
- Electrical leakage
Example: Why a Product Passes Functional Testing but Fails Humidity Testing
A common example involves PCB assemblies used in outdoor communication equipment.
During factory inspection, the product may pass all electrical and functional tests without issue. However, after several days of exposure to 40°C and 93% relative humidity, moisture can penetrate microscopic gaps in protective coatings and accumulate around conductive traces.
This can trigger electrochemical migration, creating conductive paths between circuits that were originally isolated.
The result is often intermittent failures that are difficult to reproduce under normal conditions but become obvious during environmental testing.
This is one reason why humidity testing remains a critical part of product reliability validation.
Common Failure Modes Found During Environmental Testing
Environmental testing frequently reveals hidden weaknesses before products enter mass production.
- PCB Corrosion and Dendrite Growth
High humidity can initiate electrochemical migration between conductive paths, increasing the risk of short circuits and signal instability.
- Connector Oxidation
Moisture exposure may degrade contact surfaces, resulting in intermittent communication failures or increased contact resistance.
- Battery Performance Degradation
Elevated temperatures accelerate chemical aging, while extremely low temperatures can reduce discharge efficiency and available capacity.
- Adhesive and Seal Failure
Repeated thermal expansion and contraction can weaken seals, gaskets, and adhesives, leading to water ingress and reduced product protection.
- Display and Optical Defects
LCD panels, touchscreens, and optical assemblies may experience fogging, delamination, or image quality issues after prolonged environmental exposure.
Typical Environmental Test Conditions Used in Laboratories
| Test Type | Typical Conditions | Typical Duration |
|---|---|---|
| Cold Test (IEC 60068-2-1) | -40°C | 16h / 72h / 96h |
| Dry Heat Test (IEC 60068-2-2) | +85°C | 16h / 72h / 96h |
| Damp Heat Steady-State (IEC 60068-2-78) | 40°C / 93% RH | 48h / 96h / 21 Days |
| Accelerated Reliability Verification | 85°C / 85% RH | 500h / 1000h |
| Automotive Climate Validation | -40°C to +125°C | Profile Dependent |
The selected conditions should always reflect the product's intended operating environment and applicable industry requirements.
Choosing the Right Chamber for IEC 60068 Testing
Selecting the correct test chamber is just as important as selecting the appropriate test method.
Constant Temperature and Humidity Chambers
These chambers are commonly used for steady-state humidity testing such as IEC 60068-2-78.
They provide stable temperature and humidity control throughout long-duration exposure tests.
High and Low Temperature Chambers
Designed for temperature-only testing, these chambers are commonly used for IEC 60068-2-1 and IEC 60068-2-2 applications.
They allow engineers to evaluate product performance under controlled hot and cold conditions.
Thermal Shock Chambers
Thermal shock chambers expose products to rapid transitions between extreme temperatures.
These systems are widely used to evaluate structural integrity and electrical reliability under sudden temperature changes.
Industries That Rely on IEC 60068 Compliance
- Consumer Electronics
Smartphones, tablets, wearables, and IoT devices are routinely subjected to environmental testing before commercial release.
- Battery Manufacturing
Battery cells, battery modules, and energy storage systems are frequently evaluated under temperature and humidity stress conditions.
Battery manufacturers often combine environmental testing with dedicated safety validation programs to assess long-term reliability.
- Automotive Electronics
Electronic control units (ECUs), sensors, connectors, and ADAS components must withstand demanding environmental conditions throughout their service life.
- Industrial Equipment
Industrial control systems and automation equipment often operate in harsh environments where environmental durability is critical.
- Medical Devices
Environmental testing helps ensure consistent performance and reliability throughout storage and operational lifecycles.
FAQ
- What is the core purpose of IEC 60068?
IEC 60068 provides standardized and repeatable environmental testing procedures used to evaluate how products respond to temperature, humidity, vibration, shock, corrosion, and other environmental stresses.
- Is IEC 60068 compliance mandatory?
While IEC 60068 itself is not always a legal requirement, many industries, procurement specifications, and certification programs reference IEC 60068 test methods as part of product qualification requirements.
- What is the difference between IEC 60068-2-30 and IEC 60068-2-78?
IEC 60068-2-30 is a cyclic humidity test that creates condensation through temperature variation. IEC 60068-2-78 maintains constant temperature and humidity conditions throughout the test period.
- Should the specimen be powered during testing?
It depends on the specific test objective and applicable standard. Certain IEC 60068 procedures include requirements for evaluating heat-dissipating equipment while operating under full electrical load.
- What chamber is required for IEC 60068 humidity testing?
Most humidity testing applications require a constant temperature and humidity chamber capable of accurately controlling both temperature and relative humidity throughout the test period.
Final Thoughts
Environmental stress remains one of the leading causes of long-term product failure.
By understanding how IEC 60068 temperature and humidity testing works, manufacturers can identify design weaknesses earlier, improve product reliability, and reduce the risk of costly field failures after products reach the market.
Whether validating consumer electronics, battery systems, automotive components, medical devices, or industrial equipment, selecting the right test method and chamber configuration is essential for building an effective reliability testing program.
Need assistance selecting an environmental chamber for IEC 60068 testing?
Contact the ITM-LAB engineering team for application support, chamber recommendations, and customized testing solutions.
