What Is Solar Radiation?
The solar radiation test is one in which the sample is exposed to simulated sunlight at a defined irradiance to assess surface heating and material degradation. It is defined as method Sa in IEC 60068-2-5.
Purpose of Solar Radiation
The purpose is to determine the temperature the product reaches in direct sunlight and its effect on function, and to assess photochemical degradation.
Which Products Is Solar Radiation Applied To?
- Outdoor electronic enclosures
- Automotive dashboard and trim parts
- Military field equipment
- Lighting fixtures
In Which Sectors Is Solar Radiation Used?
Standards Related to Solar Radiation
- IEC 60068-2-5series of environmental testing methods test
- MIL-STD-810 Method 505
- RTCA DO-160 Section 4
Solar Radiation Conditions
- Irradiance
- Defined in the standard; Typically 1120 W/m² in MIL-STD-810
- Cycle
- 24-hour cycle of light and dark phases
- Ambient temperature
- Defined in the specification
- Spektrum
- Lamp arrangement approximating the solar spectrum
Equipment for Solar Radiation
- Solar simulation chamber or lamp array
- Calibrated radiometer
- Multi-channel temperature recording
- Function-monitoring rig
Sample Requirements for Solar Radiation
- The sample must be placed in its actual use orientation
- Thermocouples must be connected for surface and internal temperatures
- Function must be checked before the test
- Colour and surface condition must be recorded
Duration of Solar Radiation
Depends on the number of cycles defined in the specification; typically 3 – 10 days.
Solar Radiation Procedure
- 1The sample is placed and thermocouples connected.
- 2Irradiance level is verified with a radiometer.
- 3The cycle programme is run.
- 4Surface and internal temperatures are continuously logged.
- 5Function is monitored and a visual assessment is made at the end.
Solar Radiation Acceptance Criteria
The acceptance criterion is defined in the specification: internal temperature not exceeding the limit, continuity of function, and no surface deformation/colour change.
Evaluation of Results
The maximum internal temperature reached is compared against design limits. A separate UV or xenon test may be needed for photochemical degradation.
Solar Radiation Report
- Standard applied
- Irradiance level, spectrum and cycle programme
- Measured surface and internal temperatures
- Functional status and visual assessment
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
- Defence and aviation equipment specifications
Environmental and Climatic Testing — What Does This Testing Field Cover?
The section below describes the field that the Solar Radiation 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 Solar Radiation
According to which standard is Solar Radiation made?
Solar Radiation is executed in scope IEC 60068-2-5, MIL-STD-810 Method 505 and RTCA DO-160 Section 4. 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 Solar Radiation apply to?
Mainly applied to Outdoor electronic enclosures, Automotive dashboard and trim parts, Military field equipment and Lighting fixtures. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Solar Radiation done?
The determining parameters are: Irradiance — Defined in the standard; Typically 1120 W/m² in MIL-STD-810, Cycle — 24-hour cycle of light and dark phases and Ambient temperature — Defined in the specification. 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 Solar Radiation?
The sample must be placed in its actual use orientation, Thermocouples must be connected for surface and internal temperatures and Function must be checked before the test. The number of samples is determined according to the product standard and the scope to be reported.
How long does Solar Radiation take?
Depends on the number of cycles defined in the specification; typically 3 – 10 days. 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 Solar Radiation result called "appropriate"?
The acceptance criterion is defined in the specification: internal temperature not exceeding the limit, continuity of function, and no surface deformation/colour change.