UV Aging Test — ISO 4892-3 / ASTM G154 / ASTM D4329

What Is UV Aging?

The UV ageing test is one in which the sample is aged under fluorescent UV lamps together with humidity and temperature cycles. It is applied under ISO 4892-3 and ASTM G154 using UVA-340 or UVB-313 lamps.

Purpose of UV Aging

The purpose is to determine, in accelerated form, colour change, gloss loss, cracking and loss of mechanical properties in materials and coatings used outdoors.

Which Products Is UV Aging Applied To?

Paint and varnish systems
Plastic exterior parts
Automotive exterior trim
Building profiles and membranes
Textiles and coated fabrics

In Which Sectors Is UV Aging Used?

ElectronicsElectricalAutomotiveDefenceAerospace

Standards Related to UV Aging

ISO 4892-3
ASTM G154fluorescent UV accelerated aging test
ASTM D4329
ISO 16474-3

UV Aging Conditions

Lamp type: UVA-340 (representing solar UV) or UVB-313 (more aggressive)
Radiation: Irradiance intensity defined in the standard (e.g. 0.76 W/m²/nm at 340 nm)
Cycle: Defined duration of light and condensation/dark phases
Panel temperature: Black panel temperature in the light phase is defined in the standard

Equipment for UV Aging

Fluorescent UV ageing chamber
Irradiance and temperature control system
Colour and gloss meter
Calibrated radiometer

Sample Requirements for UV Aging

The sample must be cut to panel size
Initial colour, gloss and mechanical values must be measured
A reference sample must be kept (for comparison)
Generally at least three specimens

Duration of UV Aging

Applied in stages such as 250, 500, 1000 or 2000 hours depending on the specification.

UV Aging Procedure

1Initial colour, gloss and, if required, mechanical measurements are taken.
2Lamp type, irradiance and cycle programme are set.
3Samples are placed on the panels.
4Cycles are run for the defined duration; lamp positions are rotated per the standard.
5Interim measurements are taken at defined intervals.
6At the end of the exposure, colour difference, gloss loss and surface condition are assessed.

UV Aging Acceptance Criteria

The acceptance criterion is given in the specification as maximum colour difference (ΔE), maximum gloss-loss percentage, or absence of cracking/chalking.

Evaluation of Results

Colour difference and gloss loss are assessed numerically, and surface degradation by visual grading. Fluorescent UV results are not directly comparable with xenon arc.

UV Aging Report

Applied standard and lamp type
Irradiance, cycle programme and panel temperature
Total exposure duration
Colour difference and gloss loss values
Visual assessment 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 authorisations

Related Regulations

Paint, plastics and construction material specifications

Environmental and Climatic Testing — What Does This Testing Field Cover?

The section below describes the field that the UV Aging 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 UV Aging

How is a choice made between UVA-340 and UVB-313?

UVA-340 represents the short-wavelength UV region of sunlight well and is preferred for correlation. UVB-313 is more aggressive and is used for fast screening, but it can produce unrealistic degradation mechanisms.