What Is UV?
UV aging test is performed in which the sample is exposed to radiation produced by fluorescent UV lamps along with defined temperature and condensation/water spray cycles; It is an experiment in which color, brightness and mechanical property changes are monitored.
Purpose of UV
The aim is to comparatively evaluate the degradation of the material under the influence of light and moisture under accelerated conditions.
Which Products Is UV Applied To?
- Outdoor plastic parts
- Paints and coatings
- Textiles and coated fabrics
- Rubber and elastomer profiles
In Which Sectors Is UV Used?
Standards Related to UV
- ISO 4892-3
- ASTM G154fluorescent UV accelerated aging test
- ASTM D4329
- ASTM G151 (genel gereksinimler)
UV Conditions
- Lamp type
- Standard-defined fluorescent UV lamps such as UVA-340 or UVB-313
- Radiation
- Set and monitored in W/m²·nm at defined wavelength
- Cycle
- Alternating periods of light and condensation/water spraying
- Temperature
- Identified and recorded as black panel temperature
Equipment for UV
- Fluorescent UV weathering chamber
- Irradiance measurement and control system
- Siyah panel termometresi
- Colorimeter, gloss meter and tensile device
Sample Requirements for UV
- Sample surface should be representative of the final product
- Initial colour, gloss and mechanical values should be recorded
- Sample position should be rotated within the cabin
- Control samples should be kept for comparison
Duration of UV
2 weeks to several months, depending on the exposure time defined in the specification.
UV Procedure
- 1Initial measurements are taken.
- 2Lamp type, irradiance and cycle are selected.
- 3Specimens are placed in the chamber.
- 4Exposure is maintained for the defined duration.
- 5Interim measurements are taken.
- 6Colour, gloss and mechanical change are evaluated.
UV Acceptance Criteria
Acceptance criteria are given in the specification: color difference, loss of gloss and loss of mechanical properties remain below the limit at the end of defined exposure.
Evaluation of Results
UVB-313 lamps contain short wavelengths not found in natural sunlight and create unrealistic degradation of some materials; Whichever lamp the material standard requires should be used. The number of accelerated hours cannot be converted to years of natural exposure.
UV Report
- Applied standard and lamp type
- Irradiance level and cycle program
- Black panel temperature
- Exposure duration
- Before/after measurements and evaluation
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
- Product standards and OEM specifications
Plastics Testing — What Does This Testing Field Cover?
The section below describes the field that the UV 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.
Plastics testing determines the mechanical, thermal and burning behaviour of a polymer material. Unlike metals, plastics are VISCOELASTIC: their behaviour depends on loading rate, temperature and moisture. The same material therefore gives different results under different conditions, and the test conditions are an inseparable part of the result.
The practical consequence of viscoelasticity is this: a plastic part continues to deform over time under a constant load (creep) and the stress it carries at constant deformation falls over time (stress relaxation). A screwed joint loosens, a clamp loses its clamping force, a shelf sags over time. A short-term tensile test does not show this behaviour; a long-term test or an accelerated model is needed.
Thermal behaviour is the second main axis. Melt flow rate indicates the processability of the material and lot-to-lot consistency; heat deflection temperature and the Vicat softening point give a rough limit for service temperature. Thermal analysis (DSC, TGA, DMA) reveals the identity of the material: glass transition temperature, melting behaviour, crystallinity, filler content and decomposition temperature.
Burning behaviour is the third axis and ties directly into product standards. The UL 94 class and the limiting oxygen index are written into the material data sheet; a particular class is required for the housing of an electrical appliance, while a different classification system applies to a construction product.
Ageing is the most frequently skipped part of the field. Plastics degrade under UV, heat, moisture and oxygen: colour changes, the surface cracks, impact strength falls. For a part intended for outdoor use, what matters is not its values on day one but its values after ageing. Xenon arc and fluorescent UV equipment accelerate this degradation and allow comparison.
The output of this family is usually written into the material data sheet, and product standards refer to that sheet. But there can be a difference between the data sheet value and the behaviour of the actual part: orientation formed during moulding, weld lines and internal stresses make the part behave differently from the specimen.
The use of recycled content has added a new question to the field. Recycled resin varies from lot to lot; mechanical properties, colour and burning behaviour can shift between batches. For a manufacturer using recycled material, incoming material control is therefore not a choice but a necessity.
Method groups in this field
Mechanical
Tension, compression, bending, Charpy and Izod impact, hardness (Shore), creep and environmental stress cracking.
Thermal
Melt flow index (MFI), heat deflection temperature (HDT), Vicat softening temperature, linear thermal expansion.
Thermal analysis
Transition temperatures and crystallinity by DSC, composition and decomposition by TGA, dynamic mechanical behaviour by DMA.
Burning
UL 94 classification, limiting oxygen index (LOI), glow wire and needle flame tests.
Ageing
Accelerated ageing by xenon arc and fluorescent UV, hot air ageing, humidity and condensation.
Physical
Density, water absorption, ash content, gas and water vapour permeability of films and sheets.
Commonly confused in this field
- A plastics result without a stated test rate and temperature cannot be interpreted; viscoelastic behaviour depends on these parameters.
- A specimen result does not transfer directly to the actual part; moulding orientation and weld lines are decisive.
- HDT and Vicat values are NOT service temperatures; they are a rough indication of an upper limit and do not apply under load.
- The UL 94 class depends on thickness; a different wall thickness requires re-verification.
- For moisture-absorbing polymers (such as polyamide), results are misleading unless conditioning is carried out.
- ASTM D638 and ISO 527 results are not directly equivalent; the specimen geometries and rate definitions differ.
Which decisions these results support
- Material selection and supplier approval
- Meeting the flammability and thermal requirements of the product standard
- Verifying the use of recycled content and lot control
- Moulding process control and lot consistency
- Demonstrating ageing resistance for outdoor use
Related Tests
Frequently Asked Questions About UV
How many years of outdoor exposure does 1000 hours of UV correspond to?
Such a cycle cannot be made. Time-lapse UV testing is used to compare materials and capture formulation changes; cannot be converted to natural exposure time.