- HOME
- Contact
- Members
- Library
- Library Overview
- Library Catalogue Search
- List of Journals
- Paint Titles (Alerting)
- Patent Searching Service
- World Surface Coatings Abstracts (WSCA)
- Hygienic Coatings Special Interest Group
- Conference Proceedings
- Books from PRA and Other Publishers
- Directory of Paint Manufacturers in Central & Eastern Europe
- PRA Select
- Publications
- Consultancy
- Business Consultancy
- Market Research
- Technical Consultancy
- Irfab Multi-client Studies
- Environmental Monitoring
- Patent Searching
- Research Overview
- Research Consultancy
- A Smarter Way to Develop Products & Processes
- Research Projects - Future
- Research Projects - Current
- Research Projects - Completed
- Research Projects - Reports & Updates
- Laboratory
- Events
- Training
Artificial Weathering using a Xenon Arc Source
|
 |
Scope and Field of Application
BS EN ISO 11341 is a method of determining either the lightfastness of paint films and allied materials or their resistance to artificial weathering. It aims to replicate the degradation caused by sunlight (either direct or through window glass) and rainfall.
ISO 12040 is a method of determining the lightfastness of printed material, printing inks and substrates (paper, board, metal and plastic) used in printing processes
Like all laboratory tests, the methods described here have their advantages and limitations and these are summarised, in general terms, on our Testing Paints for Resistance to Weathering page.
The xenon arc source, when used in conjunction with appropriate filters, is generally regarded as giving the closest approximation to natural sunlight that can be obtained in the laboratory. The equipment also allows for a greater degree of control of temperature, humidity and radiation dose than is possible with other forms of accelerated weathering.
The main disadvantages of the xenon arc method are:-
- it is one of the most expensive weathering tests.
- the test samples have to be flat and there are limitations on the size of samples that can be tested.
The main advantage of the xenon arc method is that it gives the best correlation with natural weathering.
An alternative and less expensive method of measuring lightfastness involves the use of a fluorescent lamp weatherometer. Please refer to our lightfastness testing page for details.
The fluorescent lamp weatherometer can also be used as a cheaper artificial weathering method. Details can be found on our fluorescent lamp test page
Test methods that use the xenon arc or fluorescent lamp weatherometers require samples to be submitted in the form of test panels. If you need to test larger objects you may also wish to consider the advantages and limitations of the enclosed carbon arc method.
There are no pass/fail criteria defined in the standard. This is a matter of agreement between the parties concerned.
The actual standards are copyright-protected documents and we are not able to provide you with copies. If required however, you can easily obtain copies from the British Standards Institution or The International Organisation for Standardisation.
Summary of Methods
The same equipment is used for both methods. It consists of a chamber in which test samples are mounted on a circular carousel which rotates around a xenon arc lamp. A number spray nozzles are positioned in the chamber so that, if required, they can wet the test surfaces of the panels. The parameters that can be controlled and monitored include black panel temperature, humidity, irradiance, light-dark periods and wet-dry periods.
BS EN ISO 11341
The standard defines four different operating conditions, two for lightfastness testing and two for resistance to artificial weathering. The lightfastness testing is carried out dry using optical radiation filters equivalent to terrestrial solar radiation through 3 mm thick window glass. Artificial weathering testing is carried out using wet / dry cycles and optical radiation filters which transmit a spectral range close to that of terrestrial solar radiation.
ISO 12040
The standard defines one set of operating conditions which are used to measure the lightfastness of printed material, printing inks and substrates. A pane of plate glass is placed between the light source and the test piece. The thickness and composition of the pane is such the it absorbs all wavelengths below 310 nanometres and has at least 90% transmission between 380 and 700 nanometres. The intention is to simulate the effect of sunlight through window glass.
The sample is exposed until it has undergone a distinct colour change. Blue Wool Scale standards are exposed at the same time. At the end of the exposure period the Blue Wool Scale standards are examined in order to determine which one has faded to the same extent as the sample. The Blue Wool scale is made up of eight standard ranging in lightfastness from Number 1 (very poor) to Number 8 (outstanding).
Sample Requirements
These are the same for all methods.
We require 150 x 75 mm samples not more that 5 mm thick. If you have smaller samples, you can fix them to 150 x 75 mm panels provided the overall thickness does not exceed 5 mm.
We recommend that samples are run in triplicate.
Accreditation
PRA is accredited to ISO 17025 by the United Kingdom Accreditation Service (UKAS) to carry out the BS EN ISO 11341 test.
We are not accredited to test to ISO 12040.
Please contact Peter Collins for further details.
Back to Paint Testing Laboratory Page