CEN/TC 249/WG 19 - Light exposure

This European Standard specifies a method for estimating the temperature increase of a flat polymer surface, due to its solar radiant energy absorption, compared to the ambient temperature.
For that purpose, a specimen and black and white reference plates are exposed to simulated solar radiation under specified conditions (simulated solar radiation, ambient air temperature, convective flow). For opaque specimens, a thermally sensitive electrical element at the backside or a pyrometer is used to measure the surface temperature. For translucent specimens, a pyrometer is used to measure surface temperature.
NOTE   Some specific polymeric materials are translucent (transparent) and might have a transmittance window in a wavelength range where the used pyrometer is sensitive (e.g. polyethylene). The surface temperature of these materials cannot be measured with the contact and the contactless method.

This European Standard specifies traceable calibration methods of black-standard thermometers (BST), white-standard thermometers (WST), black-panel thermometers (BPT) and white-panel thermometers (WPT) for use in natural and artificial weathering:
-   method A, a contact method, uses a traceable calibrated resistance standard thermometer;
-   method B, a contactless method, uses a traceable calibrated pyrometer.
A basic design of types of the thermometers is described in EN ISO 4892 1.
NOTE 1   Historically method A has been used for weathering applications for many years: Method B has been developed recently. Both methods are qualified for weathering applications. They may provide different calibration results that are not interchangeable.
NOTE 2   Annex A gives information on the characteristics of BST/WST and BPT/WPT.

This European Standard specifies a method for carrying out artificial accelerated photoageing of test specimens by exposing them to medium pressure filtered mercury vapour lamp as light source, under controlled temperature conditions.