To propose standard procedures for describing the properties of glazing materials for daylighting applications, and to provide data for various innovative glazing materials. This programme is the extension of a first phase (contract JOU2-CT92-0052). In this phase, the experimentation focuses on innovative glazing materials such as translucent insulation (honeycomb and aerogel), glass panes with selective coatings (spectral and angular selectivity), holographic materials, lens array systems, triple layer plastic panels. The tasks include energy calculations and the test of two glazings in a Passys test cell.
The deliverables will be one final report, presenting glazing materials and their properties. There will be descriptions of spatial and spectral properties, graphical displays, tables of selected parameters, pictures of the products, as well as examples of applications. Diskettes of data files will be attached to the report. One standard format will be proposed.
The project deals with a measuring campaign of optical properties of glazing materials, and the production of data sets to characterize their behaviour regarding daylighting applications.
In Europe, there is today a lack of data to describe standard as well as innovative glazings in relation to their impact on daylighting of buildings. Many new glazings are proposed, mainly for their thermal and accoustical behaviour. But these improvements often have a visual effect which can be spectral (colouring) or spatial (light scattering, light deviation). There is a need to define what is, and what is not, acceptable on the visual aspect. There is also an interest on attractive properties such as glare reduction and improvement of daylighting performances.
The major reason to undertake this task at a European level is that it is essential to bring together the following partners: - laboratories with powerful measuring capabilities for glazings: spectrophotometers, goniophotometers, integrating spheres.
- laboratories with powerful light simulation tools, able to simulate glazings with complex photometry, such as spectral selectivity and light scattering (ar.d deviation) properties.
- glazing manufacturers, for their contribution in the selection of glazings and samples, ans their active role in the dissemination of information.
The expected results deal with a proposal for standardization of properties of glazing with respect to daylighting applications. This means some raw data, but mainly processed data which could be directly correlated with design constraints.
For instance: - colour shift (shift in colour temperature and colour rendering index) - light scattering (MTF values or other more simple parameters) - graphical displays (2D and 3D) to present the new directions of transmitted light toward the indoor space.
The main applications concern new recommandations to use advanced glazing materials, especially those which modify the spectrum of natural light or those which modify the spatial distribution of light indoor.
The proposed standard description should also ease the presentation of products by manufacturers.
Funding SchemeCSC - Cost-sharing contracts
79110 Freiburg (In Breisgau)
2600 Aa Delft
TW11 0LW Teddington
751 21 Uppsala