Admission of CLT into WUFI extends design opportunities
Insufficient moisture protection can on the one hand lead to an increase of transmission heat losses (addressing the thermal protection), but can on the other hand also cause damage to the building envelope (e.g. mold, rot, frost), associated with health and hygienic problems. Through careful planning and proper execution, these risks can be avoided.
In the past, the assessment of moisture protection of components was carried out by the so-called Glaser method mainly, which however allows only rough assessments regarding hygric functional efficiency of layer compositions. The development of hygrothermal simulation programs resulted in new opportunities for realistic and detailed calculation of the hygrothermal transport- and storage processes in building components under real climate conditions.
However, with this realistic calculation, the complexity and number of building material characteristics required increases.
As part of a master's thesis at Hamburg University (Faculty of Mathematics, Computer Science and Natural Sciences; Field of study: Timber Industry), the for Stora Enso CLT essential material-specific properties for the simulation program WUFI Pro (developed by the Fraunhofer Institute for Building Physics (IBP)) were determined. Apart from that, an experimental validation of a hygrothermal simulation for a Cross Laminated Timber-element was carried out for the first time, at which a good agreement could be achieved.
Simulations of various CLT-layer compositions taking into account different climatic conditions confirmed the unproblematic and solid hygrothermal building element-behavior of CLT-constructions!
As a result of the master's thesis mentioned, Stora Enso CLT was positively tested for plausibility by the Fraunhofer Institute and included in the material database of WUFI (Wärme und Feuchte instationär – Transient Heat and Moisture). WUFI is available in eleven languages (German, English, Finnish, Polish, French, Norwegian, Swedish, Spanish, Italian, Portuguese and Czech), at which also a in range of functions limited research- or teaching version is available on www.wufi.de to download for free.
Thus we do offer to our customers and planners another promising and valuable design tool for CLT-constructions, which particularly, at high building's internal moisture loads or at use of timber structures in regions with extreme climate conditions is indispensable!
To find the WUFI-file for Stora Enso CLT as download, pleas click the file below. The Stora Enso CLT file will be also a part of the next database release of WUFI.